Heat pumps

Scout intake sheet

Challenge description

Within the heat integration cluster of the Institute for Sustainable Process Technology (ISPT), the foundation is laid for a nationally supported cross-sectoral Integrated Circular Heat Program, in which innovation and practice are actively linked. Indeed, for a large number of companies in the agro-food, paper, chemical, horticultural and food sectors, heat is the biggest energy consumer. Therefore, heat technologies need to be vastly integrated to reach a carbon neutral heat supply for all temperature levels by 2050. As this knowledge is spread through various industries and discipline, ISPT wants to present to its partners an overview of the existing technologies that are linked with the (re-)use and storage of heat. This specific scouting case will focus on heat pumps. Heat pumps move thermal energy in the opposite direction of spontaneous heat transfer, by for example absorbing heat from a cold space and releasing it to a warmer one. A heat pump uses external power to accomplish the work of transferring energy from the heat source to the heat sink. Of interest are the absolute temperature, the delta T, the COP, the size and dynamics of the system and the energy density.

Scope

Current known technique(s)

Air to air

Water source

Thermoaccoustic heat pumps

Mechanical and thermal vapour recompression (MVR, TVR))

Absorption (compression) heat pump

Ideal outcome

An overview of all the existing heat pumps with their specification and suppliers

Minimum viable outcome

A list of all the existing heat pump technologies

Objective(s)

Absolute temperature

Delta T

COP

System dynamics

Energy density

Type of compression unit required

Medium

Constraint(s)

Capacity

Power range

Source temperature (°C)

Sink temperature (°C)

COP

Additional Requirements

Functions
Action = [elevate] OR [is]

Object = [heat] OR [heat pump]

Environment = [heat pump] OR [review] OR [categories] OR [air source] OR [airsource] OR [air source] OR [hybrid] OR [solar] OR [air to air] OR [ground] OR [geothermal] OR [ground water] OR [single] OR [stage] OR [double] OR [water] OR [heat recovery] OR [high temperature] OR [industrial] OR [review] OR [flue gas] OR [mechanical] OR [vapor] OR [recompression] OR [MVR] OR [exhaust] OR [waste heat] OR [compressor] OR [recovery] OR [screw] OR [co2] OR [R600] OR [water] OR [absorption] OR [compression] OR [absorption] OR [thermoacoustic] OR [Twostage] OR [solar] OR [direct expansion] OR [LG5] OR [cascade] OR [high temperature heat pump]

Terminology

Sink / source

Preliminary Results

Concept	Technology
1. General construction and trends General construction differences that can be found between heat pumps as well as trends in their developments	1.1 Single-stage	0 of 0
	1.2 Two stage compressor	0 of 0
	1.3 Variable Capacity (Variable speed)	0 of 0
	1.4 Transcritical CO2	0 of 0
	1.5 Liquid dessicant	0 of 0
	1.6 Regenerative silica gel rotor	0 of 0
	1.7 Low Global Warming Potential refrigerant (To water)	0 of 0
	1.8 Phase change materials	0 of 0
2. Air source (to air or to water) Heat is extracted from ambient air drawn across its heat exchanger. The heat can be converted to heat in air or water.	2.1 Air to air (through fan)	0 of 0
	2.2 Air to water distribution	0 of 0
	2.3 Exhaust air recovery heat pumps (A/W)	0 of 0
	2.4 Heat-pump water tank heater	0 of 0
	2.5 Dehumidification - Drying	0 of 0
	2.6 Vapour / Refrigerant injection	0 of 0
3. Water source open loops (including Geothermal) Heat is extracted from a water source in an open loop. The relative constancy in the source temperature permits optimization of the design and, generally achievement of higher seasonal efficiencies.	3.1 Ground-water (Open loop system)	0 of 0
	3.2 Standing column well systems (Open loop system)	0 of 0
	3.3 Surface Water (open loop)	0 of 0
	3.5 Waste water/heat recovery	0 of 0
	3.6 Nanofuids	0 of 0
4. Soil and water source closed loops (Including geothermal) Heat extracted from the soil of water source in a closed loop.	4.1 Surface water (Closed loops)	0 of 0
	4.2 Vertical Ground-coupled heat pumps (closed loop systen)	0 of 0
	4.3 Horizontal Ground-coupled heat pumps	0 of 0
5. Multi-temperature heat pumps A simple vapor compression cycle is not suitable for multi-temperature applications. More advanced systems are required to address multiple heat sinks and sources and to improve performance and are presented in this concept.	5.1 Cascade heat pumps	0 of 0
	5.2 Multistage compressor	0 of 0
	5.3 Multi-Ejector	0 of 0
	5.4 Multistage expansion valves	0 of 0
	5.5 Secondary loop	0 of 0
	5.6 Separated gas cooler	0 of 0
6. High Temperature applications High temperature heat pumps can reach higher heating water temperatures (62°C) by employing special “heating” compressors which inject the refrigerant into the compressor head, and due to larger heat exchangers (condenser and evaporator units).	6.1 50 to 70°C	0 of 0
	6.2 70 to 80°C	0 of 0
	6.3 80 to 95°C	0 of 0
	6.4 90 to 105°C	0 of 0
	6.5 105 to 140°C	0 of 0
7. Hybrid Hybrid combination of different heat pumps	7.1 Solar assisted heat pump	0 of 0
	7.2 Gas assisted heat pumps	0 of 0
	7.3 Gas engine heat pumps	0 of 0
	7.4 Hybrid heat pump systems with assisted cooling towers	0 of 0
	7.5 Absorption combined heat pumps	0 of 0

Published 07/17/2019

Based on the case described above we have executed the first line of queries in IGOR^AI. The goal was to obtain a broad set of heat pumps that lift heat. 7 concepts are distinguished based on the results: 1. General construction and trends 2. Air source (to air or to water) 3. Water source open loops (including Geothermal) 4. Soil and water source closed loops (Including geothermal) 5. Multi-temperature heat pumps 6. High Temperature applications 8. Hybrid Every concept comprises multiple heat pumps (38 in total). Below the table, short descriptions, research findings and sources per heat pumps are listed as well. You can use this information to get a better understanding of the heat pumps. During the midway meeting, we would like to discuss the heat pumps and concepts, determine their relevance and select the top selection that needs to be deepened in the second phase of the project.

To determine which technologies are relevant to proceed to the next scouting phase you can play the technology selection game by clicking on the button below.

Concept	Technology
1. General construction and trends General construction differences that can be found between heat pumps as well as trends in their developments	1.1 Single-stage	0 of 0
	1.2 Two stage compressor	0 of 0
	1.3 Variable Capacity (Variable speed)	0 of 0
	1.4 Transcritical CO2	0 of 0
	1.5 Liquid dessicant	0 of 0
	1.6 Regenerative silica gel rotor	0 of 0
	1.7 Low Global Warming Potential refrigerant (To water)	0 of 0
	1.8 Phase change materials	0 of 0
2. Air source (to air or to water) Heat is extracted from ambient air drawn across its heat exchanger. The heat can be converted to heat in air or water.	2.1 Air to air (through fan)	0 of 0
	2.2 Air to water distribution	0 of 0
	2.3 Exhaust air recovery heat pumps (A/W)	0 of 0
	2.4 Heat-pump water tank heater	0 of 0
	2.5 Dehumidification - Drying	0 of 0
	2.6 Vapour / Refrigerant injection	0 of 0
3. Water source open loops (including Geothermal) Heat is extracted from a water source in an open loop. The relative constancy in the source temperature permits optimization of the design and, generally achievement of higher seasonal efficiencies.	3.1 Ground-water (Open loop system)	0 of 0
	3.2 Standing column well systems (Open loop system)	0 of 0
	3.3 Surface Water (open loop)	0 of 0
	3.5 Waste water/heat recovery	0 of 0
	3.6 Nanofuids	0 of 0
4. Soil and water source closed loops (Including geothermal) Heat extracted from the soil of water source in a closed loop.	4.1 Surface water (Closed loops)	0 of 0
	4.2 Vertical Ground-coupled heat pumps (closed loop systen)	0 of 0
	4.3 Horizontal Ground-coupled heat pumps	0 of 0
5. Multi-temperature heat pumps A simple vapor compression cycle is not suitable for multi-temperature applications. More advanced systems are required to address multiple heat sinks and sources and to improve performance and are presented in this concept.	5.1 Cascade heat pumps	0 of 0
	5.2 Multistage compressor	0 of 0
	5.3 Multi-Ejector	0 of 0
	5.4 Multistage expansion valves	0 of 0
	5.5 Secondary loop	0 of 0
	5.6 Separated gas cooler	0 of 0
6. High Temperature applications High temperature heat pumps can reach higher heating water temperatures (62°C) by employing special “heating” compressors which inject the refrigerant into the compressor head, and due to larger heat exchangers (condenser and evaporator units).	6.1 50 to 70°C	0 of 0
	6.2 70 to 80°C	0 of 0
	6.3 80 to 95°C	0 of 0
	6.4 90 to 105°C	0 of 0
	6.5 105 to 140°C	0 of 0
7. Hybrid Hybrid combination of different heat pumps	7.1 Solar assisted heat pump	0 of 0
	7.2 Gas assisted heat pumps	0 of 0
	7.3 Gas engine heat pumps	0 of 0
	7.4 Hybrid heat pump systems with assisted cooling towers	0 of 0
	7.5 Absorption combined heat pumps	0 of 0

1. General construction and trends

Back

General construction differences that can be found between heat pumps as well as trends in their developments

1.1 Single-stage

Single stage compressor lead to lower equipment cost, less likely to break, low repair cost, low to average efficiency and high electricity cost A single-stage compressor always operates at 100% capacity

1.2 Two stage compressor

Two stage compressor lead to moderate equipment cost, less likely to break, low to moderate repair cost, good to excellent efficiency and average electricity cost A two-stage compressor has a low capacity, which is about 70% in most models, and high capacity (100%)

1.3 Variable Capacity (Variable speed)

Variable capacity (or variable speed) compressor lead to higher equipment cost, more likely to break, moderate-to-high repair cost, excellent efficiency and low electricity cost Variable-capacity (also variable-speed and modulating) compressors vary capacity from about 40% to 100% in increments of less than 1%. Using inverters The inverter-controlled compressor constantly adjusts the heat load according to the current heat demand. You never use more energy than is needed, further reducing your energy bills. https://thermia.com/products/air-source-heat-pumps/thermia-itec/

1.4 Transcritical CO2

The CO2 heat pump water heater cycle is transcritical, operating at much higher temperatures and pressures than conventional subcritical cycles. The transcritical cycle operation provides a large continuous temperature glide and can offer a higher service temperature with limited capacity loss. O2 heat pumps for hot water production can save up to 75% of primary energy needed to operate a conventional domestic hot water (DHW) system with electric immersion heaters. Moreover, they can save 20-35% of annual primary energy even compared to systems based on solar collectors, while outperforming these cutting-edge solar heaters.

1.5 Liquid dessicant

Desiccant air handling processors (DAHP) driven by heat pump have become more and more popular recently due to their compact size and high efficiency. Both the cooling capacity from an evaporator and heat from a condenser are utilized in these systems.

1.6 Regenerative silica gel rotor

The regenerative silica gel rotor has high air purification efficiency, and it doesn’t produce any by-product during the air purification process. To allow this air cleaning technology to be applicable in ventilation system, silica gel rotor was designed to be cooperated with heat pump in the proposed CAHP ventilation technology

1.7 Low Global Warming Potential refrigerant (To water)

Various refrigerant are studied to replace global warming contributing refrigerants. Also hydrocarbons as refrigerant (more information available [here]).

1.8 Phase change materials

Heat pumps for space heating and cooling are a mature and highly efficient technology that can take advantage of renewable energies. They can also provide energy savings by load shifting when they operate together with thermal energy storage (TES) and phase change materials. There are different substances with different phase-change temperatures that can be used for storing heating or cooling implemented in heat pump systems for applications of space heating and cooling, ventilation or domestic hot water production. Reducing the size of the buffer tanks used with heat pumps, avoiding the oversizing of heat pumps or detaching thermal energy production and consumption are among the benefits that could result from the combination of heat pumps and latent heat thermal energy storage. In addition, this form of thermal energy storage allows enhancing the use of renewable energy sources as heat sources for heat pump systems.

2. Air source (to air or to water)

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Heat is extracted from ambient air drawn across its heat exchanger. The heat can be converted to heat in air or water.

2.1 Air to air (through fan)

An air-to-air system produces warm air which is circulated by fans, from ambient air. They can come as - Ducted - Split - Multisplit systems

Suppliers

Nibe

2.2 Air to water distribution

An air-to-water system distributes heat via your at central heating system. Heat pumps work much more efficiently at a lower temperature than a standard boiler system would. This makes them more suitable for underfloor heating systems or larger radiators, which give out heat at lower temperatures over longer periods of time.

Suppliers

Nibe

2.3 Exhaust air recovery heat pumps (A/W)

An Exhaust Air Heat Pump (EAHP) extracts heat from the exhaust air of a warm flow and transfers the heat to the supply air, hot tap water and/or hydronic heating system (underfloor heating, radiators). This requires at least mechanical exhaust can be used in: **_Applications:_** - Building - Flue gases cooling - Waste heat recovery

Suppliers

Nibe

2.4 Heat-pump water tank heater

A heat pump water heater works by transferring heat from the surrounding air to the water heater as opposed to drawing energy from gas or electricity and heating the water that way. When you compare them to a traditional electric water heater, they are as much as three times more energy efficient and can still use the electric heating elements as found on the electric units. One drawback to an air source heat pump water heater is that it tends to be effective only when it is warm. If you live in an area where winters are harsher, you won’t be able to use it during the winter as efficient as if you live in warmer. You also need to give it a chance to recover between uses, so many people using it in the morning can mean that some later users will have less than toasty hot water. Usually, when the ambient temperature is low than 5 ℃ or the heat pump water heater setting temperature higher than 80 ℃, then an electric backup element with 1.5 kW loading will automatically activate. **_Applications:_** - Domestic water heating

Suppliers

GMO HiTech

Gorenje

2.5 Dehumidification - Drying

Drying is an important industrial process. Various temperature levels and drying principles are applied in industrial dryers. The most common dryer type is one in which air is heated with steam, gas or hot water and then circulated over the wet product. As the air picks up moisture from the wet product, its humidity increases and the energy contained in this stream may make it a useful heat source. Standard procedure is to exhaust this humid air or dehumidify it. With a heat pump, heat can be extracted from the humid air. The air is cooled down and dehumidified. The extracted heat can be increased in temperature and can be used to heat the dryer. Thus, the use of a heat pump serves two purposes - heat the dryer and dehumidify and recirculate air. Heat pump assisted drying can give high efficiencies because of this. **_Applications:_** - Drying/Dehumidification

Suppliers

Phnix-e

Grain dryer

2.6 Vapour / Refrigerant injection

Refrigerant injection is a technique that involves injecting the refrigerant from the condenser outlet to the suction line, or the sealed compressor pocket, or the condenser inlet in a vapor compression system. It has proven to be effective in ensuring the reliable cycle operation and improving the performance of vapor compression systems. It has been proven be an effective access to acquire a better performance in the cold regions. more info also available [here](https://reader.elsevier.com/reader/sd/pii/S0140700710002239?token=D1B3B752806109919BB47CAF45EEA14D22C2954739705D1BAB8E0FA766FC62DDCB1D5AF5704071D4A2E0A5EA93F873D2). **_Applications:_** - Cold climates

Suppliers

Wamak

3. Water source open loops (including Geothermal)

Back

Heat is extracted from a water source in an open loop. The relative constancy in the source temperature permits optimization of the design and, generally achievement of higher seasonal efficiencies.

