GB2229804A

GB2229804A - Heat reclaiming system for an air conditioner unit

Info

Publication number: GB2229804A
Application number: GB9004331A
Authority: GB
Inventors: Wong Yoon Fah
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-03-04
Filing date: 1990-02-27
Publication date: 1990-10-03
Anticipated expiration: 2010-02-27
Also published as: GB9004331D0; GB2229804B

Abstract

An air conditioner unit comprises an evaporator coil (10), a hot water storage tank (3), and an auxiliary water tank (14). Water contained in tank (24) is heated by the hot refrigerant discharging from compressor (7) to a first condenser (11). Further condensation of the refrigerant is effected by a secondary condenser (15) located in tank (30). A temperature sensitive valve (16) is normally closed and preset to open when the water temperature in the vicinity of the secondary condenser (15) exceeds a certain temperature limit. Tank (30) is preferably not insulated and may have good metal to metal contact with secondary heat exchanger (15). The tank (14) may enclose the tank (3). Liquid refrigerant flowing out of the secondary condenser (15) passes through filter drier (6), expansion device (9), evaporator coil (10) and compressor suction line (22). Evaporator fan (8) discharges cold air into the air condition space. <IMAGE>

Description

COMBINATION HEAT RECLAIMING SYSTEM AND AIR CONDITIONER TECHNICAL FIELD The present innovation relates generally to a combination of heat reclaiming system and an air conditioning unit. More particularly, the innovation relates to reclaiming the normally wasted heat rejected by the air conditioner for the purpose of heating water while cooling the space.

BACKGROUND ART It is well known that in an air conditioning unit, considerable heat is generated during the compression of the system refrigerant, and this heat is dissipated to the atmosphere via an air-cooled or water-cooled condenser coil. The possibility of utilising this rejected heat for the purpose of heating water has long been recognised. Various devices and systems have been employed in an attempt to utilise this rejected heat and reference may be made to the zircon water heating unit" sold by Pacific Engineering Sdn. Bhd. and South Engineers Sdn. Bhd.

A typical approach used by Pacific Engineering Sdn.

Bhd. and South Engineers Sdn. Bhd. to recover the waste heat from an air conditioner is as shown in FIG. 1. It consists of an outdoor condensing unit 1, an indoor fan coil unit 2 and a hot water storage tank 3. The outdoor condensing unit 1 includes a condenser fan 4, a condenser coil 5, filter-drier 6 and a compressor 7.

The indoor fan coil unit 2 includes an evaporator fan 8, expansion device 9 and an evaporator coil 10. The hot water storage tank 3 includes a heat exchanger 11, a cold water inlet line 12 and a hot water delivery main 13. The above arrangement will produce hot water in the hot water storage tank 3, but to ensure proper condensation of the. hot refrigerant in the event that water in storage tank 3 gets too hot, condenser fan 4 and condenser coil 5 have to operate in series with heat exchanger 11.

Another approach as shown in FIG. 2, is to couple a hot water storage tank 3 complete with a heat exchanger 11 with a window mounted air conditioner. Similarly the existing air-cooled condenser system cannot be removed.

This is to ensure proper condensation of the hot refrigerant in the event that water in storage tank 3 gets too hot. In another approach, a water-cooled air conditioner is coupled with a hot water storage tank 3 together with a heat exchanger 11. Here the existing cooling tower system needs to operate in series with heat exchanger 11. Again this is to ensure proper condensation of the hot refrigerant in the event that the water in storage tank 3 gets too hot.

While the arrangements disclosed in these existing systems serve to utilise otherwise wasted energy, they require an air-cooled condenser system or cooling tower system to maintain efficient operation of the air conditioner. Another disadvantage of the existing systems is that compressor 7 and heat exchanger 11 are located very far apart which result in excessive heat loss due to the long travel distance of the superheated refrigerant from compressor 7 to heat exchanger 11.

SUMMARY OF INVENTION In view of the foregoing, the main object of the invention is a combination heat reclaiming system and air conditioner unit that can be employed to cool the air simultaneously with heating the water and yet eliminate the air cooled condenser or cooling tower systems required by the existing systems.

