WO2008113121A1

WO2008113121A1 - A thermal transfer, recovery and management system

Info

Publication number: WO2008113121A1
Application number: PCT/AU2008/000384
Authority: WO
Inventors: Peter Milojkovic
Original assignee: L.P.E. Group Pty Ltd
Priority date: 2007-03-16
Filing date: 2008-03-17
Publication date: 2008-09-25

Abstract

The present invention relates to a highly efficient thermal transfer, recovery and management system adapted to provide, store and distribute hot energy, cold energy, and both hot and cold energy simultaneously. The system works on the basis of 'shifting' energy for a useful purpose. Where the system is used domestically, it can be used to provide hot water services to households, as well as hot and cold liquid for the purpose of air conditioning. The system is controlled so as to work at maximum efficiency, thereby providing significant energy and cost savings, particularly during times of peak energy demands.

Description

A thermal transfer, recovery and management system

The present invention relates to a thermal transfer, recovery and management system and, in particular, to a system which is capable of controllably producing, storing and distributing hot energy, cold energy, and both hot and cold energy simultaneously when required.

BACKGROUND OF THE INVENTION

Thermal transfer systems are systems which involve the transfer of hot or cold energy for a useful purpose. For example, a vapour-compression refrigeration cycle such as that which is used in conventional reverse cycle air-conditioners, is a type of thermal transfer system in that hot or cold energy is produced at any one time for a purpose, being the heating or cooling of an enclosed space.

In the case of domestic homes, for example, such a system comprises an outdoor unit including a compressor, condenser and expansion valve, and an indoor component in the form of an evaporator, for example, a fan coil unit inside the home. The compressor is used to compress and circulate gaseous refrigerant from the evaporator, and the condenser is then used to cool the hot and highly pressured gas to form a liquid. As the liquid passes through the expansion valve, it is de-pressurised to form a saturated vapour. Finally, when the cold refrigerant liquid-vapour mixture is passed through the indoor evaporator, air passing through the coils evaporates the refrigerant and a transfer of cold energy takes place, providing cold air to the inside of the building. Refrigerant is then pumped back to the compressor, and the cycle repeats itself. Such systems can also be reversed so as to provide heat energy, typically through the use of a reversing valve which reverses the direction of flow of refrigerant.

There is increasing recognition of the need for systems to "shift" energy for a useful purpose, both for environmental and financial reasons and the need to avoid excessive consumption of electricity during peak load demands, rather than systems which simply provide reduced energy consumption.

It is therefore an object of the present invention to provide a thermal transfer system which overcomes at least some of the aforementioned problems or provides the public with a useful alternative.

It is a further object of the present invention to provide a thermal transfer system which It is a still further object of the present invention to provide a heat transfer system capable of controllably producing, storing and distributing hot or cold energy.

It is a yet further object of the present invention to provide a thermal transfer system capable of controllably producing, storing and distributing both hot and cold energy simultaneously.

SUMMARY OF THE INVENTION

Therefore in one form of the invention there is proposed a thermal transfer system characterised by: a compressor; a heat exchanger operable as a condenser; a hot reservoir connected to said heat exchanger; a decompression means; an evaporator; and an energy distribution means connected to said hot reservoir; wherein refrigerant is passed through said compressor, heat exchanger, decompression means and evaporator in a closed loop cycle to thereby produce heat energy at said heat exchanger, said hot reservoir being configured to store said heat energy, and said distribution means being configured to distribute said heat energy.

Preferably said thermal transfer system further including a control means configured to operate said system to maintain the temperature of said hot reservoir at a predetermined temperature or between a predetermined temperature range.

In preference said hot reservoir is fed heated liquid from said heat exchanger at the top of the reservoir, thereby facilitating stratification inside the reservoir.

In preference said distribution means is in the form of a domestic hot water service, whereby mains water is fed upwardly through a coil inside said hot reservoir and thereby gradually heated to a temperature corresponding with the temperature of stratified water at the top of the hot reservoir.

Alternatively said distribution means is in the form of one or more air conditioning fan coil Preferably said hot reservoir is in the form of a hot liquid tank.

Preferably said hot liquid tank includes a temperature sensor, said control means being adapted to receive feedback from said temperature sensor and operate said system accordingly.

In preference said thermal transfer system further includes a second condenser located between said heat exchanger and said decompression means.