3.1 Ground-water (Open loop system)

Open loop heat exchange systems interact directly with the ground. These systems use local groundwate. Heat is either extracted or added by the primary refrigerant loop, and the water is returned to a separate injection well, irrigation trench, tile field or body of water. The supply and return lines must be placed far enough apart to ensure thermal recharge of the source. The amount of water that can be extracted for open loop GHPsystems is sometimes limited by local water resource regulation. The main disadvantage of open loops is the need to protectwater quality, usually by following clean water and surface waterregulations; sometimes open loop systems not allowed. The heat exchanger between the heat exchange loop and the heatpump unit is subject to corrosion, fouling and scaling, so the watershould have a fairly neutral chemistry and a low amount of miner-als such as iron. If the water chemistry is not neutral wellsmay require maintenance, increasing user involvement. Water is extracted from a drilled production well reaching the water table and, after passing through the heat pump heat exchanger, is injected back into the water table a distance from the production well, which is sufficient to allow adequate heat transfer from the ground to the water between the wells [9]. Reinjection can be excluded; open drainage is inexpensive but requires the water source, supplying the heat pump, to have a high capacity with little draw down in order to provide prolonged use. The water flow rate to the heat pump unit is generally between 5.7 and 11.4 litres per minute per ton of heating capacity. Heat source: Gound water Heat source recharge: Geothermal Typical working depth: 6 - 100 m More information available [here](https://reader.elsevier.com/reader/sd/pii/S0306261912000542?token=7C9B999097968506C0D72768368BE16564042E056FA1704AFE0C4C71B9E23576450329FF116E804B7F85037ABAA89BCA) **_Applications:_** - Domestic - Residential

Suppliers

HP Sirac

Gorenje

3.2 Standing column well systems (Open loop system)

Standing column wells combine aspects of open and closed water heat exchange systems. They are essentially groundwater heat pump systems that use groundwater drawn from wells in a semi-open loop arrangement. In such a system, a vertically drilled borehole draws warm water from the bottom of a deep rock well using a submersible pump and feeds it to the heat pump unit. The cool return water is injected near the top of the original well. The cold water moves down towards the extraction pipe and is heated by the surrounding rock [9], eliminating the need for a separate injection well. Standing column wells are recently receiving increased attention because of their good overall performance in suitable regions. These systems are installed in locations having bedrock within 45–60 m of the surface. Domestic wells that have been used for drinking water can be retrofitted easily to accommodate this system. This system can also be applied to water filled mines and tunnels. Heat source: Ground water Heat source recharge: Geothermal Typical working depth: up to 45-60 m **_Applications:_**

3.3 Surface Water (open loop)

A Surface Water Source Heat Pump system works by recovering the solar energy stored naturally in river water, open water or the sea. Water is passed through heat pumps to yield its low grade heat before being returned to the river or to a sewer with a temperature change of around 3°C. **_Applications:_** - Domestic / Residential - Industrial?

Suppliers

Kensa

3.5 Waste water/heat recovery

A heat pump prevents waste heat from leaving a refrigeration plant by reusing it, and upgrading it to become useful elsewhere in the production process for functions such as: - Washing and cleaning water operations - Heating water for processing purposes such as pasteurization, blanching and drying **_Applications:_** - Industrial - Domestic drain water

Suppliers

GEA

3.6 Nanofuids

Use of nanofluids to replace conventional ethylene glycol/water mixture as heat carrier in a BoreHole Heat Exchanger. Nanofluids contain suspended metallic nanoparticles: increasing their concentration, in comparison to the base fluid, the thermal conductivity increases and the volumetric heat capacity decreases. The first effect is positive for the reduction of borehole thermal resistance, since it causes the grow of fluid convective heat transfer coefficient, while the second one is detrimental, due that it decreases the heat transfer between fluid and borehole wall.

4. Soil and water source closed loops (Including geothermal)

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Heat extracted from the soil of water source in a closed loop.

4.1 Surface water (Closed loops)

Closed pond loops, which are the least common of the closed loop heat exchange systems, are essentially a spiral loop systems submerged in a water body. The coiled piping is attached to framework and submerged using concrete anchors. The framework is typically supported 23–48 cm above the pond bottom to allow for convective flow around the piping. The loop is normally at least 1.8 m below the water surface. It is necessary to assure sufficient thermal mass is maintained during low water conditions and prolonged draughts, and to ensure the temperature of the water immediately surrounding the loop never drops below the freezing point of water during cold seasons. Rivers are not ideal for this application due to their unpredictable behaviors, including flooding and draughts that can damage systems as well as hazards due to moving debris. Pond loops are gaining popularity partly because they potentially require less piping than other closed loop systems, due to their superior heat transfer characteristics, and they require neither drilling nor trenching. The main disadvantages of this system include the requirement of a sufficiently large body of water and the limitations on its use for other purposes such as boating. Heat source: Surface water Heat source recharge: Solar irradiation + balance with atmosphere + Geothermal Typical working depth: 0 - 5 m **_Applications:_** - Pond loop (when a large water body is available next to the application) - Domestic / Residential - Industrial if large enough?

Suppliers

Kensa

Provides Heat Pumps and also Pond mats, which feature slinky pipe attached to corrosion resistant stainless steel frames which are sunk to the bottom of the water source or secured underneath a floating pontoon.

4.2 Vertical Ground-coupled heat pumps (closed loop systen)

A vertical closed loop system includes a loop field consisting of vertically oriented heat exchange pipes. A hole is bored into the ground, typically ranging 45–75 m deep for residential and over 150 m for larger industrial applications. Pairs of pipes, connected at the bottom by a U-shaped connector, are fed into the hole. To enhance heat transfer, the gap between the pipes and the borehole wall are filled with a pumpable grout material. The borehole diameter is approximately 102 mm for a typical residential home. For a typical residential application the spacing between boreholes is around 5–6 m in order to prevent adjacent boreholes from affecting one another and changing ground conditions. To assure equal flows for multiple borehole systems a manifold system is used, which can be located in the building or buried in the loop field. An advantage of the vertical loop configuration is reduced installation area, making them advantageous where land is limited. Another incentive for these systems is low landscape disturbance, since drilling has a reduced impact compared to trenching. Also, locating the piping deep in the ground, where the temperature is constant year round, allows consistent heat pump performance and reduces overall loop length. The main disadvantage of using a vertical system is the installation costs, since drilling is normally more costly than horizontal trenching. Consequently, vertical loop systems are normally more economic for larger applications Heat source: Soil Heat source recharge: Geothermal Typical working depth: 6 - 120 m **_Applications:_** - Large applications (Industrial / Residential)

Suppliers

AE Systems

Installer for the complete system

Kensa

Vaillant

4.3 Horizontal Ground-coupled heat pumps

In horizontal closed loop systems, which are common where ample ground area is available, the ground loop is laid out horizontally slightly below the earth’s surface in backfilled trenches. The arrangement of the loops can vary depending on heat transfer requirements and land availability. The three most common configurations are basic loop, series loop, and parallel. The basic layout usually requires a substantially larger land surface area than the series and parallel setups. The series layout is common for its reduced land requirement and simplicity [9]. Series and parallel loops can also be combined, increasing the flexibility horizontal installations. Horizontal heat exchange systems are normally more cost effective than vertical for residential installations, through lower costs involved with trenching compared to drilling. Heat source: Soil Heat source recharge: Solar irradiation + Geothermal Typical working depth: 1.5 m **_Applications:_** - Residential (with large spaces)

Suppliers

Nibe

Thermia

Gorenje

5. Multi-temperature heat pumps

Back

A simple vapor compression cycle is not suitable for multi-temperature applications. More advanced systems are required to address multiple heat sinks and sources and to improve performance and are presented in this concept.

5.1 Cascade heat pumps

Most commercial and industrial facilities require very low temperatures for refrigeration and high temperatures for space heating and hot water purposes. Single stage heat pumps have not been able to meet these temperature demands and have been characterized by low capacities and coefficient of performance (COP). Cascade heat pump has been developed to overcome the weaknesses of single stage heat pumps. A real cascade system is a combination of two or more heat pumps (or refrigeration cycles), where the intermediate heat exchangers connect the cycles. A cascade offers the possibility of having a different working fluid in each cycle. Each fluid can be selected for optimum performance in the specified temperature range. The refrigerants selected should have suitable pressure–temperature characteristics. A frequent example of refrigerant combination is the use of CO2 in the low temperature cascade and NH3 or hydrofluorocarbon (HFC) refrigerants in the high temperature cascade. The cascade circuits may also be built with a rack of parallel compressors for capacity modulation. This arrangement enables cycles to reach an extended operation range, e.g. high-temperature lifts between heat source and sink ranging from −70 to +100 °C without any oil migration issues. On the other hand, the temperature difference in the cascade heat exchangers degrades the system performance, which is a major challenge in terms of energy efficiency. Applications: point of view, cascades are commonly employed in supermarket refrigeration, high temperature heat pumps for heat recovery , or for gas liquefaction Challenge: Temperature gap TRL: Established in industry

Suppliers

Kensa

Thermia

5.2 Multistage compressor

Multi-stage compressor cycles are systems with two or more compression stages in the same heat pump cycle. The compressors are connected either in series or in parallel using single or multiple compressors, or even with single multi-stage compressors that feature injection ports between the compression chambers (so-called EVI enhanced vapor injection). Multi-stage compression is recognized to provide high coefficients of performance. Intercooling of the discharge vapor between the first-stage and the second-stage compressors is an important additional feature to improve the efficiency and performance of the cycle. Multi-stage compressor cycles are a common configuration in supermarket refrigeration (e.g. cooler, freezer) or water heaters. In the food refrigeration industry, facilities maintain space at typically −23 °C for storing frozen food and +2 °C for unfrozen fruit and vegetables. In supermarkets, multi-stage compressors in parallel and in series with transcritical CO2 are an established technology Challenge: Oil Migration TRL: Key technology in supermarkets **_Applications:_** - Supermarket - Heating - Domestic hot water

5.3 Multi-Ejector

The use of ejector cycles has recently become a promising cycle modification, thanks to the absence of moving parts, its lowcost, simple structure, and low maintenance requirements. An ejector works as a pump-expansion device that uses the expansion of a high-pressure fluid (motive stream) to entrain and increase the pressure of a low-pressure fluid(suction stream).The result is a pressure increase provided to the low-pressure fluid. The integration of ejectors reduces the compressor work by increasing the suction pressure or by re-ducing the exhaust pressure.The main advantage of an ejectoris the recovery of the expansion work (COP improvement), andflash gas bypass (evaporator size reduction) Challenge: Capacity control TRL: Prototype status in industry **_Applications:_** - CO2 supermarket refrigeration - household refrigeration (e.g. fridge, freezer), - Transport refrigeration.

5.4 Multistage expansion valves

Expansion valve cycles are established technology in house-hold refrigerators and freezers, as well as in heat pumpapplications, as they are simple and cost competitive. Com-pared to multi-stage compressor cycles the investment costsare lower. Cascades with secondary distribution loops and/or multiple ejectors are also emerging.The technological readiness level for multi-stage compressors and secondary loops is already very high Challenge: Energy efficiency TRL: Established in industry **_Applications:_** - Household refrigeration

5.5 Secondary loop

Secondary loop systems coupled to conventional cascade refrigeration systems have recently seen increased popularity in retail food applications, i.e. supermarkets and storage warehouses, due to the important reduction in working fluid charge compared to traditional direct expansion refrigeration systems. Secondary loop circles are preferably connected to the medium temperature refrigeration systems (e.g. meat, prepared foods, dairy or refrigerated drinks), typically hold at −7 °C. A secondary loop system comprises two circuits, a primary load with a refrigerant and a secondary loop that is pumped throughout the supermarket facility to remove heat from the displays. The secondary loop fluid is often a brine solution, like glycol, which is non-toxic and non-flammable. A heat exchanger transfers energy from the secondary loop to the primary loop. The temperature gap in this intermediate heat exchanger is a challenge in terms of energy efficiency. Secondary loop systems can also be operated with more than one separate loop depending on the temperatures needed in the facility. Challenge: T gap and pumping losses TRL: Established in industry **_Applications:_** - Supermarket

5.6 Separated gas cooler

Heat pump cycles with separated gas cooler sections present a less commonly encountered system for multi-temperature purposes. However, it offers an elegant way for applications, such as single phase heating (e.g. water heating). Separated gas coolers for space and hot water heating haverecently attracted attention in particular with regard to the com-bination with supercritical CO2 cycles. The working fluids areprimarily selected based on the operating temperature and pres-sures. There clearly is a trend toward natural working fluidsdue to their low ODP and GWP (Advansor, 2015). Except for CO2these fluids are, however, either flammable or toxic.The majortypes of refrigerant applied in supermarkets are dominantlyCO2, followed by R134a and R600a. Challenge: Energy efficiency TRL: underdevelopment, lab **_Applications:_** - Supermarkets - Water heating in residential buildings

6. High Temperature applications

Back

High temperature heat pumps can reach higher heating water temperatures (62°C) by employing special “heating” compressors which inject the refrigerant into the compressor head, and due to larger heat exchangers (condenser and evaporator units).