In accordance with with present invention, there is provided a combination heat reclaiming system and air conditioner unit comprising an evaporating unit comprising an expansion device evaporator fan and an evaporator coil, and a condensing unit comprising, in series, a compressor, a first heat exchanger located within a hot water storage tank and a second heat exchanger located within an auxiliary water tank which is provided with temperature control means.

In use, a refrigerator is circulated between the evaporating unit and the condensing unit such that heat is absorbed by the refrigerant in the evaporating unit and released in the condensing unit, condensation of the refrigerant in the first heat exchanger heats water held in the hot water storage tank. The water held in the auxiliary water tank is maintained at such a temperature so as to ensure substantially complete condensation of the refrigerant before it is re-circulated to the evaporator.

Preferably, the temperature control means comprises a temperature sensitive valve. The temperature sensitive valve may be set such that when the water in the auxiliary water tank exceeds a preset temperature, the valve opens to allow discharge of water from the auxiliary tank, the auxiliary tank being replenished by cold water.

Preferably, the auxiliary water tank is adapted to serve one or more cold water taps or valves. Water drawn from the auxiliary water tank to supply one or more cold water tape or valves is replaced in the tank by cold water. The resultant flow of water through the auxiliary tank helps to maintain the water in the auxiliary tank at a temperature sufficiently low to ensure complete condensation of the refrigerant whilst minimising the wastage of cooling water.

Preferably, the auxiliary water tank is not insulated and in good thermal contact with the second heat exchanger. This feature assists in the efficient dissipation of heat from the second heat exchanger Preferably, the auxiliary water tank encloses the hot water tank. Such an arrangement provides for a particularly compact condensing unit.

While this innovation relates to newly manufactured combination heat reclaiming system and air conditioner unit, another object of this innovation is also the conversion of the existing air conditoners which are still in service to provide heat reclaiming system simultaneously removing the air-cooled condenser or cooling tower systems, thereby saving some power expended by the condenser fan motor or cooling tower fan motor and condenser water pump.

These objects of the innovation are given only by way of example. Thus, other desirable objectives and advantages inherently achieved by the innovation may be apparent to those skilled in the art. Nonetheless, the scope of the innovation is to be limited only by the appended claim.

SPECIFIC EXAMPLE These and other objects and advantages of the innovation will become more apparent from the following detailed description of the innovation in reference to the accompanying drawings in which: FIG. 1 is a schematic view of a prior art energy recovery system for air-cooled split air conditioner.

FIG. 2 is another schematic view of a prior art energy recovery system for window mounted air conditioner.

FIG. 3 is a schematic view of a typical conventional air-cooled split air conditioner.

FIG. 4 is a schematic view of one embodiment of this innovation showing the air conditioning and water circuits.

FIG. 5 is a cross-sectional view of a hot water storage tank and an auxiliary water tank combined to form a single unit.

It should be understood that the present disclosure is considered to be an exemplification of the principles of the innovation, and is not intended to limit the innovation to this embodiment.

One embodiment of the innovation is shown in FIG. 4.

Same reference numerals are used in FIG. 4 to designate the parts that remain the same in FIG. 1. As can be seen from FIG. 4, the first change to be noted, relative to FIG. 1, is that an auxiliary water tank 14 complete with secondary heat exchanger 15 and temperature sensitive valve 16 have replaced the air cooled condenser system. Compressor 7 is now relocated at the hot water storage tank 3.

With reference to FIG. 4, a combination heat reclaiming system and air conditioner unit that can be employed to cool the air simultaneously vith heating the water and yet eliminate the air-cooled condenser system or cooling tower, includes a hot water storage tank 3, auxiliary water tank 14 and indoor fan coil unit 2.

