AN AIR CONDITIONING ASSEMBLY

Technical Field

The present invention relates to air conditioning apparatus and more particularly to air conditioning apparatus employing a thermal storage facility.

Background of the Invention

Most new and many older domestic dwellings, office buildings, commercial premises (such as hotels) and industrial buildings (such as a meat factory) require air conditioning and/or refrigeration. This air conditioning can use a large amount of energy especially on a hot summer afternoon when most of these air conditioners are operating at their limits. The sum of all these air conditioners places a massive peak load for electricity companies about twice the average daily peak. This peak load is a huge burden for the electricity generators and expensive infrastructure must be added to accommodate the load for only a small period of time.

Traditional air conditioning and refrigerant systems utilise a condensing unit to supply high pressure refrigerant to an evaporator coil that directly cools the air, water or coolant for the required application. Similarly, larger systems employ some form of chiller to provide chilled water or coolant to the fan coils that then provide cooling for the application. In both cases, the compressor and fans in the condensing unit and optional cooling tower use a large amount of energy (especially on a hot day) and without an energy storage mechanism, the system can only provide instantaneous cooling.

The major disadvantage is that when the system is under greatest load (such as a summer afternoon), it operates in the hottest ambient conditions and efficiency is dramatically reduced. The systems are also specified to meet the average peak heat load for any particular building. It is commonly known that the average peak load is exceeded for about 2 weeks each year and the air conditioning system struggles to keep up. Thermal storage systems are specified to meet the average loads and are well-suited to meet large peaks or transient loads. Electrical power sub stations require upgrading to meet increasing peak demands and this is a costly process. In some cases, these upgrades are not occurring for some time, so large air conditioning systems cannot operate at capacity during peak periods since the extra power is not available. If there is a power outage, then all cooling or heating is lost and there is no redundancy.

Thermal storage uses off-peak electricity to build a large amount of ice (or heat storage) at night that is then used to provide cooling (or heating) during the day effectively shifting the massive peak electrical load to off-peak periods. There are many

other benefits of the technology including improved energy efficiency (the system builds ice at night with much lower ambient conditions for improved heat rejection), able to specify smaller refrigeration systems (specified to meet average and not peak loads), built-in redundancy (only a pump needs to operate to provide refrigeration in an equipment breakdown or blackout), reduced greenhouse gas emissions (using less energy), reduced water consumption and no risk of legionnaires disease (closed system with no cooling towers required).

Current Thermal Storage systems are bulky, expensive and designed for large commercial applications. They are generally assembled on site and the infrastructure complexity and expense do not encourage the technology to be used in volume or for everyday applications such as domestic air conditioning. They are also designed to store energy only and do not operate to provide instantaneous cooling or heating.

Object of the Invention

It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages.

Summary of the Invention

There is disclosed herein an apparatus to cool a primary fluid, said apparatus including: a first heat exchanger means through which a compressed refrigerant is passed to provide for the removal of heat from the refrigerant; ^~ an expansion valve means through which the compressed refrigerant passes, from the first heat exchanger means, to cause expansion of the refrigerant; a second heat exchanger means, the second heat exchanger means being in communication with the valve means to receive the refrigerant therefrom to provide for the absoiption of heat by the refrigerant; a compressor means that receives the refrigerant from the second heat exchanger means and compresses the refrigerant and delivers the refrigerant to the first heat exchanger means; a thermal storage unit operatively associated with the second heat exchanger means and containing a working fluid, temperature of the working fluid being lowered by operation of the second heat exchanger means; a third heat exchanger means through which the primary fluid is to pass to be cooled, the third heat exchanger means being operatively associated with the thermal storage unit to be selectively cooled by circulation of the working fluid;

a cooling circuit operatively associated with the third heat exchanger means to selectively cool the third heat exchanger means by operation of the circuit; and wherein the third heat exchanger means is selectively cooled by operation of the first thermal storage unit and/or said circuit. Preferably, said cooling circuit is a second cooling circuit, and said apparatus includes a first cooling circuit operatively associated with the thermal storage unit and the third heat exchanger means to selectively cool the third heat exchanger means by circulation of the working fluid via the first circuit.