6.1 50 to 70°C

Systems with the following components available: Refrigerants: - R717 (Amonia) - R134a (Freon) - R410A (EcoFluor) Compressors: - Reciprocating - Scroll - Screw More information available [here](http://www.biowkk.eu/wp-content/uploads/2015/02/download-15.pdf)

6.2 70 to 80°C

Systems with the following components available: Refrigerant: - R717 (Amonia - R134a (Freon) Compressors; - Reciprocating - Screw More information available [here](http://www.biowkk.eu/wp-content/uploads/2015/02/download-15.pdf)

6.3 80 to 95°C

Systems with the following components available: Refrigerants: - R717 (Amonia) - R245fa Compressors: - Screw - Centrifugal More information available [here](http://www.biowkk.eu/wp-content/uploads/2015/02/download-15.pdf)

6.4 90 to 105°C

Systems with the following components available: Refrigerant: - R245fan (Pentafluoropropane) Compressor: - Centrifugal More information available [here](http://www.biowkk.eu/wp-content/uploads/2015/02/download-15.pdf)

6.5 105 to 140°C

Currently in development. Systems with have the following components available: Refrigerant: - R718 (water) Compressor: - Centrifugal More information available [here](http://www.biowkk.eu/wp-content/uploads/2015/02/download-15.pdf)

7. Hybrid

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Hybrid combination of different heat pumps

7.1 Solar assisted heat pump

A solar-assisted heat pump (SAHP) is a machine that represents the integration of a heat pump and thermal solar panels in a single integrated system. Typically these two technologies are used separately (or only placing them in parallel) to produce hot water. In this system the solar thermal panel performs the function of the low temperature heat source and the heat produced is used to feed the heat pump's evaporator. The goal of this system is to get high COP and then produce energy in a more efficient and less expensive way. It is possible to use any type of solar thermal panel (sheet and tubes, roll-bond, heat pipe, thermal plates) or hybrid (mono/polycrystalline, thin film) in combination with the heat pump. The use of a hybrid panel is preferable because it allows covering a part of the electricity demand of the heat pump and reduce the power consumption and consequently the variable costs of the system.

7.2 Gas assisted heat pumps

Heat pumps assisted by a gas burner to provide heating when performance is not met by the heat pump solely

7.3 Gas engine heat pumps

Gas engine heat pumps (GHP) differ from a conventional heat by the fact that the compressor is driven by a gas engine rather than an electric motor. One of the major differences with electrical driven heat pumps is that part of the heat released by the engine is recovered and used for heating the water. The heat can be collected from the engine cooling water or from the exhaust gas for large systems. Generally, gas heat pumps use ambient air as heat source, but in some cases ground couple systems are used. For the case of air-source systems, the COP will never drop below 1, even in case of very low ambient temperatures. This means that for the worst case, the useful heat is equal to the combustion heat. Furthermore, GHP manufacturers claim having better performance in part load compared to electrical driven heat pump. This might be true with the first generation of heat pumps, but for new heat pumps with variable speed compressor this not the case anymore.

7.4 Hybrid heat pump systems with assisted cooling towers

Hybrid ground source heat pump systems have the potential to make ground source heat pump systems (GSHP) more cost effective. Though GSHP systems can significantly reduce energy consumption in commercial buildings, the high first cost of installing the ground heat exchanger (GHX) can be a barrier. A hybrid system uses conventional technology such as a cooling tower or boiler (Figure 1) to meet a portion of the peak heating or cooling load. This innovation allows you to install a smaller, less expensive GHX Many buildings have large internal zones that require cooling only during occupied hours, or cooling, year round due to internal heat gains. The chiller condenser water heat is recovered, instead of being rejected to the outside, and used as a heat source for a water-source heat pump system serving the perimeter spaces.

7.5 Absorption combined heat pumps

compression resorption heat pumps, combine technologies of an absorption and compression heat pump. Hybrid heat pumps use a mixture of media, for example, NH3 and water. Due to changes in composition of the mixture caused by absorption and desorption, heat is extracted and emitted at a non-constant temperature. This temperature glide may lead to an increase in efficiency. A large temperature glide for absorption and desorption is favourable to decrease the ratio of compression inside a heat pump. As compared to the conventional mechanical heat pump ,an equal lift in temperature can be realised with a lower compression ratio when using a hybrid heat pump. As a result a higher COP can be reached. To increase the range of the temperature glide, the sizes of absorber and desorber should be increased as well (making them more expensive). Proper adjustment of the temperature glides and temperature ranges of the heat pump, is therefore essential to maximize efficiency. The use of media that can condensate or evaporate will lower the COP dramatically.

Final Results

Published 09/24/2019

After the midway results meeting, 23 industrial heat pump categories have been reviewed and deepened. The results are organised based on the concept and presented per industrial heat pump category comprising a description, findings, suppliers (if applicable), images, videos, useful links and a reference list. The technology requirements are measured and shown in the [requirements table](#requirements-table). By using the concept links below, you can quickly navigate to the concepts and their industrial heat pump category descriptions.

Table of concepts:

1. Screw
2. Double screw
3. Piston
4. Turbo / Centrifugal
5. Others

Technology Radar

Requirements Table

Technology	Ranking	Power range	Source temperature (°C)	Sink temperature (°C)
1.1 R245fa	0.00 ( 0 )	170 - 750 kW (Twin unit up to 1.5 MW)	35 - 55	70 - 130
1.2 R134a/R245fa	0.00 ( 0 )	60 - 850 kW	8 - 45	40 - 95
1.3 R717	0.00 ( 0 )	0.23 - 13 MW	35-50	90
1.4 R744	0.00 ( 0 )	89 - 120 kW	0-40	60 - 120
2.1 R717	0.00 ( 0 )	2 - 15 MW	~35	85
2.2 R134a / r245fa	0.00 ( 0 )	70 - 660 kW	25 - 70	90/120 - 165
2.3 R718	0.00 ( 0 )	46-58 kW	80 - 90	120 - 130
2.4 R1233zd(E)	0.00 ( 0 )
3.1 R245fa	0.00 ( 0 )	62-252 kW	30-70	120
3.2 R717	0.00 ( 0 )	339 - 1355 kW	35	90
3.3 R744	0.00 ( 0 )	51 -1460 kW	-10 - ~60	110
3.4 R1234ze	0.00 ( 0 )	57 - 390 kW	0 - 50	90
3.5 R1336mzz-Z	0.00 ( 0 )	195 - 250 kW	50-120	165
3.6 R717/H₂O (Hybrid absorption/compression)	0.00 ( 0 )	0.25 - 2.5 MW	15 - 75	75 - 120
3.7 R600	0.00 ( 0 )	150 kW	50 - 80	115 - 140
4.1 R134a	0.00 ( 0 )	340 - 20000 kW	50	90
4.2 R1234ze	0.00 ( 0 )	0.6 - 3.6 MW	34	95
4.3 R718	0.00 ( 0 )	N.C.	N.C.	130
5.1 Travelling wave thermoaccoustics	0.00 ( 0 )	N.C. (Low)	50 - 120	130 - 200 temperatures achieved of -39 - 270
5.2 Thermoacoustic Stirling engine	0.00 ( 0 )	300 W	Ambiant	340 - 620
5.3 Cascade heat pumps	0.00 ( 0 )	N.C.	34	up to 142
5.4 Two stage direct expansion solar assisted heat pump	0.00 ( 0 )	N.C.	N.C.	N.C.
5.5 Mechanical vapor recompression	0.00 ( 0 )

1. Screw

Back

Screw compressors are positive displacement machines that run according to the principle and are operate by oil injection. Screw compressors are operated with refrigerant (Standard: Ammonia NH3, other refrigerants upon request). The refrigeration machine oil for the particular refrigerant must be selected according to thelubrication oil information for screw compressors. Various series and sizes of screw compressors are available for different fields of application. The screw compressors are driven directly by the compressor drive motor via a coupling

1.1 R245fa

The synthetic refrigerant R245fa(ÖKO1) is not flammable but toxic. Therefore it is classified in safety group B1. It has a high critical temperature and a moderate pressure level. Since R245fa is a pure substance, it has no temperature glide in the condenser. Therefore this refrigerant can be used to heat water with small temperature lifts or to produce steam. Theoretically, CCC heat pumps using R245fa can provide Temperatures up to 140 °C. R245fa is a hydrofluorocarbon which has a relatively high GWP of 858. It has a normal boiling point of 14.9 °C with a critical temperature of 154 °C, critical pressure of 36.5 bar and a molar mass of 134 g/mol. R245fa is placed in the safety group B1. ***Specs:*** * Input media: water * Input temperature: 35-55°C * Output media: water * Output temperature: 70-130°C * Power range: 17-750 kW (Twin unit 1.5MW) ***Applications:*** * Residential heating

Suppliers

Ochsner

Model IWWDS

References

Ochsner heat pumps

Specifications

Ochsner heat pumps

Ochsner steam temperature heat pump series (IWWDS ER3c4) with corresponding flow scheme

1.1.1	R245fa
	Experimental exergy and energy analysis of a novel high-temperature heat pump with scroll compressor for waste heat recovery
	Abstract The industrial sector demands novel sustainable energy systems to advance in its decarbonisation and meet the targets of the Paris Agreement for the climate change mitigation. High-Temperature Heat Pumps (HTHPs) are being investigated as a feasible energy conversion technology alternative to traditional fossil fuel boilers. This paper presents the first experimental results of an HTHP prototype equipped with a modified scroll compressor and internal heat exchanger (IHX). The elements of the main and secondary circuits are presented, as well as the test methodology and heat balances are exposed. The tests have been performed using HFC-245fa at heat source temperatures between 60 and 80 °C, and heat sink temperatures between 90 and 140 °C. The heating capacity and coefficient of performance (COP) varied between 10.9 and 17.5 kW and between 2.23 and 3.41, respectively. An exergetic analysis indicated that the expansion valve was the component with the worst second law efficiency and the compressor presented the highest potential improvement over the other cycle components. A computational analysis of low global warming potential (GWP) refrigerant alternatives was carried out, which confirmed the benefits of using an internal heat exchanger (IHX) and the good performances of the low-GWP refrigerants: HCFO-1224yd(Z), HCFO-1233zd(E), and HFO-1336mzz(Z). Finally, we proved that the proposed system can save up to 57% of the equivalent CO 2 emissions of a natural gas boiler. This paper provides a reference for the high-temperature heat pump recovery of the low-grade waste heat from industrial energy processes.
	11/01/2019 00:00:00
	Link to Article
1.1.2	R245fa
	High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials
	Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.
	06/01/2018 00:00:00
	Link to Article
1.1.3	R245fa
	Performance analysis of different single stage advanced vapor compression cycles and refrigerants for high temperature heat pumps
	Abstract High temperature heat pumps can reduce the energy consumption and have huge potential for applications. In order to obtain higher performance and achieve lower cost, single stage high temperature heat pump employing expander (EX), ejector (EE), internal heat exchanger (IHX), oil flooded compression (OFC) or coupled (EXIHX and EEIHX) cycles and various refrigerants are studied in this paper. Simulation results show that the efficient configuration is EX, EXIHX, EE, EEIHX, OFC and IHX in order in term of COP and EEIHX, EE, OFC, EXIHX, IHX, and EX in order in term of specific heating capacity ( Q c ) respectively. Results also show that R245fa, R600 and R1234ze(Z) have similar performance while the COP of the system with R600a is 4%-14% lower than that with R245fa. Moreover, in term of the Q c , there is an increase of 8%-25%, 18%-56% and 6%-11% respectively for BC configurations employing R600, R600a and R1234ze(Z) instead of R245fa.
	05/01/2019 00:00:00
	Link to Article
1.1.4	R245fa
	Performance evaluation of a capacity-regulated high temperature heat pump for waste heat recovery in dyeing industry
	In this paper, a capacity-regulated high temperature heat pump (HTHP) system using a twin-screw compressor was designed to recover waste heat in dyeing industry. The performance of the HTHP system was investigated under an on-site skein dyeing process condition. Results showed that the HTHP system could effectively utilize the waste heat at different temperatures to provide the energy required by the dyeing process. The heating capacity of the HTHP system could be well controlled to achieve the desired dyeing liquid temperature rising rate between 0.6 and 2.5 °C/min during different heating processes. The on-site testing results further demonstrated that the HTHP system could be reliably operated to heat the dyeing liquid temperature up to 95 °C with an average system COP of 4.2 during the entire heating process. Economic analysis indicated that the HTHP system could save about 47% of the operating cost in comparison to the traditional steam heating.
	01/01/2016 00:00:00
	Link to Article

1.2 R134a/R245fa

Based on two different refrigerant loop (R134a and R245fa). Remark on dynamics: the mechanical start unloading is done by pressure equalization when switching on the compressor. R245fa is a hydrofluorocarbon which has a relatively high GWP of 858. It has a normal boiling point of 14.9 °C with a critical temperature of 154 °C, critical pressure of 36.5 bar and a molar mass of 134 g/mol. R245fa is placed in the safety group B1. R134a is also a hydrofluorocarbon which has a high GWP of 1430. It has a normal boiling point of -26.1 °C, a critical temperature of 101.1 °C, critical pressure of 40.6 bar and a molar mass of 102 g/mol. R134a is placed in the safety group A1. ***Specs:*** * Input media: water * Input temperature: 8-45°C * Output media: Water * Output temperature: 40-95°C * Power range: 60-850 kW (Twin units available at 1.7 MW) ***Applications:*** * Residential heating

Suppliers

Ochsner

References

Ochsner heat pumps

From waste heat to cheese: Ochsner IWWHS with R1234ze(E)

Specifications

Ochsner heat pumps

Ochsner steam temperature heat pump series (IWWDSS R2R3b) with corresponding flow scheme

1.2.1	R134a/R245fa
	High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials
	Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.
	06/01/2018 00:00:00
	Link to Article

1.3 R717

Ammonia is flammable, but in addition to that, it is also toxic. Because of this, ammonia is placed in the safety group B2L. Therefore appropriate safety measures have to be applied when using this refrigerant. Contrary to butane the needed refrigerant amount of ammonia is relatively low, due to its high refrigerating effect per unit of swept volume. And ammonia has a GWP of 0. The normal boiling point of ammonia is -33.3 °C and has a high critical temperature of 132.3 °C, but due to its high working pressure, the maximum reachable temperature of currently available ammonia CCC heat pumps is 90 °C. With a critical pressure of ammonia being 113.3 bar. For higher temperatures, very sophisticated constructed compressors are required. ***Specs:*** * Working pressure: 76 bar * Input media: water * Input temperature: 35-50 ºC * Output media: water * Max output temperature: 90 ºC * Power range: 0.23-13 MW ***Applications:*** * HVAC * District heating * District cooling with heating * District cooling with desalination * Dehumidification * Steam raising * Process cooling with heating

Suppliers

Star refrigeration

Model: Neatpump

Sabroe

Model: HeatPac Screw

References

Star Refrigeration

Neatpump

Johnson Controls (SABROE)

Specifications

Star Refrigeration

Neatpump

Johnson Controls (SABROE)

Product brochure

Star Refrigeration, Neatpump NP601 with corresponding flow scheme

1.3.1	R717
	High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials
	Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.
	06/01/2018 00:00:00
	Link to Article