Preferably said second condenser is in the form of an outdoor air coil. Preferably said outdoor air coil includes a cooling fan.

Preferably said heat exchanger is a refrigerant-side to liquid-side plate heat exchanger.

In preference said decompression means is in the form of an expansion valve.

Preferably said hot reservoir includes a phase change material.

In preference said hot reservoir liquid is water, said water including a corrosion inhibitor.

In a further form of the invention there is proposed a thermal transfer system characterised by: a compressor; a condenser; a decompression means; a heat exchanger operable as an evaporator; a cold reservoir connected to said heat exchanger; and a distribution means connected to said cold reservoir; wherein refrigerant is passed through said compressor, condenser, decompression means and heat exchanger in a closed loop cycle to thereby produce cold energy at said heat exchanger, said cold reservoir being configured to store said cold energy, and said distribution means being configured to distribute said cold energy.

Preferably said thermal transfer system further including a control means configured to operate said system to maintain the temperature of said cold reservoir at a predetermined In preference said distribution means is in the form of one or more air conditioning fan coil units.

Preferably said cold reservoir is in the form of a cold liquid tank.

In preference said cold liquid tank includes a temperature sensor, said control means being adapted to receive feedback from said temperature sensor and operate said system accordingly.

Preferably said condenser is in the form of an outdoor air coil.

In preference said outdoor air coil includes a cooling fan.

Preferably said thermal transfer system further including a reversing valve connected between said compressor and said condenser.

In preference said reversing valve includes a first and second position, said first position routing said refrigerant to said condenser and said second position routing said refrigerant to the compressor.

In a yet further form of the invention there is proposed a thermal transfer system characterised by: a compressor; a first heat exchanger operable as a condenser; a hot reservoir connected to said first heat exchanger; a decompression means; a second heat exchanger operable as an evaporator; a cold reservoir connected to said second heat exchanger; a first distribution means connected to said hot reservoir; and a second distribution means connected to said cold reservoir; wherein refrigerant is passed through said compressor, first heat exchanger, decompression means and second heat exchanger in a closed loop cycle to thereby produce hot and cold energy simultaneously at said first and second heat exchangers respectively, said hot and cold reservoirs being configured to store respective hot and cold energy, and said first and second distribution means being configured to distribute said hot and cold energy. Preferably said thermal transfer system further including a control means configured to operate said system to maintain the temperature of said hot and cold reservoirs at a predetermined temperature or between a predetermined temperature range.

In preference said hot reservoir is fed heated liquid from said first heat exchanger at the top of the reservoir, thereby facilitating stratification inside the reservoir.

Preferably said distribution means is in the form of a domestic hot water service, whereby mains water is fed upwardly through a coil inside said hot reservoir and thereby gradually heated to a temperature corresponding with the temperature of stratified water at the top of the hot reservoir.

Alternatively said distribution means is in the form of one or more air conditioning fan coil units.

In preference said hot and cold reservoirs are in the form of hot and cold liquid tanks.

In preference said hot and cold liquid tanks include temperature sensors, said control means being adapted to receive feedback from said temperature sensors and operate said system accordingly.

Preferably said thermal transfer system further includes a second condenser located between said first heat exchanger and said decompression means.

In preference said second condenser is in the form of an outdoor air coil. Preferably said outdoor air coil includes a cooling fan.

Preferably said thermal transfer system further includes a reversing valve connected between said first heat exchanger and said second condenser.

In preference said reversing valve includes a first and second position, said first position routing said refrigerant to said second condenser and said second position routing said refrigerant to the first heat exchanger. Preferably said thermal transfer system is operable in a first, second or third mode of operation, said first mode producing cold energy, said second mode producing heat energy, and said third mode producing cold and heat energy simultaneously.