The refrigeration circuit includes a compressor 7, compressor discharge line 17, heat exchanger 11, connecting line 18, secondary heat exchanger 15, connecting line 19, filter-drier 6, connecting line 20, expansion device 9, connecting line 21, evaporator coil 10 and compressor suction line 22. Evaporator fan 8 is driven by an electric motor discharging cold air into the air condition space. Appropriate openings are provided in chamber 23 to improve the cooling of compressor 7 by natural ventilation. The water circuit, as disclosed, consists of a hot water storage tank 3 and an auxiliary water tank 14.The water circuit in hot water storage tank 3 includes tank 24, thermal insulation 25, outer casing 26, incoming cold water line 12, hot water delivery main 13 and a drain outlet together with a drain valve (not shown) located at the lowest part of tank 24. If necessary, a standard pressure temperature relief valve 27, electric heating element 28 and thermostat 29 are provided in hot water storage tank 3. The water circuit in auxiliary water tank 14 includes tank 30, temperature sensitive valve 16, water drainage line 31, incoming cold water line 32 and water connecting line 33.

Preferably, ' heat exchanger 11 and secondary heat exchanger 15 are finned tube type of heat exchanger. It should be specifically noted, though, that many types of heat exchangers are well know in the art and may be used in lieu of the finned tube heat exchanger. For example, in some countries, the heating of water through refrigerant heat exchangers is governed by certain safety rules. In this case, a double wall protection type heat exchanger or spirally wound finned tube with safety tube and leak detector built-in type heat exchanger may be used in lieu of finned tube heat exchanger.

The expansion device 9 may be the usual capillary tube but if desired, other types of expansion devices may be used such as thermostatic expansion valve that is responsive to temperature or automatic expansion valve that is responsive to pressure.

The tanks 24 and 30 may comprise any of the conventional pressurised or non-pressurised vessels.

For example, the tanks 24 and 30 may be made of noncorrosive materials such as stainless steel, copper or the like or a hot dipped galvanised steel tank or may comprise a steel tank that is lined with some noncorrosive interior such as copper, glass or the like.

Tank 24 is surrounded by insulation and enclosed in an outer mild steel casing coated with a non-corrosive finishing paint or enclosed in fibre-glass casing or the like. Tank 30 is not insulated and normally expose to cool air or under shade away from sun ray. The tanks 24 and 30 may be cylindrically shaped although any other shape may be employed as desired depending upon the nature of the installation.

Temperature sensitive valve 16 may be electric, pneumatic, electronic powered or self-powered with built-in sensor or remote sensor or the like.

When the compressor 7 is energised to provide cooling to the room or enclosure, the refrigerant is compressed to superheated gas, passes through line 17 to heat exchanger 11 where thermal transfer between the superheated refrigerant gas in heat exchanger 11 and the water in tank 24 heats the water while condensing the refrigerant vapour. Refrigerant from heat exchanger 11 flows via line 18 to secondary heat exchanger 15 where further condensation of the refrigerant is effected by the water in tank 30. The refrigerant will be at the sub-cooled state when it leaves secondary heat exchanger 15. Liquid refrigerant leaving secondary heat exchanger 15, passes through line 19 to filterdrier 6, connecting line 20 to expansion device 9, passes through line 21 to evaporator coil 10.The evaporator fan 8 draws air past evaporator coil 10 to heat exchange with the cold liquid refrigerant and cause it to vaporise and cool the air. The vaporised refrigerant is then returned to the suction port of compressor 7 via line 22 to complete the refrigerant cycle.

The unheated, relatively cold water entering into the bottom area of tank 24 via line 12, makes this area relatively cold with respect to the upper portion of tank 24. The cold water in the vicinity of heat exchanger 11 is heated by superheated refrigerant flowing in heat exchanger 11, and hence by the normal convection phenomenon begins to move toward the upper portion of tank 24. The water already in the upper portion of tank 24 is displaced downwardly, travelling along the wall of tank 24. When this water reaches the bottom of tank 24, it moves inwardly toward heat exchanger 11 and begins the upward movement.

Hot water is delivered to the point of use from tank 24 through delivery main 13 when users open one or more taps or valves throughout the area served by the system. Make-up water for tank 24 is received through incoming cold water line 12, which typically would be connected to a suitable city water supply or pressurised water main or main water storage tank located above tank 24.