1.4 R744

CO₂ is non-toxic, non-flammable, non-corrosive, has no ODP and a GWP of 1. At first, its low critical temperature seems to contradict the requirements of an industrial heat pump. To reach the required temperatures CO₂ has to be compressed to a supercritical state (critical pressure of 73.8 bar). It then releases its heat at a high temperature by means of a gas heat exchanger instead of a condenser. Due to its supercritical state CO₂ has a big temperature glide in the heat exchanger. By adjusting the CO₂ flow rate the average temperature difference in the heat exchanger can be reduced when the heat pump is used to heat cold water to a high temperature. This reduces the exergetic losses in the heat exchanger and therefore increases the energy efficiency of the heat pump. Because of the critical temperature of 31 °C, the temperature of the heat source cant be high. Today available CO₂ heat pumps can provide hot water at temperatures up to 130 °C. ***Specs:*** * Input media: water * Input temperature: 0-40 °C * Output media: air or water * Output temperature: 60-120 °C * Power range: 89-120 kW ***Applications:*** * Drying / dehumidifying applications (plastics, automobile, chemical, medical and other industries; dried vegetables, seasoning powder, other food processing and heating applications) * Heating (laminator, coater and gravure printing)

Suppliers

Mayekawa

Eco Sirocco

Specifications

Mayekawa

Eco Sirocco

Mayekawa Eco Sirocco with corresponding flow scheme

1.4.1	R744
	CO2 heat pump for waste heat recovery and utilization in dairy industry with ammonia based refrigeration
	Abstract Based on field data from a medium scale ammonia based milk refrigeration plant located in northern India, a trans-critical CO 2 heat pump system with IHX is conceptualized for waste heat utilization. The waste heat is utilized to pre-heating the boiler feed water and thereby reduces energy consumption. A thermodynamic model of the refrigeration system is built and simulated for year-round field data. In this study, the condenser of the ammonia based refrigeration system is coupled with the evaporator of the proposed CO 2 heat pump which is maintained at 20 °C year-round. The heat pump delivers heat at about 70 °C to pre-heat the boiler feed water drawn from underground source and is available in temperature range of 25 °C to 29 °C year-round. Thus, the CO 2 heat pump performance is essentially independent of variation in ambient temperature. We reported reduction in CO 2 emission and reduction in total energy cost by approximately 45.7% and 33.8% respectively. Economic analysis shows the payback period (PBP) is about 40 months.
	06/01/2017 00:00:00
	Link to Article
1.4.2	R744
	Estimating the potential of industrial (high-temperature) heat pumps for exploiting waste heat in EU industries
	Abstract A mapping of the potential of industrial heat pumps in EU industries is presented at both industrial branch and country level. This task required the estimation of the waste heat and its temperature level that can supply this type of heat pumps, as well as the industrial heat consumption within appropriate temperature bands. The matching of these two heat flows in each branch resulted to the potential of this upcoming technology for waste heat recovery towards the decarbonization of EU industries. The results of this analysis showed that the total potential of industrial heat pumps is 28.37 TWh/year in EU that corresponds to 1.5% of the total heat consumption. The necessary waste heat to be recovered and then upgraded by the heat pump for covering this consumption is about 21 TWh/year, which is 7% of the total waste heat potential in EU industries. Moreover, the most promising branches for applying this technology have been identified, which are the non-metallic minerals, food, paper, and non-ferrous metal ones, with chemical and other industries showing a much lower potential. The overall results of this work provide the amount of the wasted energy that can be exploited even with today’s heat pump technology, producing heat at a temperature up to 150 °C. The focus is on the EU level, and the main findings and conclusions provide an initial and reliable screening of the heat recovery opportunities in the most promising sectors. A case study of a paper industry is also included in this work, providing some first highlights of this potential, including the calculation of the payback period of this solution. However, a more detailed study at the site-level should follow for the actual estimation of an industrial heat pump potential and any possible site restrictions, as well as alternative heat recovery options, which is outside the scope of the current work.
	06/01/2019 00:00:00
	Link to Article
1.4.3	R744
	High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials
	Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.
	06/01/2018 00:00:00
	Link to Article

2. Double screw

Back

2.1 R717

Ammonia is flammable, but in addition to that, it is also toxic. Therefore appropriate safety measures have to be applied when using this refrigerant. Contrary to butane the needed refrigerant amount of ammonia is relatively low, due to its high refrigerating effect per unit of swept volume. Ammonia has a high critical temperature of 133 °C, but due to its high working pressure, the maximum reachable temperature of currently available ammonia CCC heat pumps is 90 °C. For higher temperatures, very sophisticated constructed compressors have to be used. ***Specs:*** * Input media: water * Input temperature: 35 °C * Output media: water * Output temperature: 85 °C * Power range: 2 - 15 MW * Operating pressure: 52 - 63 bar ***Applications:*** * Combined heating and cooling possible

Suppliers

GEA

Customized heat pump

References

GEA

GEA Grasso FX P heat pump with corresponding flow scheme

2.1.1	R717
	High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials
	Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.
	06/01/2018 00:00:00
	Link to Article
2.1.2	R717
	Theoretical and experimental investigation of a novel high temperature heat pump system for recovering heat from refrigeration system
	Abstract Ammonia has been widely employed as the working media in industrial refrigeration systems including cold chain or pharmaceuticals industry. The condensers of such system are releasing large amount of heat especially in large capacity applications. On the other hand, heating supply at the temperature of 80 °C or even higher is also greatly demanded in related processing systems. High temperature heat pumps, which are capable of recovering heat from condensers of refrigeration systems, could be much more highly efficient compared to boilers or electric heaters. Conventional heat pumps employ heat exchangers on existing refrigeration system condenser, but have much drawback and less efficiency in practical applications. In this paper, a novel system employing higher temperature ammonia twin screw compressors is introduced and analyzed for recovering heat and supplying hot water. A new semi-empirical model is specially developed for high pressure twin screw compressors. Both theoretical and experimental investigations are conducted on such system, while validation of simulation accuracy and efficiency analysis of such system is also given.
	08/01/2016 00:00:00
	Link to Article

2.2 R134a / r245fa

The SGH 120 system consists of a heat pump and a flash tank. The heat pump lifts the heat from a water source of 25-65 °C and transfers it to the pressurized circulating water. The pressurized water is decompressed and evaporated in the flash tank which provides the flashed steam of up to 120 °C (0.1 MPaG). The remaining saturated water is sent back to the heat pump and recirculated. The SGH 165 has in addition to the SGH 120 system a steam compressor. The steam compressor is used to compress the flashed saturated steam from the flash tank. Water is injected in the compressor to prevent superheat of steam. The steam can be provided up to 175 °C (0.8 MPaG) and the mist is separated at the drain separator. In the SGH 120 type R245fa is used as a refrigerant and in the SGH 165 systems, a mixture of R134a and R245fa is used. More information available [here](https://www.researchgate.net/publication/281059288_Experimental_performance_evaluation_of_heat_pump-based_steam_supply_system). ***Specs:*** SGH 120/SGH 165 * Input media: water * Input temperature: 25-70 °C * Output media: steam * Max output temperature: 120/165 °C * Steam pressure: 0-1.0 MPaG (regulation valve) * Steam production: 2-1000 kg/h (regulation valve) * Power range: 70 - 370/ 70 - 660 kW Also for lower temperatures (HEM-HR90). * Input media: air * Input temperature: -10 -40 °C * Output media: water * Output temperature: 65 - 90 °C * Power range: 70 - 230 kW

Suppliers

Kobelco (Steam Grow Heat Pump)

Models: SGH 120, 165 ; HEM-HR90

Experimental flow scheme used for the Kobelco heat pumps

2.2.1	R134a / r245fa
	An Industrial Heat Pump for Steam and Fuel Savings
	Currently many consumers in the India are facing with increasing shortages of electricity and petroleum gas. Prices have yet to stabilize and continue to increase as the shortages continue. What can then consumers do when facing with high heating bills and the need to stay warm and comfortable ? The answer to this may come from alternate heating systems. One such alternative to current heating systems is called a heat pump. A heat pump is defined as an electrically driven device used to transfer heat energy from one location to another. A heat pump can be used as a heating unit, an air-conditioning unit or a water heater. Industrial heat pumps are a class of active heat-recovery equipment that allows the temperature of a waste-heat stream to be increased to a higher, more useful temperature. Consequently, heat pumps can facilitate energy savings, when conventional passive-heat recovery is not possible. The focus is on the most common applications, with guidelines for initial identification and evaluation of the opportunities being provided. Heat pump is a device that can increase the temperature of a waste-heat source to a temperature, where the waste heat becomes useful. The waste heat can then replace purchased energy and reduce energy costs. However, the increase in temperature is not achieved without cost. A heat pump requires an external mechanical- or thermalenergy source. The goal is to design a system in which the benefits of using the heat-pumped waste heat exceed the cost of driving the heat pump. Heat can be extracted from various sources such as cooling tower water or various heating sources.
	01/01/2014 00:00:00
	Link to Article
2.2.2	R134a / r245fa
	High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials
	Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.
	06/01/2018 00:00:00
	Link to Article
2.2.3	R134a / r245fa
	Recent Researches on Steam Generation Heat Pump System
	This paper reviews the latest researches on steam generation heat pump (SGHP) to cover diverse technologies to enhance the performance depending on its applications. High temperature heat pump that can produce steam was reviewed first, and SGHP which recovers waste heat from low grade heat source (evaporator) was outlined. Conventional waste heat recovery from many industrial sites was reviewed, and SGHP to produce higher temperature steam by re-compression after heat sink (condenser) was discussed.
	12/01/2017 00:00:00
	Link to Article

2.3 R718

Compared with other refrigerants in the fourth generation, water has many advantages as follows. (1) No pollution to the environment. (2) Easy access to raw materials and low cost. (3) Good security. (4) Good stability and durable. (5) Large latent heat of vaporization. (6) System operation safety. Therefore, water is the most suitable refrigerant for the HTHP system with supply temperature above 120 °C. ***Summary of research results:*** * A new water vapor HTHP system with 80–90 °C waste heat recovery and 120–130 °C hot water supply. The water vapor HTHP system model is established to investigate the system performance under different working conditions. Then, the experimental study of the HTHP system with water refrigerant is carried out to validate the simulation results. The simulation results present that when the evaporation temperature is under 83–87 °C and the condensation temperature among 120–128 °C, the compressor power ranges from 46.1 to 58.1 kW and system COP ranges from 3.64 to 4.87. (Art. [#ARTNUM](#article-36387-2902289385)). \-In the study, the system was modelled and compared to the experimental data. The simulation model results showed good agreement with the experimental data. With the model higher condensation temperatures were investigated. \-Based on the model; when the evaporation temperature is 80 °C and the condensation temperature was increased from 115 to 160 °C. The compression ratio increased from 3.57 to 13.04, this required a power increase from 39.5 to 87.8 kW for the compressor. The injected volume flow increased from 47.2 to 104.2 L/h and the heating capacity increased from 179.1 to 192.4 kW. While the COP decreased from 4.53 to 2.19. ***Specs:*** * Input media: water * Input temperature: 80 - 90 °C * Output media: water * Output temperature: 120 - 130 °C * Power range: 46- 58 kW

Schematic diagram of the heat pump system

2.3.1	R718
	Modeling and simulation on a water vapor high temperature heat pump system
	Abstract In the face of more and more serious energy and environmental problems, energy conservation and environmental protection have attracted more attention all over the world. Combining the advantages of high temperature heat pump (HTHP) and natural refrigerant, water vapor HTHP system can effectively recover low-grade energy and is more green and environmental friendly. This paper presents a new water vapor HTHP system with 80–90 °C waste heat recovery and 120–130 °C hot water supply. The water vapor HTHP system model is established to investigate the system performance under different working conditions. Then, the experimental study of the HTHP system with water refrigerant is carried out to validate the simulation results. The simulation results present that when the evaporation temperature is under 83–87 °C and the condensation temperature among 120–128 °C, the compressor power ranges from 46.1 to 58.1 kW and system COP ranges from 3.64 to 4.87. The comparison between simulation and experimental results show good agreement with each other, which indicates that the model established in this paper has great reliability and accuracy for water vapor HTHP system.
	02/01/2019 00:00:00
	Link to Article

2.4 R1233zd(E)

R1233zd(E) is a refrigerant which is commercially being produced by Honeywell as Honeywell Soltrice. It is introduced as low GWP non-flammable replacement for blowing agent applications. The refrigerant has a critical temperature of 166.5 °C, which allows for higher sink temperatures. The ozone depletion potential potential is negeliable and the GWP is 1 while being in safety group A1. ***Specs:*** * Input media: water * Input temperature: 60-100 °C * Output media: water * Output temperature: 100-140°C * Power range: HP1 60-120 kW, HP2 120-240 kW and HP3 250-500 kW * Capacity: 6-22 m³/h ***Applications:*** * Industrial processes * Drying

Suppliers

Rank

Rank HP3 product brochure

References

Rank

Rank HP3

3. Piston

Back

Due to reciprocating movement, performed by the piston in an enclosed cylinder space, the change of volume of vapor of factor appears. The main characteristic element of this type of compressor is a crankshaft, which is designed to convert rotary motion of the drive shaft into reciprocating movement of the piston

3.1 R245fa

And for highest demand up to 120 °C, the refrigerant R245fa is a suitable solution which combines low-pressure characteristic, environmentally friendly properties, and valuable thermodynamic capability. And with all system, we can rely on proven standard components. Additional scope of application is the fusion of different technologies. For high-temperature differences between the heat sink and heat source, multi-stages systems can be realized. The heat pumps are available in fine graduations across the entire performance range and as single- or multiple-circuit versions. More information available [here](https://www.combitherm.de/files/pdf/Prospekte/High%20Temperature%20HP.pdf). ***Specs:*** * Input media: water/air/others * Input temperature: 30-70 °C * Output Media: water/air/others * Max output temperature: 120 °C * Power Range: 62 - 252 kW ***Applications:*** * Brewery * Sugar production * Drying of pulp * Residential heating

Suppliers

Combitherm

Specifications

Combitherm

Combitherm HWW 245fa heat pump with corresponding flow diagram

3.1.1	R245fa
	High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials
	Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.
	06/01/2018 00:00:00
	Link to Article

3.2 R717

Ammonia is flammable, but in addition to that, it is also toxic. Therefore appropriate safety measures have to be applied when using this refrigerant. Contrary to butane the needed refrigerant amount of ammonia is relatively low, due to its high refrigerating effect per unit of swept volume. Ammonia has a high critical temperature of 133 °C, but due to its high working pressure, the maximum reachable temperature of currently available ammonia CCC heat pumps is 90 °C. For higher temperatures, very sophisticated constructed compressors have to be used SABROE HeatPAC HPX heat pumps are compact units with an integrated single-stage configuration that features less than half the space and weight requirements of any other heat pump designs usually needed to achieve 90 °C hot water outputs. ***Specs:*** * Input media: air/water * Input temperature: 39 °C * Output media: water * Output temperature: 90 °C * Power range: 339 - 1355 kW * Operating pressure: 60 bar ***Applications:*** * Sterilization and pasteurization * Hygiene-sensitive functions and processes

Suppliers

Johnson Controls

Model: SABROE HeatPac-HPX

References

Johnson Controls (SABROE)

Specifications

Johnson Controls (SABROE)

Product brochure

Johnson controls SABROE HeatPAC-HPX heat pump with flow diagram

3.2.1	R717
	High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials
	Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.
	06/01/2018 00:00:00
	Link to Article