In preference said first and second heat exchangers are refrigerant-side to liquid-side plate heat exchangers.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several implementations of the invention and, together with the description, serve to explain the advantages and principles of the invention. In the drawings,

Figure 1 illustrates in perspective view one embodiment of the present invention, that is, a home utilising the thermal transfer system of the present invention to provide domestic hot water and reverse cycle air-conditioning;

Figure 2 illustrates schematically the thermal transfer system according to the embodiment of Figure 1 , in a first mode of operation;

Figure 3 illustrates schematically the thermal transfer system according to the embodiment of Figure 1 , in a second mode of operation;

Figure 4 illustrates schematically a 2-pipe circulation circuit between the hot and cold reservoirs and two fan coil units; and

Figure 5 illustrates an enlarged, cutaway perspective view of the hot water tank and its contents, forming part of the thermal transfer system embodied in Figures 1-3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description of the invention refers to the accompanying drawings. Although the description includes exemplary embodiments, other embodiments are possible, and changes may be made to the embodiments described without departing from the spirit and scope of the invention. Wherever possible, the same reference numbers will be used throughout the drawings and the following description to refer to the same and like parts. The present invention relates to a thermal transfer system 10 for the controlled production, storage and distribution of hot and/or cold energy. In the embodiment shown and described herein, the system 10 is used to supply hot and cold energy to a domestic house for the purpose of providing hot and cold water to fan coil units and to an underfloor heater/cooler, as well as for heating mains water supply to the house. It is however to be understood that this is shown by way of example only, and that the present invention is not intended to be limited to only providing hot and cold energy for these purposes.

For example, the hot and cold energy which is produced and stored could be provided to other distribution systems such as to assist existing refrigeration systems so that they operate more efficiently, pool and spa heating/cooling, and cool rooms and the like. Furthermore, both hot and cold energy need not be produced simultaneously, either one or the other could be produced at any one time depending on the user requirements. Further still, the liquid inside the hot and cold reservoirs need not be limited to water, but any other suitable liquid.

Turning now to the drawings, Figure 1 illustrates an embodiment of the present invention wherein the thermal transfer system 10 is used to provide hot and cold water, as required, to fan coil units 12 within spaces inside a house 14 to be air-conditioned, and to an underfloor heater/cooler 15, as well as providing domestic hot water services to the house 14, for example, to showers 16 and taps. The main components of the system, a heat pump unit 18, a hot water tank or hot reservoir 20, and a cold water tank or cold reservoir 22, are illustrated positioned alongside the house 14 where mains water is connected through pipe 23 to the hot water tank 20.

The thermal transfer system 10 comprises a heat pump side 24 and a heat load side 26, as shown in Figure 2. The heat pump side 24 includes components housed within the heat pump unit 18 including a compressor 28 and an outdoor air coil 30 which acts as a condenser. The outdoor air coil includes a fan 31 for cooling the coil 30 when required. Other heat pump unit components include an expansion valve 32, a receiver 34, and a gas-liquid separator 36 connected as illustrated in Figure 2. The function of each of these components, as well as their associated valve and pipe work is considered known and so will not be described in any further detail. The heat load side 26 includes the hot water reservoir 20, the cold water reservoir 22, the hot and cold water circulation systems 38 and 40 respectively, the associated pumps 42 and 44, and the at least one fan coil unit 12 for air-conditioning the indoor environment. The skilled addressee will appreciate that the thermal transfer system 10 includes a modified reverse cycle refrigeration system, with the addition of two plate heat exchangers 46 and 48 forming part of the hot and cold water circulation systems 38 and 40 respectively, as well as the hot and/or cold reservoirs 20 and 22. The skilled addressee would realise that plate heat exchanger 46 is operable as a condenser for heating liquid pumped from the bottom of the hot water tank 20 using pump 42, and plate heat exchanger 48 is operable as an evaporator for cooling liquid pumped from the top of the cold water tank 22 using pump 44. The liquid inside the tanks 20 and 22 is preferably, but not intended to be limited to, water. In preference, both heat exchangers 46 and 48 are housed inside the heat pump unit 18.

It is the addition of the heat exchangers 46 and 48, the hot and cold reservoirs 20 and

22, and a programmable controller for intelligently operating each of these components (described in further detail below), which ensures that hot and/or cold energy is not lost but rather shifted and stored for future use and/or immediately distributed.

A reversing valve 50 is connected to the heat exchanger discharge and includes first and second positions defining hot and cold modes of operation. In the first position shown in Figure 2, the system works in a cooling mode, that is, refrigerant (or other liquid) is routed to the outdoor air coil 30 which operates to reject heat. Therefore in this mode, the thermal transfer system 10 is operable to heat the hot liquid reservoir 20, to cool the cold liquid reservoir 22, or simultaneously heat and cool the respective reservoirs 20 and 22. In this way, little, if any, heat need be rejected through the outdoor air coil 30 and therefore, essentially, energy is "shifted" to the hot reservoir 20 with minimal waste. As already mentioned, in the embodiment shown, this heat is utilised to provide heated air and domestic hot water services. In other applications, the heat could be used for underfloor heating, pool or spa heating or any other heating requirements.

