Central air conditioning and heat pump system with cooling arrangement

A central air conditioning and heat pump system includes a main heat exchange system and a cooling arrangement. The main heat exchange system includes a compressor, a first heat exchanger, a second heat exchanger. The cooling arrangement includes a cooling tower and a cooling heat exchanger. When the central air conditioning and heat pump system is selectively operated in a comprehensive air conditioning mode, refrigerant may be cooled both by water and ambient air in the cooling arrangement and the second heat exchanger respectively.

BACKGROUND OF THE PRESENT INVENTION

Field of Invention

The present invention relates to a central air conditioning and heat pump system which is capable of saving a substantial amount of energy when the central air conditioning and heat pump system is being operated in a heat pump mode.

Description of Related Arts

Conventional air conditioning and heat pump systems may be broadly divided into two main types. The first type is air conditioning and heat pump systems which are arranged to directly heat up or cool down the air of an indoor space. An example of the first type is window-type air conditioning and/or heat pump units, which controllably suck air from the indoor space and directly heat up or cool down the air. After the air has been heated or cooled, it is delivered back to the indoor space.

The second type is central air conditioning heat pump systems in which a heat exchange medium (usually water) may be used to heat up or cool down the air in the indoor space. Referring toFIG.1toFIG.5of the drawings, the central air conditioning and heat pump system comprises a main heat exchange system10P and a heat delivery system20P. The main heat exchange system10P comprises an outer casing11P, a compressor12P, at least one heat exchanger13P, a gas-liquid heat exchanging device14P, and a fan assembly15P. The main heat exchange system10P is usually installed on a roof of a building so that it may absorb heat from or discharge heat to ambient air. A predetermined amount of refrigerant may circulate through the compressor12P, the heat exchanger13P, the gas-liquid heat exchanging device14P and other components for carrying out several heat exchanging processes.

On the other hand, the heat delivery system20P comprises a water pump21P and a water pipeline system22P connected to the water pump21P. The water pipeline system22P is configured to transport water to different designated indoor spaces in the building. The water circulating in the heat delivery system20P is arranged to perform heat exchange with the refrigerant in the gas-liquid heat exchanging device14P of the main heat exchange system10P. Furthermore, the heat delivery system20P may further comprise a fresh air supplying device23P connected to the water pipeline system22P. As shown inFIG.5of the drawings, the fresh air supplying device23P usually comprises a supporting frame231P, a centrifugal fan232P received in the supporting frame231P, and a fresh air heat exchanger233P also received in the supporting frame231P. The supporting frame231P has an air inlet2311P, wherein ambient air may be drawn into the fresh air supplying device23P through the air inlet2311P.

The refrigerant circulating in the main heat exchange system10is arranged to absorb heat from ambient air and release heat to the water circulating through the gas-liquid heat exchanging device14P. The water having absorbed heat from the refrigerant is then pumped to various terminal devices such as the fresh air supplying device23P. The purpose of the terminal devices is to regulate and ventilate air to and from a designated indoor space. Within a heat delivery system20P, there may exist a number of terminal devices which may include the above-mentioned fresh air supplying device23P, or other air handlers.

The water delivered to the fresh air supplying device23P is arranged to carry out heat exchange with the ambient air in the fresh air heat exchanger233P. The water is arranged to release heat to the air. The heated air may be transported to the designated indoor space for supplying fresh air to the indoor environment. The heating of the ambient air is essential because the temperature of the ambient air is usually very low and that is the very reason why the central air conditioning heat pump system is used to generate heat in the indoor space.

Although the above-mentioned air conditioning and heat pump systems have widely been utilized around the world for many years, these systems suffer a common deficiency of a relatively low Coefficient of Performance (COP), which may be defined as a ratio of heat supplied to or removed from a reservoir to the work required.

Accordingly, there is a need to develop an air conditioning and heat pump system which has substantially improved COP.

SUMMARY OF THE PRESENT INVENTION

Certain variations of the present invention provide an air conditioning and heat pump system which is capable of saving a substantial amount of energy when the air conditioning and heat pump system is being operated.

Certain variations of the present invention provide an air conditioning and heat pump system which may selectively utilize cooling water in a cooling tower to cool down the temperature of the refrigerant when the air conditioning and heat pump system is being operated in a comprehensive air conditioning mode.

Certain variations of the present invention provide an air conditioning and heat pump system which may allow refrigerant to be cooled by either heat exchangers (air-cooled) or a cooling tower (water-cooled), or both.