Preferably, the apparatus includes a fourth heat exchanger means, the fourth heat exchanger means being operatively associated with the thermal storage unit so as to be selectively cooled thereby and selectively coupleable to said third heat exchanger means to cool said third heat exchanger means by operation of said first circuit, and said third heat exchanger means is connected to said valve means and said compressor means by said second circuit and is cooled by selective operation thereof. Preferably, said second heat exchanger means is located in said thermal storage unit, and said apparatus includes a fourth heat exchanger means, the fourth heat exchanger means being located in said thermal storage unit to be cooled by said working fluid and coupled to said third heat exchanger means to be operated to selectively cool said third heat exchanger means, with said third heat exchanger means being connected to said valve means and said compressor means by said circuit to be selectively cooled by operation of said circuit.

Preferably, said circuit is a second circuit, and said apparatus includes a first circuit, the first circuit connecting said fourth heat exchanger means and said thermal storage unit between which the working fluid is circulated when said fourth heat exchanger means is to cool by said thermal storage unit.

Preferably, said fourth heat exchanger means is connected to said third heat exchanger means to provide for the flow of refrigerant therebetween when said fourth heat exchanger means is to cool said third heat exchanger means.

Preferably, said third heat exchanger means includes a first heat exchanger portion connected to said thermal storage unit by said first circuit so that upon operation of said first circuit said third heat exchanger means is cooled, and said third heat exchanger means includes a second heat exchanger portion connected to said valve means and said compressor means by said second circuit so that upon operation of said second circuit said third heat exchanger means is cooled. Preferably, said working fluid is water, and said second heat exchanger means is operable to produce ice for storage in said thermal storage unit.

Preferably, said apparatus includes a fourth heat exchanger means and an enclosure therefore, said fourth heat exchanger means being connected to said valve means and said compressor means by said second circuit to provide for the flow of the refrigerant therebetween to cool the fourth heat exchanger means, and said fourth heat exchanger means is connected to said thermal storage unit by said first circuit so that said working fluid can be circulated therebetween, and said enclosure is also connected to said third heat exchanger for the circulation therebetween of said working fluid with operation of said first circuit cooling said third heat exchanger means by circulation of the working fluid from said thermal storage unit through said third heat exchanger means, while operation of said second circuit by circulation of said working fluid between said enclosure and said third heat exchanger means cooling said third heat exchanger means.

Preferably, said second heat exchanger means is located in said thermal storage means and said apparatus includes a fourth heat exchanger means also located in said thermal storage means, said fourth heat exchanger means being connected to said valve means and said compressor means by said circuit, with said circuit being a second circuit, and said apparatus including a first circuit, said first circuit connecting said thermal storage unit and said third heat exchanger means for the circulation of the working fluid therebetween, with said third heat exchanger means being selectively cooled by operation of said first circuit, or operation of the first and second circuits.. Preferably, said working fluid is water, and said second heat exchanger means is operable to produce ice in said thermal storage unit.

Preferably, said working fluid is water and said second heat exchanger means is located in an enclosure, with said second heat exchanger means being operable to produce ice and said thermal storage unit is operatively associated with said enclosure to receive said ice, and said third heat exchanger means is connected to said thermal storage unit by said first circuit, and is connected to said enclosure by said second circuit, and said working fluid is circulated through said first circuit and/or said second circuit to cool said third heat exchanger means.

Preferably, said primary fluid is air and therefore said apparatus an airconditioning apparatus.