Referring now to figure 3, the heat pump system is shown in "reverse cycle" or heating mode. In this mode, the reversing valve 50 is in the second position whereby refrigerant (or other liquid) that has passed through heat exchanger 46 is routed through the second heat exchanger 48, from which it passes through the receiver 34, expansion valve 32 and then the outdoor air coil 30 before passing through the gas-liquid separator 36 before entering the intake of the compressor 28. In this "reverse cycle" mode, the refrigerant passes through the heat exchanger 48 with little or no heat transfer, the heat being extracted from outside through the outdoor air coil 30. Therefore, both domestic hot water and hot water for the fan coil units 12 is Turning now to the fan coil arrangement, each fan coil unit 12 is fed by hot liquid from the hot reservoir 20 and cold liquid from the cold reservoir 20 by respective hot and cold water recirculation systems. Each recirculation system includes a respective pump 52 and 54. It is to be understood that this 4-pipe circulation system is once again shown by way of example only, and that other arrangements could equally well be used. For example, the system could be set up with multiple independent circulation circuits. Figure 4 illustrates an example of a 2-pipe system 56.

Figure 6 illustrates the contents of the hot reservoir 20. As shown, mains liquid is fed into inlet 60 from the bottom of the tank up through coils 62 to the top of the tank and out through exit port 64 where it is then distributed to the relevant hot water service. Along the way, heat energy is transferred from the heated water (or other liquid) inside the tank 20 to the mains water. Water inside the tank remains hot because it is being fed liquid which has passed through heat exchanger 46. Heated water from the heat exchanger 46 enters the tank through inlet 66 at the top of the tank 20, and exits from the bottom exit port 68 at the bottom of the tank back to the heat exchanger 46. This results in stratified layers of water inside the tank, wherein the top layer is at a maximum temperature. This is important because as mains water is rises up the coil 62, it is gradually heated until it reached a designated peak temperature just before exiting the tank 20 through exit port 64. Two further inlet and exit ports 70 and 72 respectively are shown which correspond with the fan coil unit recirculation system.

Temperature sensors are also provided in each tank. Figure 7 shows a temperature sensor 74 extending through the lid 76 of the tank to a top layer of liquid. In having the sensor 74 positioned like so, an accurate reading is obtained because the stratified layer of liquid at the top of the tank is reflective of the liquid which exits the tank for subsequent use. The cold reservoir tank temperature sensor is not shown. Each temperature sensor is used to measure the temperature of liquid inside each reservoir on a continual basis, and in turn transmit that data back to the controller in the heat pump unit 18. The controller then operates the system accordingly, to maintain the hot and/or cold reservoirs at a required temperature or within a range of temperatures. The controller is also used to operate the outdoor air coil fan 31 based on feedback from the temperature sensors.

The programmable controller is therefore responsible for optimising system operation. In the case of domestic houses where the maximum allowed temperature for hot water services is typically 50 degrees Celcius, this maximum temperature threshold can be input into the the hot reservoir is maintained at this temperature, or at least between this temperature and a specified lower threshold temperature. The same applies to the cold reservoir.

The above described invention therefore provides a highly efficient thermal transfer system that is capable of providing, storing and distributing hot energy, cold energy, and both hot and cold energy simultaneously. For example, where the system is used domestically, it can be used to provide hot and cold energy to various distribution means in the house including the house hot water service, and fan coil units for air conditioning the house at maximum efficiency. A person skilled in the art would realise the potential energy and cost savings such a system may provide to a user, particularly during times of peak energy demands.

As mentioned, the present invention is not intended to be limited to the preferred embodiment described and may include additional features for specific user requirements. For example:

• the size and number of hot and cold reservoirs can be varied depending on the requirement for storage of energy for use in heating and cooling;

• the system can operate to minimise the condensation in the indoor fan coil units 12 by having the liquid within the fan coil units at a higher temperature than would otherwise be the case with a conventional refrigerant gas indoor evaporator;

• the system could also facilitate the use of a Phase Change Material (PCM) which would further increase the storage capacity of the tanks;

• the system could be utilised with a variable speed compressor, commonly referred to as an inverter compressor, to further increase system efficiency. The system also has the capacity to integrate chilled beams.