Although the hot water system can be operated without using an electric resistance heating element 28, it may be desirable to have heating element 28 located near the top of tank 24. Heating element 28 is responsive to thermostat 29 to energise the electric resistance heating element 28 when the water temperature at the upper portion of tank 24 drops to an undesirable low level due to the air conditioner system not able to accommodate the demand for hot water.

The secondary heat exchanger 15 is sized 80 that it is capable of satisfying the entire condensation needs of the air conditioning system, allowing the air conditioning system to operate independently of heat exchanger 11. This is to ensure proper condensation of the hot refrigerant vapour regardless of the changing water temperature in vicinity of heat exchanger 11. If secondary heat exchanger 15 is not provided for, under the condition where no hot water is withdrawn from tank 24 for a prolong period, the rising temperature of the water in tank 24 will approach the temperature of the refrigerant passing through heat exchanger 11. As a result, the hot refrigerant vapour could not be condensed properly and operation of the air conditioning system would be impaired or even stopped.

In the event that the water in tank : gets heated up, complete condensation of hot refrigerant flowing in secondary heat exchanger 15 cannot be accomplished. To solve this problem, a temperature sensitive valve 16 is connected in water drainage line 31. The temperature sensitive valve 16 is normally closed and is preset to open when the water temperature in vicinity of secondary heat exchanger 15 exceed the temperature limit where complete condensation of the hot refrigerant flowing in secondary heat exchanger 15 could not occurs. When temperature sensitive valve 16 senses a predetermined elevated water temperature, it will open and discharge the hot water in tank 30 through water drainage line 31 to a suitable drain.

Make-up cold water for tank 30 is received through incoming cold water line 32 causing the water temperature in the vicinity of secondary heat exchanger 15 to become cold and hence ensure complete condensation of hot refrigerant flowing through secondary heat exchanger 15. Incoming cold water line 32 would be typically connected to a suitable city water supply or pressurised water main or main water storage tank located above tank 30.

To reduce the wastage oi water discharging to the drain via conduit 31, tank 30 is connected with water connecting line 33 which serve one or more cold water taps or valves. When users open one or more water taps or valves throughout the area served by connecting line 33, make-up water for tank 30 is received through incoming cold water line 32 thereby maintaining the water in tank 30 at ambient temperature as long as the users open the taps or valves connected to conduit 33.

Furthermore tank 30 is not insulated and kept under shade away from sun ray thereby assist to dissipate some heat and cool any hot water present in tank 30. An additional feature to reduce the wastage of hot water discharging into the drain via conduit 31 is to provide good metal to metal contact between secondary heat exchanger 15 and tank 30 such as by welding. Tank 30 act as a heat sink to dissipate part of the heat from any hot refrigerant flowing through secondary heat exchanger 15.

FIG. 3 shows a typical conventional air-cooled split air conditioner. Same reference numerals are used in FIG. 3 to designate the parts that remain the same ivn FIG. 1 and thus will not be described in any further detail. The typical existing air-cooled split air conditioner FIG. 3 which are still in service can be readily converted into combination heat reclaiming system and air conditioner unit of this innovation in a relatively simple and inexpensive manner. Air-cooled split air conditioner of FIG. 3 can be converted into combination heat reclaiming system and air conditioner of FIG. 4 by removing outdoor condensing unit 1, installing hot water storage tank 3 complete with heat exchanger 11 and auxiliary water tank 14 complete with secondary heat exchanger 15.Compressor 7 is removed from existing outdoor condensing unit 1 and relocate compressor 7 to the bottom of hot water storage tank 3.

Lines 17, 18, 19, 20, 22 and filter-drier 6 are then connected to complete the refrigeration circuit.

Incoming cold water line 12, hot water delivery main 13 and a drain outlet together with a drain valve (not shown) are installed to complete the water circuit in hot water storage tank 3. If desired, a standard pressure temperature relief valve 27, electric resistance heating element 28 and thermostat 29 may be installed at the upper portion of tank 24. Incoming cold water line 32, water drainage line 31, temperature sensitive valve 16 and water connecting line 33 which serve one or more cold water taps or valves are installed to complete the water circuit in auxiliary water tank 14. Similarly, the conversion of existing window mounted air conditioners or water-cooled air conditioners to the combination heat reclaiming system and air conditioner of FIG. 4 can be easily attained with minimum alteration.