3.3 R744

CO2 is non-toxic, non-flammable, non-corrosive, has no ODP and a GWP of 1. At first, its low critical temperature seems to contradict the requirements of an industrial heat pump. To reach the required temperatures CO₂ has to be compressed to a supercritical state. It then releases its heat at a high temperature by means of a gas heat exchanger instead of a condenser. Due to its supercritical state CO₂ has a big temperature glide in the heat exchanger. By adjusting the CO₂ flow rate the average temperature difference in the heat exchanger can be reduced when the heat pump is used to heat cold water to a high temperature. This reduces the exergetic losses in the heat exchanger and therefore increases the energy efficiency of the heat pump. Because of the critical temperature of 31 °C the temperature of the heat source should not be higher than 30 °C. Today available CO₂ heat pumps can provide hot water at temperatures up to 130 °C. ***Specs:*** * Input media: air / water * Input temperature: -10- \~60 °C * Output media: air/water * Max output temperature: 110 °C * Power range: 51-1460 kW ***Applications:*** * District heating * Brine cooling * Drying * Condensation dehumidification in process

Suppliers

Engie

Model: Thermeco2

References

Thermeco2

Specifications

Thermeco2

Engie thermeco2 with flow diagram

3.3.1	R744
	High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials
	Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.
	06/01/2018 00:00:00
	Link to Article

3.4 R1234ze

Refrigerant R1234zeE (trans-1,3,3,3-Tetrafluoroprop-1-ene, CF3CH=CHF ) belongs to the family of HFO fluids that contain a carbon-carbon double bond and characterized by very low GWP of less than one. It should be noted that the molecule of R1234ze has 2 isomers, R1234ze(Z) and R1234ze(E), with rather different properties. R-1234ze(Z) has a high boiling point (9.8°C) associated with a higher critical temperature (153.7°C) and a volumetric capacity of roughly 50% lower than R-1234ze(E). Therefore R-1234ze(Z) could be primarily utilized in specific applications like high temp heat pumps, whereas R-1234ze(E) will show operating conditions and applied costs much more in line with R-134a according to system and compressor sizes. ***Specs Vitocal 350-HT Pro:*** * Input media: Brine * Input temperature: 0-50 °C * Output media: Water * Output temperature: 90 °C * Power range: 56.6-144.9 kW (brine 0 °C/ Water 35 °C) and 148-390 kW (Water 50 °C/Water 90 °C) ***Specs Oilon Chilheat P-series:*** * Input media: water * Input temperature: 40-45 °C * Output media: water * Output temperature: 80-100 °C * Power range: 30-1000 kW ***Applications Vitocal 350-HT Pro:*** * Brine heat source ***Applications Oilon Chilheat P-series:*** * Large properties * District heating and cooling * Industry * Processes and ground source heat applications requiring high temperatures

Suppliers

Viessmann

Model: Vitocal 350-HT Pro

Oilon

Model: Oilon Chilheat P60 - P450

References

Viessmann

Oilon

Specifications

Viessmann

Product brochure

Oilon

Product brochure: Oilon Chilheat P60 - P450

Vitocal 350-HT Pro; 1: COP boosted by internal heat exchanger, 2: PLC control unit with colour touchscreen, 3: Circulator, 4: Pressure monitoring. 5: Refrigerant collector for large temperature application range, 6: Condenser/evaporator, 7: Piston compressor, 8: Highly attenuating sound insulation, 9: Anti-vibration measures

3.4.1	R1234ze
	High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials
	Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.
	06/01/2018 00:00:00
	Link to Article
3.4.2	R1234ze
	Thermodynamic analysis of low GWP alternatives to HFC-245fa in high-temperature heat pumps: HCFO-1224yd(Z), HCFO-1233zd(E) and HFO-1336mzz(Z)
	Abstract This paper analyses the feasibility of HCFO-1224yd(Z), HCFO-1233zd(E) and HFO-1336mzz(Z), three low global warming potential (GWP) refrigerants, as alternatives to HFC-245fa in high-temperature heat pump (HTHP) systems for low-grade waste heat recovery. HTHPs are a sustainable technology that can help to mitigate climate change through the thermal valorisation of the industrial low-grade waste heat. Before presenting and analysing the results, mapping of the minimum superheat degree requirement in the operating range, and the influence of the Internal Heat Exchanger (IHX) on each alternative are studied. The simulations were carried out at condensing temperatures from 115 to 145 °C and evaporating temperatures from 45 to 75 °C, using a single-stage cycle with and without IHX. Finally, the Total Equivalent Warming Impact (TEWI) evaluation is performed to illustrate the environmental effect of each alternative. Attending to the results, HCFO-1233zd(E) improves the COP about 27% compared to HFC-245fa, whereas HFO-1336mzz(Z) and HCFO-1224yd(Z) show an improvement of approx. 21 and 17%, respectively. Although HCFO-1233zd(E) and HCFO-1224yd(Z) present similar suction volumetric flow rate to HFC-245fa, HFO-1336mzz(Z) shows a relative increment up to 80%, and therefore, higher compressor and installation size are expected for this refrigerant. Finally, the TEWI analysis presents a significant reduction of the equivalent CO 2 emissions for each low GWP alternative, between 59 and 61%. HCFO-1233zd(E) shows the highest reduction in all the simulation cases, followed by HCFO-1224yd(Z) and HFO-1336mzz(Z).
	04/01/2019 00:00:00
	Link to Article

3.5 R1336mzz-Z

Non-flammable single component fluid R1336mzz-Z with GWP of just 2 has been recently revealed by DuPont - American chemical manufacturer. The substance, previously known as development refrigerant DR-2, is, in fact, an olefin of butane (that is an unsaturated molecule of butane containing a carbon-carbon double bond). Boiling and critical temperatures of R1336mzz-Z are 33.5 and 171.3 °C respectively. Therefore, it can be potentially used as a working fluid for high-temperature heat pump applications. For this range of temperatures, it can be considered as an alternative to refrigerants HFC-245fa and HCFC-123. Given that the later consist of chlorine and thus going to be completely phased out, R1336mzz-Z should be put into comparison with HFC-245fa. Performance experiments have been done on the heat pump system, more information is available [here](http://hpc2017.org/wp-content/uploads/2017/05/O.3.4.2-Measured-performance-of-a-novel-high-temperature-heat-pump-with-HFO-1336mzzZ-as-the-working-fluid.pdf). ***Specs:*** * Input Media: Water / Steam * Input Temperature: 50-120 °C * Output Media: Water / Steam * Output Temperature: 165 °C * Power Range: 195-250 kW * Pressure: Up to 25 bar Note: HeatBoosters in the megawatt range will be available in 2019. ***Applications:*** * Replaces energy-intensive gas, oil, coal and electric boilers

Suppliers

Viking Heating Engines

Model: HeatBooster

References

HeatBooster

Specifications

HeatBooster

Model: HBS4

Viking Heating Engines HeatBooster with flow diagram

3.5.1	R1336mzz-Z
	Estimating the potential of industrial (high-temperature) heat pumps for exploiting waste heat in EU industries
	Abstract A mapping of the potential of industrial heat pumps in EU industries is presented at both industrial branch and country level. This task required the estimation of the waste heat and its temperature level that can supply this type of heat pumps, as well as the industrial heat consumption within appropriate temperature bands. The matching of these two heat flows in each branch resulted to the potential of this upcoming technology for waste heat recovery towards the decarbonization of EU industries. The results of this analysis showed that the total potential of industrial heat pumps is 28.37 TWh/year in EU that corresponds to 1.5% of the total heat consumption. The necessary waste heat to be recovered and then upgraded by the heat pump for covering this consumption is about 21 TWh/year, which is 7% of the total waste heat potential in EU industries. Moreover, the most promising branches for applying this technology have been identified, which are the non-metallic minerals, food, paper, and non-ferrous metal ones, with chemical and other industries showing a much lower potential. The overall results of this work provide the amount of the wasted energy that can be exploited even with today’s heat pump technology, producing heat at a temperature up to 150 °C. The focus is on the EU level, and the main findings and conclusions provide an initial and reliable screening of the heat recovery opportunities in the most promising sectors. A case study of a paper industry is also included in this work, providing some first highlights of this potential, including the calculation of the payback period of this solution. However, a more detailed study at the site-level should follow for the actual estimation of an industrial heat pump potential and any possible site restrictions, as well as alternative heat recovery options, which is outside the scope of the current work.
	06/01/2019 00:00:00
	Link to Article
3.5.2	R1336mzz-Z
	High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials
	Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.
	06/01/2018 00:00:00
	Link to Article
3.5.3	R1336mzz-Z
	Simulation Optimization of a New Ammonia-Based Carbon Capture Process Coupled with Low-Temperature Waste Heat Utilization
	Although ammonia-based CO2 capture has attracted global research attention, several inherent issues with this technology remain to be resolved. To address these problems, a new design for carbon capture using ammonia is proposed on the basis of anti-solvent crystallization, also known as precipitation crystallization. The crystallization of a low carbonized absorbent was found to be enhanced in the crystallizer using an anti-solvent process, which can maintain a high absorption rate and simultaneously prevent crystallization from occurring in the absorption tower. Energy consumption for sorbent regeneration is reduced by regenerating the crystal product rather than the rich solution. Energy-cascade utilization is an effective way to improve the use of energy. In this work, steam was used to drive a heat pump that extracts energy from discharged flue gas from a wet flue gas desulfurization system in a power plant to enable the recovery of low-temperature residual energy; this energy can be used in the crys...
	04/20/2017 00:00:00
	Link to Article
3.5.4	R1336mzz-Z
	Thermodynamic analysis of low GWP alternatives to HFC-245fa in high-temperature heat pumps: HCFO-1224yd(Z), HCFO-1233zd(E) and HFO-1336mzz(Z)
	Abstract This paper analyses the feasibility of HCFO-1224yd(Z), HCFO-1233zd(E) and HFO-1336mzz(Z), three low global warming potential (GWP) refrigerants, as alternatives to HFC-245fa in high-temperature heat pump (HTHP) systems for low-grade waste heat recovery. HTHPs are a sustainable technology that can help to mitigate climate change through the thermal valorisation of the industrial low-grade waste heat. Before presenting and analysing the results, mapping of the minimum superheat degree requirement in the operating range, and the influence of the Internal Heat Exchanger (IHX) on each alternative are studied. The simulations were carried out at condensing temperatures from 115 to 145 °C and evaporating temperatures from 45 to 75 °C, using a single-stage cycle with and without IHX. Finally, the Total Equivalent Warming Impact (TEWI) evaluation is performed to illustrate the environmental effect of each alternative. Attending to the results, HCFO-1233zd(E) improves the COP about 27% compared to HFC-245fa, whereas HFO-1336mzz(Z) and HCFO-1224yd(Z) show an improvement of approx. 21 and 17%, respectively. Although HCFO-1233zd(E) and HCFO-1224yd(Z) present similar suction volumetric flow rate to HFC-245fa, HFO-1336mzz(Z) shows a relative increment up to 80%, and therefore, higher compressor and installation size are expected for this refrigerant. Finally, the TEWI analysis presents a significant reduction of the equivalent CO 2 emissions for each low GWP alternative, between 59 and 61%. HCFO-1233zd(E) shows the highest reduction in all the simulation cases, followed by HCFO-1224yd(Z) and HFO-1336mzz(Z).
	04/01/2019 00:00:00
	Link to Article

3.6 R717/H₂O (Hybrid absorption/compression)

A Hybrid Heat Pump is built with standard ammonia compressors, with a design pressure of 25 bar. A traditional heat pump using pure ammonia can heat water to 50 °C at this pressure. A Hybrid Heat Pump can heat water to 120 °C using the exact same equipment. It can cover a whole new range of temperatures than traditional heat pumps, meeting the demands of a lot of industrial processes. ***Specs:*** * Input media: water/air * Input temperature: 15-75 °C * Output media: water * Output temperature: 75-120 °C * Power range: 0.25-2.5 MW * Operating pressure: below 25 bar ***Applications:*** * District heating * Water processing * Drying