Brief Description of the Drawings

Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings wherein:

Figure 1 is a schematic diagram of an air conditioning system;

Figure 2 is a schematic diagram of a modification of the air conditioning system of Figure 1;

Figure 3 is a schematic diagram of a modification of the air conditioning system of Figure 2; and Figure 4 is a schematic diagram of a still further modification of the air conditioning system of Figure 1

Detailed Description of the Preferred Embodiments

In Figure 1 there is schematically depicted an apparatus to cool a fluid, in this embodiment the apparatus is an air conditioning apparatus 10. The air conditioning system 10 includes a compressor 11 that delivers a compressed refrigerant to a heat exchanger 12 that acts as a condenser. The refrigerant passing through the heat exchanger 12 has heat extracted from it typically by air passing through the heat exchanger 12. The refrigerant is then delivered to a throttling (expansion) valve 13 that provides for the delivery of an expanding refrigerant to a heat exchanger 14. The heat exchanger 14 then returns the expanded refrigerant to the compressor 11. The compressor 11 may be an electrically driven mechanical compressor or as another example thermal compressor powered by heat.

In this embodiment the heat exchanger 14 is located in a thermal storage unit 15. Typically the thermal storage unit 15 would contain a working fluid, which in this embodiment is water, having a temperature lowered by the heat exchanger 14. The compressor 11 is selectively operable by operation of the controller 16 to produce ice to be contained in the thermal storage unit 15. The heat exchanger 14 is connected to the throttling valve 13 by means of an operable valve 17 and a one-way valve 18, the oneway valve 18 restricting refrigerant to flow in the direction of the arrow 19. The valve 17 is operable to isolate the heat exchanger 14 and is controlled by the controller 16.

Also connected to the valve 13 and compressor 11 is a heat exchanger 20 contained in an enclosure 21. The heat exchanger 20 is connected to the valve 13 by an operable valve 22 and a pump 23. The valve 22 is operated by the controller 16 to isolate the heat exchanger 20. The system 10 further includes a heat exchanger 24 through which a primary fluid such as air is passed to be cooled by the heat exchanger 24. The heat exchanger 24 is also connected to the valve 13 and compressor 11 via an operable valve 25 and a oneway valve 26. In this regard the heat exchanger 20 is also connected to the compressor 11 via the valve 26.

The system 10 still further includes a first cooling circuit 27 including pipes 28 and 29 and a pump 30. The pipes 28 connect the thermal storage unit 15 and enclosure 21 so that operation of the pump 30 causes the working fluid (water) to circulate between the enclosure 21 to remove heat from the heat exchanger 20 and thermal storage unit 15. In an alternate embodiment, the heat exchanger 20 may be located in the enclosure 15 with the heat exchanger 14.

In operation of the above described apparatus 10, during off peak pricing of electricity the heat exchanger 24 is cooled by expanding refrigerant passing therethrough the valve 25, the valves 17 and 22 being closed so that the heat exchangers 14 and 20 are not operative. During off peak pricing of electricity, the valve 17 may also be opened so that the heat exchanger 14 cools the water in the thermal storage unit 15 to preferably make ice. During high pricing of electricity, the valve 25 can be closed together with the valve 17. The motor 30 is operated together with the pump 23 and the valve 22 opened. Accordingly refrigerant is circulated between the heat exchanger 20 and the heat exchanger 24, with that refrigerant being cooled by water circulated between the thermal storage unit 15 and the enclosure 21.

In the abovementioned alternative embodiment, the heat exchanger 20 would be directly cooled by the heat exchanger 14.

In the above described preferred embodiment, the heat exchanger 24 is cooled by operation of the first cooling circuit 27, or by operation of a second cooling circuit 33 including pipes 31 and 32 and valves 25 and 26.

In Figure 2 there is schematically depicted a modification of the apparatus 10. In this apparatus 10, the heat exchanger 24 includes a first heat exchanger portion 34 and a second heat exchanger portion 35. The circuit 27 is operatively associated with the heat exchanger portion 35 so that upon operation of the pump 30, water is circulated through the heat exchanger portion 35 to cool the heat exchanger 24 and therefore the air passing therethrough. The heat exchanger portion 34 receives compressed refrigerant via the second circuit 33. The circuit 33 includes pipes 31 and 32 and valves 25 and 26.