FIG. 5 shows another form of hot water storage tank 3 and auxiliary water tank 14 where they are combined to form a single unit. Same reference numerals are used in FIG. 5 to designate the parts that remain the same in FIG. 4. The combined unit of FIG. 5 comprises thermal insulation 25, tank shell 24 of hot water storage tank 3, inner tank shell 34 and outer tank shell 30 of auxiliary water tank 14. Appropriate openings are provided in chamber 23 to improve the cooling of compressor 7 by natural ventilation. Heat exchanger 11 is located inside tan-k 24 while secondary heat exchanger 15 is located in tank 30. Incoming cold water line 12 and hot water delivery main 13 are connected to tank 24 while incoming cold water line 32, water connecting line 33 and water drainage line 31 together with temperature sensitive valave 16 are connected to tank 30.Connecting lines 17, 18, 19 and 22 are refrigerant lines similar to that shown in FIG. 4.

While there has been illustrated and described what is at present to be preferred embodiment of the present innovation, it will be understood by those skilled in the art that various changes and modifications may be made and equivalents may be substituted for elements thereof without departing from the true scope of the innovation. Thus, a liquid accumulator may be added to suction line 22 in order to prevent liquid refrigerant flooding back to compressor 7. A liquid receiver may be added to line 18 or line 19 to cater for cooling load changes or when line 18 is excessively long. Hot water storage tank 3 and auxiliary water tank 14 may be combined to form a single unit as shown in FIG. 5. As an added protection, the air-cooled condenser system or cooling tower system may not be removed but act as standby by connecting in series after secondary heat exchanger 15. Therefore, it is intended that this innovation not be limited to the specific examples disclosed as the best mode contemplated for carrying out this innovation but that the innovation will include all embodiments falling in the scope of the appended claim.

Claims

I. A combination heat reclaiming system and air conditioner unit comprising an evaporating unit (1) comprising an expansion device (9), evaporating fan (8) and an evaporator coil (10), and a condensing unit compirsing, in series, a compressor (7), a first heat exchanger (11), located within a hot water storage tank (3) and a second heat exchanger (15) located within an auxiliary water tank (14) which is provided with temperature control means.
2. A combination heat reclaiming system and air conditioner unit according to claim l wherein the temperature control means comprises a temperature sensitive valve (16).
3. A combination heat reclaiming system and air conditioner unit according, to claim 1 or 2 wherein the auxiliary water tank (14) is adapted to serve or more cold water taps or valves.
4. A combination heat reclaiming system and air conditioner unit according to any one of claims l to 3 wherein the auxiliary water tank is not insulated an in good thermal contact with the second heat exchanger (15).
5. A combination heat reclaiming system and air conditioner unit according to any one of claims 1 to 4 wherein the auxiliary water tank (14) encloses the hot water storage tank (3).

5. A combination heat reclaiming system and air conditioner unit according to any one of claims 1 to 4 wherein the auxiliary water tank (14) encloses the hot water storage tank (3).

6. A combination heat reclaiming system and air conditioner unit substantially as described hereinabove with reference to Figure 4 or 5.

Amendments to the claims have been filed as follows 1. A combination heat reclaiming system and air conditioner unit comprising an evaporating unit (2) comprising an expansion device (9), evaporating fan (8) and an evaporator coil (10), and a condeflsing unit compirsing, in series, a compressor (7), a first heat exchanger (11), located within a hot water storage tank (3) and a second heat exchanger (15) located within an auxiliary water tank (14) which is provided with temperature control means.

2. A combination heat reclaiming system and air conditioner unit according to claim 1 wherein the temperature control means comprises a temperature sensitive valve (16).

3. A combination heat reclaiming system and air conditioner unit according to claim 1 or 2 wherein the auxiliary water tank (14) is adapted to serve or more cold water taps or valves.

4. A combination heat reclaiming system and air conditioner unit according to any one of claims 1 to 3 wherein the auxiliary water tank is not insulated and in good thermal contact with the second heat exchanger (15).