Certain variations of the present invention provide an air conditioning and heat pump system which is capable of producing more heat to designated indoor space for a given work done by the system as compared with conventional air conditioning and heat pump system as described above.

In one aspect of the present invention, the present invention provides a central air conditioning and heat pump system for a heat distribution system, comprising:a plurality of connecting pipes;a main heat exchange system, which comprises:a compressor having a compressor outlet and a compressor inlet;a first heat exchanger connected to the compressor through at least one of the connecting pipes; anda second heat exchanger connected to the compressor and the first heat exchanger through at least one of the connecting pipes;a refrigerant storage tank; anda cooling arrangement, which comprises:a cooling tower, which comprises:a tower casing having a cooling tower air inlet and a cooling tower air outlet;a fan provided in a vicinity of the cooling tower air outlet;a water storage tank provided in the tower casing for storing a predetermined amount of cooling water;a water distributor provided in the tower casing and connected to the water storage tank through at least one of the connecting pipes, the water distributor comprising at least one spraying head arranged to spray water at a predetermined direction,a pump connected between the water storage tank and the water distributor so that the cooling water in the water storage tank is arranged to be pumped to the water distributor through the pump; anda cooling heat exchanger provided in the tower casing and connected to the second heat exchanger, the first heat exchanger, and the refrigerant storage tank through at least one of the connecting pipes, the water distributor being arranged to spray the cooling water on the cooling heat exchanger so that refrigerant passing through the cooling heat exchanger is allowed to perform heat exchange with the cooling water;the air conditioning and heat pump system being selectively operated between a comprehensive air conditioning mode and a heat pump mode, wherein in the comprehensive air conditioning mode, a predetermined amount of vaporous refrigerant is arranged to leave the compressor and guided to enter the second heat exchanger for releasing heat thereto, the refrigerant leaving the second heat exchanger being guided to flow into the cooling heat exchanger for further releasing a predetermined amount of heat to the water circulating in the cooling arrangement, the refrigerant leaving the cooling heat exchanger being guided to flow through the first heat exchanger for absorbing heat from the heat distribution system, the refrigerant leaving the first heat exchanger being guided to flow back to the compressor to complete an air conditioning cycle,wherein in the heat pump mode, a predetermined amount of vaporous refrigerant is arranged to leave the compressor and guided to flow into the first heat exchanger for releasing heat to the heat distribution system, the refrigerant leaving the first heat exchanger being guided to flow into the refrigerant storage tank for being temporarily stored, the refrigerant leaving the refrigerant storage tank being guided to flow to the second heat exchanger for absorbing heat from ambient air, the refrigerant leaving the second heat exchanger being guided to flow back to the compressor to complete a heat pump cycle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The following detailed description of the preferred embodiment is the preferred mode of carrying out the invention. The description is not to be taken in any limiting sense. It is presented for the purpose of illustrating the general principles of the present invention.

It should be appreciated that the terms “install”, “connect”, “couple”, and “mount” in the following description refer to the connecting relationship in the accompanying drawings for easy understanding of the present invention. For example, the connection can refer to permanent connection or detachable connection. Furthermore, “connected” may also mean direct connection or indirect connection, or connection through other auxiliary components. Therefore, the above terms should not be an actual connection limitation of the elements of the present invention.

It should be appreciated that the terms “length”, “width”, “top”, “bottom”, “front”, “rear”, “left”, “right”, vertical“, “horizontal”, “upper”, “lower”, “exterior”, and “interior” in the following description refer to the orientation or positioning relationship in the accompanying drawings for easy understanding of the present invention without limiting the actual location or orientation of the present invention. Therefore, the above terms should not be an actual location limitation of the elements of the present invention.

It should be appreciated that the terms “first”, “second”, “one”, “a”, and “an” in the following description refer to “at least one” or “one or more” in the embodiment.

In particular, the term “a” in one embodiment may refer to “one” while in another embodiment may refer to “more than one”. Therefore, the above terms should not be an actual numerical limitation of the elements of the present invention.

Referring toFIG.6toFIG.8of the drawings, a central air conditioning and heat pump system according to a first preferred embodiment of the present invention is illustrated. Broadly, the central air conditioning and heat pump system may comprise a plurality of connecting pipes1, a main heat exchange system2, and a cooling arrangement3. A predetermined amount of refrigerant may circulate through the various components (described below) of the main heat exchange system2, while a predetermined amount of water may circulate through various components (described below) of the cooling arrangement3. The refrigerant and the water may circulate through the various components through a plurality of connecting pipes1.