Suppliers

Hybrid Energy

Model: Hybrid heat pump

References

Hybrid Energy

Simplified diagram of the hybrid heat pump

3.6.1	R717/H₂O (Hybrid absorption/compression)
	A high-temperature hybrid absorption-compression heat pump for waste heat recovery
	Abstract An absorption-compression heat pump is a promising way to recover low-temperature waste heat efficiently in industrial applications. In this paper, an advanced ammonia-water absorption-compression heat pump is proposed to recover the sensible heat of flue gas below 150 °C to generate saturated steam at 0.5 MPa (151.8 °C). The sensible heat is cascade utilized in the hybrid heat pump system. The high-temperature waste heat is recovered to generate pure ammonia vapor in the rectifier, and the low-temperature heat is used to evaporate the ammonia liquid. In the ammonia vapor compression process, the gas compression process is combined with a liquid compression process, leading to the clear decrease in power consumption. The simulation results indicate that the coefficient of performance and exergy efficiency of the proposed system reaches 5.49 and 27.62%, which is almost two times and 4.69% higher than that of the reference system, respectively. Subsequently, a sensitivity analysis is conducted to optimizing the key parameters, and the optimums values are obtained. Finally, an economic analysis is adopted to evaluate the economic performance of the proposed system. The payback period of the proposed system is 6.26 years compared to the reference system. This study may provide a new way to produce saturated steam by efficiently using the low-temperature waste heat.
	09/01/2018 00:00:00
	Link to Article
3.6.2	R717/H₂O (Hybrid absorption/compression)
	Comparison of the working domains of some compression heat pumps and a compression-absorption heat pump
	Abstract The working domains of a model of a compression heat pump using different fluids and a model of a compression-absorption heat pump using water-ammonia mixtures are defined, plotted and discussed. These domains are defined by means of limiting values for their electrical coefficient of performance, volumetric heating capacity, and low and high pressure. In the case studied in the present paper, the disappearance from use of CFC and HCFC fluids leaves only one alternative for the implementation of high temperature electric heat pumps: hydrocarbons in compression devices or water-ammonia mixtures in compression-absorption devices. Problems relating to the implementation of these systems are also mentioned.
	08/01/1997 00:00:00
	Link to Article
3.6.3	R717/H₂O (Hybrid absorption/compression)
	Experimental study of operating characteristics of compression/absorption high-temperature hybrid heat pump using waste heat
	This research describes the development of a compression/absorption hybrid heat pump system that utilizes a mixture of NH3 and H2O as a working fluid. The heat pump cycle is based on a hybrid combination of vapor compression cycle and absorption cycle. The system consists of major components of two-stage compressors, absorbers, and a desorber. There are also auxiliary parts like a desuperheater, solution heat exchangers, a solution pump, a rectifier, and a liquid/vapor separator to support stable operation of the heat pump. This compression/absorption hybrid heat pump provides many advantages of performance over conventional vapor compression heat pumps including a large temperature glide, an improved temperature lift, a flexible operating range, and greater capacity control. These benefits are optimized by changing the composition of the mixture. In this study, the effect of the composition on the operating characteristics of the compression/absorption hybrid heat pump was experimentally observed.
	06/01/2013 00:00:00
	Link to Article
3.6.4	R717/H₂O (Hybrid absorption/compression)
	High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials
	Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.
	06/01/2018 00:00:00
	Link to Article
3.6.5	R717/H₂O (Hybrid absorption/compression)
	Numerical study of a hybrid absorption-compression high temperature heat pump for industrial waste heat recovery
	The present paper aims at exploring a hybrid absorption-compression heat pump (HAC-HP) to upgrade and recover the industrial waste heat in the temperature range of 60°C–120°C. The new HAC-HP system proposed has a condenser, an evaporator, and one more solution pump, compared to the conventional HAC-HP system, to allow flexible utilization of energy sources of electricity and waste heat. In the system proposed, the pressure of ammonia-water vapor desorbed in the generator can be elevated by two routes; one is via the compression of compressor while the other is via the condenser, the solution pump, and the evaporator. The results show that more ammonia-water vapor flowing through the compressor leads to a substantial higher energy efficiency due to the higher quality of electricity, however, only a slight change on the system exergy efficiency is noticed. The temperature lift increases with the increasing system recirculation flow ratio, however, the system energy and exergy efficiencies drop towards zero. The suitable operation ranges of HAC-HP are recommended for the waste heat at 60°C, 80°C, 100°C, and 120°C. The recirculation flow ratio should be lower than 9, 6, 5, and 4 respectively for these waste heat, while the temperature lifts are in the range of 9.8°C–27.7 °C, 14.9°C–44.1 °C, 24.4°C–64.1°C, and 40.7°C–85.7°C, respectively, and the system energy efficiency are 0.35–0.93, 0.32–0.90, 0.25–0.85, and 0.14–0.76.
	12/01/2017 00:00:00
	Link to Article
3.6.6	R717/H₂O (Hybrid absorption/compression)
	Study on ammonia/water hybrid absorption/compression heat pump cycle to produce high temperature process water
	Abstract The objectives of this paper are to analyze the heat transfer characteristics during the ammonia water absorption process for the hybrid absorption/compression heat pump system application. The hybrid absorption/compression heat pump cycle aims at obtaining the high temperature process water. The parametric analysis on the effects of each key parameter, which are system high-pressure, ammonia weak solution concentration, ammonia weak solution and vapor flow rates is carried out. It is found that the increases in the high pressure and ammonia weak solution flow rate have positive effects on the absorber heat transfer rate, whereas the increase in the weak solution concentration does negative effect. It is also found that the weak solution concentration acts as the most important parameter to obtain the high temperature process water. As the weak solution concentration increases, the absorber heat transfer rate decreases, but the system COP tends to increase. It is concluded that the concentration of the weak solution should be maintained at approximately 0.40–0.45, the flow rate of the weak solution be lower than 0.03 kg/s, and the high-pressure be higher than 1700 kPa to obtain process water of higher than 80 °C.
	02/01/2018 00:00:00
	Link to Article

3.7 R600

Butane (R600), as well as ammonia and carbon dioxide, is a natural refrigerant. Its critical temperature of 154 °C is high enough to cover a wide range of industrial applications. In addition, its global warming potential is very low. However, butane is highly flammable and should thus only be used in small plants that only need small quantities of refrigerant. ***Summary of research results:*** * The compressor is a semi-hermetic, 4-cylinder piston compressor manufactured by Officine Mario Dorin S.P.A. It is designed for explosive atmosphere (ATEX) conditions suitable for hydrocarbons. This research experimentally investigates a prototype compressor in a high-temperature heat pump for industrial waste heat recovery from 50  °C to heat delivery at 115  °C. he experimental setup consists of a 20 kW heat pump designed with the flexibility for multiple operating conditions applicable to different industrial applications. The compressor is designed to enable suction and discharge temperatures up to 80  °C and 140  °C respectively. It is found to have a total compressor efficiency of 74% and a volumetric efficiency of 83%. The results showed good operating parameters (temperature, pressure) and the potential for even higher temperature heat delivery ([#ARTNUM](#article-36388-2902456880)). * Experimental temperature values at the compressor discharge and suction are 129 °C and 70 °C respectively with pressure values below 22 bar indicating the potential to increase the operating region of the heat pump to deliver higher temperature at the heat sink outlet (Art. [#ARTNUM](#article-36388-2917972757)). * The R600 pilot heat pump in the CATCH-IT project is used to produce low-pressure steam from boiler feed water and hot process water from fresh but already preheated water. The source heat is recovered from moist exhaust air from the paper machine drying section. Steam pressures to be delivered at 0.5 barg up to 2.4 barg. The design capacity is approximately 150 kW and is determined by the size of the smallest available compressor. The exact capacity is depending on the operating conditions; Hot process water at 70˚C (maximum possible 100˚C), the capacity is the maximum possible capacity given the heat pump configuration; The source heat is waste heat recovered from the exhaust of the paper machine hood. The source heat is transported in a water/glycol system, the ΔTwater/glycol = 5 K, the water/glycol approach temperature varies from 60 ˚C up to 75 ˚C. The source heat is always available when there is a demand for process heat. More information available [here](http://hpc2017.org/wp-content/uploads/2017/05/O.3.5.3-Test-results-R600-pilot-heat-pump.pdf). ***Specs:*** * Input media: moist air * Input temperature: 50-80 °C * Output media: water/steam * Output temperature: 115-140 °C * Power range: 150 kW * Operating pressure: 0.5 barg

Flow diagram of a test setup of a high temperature butane heat pump system

3.7.1	R600
	Derived thermodynamic design data for heat pump systems operating on R600
	Abstract The theoretical Rankine coefficients of performance and the compression ratios have been presented for heat pump systems operating on R600. These values are listed in tabular form for temperature lifts of 10–75°C and the condensing temperatures of 10–140°C in 5°C increments. Several graphs have been drawn to illustrate the feasible operating range of R600 heat pump systems. The derived thermodynamic design data can be used for the rapid preliminary design of heat pump systems operating on R600.
	01/01/1983 00:00:00
	Link to Article
3.7.2	R600
	Experimental investigation of a prototype R-600 compressor for high temperature heat pump
	Abstract This research experimentally investigates a prototype compressor in a high temperature heat pump for industrial waste heat recovery from 50 °C to heat delivery at 115 °C. Compressors are the limiting component in the development of high temperature heat pumps due to the high discharge pressure and temperature. The prototype compressor is tested with butane due to its favourable thermodynamic properties within the operating conditions. The compressor allows the heat pump to provide heating for industrial processes such as pasteurization, drying, sterilization and other processes which require high temperature heat. The heat pump will replace the heating capacities of low-pressure steam boilers. It will also provide cooling for industrial waste heat or other cooling demands, replacing cooling capacities from cooling towers. The experimental setup consists of a 20 kW heat pump designed with the flexibility for multiple operating conditions applicable to different industrial applications. The compressor is designed to enable suction and discharge temperatures up to 80 °C and 140 °C respectively. It is found to have a total compressor efficiency of 74% and a volumetric efficiency of 83%. The results showed good operating parameters (temperature, pressure) and the potential for even higher temperature heat delivery.
	02/01/2019 00:00:00
	Link to Article
3.7.3	R600
	High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials
	Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.
	06/01/2018 00:00:00
	Link to Article
3.7.4	R600
	Performance analysis of different single stage advanced vapor compression cycles and refrigerants for high temperature heat pumps
	Abstract High temperature heat pumps can reduce the energy consumption and have huge potential for applications. In order to obtain higher performance and achieve lower cost, single stage high temperature heat pump employing expander (EX), ejector (EE), internal heat exchanger (IHX), oil flooded compression (OFC) or coupled (EXIHX and EEIHX) cycles and various refrigerants are studied in this paper. Simulation results show that the efficient configuration is EX, EXIHX, EE, EEIHX, OFC and IHX in order in term of COP and EEIHX, EE, OFC, EXIHX, IHX, and EX in order in term of specific heating capacity ( Q c ) respectively. Results also show that R245fa, R600 and R1234ze(Z) have similar performance while the COP of the system with R600a is 4%-14% lower than that with R245fa. Moreover, in term of the Q c , there is an increase of 8%-25%, 18%-56% and 6%-11% respectively for BC configurations employing R600, R600a and R1234ze(Z) instead of R245fa.
	05/01/2019 00:00:00
	Link to Article
3.7.5	R600
	The development of a hydrocarbon high temperature heat pump for waste heat recovery
	Abstract Waste heat is an abundant resource that if recovered with a heat pump would increase energy efficiency in industrial processes. This will provide improvements in heat utilization and reduce the environmental impact of greenhouse gas emissions from the combustion of fossil fuel. A hydrocarbon high temperature heat pump has been developed to demonstrate the potential to deliver heat at a temperature of 115 °C. The heat pump provides heat for applications such as drying, pasteurization and other processes. Using hydrocarbons, the heat pump aims for a clean energy system. This paper reports on a 20 kW capacity cascade heat pump with propane in the low temperature cycle and butane in the high temperature cycle. Based on a theoretical model, an experimental setup is built with standard components that are commercially available. A prototype compressor is investigated for its performance at high temperature conditions. The heat pump can recover waste heat at 30 °C and deliver heat up to 115 °C. With an average heating coefficient of performance (COP) of 3.1 for a temperature lift of 58–72 K, the heat pump is a more cost efficient and environmentally friendly system compared to existing solutions of a steam boiler.
	04/01/2019 00:00:00
	Link to Article
3.7.6	R600
	THERMODYNAMIC COMPARISION OF R744/R600A AND R744/R600 USED IN MID-HIGH TEMPERATURE HEAT PUMP SYSTEM
	The mid-high temperature heat pump provides hot water at a relatively high temperature using some industrial waste heat as its source. Now, the main refrigerants in this application are CFC114, HCFC123, and HCFC142b, etc., which are scheduled to be phased out due to their high ozone depletion potential and global warmth potential. Some studies have been conducted to find an eco-friendly alternative. In this paper, the natural non-azeotropic mixtures R744/R600a and R744/R600 are analyzed as alternatives. The performance of the heat pump system using new mixture is discussed and compared with those with CFC114, HCFC123, and HCFC142b. Under the given operating conditions, the maximum heating COP should occur at the mass fractions of 18/82 for R744/R600a and 10/90 for R744/R600. Both of their COP are higher than those with the refrigerants of CFC114, HCFC123, and HCFC142b. The COP and volumetric heating capacity of the system with R744/R600a are superior to those with R744/R600.
	01/01/2014 00:00:00
	Link to Article

4. Turbo / Centrifugal

Back

The inherent characteristics of turbocompressors manage to fit the heat pump load while the oil-freeness allows the implementation of advanced heat exchanger technology and the deployment of advanced multi-stage cycles, both validated means to significantly enhance performance and efficiency.

4.1 R134a

Heat pumps using R134a can also be applied to provide hot water and space heating in older buildings. The critical temperature of both refrigerants is usually too low for the utilization in most industrial processes. Heat pumps using R134a can reach up to 90 °C. Mitsubishi heat pump: * Input media: water * Input temperature: 50 °C * Output media: Water * Output temperature: 90 °C * Power range: 340 - 600 kW More information available [here](https://www.mhi.co.jp/technology/review/pdf/e482/e482045.pdf). ***Applications:*** * Heating * Disinfection * Washing Chiller / OM-Titan: ***Specs:*** * Input media: water * Input temperature: N.C. * Output media: water * Output temperature: 90 °C * Power range: 5 - 20 MW

Suppliers

Johnson

Model: Titan OM

MItsubishi

Model: ETW-L

Mitsubishi heat pump with flow diagram

4.1.1	R134a
	High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials
	Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.
	06/01/2018 00:00:00
	Link to Article
4.1.2	R134a
	Investigation on advanced heat pump systems with improved energy efficiency
	Abstract Centrifugal heat pumps with waste heat recovery have a bright application future in industry field due to their large heating capacity and high supply water temperature. Two kinds of advanced heat pump systems are proposed and analyzed to improve the energy efficiency. The system performances are analyzed and compared for three kinds of centrifugal heat pump systems: the one-cycle two-compressor system, two-compressor parallel system, and two-cycle parallel system. According to the simulation results, the two-cycle parallel system shows great advantages in the heating capacity, power capacity, and system COP (coefficient of performance). For 30 °C evaporator inlet water temperature and 60 °C condenser outlet water temperature, the COP improvements of the two-compressor parallel system and two-cycle parallel system are 7.7% and 15.5%, respectively. When the condenser outlet water temperature is 80 °C, the system COP of the two-cycle parallel system is 9.6% and 19.0% higher than that of the one-cycle two-compressor system with 30 °C and 60 °C evaporator inlet water temperatures. The COP of the two-compressor parallel system is 5.2% and 10.2% higher than that of the one-cycle two-compressor system under the same working condition. When the temperature lift is kept at 30 °C and the condenser outlet water temperature changes from 60 °C to 90 °C, the maximum and minimum COP of two-cycle parallel system are 6.7 and 6.1, respectively, which is at least 6.8% higher than the COP of the two-compressor parallel system and 13.5% higher than that of the one-cycle two-compressor system. The experimental validation is conducted, and the results indicate that the two-cycle parallel system can satisfy the high-temperature, large-capacity, and high-efficiency requirements for industrial applications.
	07/01/2019 00:00:00
	Link to Article

4.2 R1234ze

Refrigerant R1234zeE (trans-1,3,3,3-Tetrafluoroprop-1-ene, CF3CH=CHF ) belongs to the family of HFO fluids that contain a carbon-carbon double bond and characterized by very low GWP of less than one. It should be noted that the molecule of R1234ze has 2 isomers, R1234ze(Z) and R1234ze(E), with rather different properties. R-1234ze(Z) has a high boiling point (9.8°C) associated with a higher critical temperature (153.7°C) and a volumetric capacity of roughly 50% lower than R-1234ze(E). Therefore R-1234ze(Z) could be primarily utilized in specific applications like high temp heat pumps, whereas R-1234ze(E) will show operating conditions and applied costs much more in line with R-134a according to system and compressor sizes. ***Specs:*** * Input media: air * Input temperature: 34 °C * Output media: air * Output temperature: 95 °C * Power range: 0.6 - 3.6 MW ***Applications:*** * District heating and district cooling systems * Dual-energy generation: heating and cooling * Industrial production plants * Large air conditioning installation

Suppliers

Friotherm

Model: Unitop22

References

Friotherm

Friortherm

Waste Heat Recovery at the Steel and Rolling Mill “Marienhütte”, Graz (Austria): Unitop