In operation of the embodiment of Figure 2, during low price electricity periods, the valve 17 is opened so that ice is produced in the thermal storage unit 15. This is done by opening the valve 17 so that expanding refrigerant passes through the heat exchanger 14. Valve 25 may also be opened so the expanded refrigerant passes through the heat exchanger portion 34 to cool the heat exchanger portion 34 to thereby cool air passing therethrough. During high cost electricity periods, the compressor 11 is inoperative but the pump 30 operated so that cooled water passes through the heat exchanger portion 35

to cool the heat exchanger 24 and therefore the air passing therethrough. Again the compressor 11 and valves 17 and 25 are operated by the controller 16.

In the embodiment of Figure 3, the apparatus 10 has the first circuit 27 including the pipes 28 and 29 and operable valves 44 and 45. The pump 30 takes water from the valve 44 and passes it through the heat exchanger 24 to cool the heat exchanger 24 by taking cold water from the thermal storage unit 15. The water is returned via the pipe 28.

The heat exchanger 50 is in an enclosure 36, with the heat exchanger 50 communicating with the valve 13 and compressor 11. In an alternate embodiment, the heat exchanger 50 is located in the enclosure 15. Cooled water contained in the enclosure 36 can be delivered to the heat exchanger 24 via operable valves 46 and 51 and the pump 30.

The heat exchanger 24 is connected to the valves 13 and heat exchanger 11 by means of pipes 47 and 48, and valves 25 and 26 that provide the second circuit 33. ,

In operation of the embodiment of Figure 3, during high priced electricity periods the heat exchanger 24 is cooled by operation of the circuit 27. The valves 44 and 45 are opened and the pump 30 operated while the valves 46 and 51 are closed. Water is circulated from the thermal storage unit 15 through the heat exchanger 24 and then returned to the thermal storage unit 15. During periods of low priced electricity, the valves 25 and/or 17 are opened so that cooled water and/or ice is produced in the thermal storage unit 15, and water contained in the enclosure 36 cooled by refrigerant being delivered to the heat exchanger 50. Note that one-way valves 18 and 26 restrict the refrigerant to flow in the direction of the arrows 49. The valves 44 and 45 would be closed and the pump 30 operated to circulate water from the enclosure 36 through the heat exchanger 24 to be returned to the enclosure 36 via the valve 46. If only the heat exchanger 14 is to be operated, the valve 17 is closed.

In the embodiment of Figure 4, the thermal storage unit 15 is spaced from the heat exchanger 14. The heat exchanger 14 is located in the enclosure 36 that receives water and can produce ice 37 to be delivered to and stored in the thermal storage unit 15. Water is also contained in the thermal storage unit 15. Extending from the thermal storage unit 15 are pipes 28 and 29 providing the circuit 27. The pipe 2S leads to an operable valve 38 as well as the pump 30 while the pipe 28 extends from an operable valve 39. The pipes 28 and 29 communicate with the heat exchanger 24, with the valves 38 and 39 opened and the pump 30 operated to circulate water from the thermal storage unit 15 through the heat exchanger 24 to cool the heat exchanger 24.

Extending from the enclosure 36 are pipes 40 and 41 providing the circuit 33.

The pipe 40 is connected to an operable valve 42 while the pipe 41 is connected to an operable valve 43. When the valves 42 and 43 are opened and the pump 30 operated, water from the enclosure 36 is pumped through the heat exchanger 24 to cool the heat exchanger 24.

In operation of the above described apparatus 10, during low priced electric periods, the heat exchanger 14 is operated to produce the ice 37 for delivery to the thermal storage unit 15 and may also be or alternatively used to produce cooled water to be circulated through the heat exchanger 24. When this occurs the valves 38 and 39 are closed and the valves 42 and 43 opened and the pump 30 operated. During high priced electricity periods, the valves 42 and 43 are closed and the valves 38 and 39 opened and again the pump 30 operated so that water from the thermal storage unit 15 is used to cool the heat exchanger 24.

In the above described preferred embodiments, the controller 16 is used to control and co-ordinate operation of the various operable valves as well as the compressor 11.

The above described preferred embodiments have the advantage of being able to use the thermal storage unit 15 during high priced periods (via use of the circuit 27), while during low priced periods the second circuit 33 is employed.