• various liquids could be used for both the hot and cold water circulation systems. However, preferably water will be used with an inhibitor added to prevent corrosion, ensuring long component life; and

• the system may allow for multiple fan cool units with a possibility of heating in one zone while cooling in another zone. Further advantages and improvements may very well be made to the present invention without deviating from its scope. Although the invention has been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope and spirit of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

In any claims that follow and in the summary of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprising" is used in the sense of "including", i.e. the features specified may be associated with further features in various embodiments of the invention.

Claims

CLAIMS:

1. A thermal transfer system characterised by: a compressor; a heat exchanger operable as a condenser; a hot reservoir connected to said heat exchanger; a decompression means; an evaporator; and an energy distribution means connected to said hot reservoir; wherein refrigerant is passed through said compressor, heat exchanger, decompression means and evaporator in a closed loop cycle to thereby produce heat energy at said heat exchanger, said hot reservoir being configured to store said heat energy, and said distribution means being configured to distribute said heat energy.

2. A thermal transfer system as characterised in claim 1 , said thermal transfer system further including a control means configured to operate said system to maintain the temperature of said hot reservoir at a predetermined temperature or between a predetermined temperature range.

3. A thermal transfer system as characterised in claim 1 or claim 2 wherein said hot reservoir is fed heated liquid from said heat exchanger at the top of the reservoir, thereby facilitating stratification inside the reservoir.

4. A thermal transfer system as characterised in claim 3 wherein said distribution means is in the form of a domestic hot water service, whereby mains water is fed upwardly through a coil inside said hot reservoir and thereby gradually heated to a temperature corresponding with the temperature of stratified water at the top of the hot reservoir.

5. A thermal transfer system as characterised in claim 3 wherein said distribution means is in the form of one or more air conditioning fan coil units.

6. A thermal transfer system as characterised in any one of the above claims wherein said hot reservoir is in the form of a hot liquid tank.

7. A thermal transfer system as characterised in claim 6 wherein said hot liquid tank includes a temperature sensor, said control means being adapted to receive feedback from said temperature sensor and operate said system accordingly.

8. A thermal transfer system as characterised in any one of the above claims, wherein said thermal transfer system further includes a second condenser located between said heat exchanger and said decompression means.

9. A thermal transfer system as characterised in claim 8 wherein said second condenser is in the form of an outdoor air coil.

10. A thermal transfer system as characterised in claim 9 wherein said outdoor air coil includes a cooling fan.

1 1. A thermal transfer system as characterised in any one of the above claims wherein said heat exchanger is a refrigerant-side to liquid-side plate heat exchanger,

12. A thermal transfer system as characterised in any one of the above claims wherein said decompression means is in the form of an expansion valve.

13. A thermal transfer system as characterised in any one of the above claims wherein said hot reservoir includes a phase change material.

14. A thermal transfer system as characterised in any one of the above claims wherein said hot reservoir liquid is water, said water including a corrosion inhibitor.

15. A thermal transfer system characterised by; a compressor; a condenser; a decompression means; a heat exchanger operable as an evaporator; a cold reservoir connected to said heat exchanger; and a distribution means connected to said cold reservoir; wherein refrigerant is passed through said compressor, condenser, decompression means and heat exchanger in a closed loop cycle to thereby produce cold energy at said heat exchanger, said cold reservoir being configured to store said cold energy, and said distribution means being configured to distribute said cold energy.

16. A thermal transfer system as characterised in claim 15, said thermal transfer system further including a control means configured to operate said system to maintain the temperature of said cold reservoir at a predetermined temperature or between a predetermined temperature range.

17. A thermal transfer system as characterised in claim 15 or claim 16 wherein said distribution means is in the form of one or more air conditioning fan coil units.

18. A therma! transfer system as characterised in any one of claims 15-17 wherein said cold reservoir is in the form of a cold liquid tank.

19. A thermal transfer system as characterised in claim 18 wherein said cold liquid tank includes a temperature sensor, said control means being adapted to receive feedback from said temperature sensor and operate said system accordingly.

20. A thermal transfer system as characterised in any one of claims 15-19, wherein said condenser is in the form of an outdoor air coil.