The main heat exchange system2may comprise a main casing201, a compressor202, a first heat exchanger203, a second heat exchanger204. The cooling arrangement3may comprise a cooling tower31, a cooling heat exchanger32supported in the cooling tower31, and a pump33connected to the cooling tower31.

The compressor202is supported in the main casing201, and may have a compressor outlet207and a compressor inlet208. The first heat exchanger203may be supported in the main casing201and connected to the compressor202through at least one of the connecting pipes1. The second heat exchanger204may be supported in the main casing201and connected to the compressor202and the first heat exchanger203through at least one of the connecting pipes1.

The cooling tower31of the cooling arrangement3may comprise a tower casing311having a cooling tower air inlet3111and a cooling tower air outlet3112, a water storage tank312provided at a bottom portion of the tower casing311for storing a predetermined amount of cooling water, a water distributor313, and a fan314.

The water distributor313may be provided at an upper portion of the tower casing311, and at a position underneath the fan314. The water distributor313may comprise at least one water spraying head3131which may be arranged to spray water at a predetermined direction. In the preferred embodiment of the present invention, the water distributor313may be configured to spray water on the cooling heat exchanger32. Accordingly, the cooling heat exchanger32may be provided in the tower casing311at a position underneath the water distributor313.

The fan314may be provided in the tower casing311for drawing air to flow from the cooling tower air inlet3111to the cooling tower air outlet3112. The cooling water collected in the water storage tank312may be arranged to be pumped back to the water distributor313for being reused. At the same time, a predetermined amount of air may be drawn from the cooling tower air inlet3111for performing heat exchange with the cooling water flowing through the cooling heat exchanger32for lowering a temperature of the cooling water so that the cooling water may be reused for another cooling cycle. The air having absorbed the heat from the cooling water may be discharged out of the tower casing311through the cooling tower air outlet3112.

The central air conditioning and heat pump system may be selectively operated between a comprehensive air conditioning mode and a heat pump mode. In the comprehensive air conditioning mode, a predetermined amount of vaporous refrigerant is arranged to leave the compressor202and guided to enter the second heat exchanger204for releasing heat thereto. The refrigerant leaving the second heat exchanger204may be guided to flow into the cooling heat exchanger32for further releasing a predetermined amount of heat to the cooling water circulating in the cooling tower31. The refrigerant leaving the cooling heat exchanger32may be guided to flow through the first heat exchanger203for absorbing heat from a heat distribution system connected to a designated indoor space. The refrigerant leaving the first heat exchanger203may be guided to flow back to the compressor202to complete an air conditioning cycle.

When the central air conditioning and heat pump system is in the heat pump mode, a predetermined amount of vaporous refrigerant may be arranged to leave the compressor202and guided to flow into the first heat exchanger203for releasing heat to the heat distribution system connected to a designated indoor space. The refrigerant leaving the first heat exchanger203may be guided to flow into the second heat exchanger204for absorbing heat from the ambient air. The refrigerant leaving the second heat exchanger204may be guided to flow back to the compressor202to complete a heat pump cycle.

According to the preferred embodiment of the present invention, the main casing201of the main heat exchange system2may be installed on the roof of a building. The central air conditioning and heat pump system of the present invention may be arranged to selectively provide air conditioning and heating to designated indoor spaces in the building. The main casing201may have an air cooling compartment223. The tower casing311of the cooling tower31may be connected to the main casing201. The main casing201and the tower casing311may be separated by a partition225. As shown inFIG.7of the drawings, the compressor202, the first heat exchanger203, the second heat exchanger204may be supported in the air cooling compartment223of the main casing201.

The compressor202may be configured to pressurize the refrigerant flowing therethrough. It forms a starting point of refrigerant circulation for a typical air conditioning cycle or a heat pump cycle.

The first heat exchanger203may have a first communicating port226and a second communicating port227, and may be configured to perform heat exchange between the refrigerant and another working fluid such as water. The first heat exchanger203may be configured to act as an evaporator (i.e. converting the refrigerant into gaseous or vaporous state) when the central air conditioning and heat pump system is operated in the comprehensive air conditioning mode. In the preferred embodiment, the first heat exchanger203may be configured to allow heat exchange between the refrigerant and a heat distribution system so as to extract heat from a designated space. The heat so extracted is to be absorbed by the refrigerant which will be heated and turned into vaporous or gaseous state. The first communicating port226and the second communicating port227may form as an inlet or outlet for the refrigerant passing through the first heat exchanger203.