4.2.1	R1234ze
	Exergy analysis of R1234ze(Z) as high temperature heat pump working fluid with multi-stage compression
	In this paper, the simulation approach and exergy analysis of multi-stage compression high temperature heat pump (HTHP) systems with R1234ze(Z) working fluid are conducted. Both the single-stage and multi-stage compression cycles are analyzed to compare the system performance with 120°C pressurized hot water supply based upon waste heat recovery. The exergy destruction ratios of each component for different stage compression systems are compared. The results show that the exergy loss ratios of the compressor are bigger than that of the evaporator and the condenser for the single-stage compression system. The multi-stage compression system has better energy and exergy efficiencies with the increase of compression stage number. Compared with the singlestage compression system, the coefficient of performance (COP) improvements of the two-stage and three-stage compression system are 9.1% and 14.6%, respectively. When the waste heat source temperature is 60°C, the exergy efficiencies increase about 6.9% and 11.8% for the two-stage and three-stage compression system respectively.
	12/01/2017 00:00:00
	Link to Article
4.2.2	R1234ze
	High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials
	Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.
	06/01/2018 00:00:00
	Link to Article

4.3 R718

Water vapor is an environmental friendly refrigerant with no Ozone Depletion Potential (ODP) and a Global WarmingPotential (GWP100yr) less than 1. It is non-toxic, non-flammable, and chemically inert at high temperature and needs slow compressing pressures. Water has a high critical temperature, therefore, its thermodynamic properties suites high-temperature ranges. Otherwise, it is easily available at low costs. Water has a high theoretical coefficient of performance (COP) due to its high latent heat of vaporization compared to other traditional refrigerants. Hence, the use of water as a refrigerant in this high-temperature heat pump offers several potentially significant advantages but involves technical and feasibility difficulties. ***Summary of research findings:*** * PACO is a completely new type of industrial heat pump that uses zero chemical fluid for its operation – just water. This unique feature allows it to supply heat up to 130°C (compared with 70°C for traditional heat pumps), making it exceptionally energy efficient and reducing its environmental impact to a minimal level. The heat pump delivers a complete response to industrial heating needs, especially for processes requiring low-pressure steam and releasing waste heat in the form of liquid discharges below 100°C. Centrifugal steam compressor with magnetic bearings has been developed to be used with water. PACO’s installation as part of an existing industrial process is now in the planning stage, and the JCI manufacturer has begun design work on a larger steam compressor (3t/hr). More information available [here](https://www.edf.fr/en/the-edf-group/world-s-largest-power-company/activities/research-and-development/flagship-projects/a-very-high-temperature-water-cooled-industrial-heat-pump)

Suppliers

EDF (partner of project)

PACO Project

PACO heat pump

4.3.1	R718
	Dynamic model of an industrial heat pump using water as refrigerant
	Abstract In order to improve industrial energy efficiency, the development of a high temperature heat pump using water vapor as refrigerant is investigated. Technical problems restraining the feasibility of this industrial heat pump are surmounted by a specifically designed heat pump and the development of a new twin screw compressor. This article presents the development of a new dynamic model of this twin screw compressor and of the heat pump using flash evaporation. This model takes into account the presence and the purging mechanism (purging reservoir) of the non-condensable gases especially during the start-up procedure. A finite volume (FV) approach is used for the plate heat-exchangers models while a moving boundary (MB) approach between phases is implemented for the purging and the flash evaporation systems models. The models are developed using Modelica as a modeling language without any library involvement and taking into account as many details as possible to closely represent the real system.
	06/01/2012 00:00:00
	Link to Article
4.3.2	R718
	High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials
	Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.
	06/01/2018 00:00:00
	Link to Article

5. Others

Back

5.1 Travelling wave thermoaccoustics

Thermoacoustically driven systems for heating or cooling have received much attention in recent years for their heat-driven mechanism, without moving parts, and structural simplicity. Thermoacoustic machines, which mainly include thermoacoustic heat engines and refrigerators, make use of thermoacoustic effect to realize the conversion between heat and sound energy. ***Summary of research results:*** * Electrical driven drivers (send an acoustic wave through the pump. At the point where Helium is compressed heat is exchanged by a heat exchanger. At the point where the helium is expanded, heat from the source is added using a second heat exchanger (4). Between the two heat exchangers, a regenerator is placed. Within the regenerator, a thermal cycle arises. In this way, the regenerator creates a temperature difference or a so-called thermal pump or heat pump. The heat exchangers and are connected to either the source or heatsink, depending on the demand of the consumer. Either heating or cooling. loop. * The tubes were filled with nitrogen. When an acoustic wave was input to the tubes, a temperature difference formed along the regenerator. Our experiments showed that this heat pump could work as both a cooler and a heater. This heat pump achieved -39 °C as a cooler and 270°C as a heater. Using antifreeze liquid and oil as heat media, the cooling and heating performance of the heat pump was measured within the temperature range from -3 to 160 °C Art. [#ARTNUM](#article-36486-1960746930). * The theoretical simulations were performed at varied waste heat temperatures (40−70 °C) and different hot end temperatures (120−150 °C). The computing results show that this new heat pump system has a high relative Carnot efficiency of about 50%–60%. In using a reliable linear compressor and a thermoacoustic heat pump with no moving parts Art. [#ARTNUM](#article-36486-2018344432). \-Later developemts of the thermoacoustic heat pump. The acoustic heat pump is expected to upgrade waste heat (50-120 °C) up to process heat of (130-200 °C). High temperature lift of 100 °C are expected. The system is made of relative simple components and is flexible in operation due to no phases involved. The medium used is helium, thus the system is environmently friendly. Furthermore, the system is expected to be economicall. The system is designed, built and tested. The heat pump was able to deliver 4 kW of thermal power at a temperature of 105 °C with a COP of 2.6 and a Carnot performance of 39%. Currently, there are prolems with acoustic losses, when fixed expected power is to go up to 10 kW. Next steps are: improving system performance, higher temperatures, devolpment of a 100 kW steam production TA system and on-site testing. More information available [here](https://hpc2017.org/wp-content/uploads/2017/06/o375.pdf) and [here](https://heatpumpingtechnologies.org/publications/o-3-7-5-development-of-a-thermoacoustic-heat-pump-for-distillation-column/). ***Specs:*** * Input media: air * Input temperature: 50-120 °C * Output media: air * Output temperature: 130-200 °C temperatures achieved of -39 °C as a cooler, 270 °C as a heater * Power Range: 4 kW when fixed 10 kW ***Applications:*** \-Distillation column

Suppliers

Sound Energy

Used for cold generation so far

Blue Heart Energy

The THEAC-25 convert solar heat or industrial waste heat directly into cold for building, utility or process cooling based on thermoacoustic energy conversion as underlying technology.

Thermoacoustic heat pump

5.1.1	Travelling wave thermoaccoustics
	Experimental Investigation on a Linear-compressor Driven Travelling-wave Thermoacoustic Heat Pump☆
	Abstract Heat pump system, offering economical alternatives in recovering waste heat from different sources for using in various industrial, commercial and residential applications, is considered to be a very environmentally-friendly heat and power transfer system. In this paper, to solve the problems of traditional vapour compression heat pump working in unconventional conditions, a novel TWTAHP (travelling-wave thermoacoustic heat pump) is presented to meet the requirement of working in ultra-low temperature. Base on the theoretical simulation and structure optimization, an experimental apparatus for preliminary test has been built, which is only one single independent unit from the whole loop of the TWTAHP system. The results show that the simulation and the testing results were agreeable as expected. Under the -20°C environment temperature and the 50°C heating temperature, we could obtain a maximal COP h (heating COP) of 2.1 and 260W heating capacity for one unit by consuming acoustic power less than 200W. Furthermore, a COP h above 3.0 could be achieved when the ambient temperature was raised to 0°C.
	08/01/2015 00:00:00
	Link to Article
5.1.2	Travelling wave thermoaccoustics
	Measurement of performance of thermoacoustic heat pump in a −3 to 160 °C temperature range
	A thermoacoustic heat pump was constructed and tested. It was composed of a looped tube, a straight tube, and a regenerator. The looped tube contained the regenerator and was connected to the straight tube. The tubes were filled with nitrogen. When an acoustic wave was input to the tubes, a temperature difference formed along the regenerator. Our experiments showed that this heat pump could work as both a cooler and a heater. This heat pump achieved ?39 ?C as a cooler and 270 ?C as a heater. Using antifreeze liquid and oil as heat media, the cooling and heating performance of the heat pump was measured within the temperature range from ?3 to 160 ?C.
	11/01/2015 00:00:00
	Link to Article
5.1.3	Travelling wave thermoaccoustics
	Study on Regenerator of a Novel Traveling-Wave Thermoacoustic Heat Pump Operating in Ultra-Low Temperature Air Environment
	In ultra-low air temperature environment,conventional heat pumps have several technical problems,such as high pressure ratio and low efficiency.To overcome the problems,a novel linear compressor driven double-acting traveling-wave thermoacoustic heat pump is studied in the paper. Through simulation and optimization,the influence of three kinds of regenerator fillers on the heat pump thermodynamic performance is revealed.The results show that a smaller wire diameter of the regenerator filler with higher porosity can lead to a higher thermodynamic efficiency.In addition,reducing the wire diameter can increase heat pump capacity.The results provide guidance for designing an efficient regenerator of the double-acting thermoacoustic heat pump operating in ultra-low ambient temperature region.
	01/01/2013 00:00:00
	Link to Article
5.1.4	Travelling wave thermoaccoustics
	Travelling-wave thermoacoustic high-temperature heat pump for industrial waste heat recovery
	Many industrial processes need steam at temperatures from 100 to 200 °C, normally produced by directly heating water via coal, natural gas or oil combustion. Nevertheless, large amounts of unused heat below 100 °C are wasted in other industrial processes. In principle, a high-temperature heat pump capable of using the industrial waste heat can provide steam above 100 °C. However, until now, efficient and reliable heat pump technology for the application is not available. In this paper, a novel TWTAHP (travelling-wave thermoacoustic heat pump) is presented to meet this requirement, which can potentially solve the problems occurring in conventional vapour-compression heat pump such as high discharge temperatures, high pressure ratio, and low efficiency. This system comprises three linear pressure wave generators which are coupled with three heat pumps into one single closed loop. Theoretically, this system is able to complete the thermoacoustic conversion with a much higher efficiency. The theoretical simulations were performed at varied waste-heat temperatures (40−70 °C) and different hot-end temperatures (120−150 °C). The computing results show that this new heat pump system has a high relative Carnot efficiency of about 50%–60%. In using a reliable linear compressor and a thermoacoustic heat pump with no-moving parts, this technology has an inherent potential for high reliability. Therefore, it is believed that the travelling-wave thermoacoustic heat pump is an enabling technology with good prospects in efficiently harvesting industrial waste heat.
	12/01/2014 00:00:00
	Link to Article

5.2 Thermoacoustic Stirling engine

A way to do this is by coupling a thermoacoustic engine with a thermoacoustic heat pump. The engine is driven by a burner and produces acoustic power and heat at the required temperature. The acoustic power is used to pump heat in the heat pump to the required temperature. This system is attractive since it uses a noble gas as a working medium and has no moving mechanical parts or sliding seals ***Summary of research results:*** * A prototype thermoacoustic heat pump working as a heater was demonstrated. The heat pump was composed of an acoustic driver, a branched tube, and a looped tube containing a regenerator; the looped tube was connected to the acoustic driver via the branched tube, and the regenerator consisted of many narrow flow channels. The measurement results of the acoustic impedance inside the looped tube indicated that the energy conversion of the acoustic power flow into the acoustic heat flow in the regenerator occurred through the inherently efficient Stirling cycle. Moreover, the heat pump generated a hot temperature of 370 °C, corresponding to a temperature lift along the regenerator of 340 °C Art. [#ARTNUM](#article-36630-1986616100). * The engine produces about 300 W of acoustic power with a performance of 41% of the Carnot performance at a hot air temperature of 620 °C. The performance of the engine can be improved by suppressing the heat leak down the thermal buffer tube and improving the HHX. A better solution might be to use a hot head instead of the HHX. The hothead with fins can be directly heated by the hot gases as usually done in conventional Stirling-engines. ***Specs:*** * Input media: air * Input temperature: ambient? * Output media: air * Output temperature: 340 -620 °C * Power range: 300 W

Torus part of the engine, schematic left and CAD drawing right

5.2.1	Thermoacoustic Stirling engine
	A hot air driven thermoacoustic-Stirling engine
	Abstract Significant energy savings can be obtained by implementing a thermally driven heat pump into industrial or domestic applications [1] . Such a thermally driven heat pump uses heat from a high-temperature source to drive the system which upgrades an abundantly available heat source (industrial waste heat, air, water, geothermal). A way to do this is by coupling a thermoacoustic engine with a thermoacoustic heat pump. The engine is driven by a burner and produces acoustic power and heat at the required temperature. The acoustic power is used to pump heat in the heat pump to the required temperature. This system is attractive since it uses a noble gas as working medium and has no moving mechanical parts or sliding seals. This paper deals with the first part of this system: the engine. In this study, hot air is used to simulate the flue gases originating from a gas burner. This is in contrast with a lot of other studies of thermoacoustic engines that use an electrical heater as heat source. Using hot air resembles to a larger extent the real world application. The engine produces about 300 W of acoustic power with a performance of 41% of the Carnot performance at a hot air temperature of 620 °C.
	11/01/2013 00:00:00
	Link to Article
5.2.2	Thermoacoustic Stirling engine
	Thermoacoustic Stirling Heat Pump Working as a Heater
	A prototype thermoacoustic heat pump working as a heater was demonstrated. The heat pump was composed of an acoustic driver, a branched tube, and a looped tube containing a regenerator; the looped tube was connected to the acoustic driver via the branched tube, and the regenerator consisted of many narrow flow channels. The measurement results of the acoustic impedance inside the looped tube indicated that the energy conversion of the acoustic power flow into the acoustic heat flow in the regenerator occurred through the inherently efficient Stirling cycle. Moreover, the heat pump generated a hot temperature of 370 °C, corresponding to a temperature lift along the regenerator of 340 °C.
	10/05/2011 00:00:00
	Link to Article