21. A thermal transfer system as characterised in claim 20 wherein said outdoor air coil includes a cooling fan.

22. A thermal transfer system as characterised in any one of claims 15-21, said thermal transfer system further including a reversing valve connected between said compressor and said condenser.

23. A thermal transfer system as characterised in claim 22 wherein said reversing valve includes a first and second position, said first position routing said refrigerant to said condenser and said second position routing said refrigerant to the compressor.

24. A thermal transfer system as characterised in any one of claims 15-23 wherein said heat exchanger is a refrigerant-side to liquid-side plate heat exchanger.

25. A thermal transfer system as characterised in any one of claims 15-24 wherein said decompression means is in the form of an expansion valve,

26. A thermal transfer system as characterised in any one of claims 15-25 wherein said cold reservoir includes a phase change material.

27. A thermal transfer system as characterised in any one of claims 15-26 wherein said cold reservoir liquid is water, said water including a corrosion inhibitor.

28. A thermal transfer system characterised by: a compressor; a first heat exchanger operable as a condenser; a hot reservoir connected to said first heat exchanger; a decompression means; a second heat exchanger operable as an evaporator; a cold reservoir connected to said second heat exchanger; a first distribution means connected to said hot reservoir; and a second distribution means connected to said cold reservoir; wherein refrigerant is passed through said compressor, first heat exchanger, decompression means and second heat exchanger in a closed loop cycle to thereby produce hot and cold ^■ energy simultaneously at said first and second heat exchangers respectively, said hot and cold reservoirs being configured to store respective hot and cold energy, and said first and second distribution means being configured to distribute said hot and cold energy.

29. A thermal transfer system as characterised in claim 28, said thermal transfer system further including a control means configured to operate said system to maintain the temperature of said hot and cold reservoirs at a predetermined temperature or between a predetermined temperature range.

30. A thermal transfer system as characterised in claim 28 or claim 29 wherein said hot reservoir is fed heated liquid from said first heat exchanger at the top of the reservoir, thereby facilitating stratification inside the reservoir.

31. A thermal transfer system as characterised in ciaim 30 wherein said distribution means is in the form of a domestic hot water service, whereby mains water is fed upwardly through a coil inside said hot .reservoir and thereby gradually heated to a temperature corresponding with the temperature of stratified water at the top of the hot reservoir.

32. A thermal transfer system as characterised in claim 28 or claim 29 wherein said distribution means is in the form of one or more air conditioning fan coil units.

33. A thermal transfer system as characterised in any one of claims 28-32 wherein said hot and cold reservoirs are .in the form of hot and coid liquid tanks.

34. A thermal transfer system as characterised in claim 33 wherein said hot and cold liquid tanKs include temperature sensors, said control means being adapted to receive feedback from said temperature sensors and operate said system accordingly.

35. A thermal transfer system as characterised in any one of claims 28-34 wherein said thermal transfer system further includes a second condenser located between said first heat exchanger and said decompression means.

36. A thermal transfer system as characterised in claim 35 wherein said second condenser is in the form of an outdoor air coil.

37. A thermal transfer system as characterised in claim 36 wherein said outdoor air coil includes a cooling fan.

38. A thermal transfer system as characterised in any one of claims 35-37, said thermal transfer system further includes a reversing valve connected between said first heat exchanger and said second condenser.

39. A thermal transfer system as characterised in claim 38 wherein said reversing valve includes a first and second position, said first position routing said refrigerant to said second condenser and said second position routing said refrigerant to the first heat exchanger.

40. A thermal transfer system as characterised in any one of claims 28-39 wherein said thermal transfer system is operable in a first, second or third mode of operation, said first mode producing cold energy, said second mode producing heat energy, and said third mode producing cold and heat energy simultaneously.

41. A thermal transfer system as characterised in any one of claims 28-40 wherein said first and second heat exchangers are refrigerant-side to liquid-side plate heat exchangers.

42. A thermal transfer system as characterised in any one of claims 28-41 Wherein said decompression means is in the form of an expansion valve.

43. A thermal transfer system as characterised in any one of claims 28-42 wherein said hot and cold reservoirs includes a phase change material.

44. A thermal transfer system as characterised in any one of claims 28-43 wherein liquid inside said hot and cold reservoirs is water, said water including a corrosion inhibitor.