5.3 Cascade heat pumps

Most commercial and industrial facilities require very low temperatures for refrigeration and high temperatures for space heating and hot water purposes. Single-stage heat pumps have not been able to meet these temperature demands and have been characterized by low capacities and coefficient of performance (COP). Cascade heat pump has been developed to overcome the weaknesses of single-stage heat pumps. A real cascade system is a combination of two or more heat pumps (or refrigeration cycles), where the intermediate heat exchangers connect the cycles. A cascade offers the possibility of having a different working fluid in each cycle. Each fluid can be selected for optimum performance in the specified temperature range.\ The refrigerants selected should have suitable pressure-temperature characteristics. A frequent example of a refrigerant combination is the use of CO₂ in the low-temperature cascade and NH₃ or hydrofluorocarbon (HFC) refrigerants in the high-temperature cascade. The cascade circuits may also be built with a rack of parallel compressors for capacity modulation. This arrangement enables cycles to reach an extended operation range, e.g. high-temperature lifts between the heat source and sink ranging from −70 to +100 °C without any oil migration issues. On the other hand, the temperature difference in the cascade heat exchangers degrades the system performance, which is a major challenge in terms of energy efficiency. ***Summary of research results:*** * A high-temperature cascade heat pump (HTCHP) using a near azeotropic mixture named BY3 as the working fluid in the low-stage refrigerant cycle and R245fa as working fluid in the high-stage refrigerant cycle was proposed in this study. Several experiments were carried out to investigate the performance of the HTCHP at the evaporating temperature from 40 °C to 60 °C and the water outlet temperature on the condensing unit of the high-stage cycle can reach 142 °C with the coefficient of performance (COP) of 1.72. The results showed that BY3 was feasible to be used in the low-stage cycle. A numerical model of the HTCHP was proposed and validated in this study to evaluate its performance. The comparison between the experimental results and the simulated results showed that the HTCHP system using BY3 and R245fa can produce hot water at 142 °C with good performance and the temperature lift of the HTCHP can reach 100 °C (Art. [#ARTNUM](#article-33261-2806225887)). * The hot water with 70 °C enters from the inlet of a water pipeline and is split into two streams, one stream is cooled into normal temperature water with 20 DEG C through a ball valve 1 and the evaporator, and the other stream is heated into vapor at 120 °C through a ball valve 2 and a condenser. The provided high-temperature heat pump system can obtain the vapor with 120 °C by utilizing the hot water with 70 °C (Art.[#ARTNUM](#article-33261-2959761313) . ***Specs:*** * Input media: air * Input temperature: 34 °C * Output media: air * Output temperature up to 100 °C * Power range: N.C. ***Applications:*** * The cascades are commonly employed in supermarket refrigeration * High-temperature heat pumps for heat recovery or for gas liquefaction

Schematic of a cascade setup

5.3.1	Cascade heat pumps
	Cascade high temperature heat pump system
	The invention discloses a cascade high temperature heat pump system. The system includes a low temperature part, a high temperature part and a water pipeline part. A refrigerant of the low temperaturepart adopts R161, liquid R161 can absorb heat and evaporate in an evaporator, a compressor 2 can suck vapor generated in the evaporator and compress the vapor to condensation pressure, the liquid R161 can be obtained by sending the vapor an evaporative condenser to perform isobaric cooling, and the condensed R161 can enter the evaporator through a throttle valve 2; A refrigerant of the high temperature part adopt R123, liquid R123 can absorb heat and evaporate in the evaporator, R123 vapor enters a compressor 1 to perform pressurization, the liquid R123 can be obtained by performing isobariccooling on the R123 while the heat can be released to hot water with 70 DEG C, and the liquid R123 can enter the evaporative condenser through a throttle valve 1; and the hot water with 70 DEG C enters from the inlet of a water pipeline and is split into two streams, one stream is cooled into normal temperature water with 20 DEG C through a ball valve 1 and the evaporator, and the other stream isheated into vapor with 120 DEG C through a ball valve 2 and a condenser. The provided high temperature heat pump system can obtain the vapor with 120 DEG C by utilizing the hot water with 70 DEG C.
	01/01/2019 00:00:00
	Link to Article
5.3.2	Cascade heat pumps
	Design and experimental study of an air source heat pump for drying with dual modes of single stage and cascade cycle
	Abstract The heat pump drying system is a prospect technology for material drying due to its advantages of high efficiency and energy saving. This paper presents a design of an air source heat pump with dual modes for drying. The operation mode changes between a single stage and a cascade cycle to satisfy the heating demand under different ambient temperatures. A prototype of this dual-mode heat pump is developed using R22 and R134a as refrigerants. To verify the feasibility and to investigate the characteristics of this heat pump, an experimental study is carried out. According to the results of this study, the supplying air temperatures satisfied the drying demand (70 °C) when the heat pump operated at its design condition which is an ambient temperature of 0 °C for the cascade cycle and 20 °C for the single stage. With the increase of the ambient temperature, the supplying air temperature, heating capacity and electric power all increased at both operation modes. The difference of electric power between the two modes also increased with the ambient temperature, but the difference of supplying air temperature decreased. Although the variation of compressors’ pressure ratio was small within each mode, the pressure ratio of the high stage’s compressor changes a lot which was about 3.8 for the single stage and 5.5 for the cascade cycle. With the same supplying air temperature, the lines of coefficient of performance (COP) at different modes crossed each other. The COP of single stage was higher after an ambient temperature of 2 °C for the developed heat pump.
	01/01/2018 00:00:00
	Link to Article
5.3.3	Cascade heat pumps
	Performance analysis of a cascade high temperature heat pump using R245fa and BY-3 as working fluid
	Abstract A high temperature cascade heat pump (HTCHP) using a near-zeotropic mixture named BY-3 as the working fluid in the low-stage refrigerant cycle and R245fa as working fluid in the high-stage refrigerant cycle was proposed in this study. Several experiments were carried out to investigate the performance of the HTCHP at the evaporating temperature from 40 °C to 60 °C and the water outlet temperature on the condensing unit of the high-stage cycle can reach 142 °C with the coefficient of performance (COP) of 1.72. The results showed that BY-3 was feasible to be used in the low-stage cycle. A numerical model of the HTCHP was proposed and validated in this study to evaluate its performance. The comparison between the experimental results and the simulated results showed that the HTCHP system using BY-3 and R245fa can product hot water at 142 °C with good performance and the temperature lift of the HTCHP can reach 100 °C.
	07/01/2018 00:00:00
	Link to Article
5.3.4	Cascade heat pumps
	Research trend of cascade heat pumps
	Most commercial and industrial facilities require very low temperatures for refrigeration and high temperatures for space heating and hot water purposes. Single stage heat pumps have not been able to meet these temperature demands and have been characterized by low capacities and coefficient of performance (COP). Cascade heat pump has been developed to overcome the weaknesses of single stage heat pumps. This study reviews recent works done by researchers on cascade heat pumps for refrigeration, heating and hot water generation. Selection of suitable refrigerants to meet the pressure and temperature demands of each stage of the cascade heat pump has been discussed. Optimization of design parameters such as intermediate temperature (low stage condensing and high stage evaporating temperatures), and temperature difference in the cascade heat exchanger for optimum performance of the cascade heat pump has been reviewed. It was found that optimising each design parameter of the cascade heat pump is necessary for maximum system performance and this may improve the exergetic efficiency, especially of cascade refrigeration systems, by about 30.88%. Cascade heat pumps have wider range of application especially for artificial snow production, in the supermarkets, for natural gas liquefaction, in drying clothes and food and as heat recovery system. The performance of cascade heat pumps can be improved by 19% when coupled with other renewable energy sources for various real time applications. Also, there is the need for much research on refrigerant charge amount of cascade heat pumps, refrigerant-refrigerant heat exchangers to be used as cascade heat exchanger, cascade heat pumps for simultaneous cooling, heating and hot water generation and on the use of variable speed compressors and their control strategies in matching system capacity especially at part load conditions.
	11/01/2017 00:00:00
	Link to Article
5.3.5	Cascade heat pumps
	Thermodynamic analysis of a cascaded compression – Absorption heat pump and comparison with three classes of conventional heat pumps for the waste heat recovery
	Abstract In present study, a new heat pump named cascaded compression-absorption heat pump (CCAHP) is introduced, thermodynamically analyzed and compared with that three other classes of heat pumps (compression, absorption, and hybrid compression-absorption) with identical waste heat source. Ammonia-water solution is used in the absorption as well as hybrid systems and pure ammonia in the compression system. The simulations are performed in EES (Engineering Equation Solver) software. Low-grade heat is externally supplied to the systems and upgraded heat is transferred to a medium with high temperature. Comparison of the results shows that with increasing the temperature lifts, the PER (Primary energy ratio) and second law efficiency of the cascaded system reach to the values of these parameters of the compression system. Even at higher values of temperature lifts, that compression system cannot perform, cascaded system operates with higher values of PER and second law efficiency compared to those of hybrid compression-absorption system. Advantages of the proposed cascaded system are small value of compression ratio, maximum pressure and exit temperature of the compressor comparing to the other investigated cycles which extend the working domain of the cascaded system.
	01/01/2018 00:00:00
	Link to Article
5.3.6	Cascade heat pumps
	Transient behavior and dynamic performance of cascade heat pump water heater with thermal storage system
	At low ambient temperature, air-source heat pump water heater suffers from decrease of both heating capacity and coefficient of performance, and increase in compressor’s pressure ratio and discharge temperature. A cascade air-source heat pump water heater with phase change material (PCM) for thermal storage application was designed to ensure the reliable operation under various weather conditions and enhance the system performance at low ambient temperature. Dynamic experiments were carried out under various operating conditions in accordance with China National Standard GB/T23137-2008. Transient operating characteristics were adopted to analyze the performance of cascade heat pump system. Dynamic performance of the heat pump water heater in single stage mode and cascade mode was compared and discussed. The heating COP values in single stage mode ranged from 1.5 to 3.05, while in cascade mode, the heating COP values ranged from 1.74 to 2.55. Based on the transient heating COP values, critical switching curve from single stage mode to cascade mode was founded for the code of the system controller. Furthermore, energy performance between water tanks with and without PCM was compared to clarify the contribution of PCM.
	03/01/2012 00:00:00
	Link to Article

5.4 Two stage direct expansion solar assisted heat pump

Direct expansion solar-assisted heat pump (DX-SAHP) systems have been proposed as viable alternatives to conventional solar-assisted heat pump systems. This study proposes the use of two-stage DX-SAHP systems for high-temperature applications in the range of 60–90 °C. The thermal performance of the systems is analyzed for refrigerant R-134a, using a one-cover solar collector. More information available [here](https://reader.elsevier.com/reader/sd/pii/S1359431108004328?token=6AFBA14ED7C8556CE45D7326AC190CF4F0F72CFA95981D875279CD56A2F47092AA60AF0E22139F56C2284ECFDC48AAB6)

5.5 Mechanical vapor recompression

Conventionally in evaporators, the energy content is only used partly. Mechanical vapor recompression (MVR) allows continuous recycling of steam by recompressing the vapor to a higher pressure. This results in a high energy content steam which can be re-used again. Instead of generating live steam, electrical energy can be used indirectly to recycle steam. The system has the ability to have high efficiency and multiple stages are possible to generate a high-temperature lift. Relatively small amounts of electrical energy are required to compress the steam to useful process steam. The COP requires to be at least 3.5 for economical feasibility, but MVR systems are able to even prove COP values of higher than 10. There are several key elements which ensure a higher COP: * A low ratio of absolute steam pressure, a maximum ratio of 6 * A minimum capacity, at least 1 ton steam per hour * Water injection after compression ***Specs:*** * Input media: steam * Input temperature: highly pressure dependent * Output media: steam * Output temperature: up to 200 °C * Power range: up to 60 MW ***Applications:*** * Oil and gas * Utilities * Chemical * Mining/minerals * Metals * Pulp & paper * Food, beverage and agricultural products * Water treatment * Desalination * Pharmaceutical

Suppliers

Howden

EVATHERM

TLT-Turbo

France evaporation

Functional ranges of compressors for vapor recompression (GEA Wiegand)

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Scope Discover Demonstrate Develop Deploy

Current known technique(s) Air to air Water source Thermoaccoustic heat pumps Mechanical and thermal vapour recompression (MVR, TVR)) Absorption (compression) heat pump

Ideal outcome An overview of all the existing heat pumps with their specification and suppliers

Minimum viable outcome A list of all the existing heat pump technologies

Objective(s) Absolute temperature Delta T COP System dynamics Energy density Type of compression unit required Medium

Constraint(s) Capacity Power range Source temperature (°C) Sink temperature (°C) COP Additional Requirements

Terminology Sink / source

1. General construction and trends

1.1 Single-stage

1.2 Two stage compressor

1.3 Variable Capacity (Variable speed)

1.4 Transcritical CO2

1.5 Liquid dessicant

1.6 Regenerative silica gel rotor

1.7 Low Global Warming Potential refrigerant (To water)

1.8 Phase change materials

2. Air source (to air or to water)

2.1 Air to air (through fan)

2.2 Air to water distribution

2.3 Exhaust air recovery heat pumps (A/W)

2.4 Heat-pump water tank heater

2.5 Dehumidification - Drying

2.6 Vapour / Refrigerant injection

3. Water source open loops (including Geothermal)

3.1 Ground-water (Open loop system)

3.2 Standing column well systems (Open loop system)

3.3 Surface Water (open loop)

3.5 Waste water/heat recovery

3.6 Nanofuids

4. Soil and water source closed loops (Including geothermal)

4.1 Surface water (Closed loops)

4.2 Vertical Ground-coupled heat pumps (closed loop systen)

4.3 Horizontal Ground-coupled heat pumps

5. Multi-temperature heat pumps

5.1 Cascade heat pumps

5.2 Multistage compressor

5.3 Multi-Ejector

5.4 Multistage expansion valves

5.5 Secondary loop

5.6 Separated gas cooler

6. High Temperature applications

6.1 50 to 70°C

6.2 70 to 80°C

6.3 80 to 95°C

6.4 90 to 105°C

6.5 105 to 140°C

7. Hybrid

7.1 Solar assisted heat pump

7.2 Gas assisted heat pumps

7.3 Gas engine heat pumps

7.4 Hybrid heat pump systems with assisted cooling towers

7.5 Absorption combined heat pumps

1. Screw

1.1 R245fa

1.2 R134a/R245fa

1.3 R717

1.4 R744

2. Double screw

2.1 R717

2.2 R134a / r245fa

2.3 R718

2.4 R1233zd(E)

3. Piston

3.1 R245fa

3.2 R717

3.3 R744

3.4 R1234ze

3.5 R1336mzz-Z

3.6 R717/H₂O (Hybrid absorption/compression)

3.7 R600

4. Turbo / Centrifugal

4.1 R134a

4.2 R1234ze

4.3 R718

5. Others

5.1 Travelling wave thermoaccoustics

5.2 Thermoacoustic Stirling engine

5.3 Cascade heat pumps

5.4 Two stage direct expansion solar assisted heat pump

5.5 Mechanical vapor recompression

Scope

Current known technique(s)

Air to air

Water source

Thermoaccoustic heat pumps

Mechanical and thermal vapour recompression (MVR, TVR))

Absorption (compression) heat pump

Ideal outcome

An overview of all the existing heat pumps with their specification and suppliers

Minimum viable outcome

A list of all the existing heat pump technologies

Objective(s)

Absolute temperature

Delta T

COP

System dynamics

Energy density

Type of compression unit required

Medium

Constraint(s)

Capacity

Power range

Source temperature (°C)

Sink temperature (°C)

COP

Additional Requirements

Terminology

Sink / source