Moreover, the first heat exchanger203may further have a third communicating port228and a fourth communicating port229. The third communicating port228and the fourth communicating port229may be connected to the heat distribution system and serve as an inlet and an outlet for the refrigerant or water circulating through the heat distribution system respectively.

The first heat exchanger203may be configured to act as a condenser (i.e. converting the refrigerant into liquid state) when the air conditioning and heat pump system is operated in the heat pump mode. Thus, the first heat exchanger203may be configured to allow heat exchange between the refrigerant and the water or refrigerant flowing through the heat distribution system so as to extract heat from the refrigerant. The heat so extracted is to be absorbed and distributed by the heat distribution system.

The central air conditioning and heat pump system may comprise two second heat exchangers204connected in parallel. Each of the second heat exchanger204may have a first passage port230and a second passage port231, and may be configured to perform heat exchange between the refrigerant and another working fluid such as air. The second heat exchangers204may be configured to act as a condenser (i.e. converting the refrigerant into liquid state) when the air conditioning and heat pump system is operated in the comprehensive air conditioning mode. In the preferred embodiment, the second heat exchangers204may be configured to allow heat exchange between the refrigerant and the ambient air drawn by a fan24so as to extract heat from the refrigerant. Each of the first passage ports230and the second passage ports231may form as an inlet or an outlet for the refrigerant passing through the corresponding second heat exchanger204. The two second heat exchangers204may be structurally identical. The fan24may be supported by the main casing201, as shown inFIG.6of the drawings.

The second heat exchanger204may be configured to act as an evaporator (i.e. converting the refrigerant into vaporous or gaseous state) when the air conditioning and heat pump system is operated in the heat pump mode. Thus, the second heat exchanger204may be configured to allow heat exchange between the refrigerant and the ambient air so as to absorb heat from the ambient air.

The main heat exchange system2may further comprise a refrigerant storage tank25having a liquid inlet251and a liquid outlet252, wherein the refrigerant storage tank25may be connected to the first heat exchanger203, the second heat exchangers204, and the cooling arrangement3. The refrigerant storage tank25may be configured to temporarily store refrigerant at a predetermined pressure.

It is important to note that the compressor202, the first heat exchanger203and the second heat exchangers204of the main heat exchange system2and the cooling arrangement3may be arranged and connected through a plurality of connecting pipes1in certain configurations. An exemplary configuration is shown inFIG.8of the drawings.

The main heat exchange system2may further comprise a switching device232connecting between the first heat exchanger203and the second heat exchanger204for altering a flowing path of the refrigerant. Specifically, the switching device232may comprise a communicative valve233having first through fourth connecting port2331,2332,2333,2334. The communicative valve233may be switched between an air conditioning switching mode and a heat pump switching mode, wherein in the air conditioning switching mode, the communicative valve233is switched such that the first connecting port2331may be connected to the second connecting port2332so that refrigerant may flow from the first connecting port2331to the second connecting port2332, while the third connecting port2333may be connected to the fourth connecting port2334so that refrigerant may flow from the third first connecting port2333to the fourth connecting port2334.

In the heat pump switching mode, the communicative valve233may be switched so that the first connecting port2331may be connected to the fourth connecting port2334so that refrigerant may flow from the first connecting port2331to the fourth connecting port2334, while the second connecting port2332may be connected to the third connecting port2333, so that refrigerant may flow from the second connecting port2332to the third connecting port2333.

As shown inFIG.8of the drawings, the first connecting port2331may be connected to the compressor outlet207of the compressor202. The second connecting port2332may be connected to the second passage ports231of the second heat exchangers204. The third connecting port2333may be connected to the cooling heat exchanger32, the first heat exchanger203, the refrigerant storage tank25, and the second heat exchanger204through several auxiliary components (described below). The fourth connecting port2334may be connected to the second communicating port227of the first heat exchanger203.

The cooling heat exchanger32may have a cooling inlet321and a cooling outlet322. Refrigerant may be guided to flow into the cooling heat exchanger32through the cooling inlet321, and flow out of the cooling heat exchanger32through the cooling outlet322. The second heat exchangers204may be connected to the cooling heat exchanger32, the first heat exchanger203, and the refrigerant storage tank25through several other components. For the sake of clarity, the refrigerant passing through the first passage ports230may either flow through or come from Path1, or flow to Path2as shown inFIG.8. Path2may connect the first passage ports230to the cooling inlet321of the cooling heat exchanger32, so that refrigerant leaving the first passage ports230may be guided to flow toward the cooling inlet321of the cooling heat exchanger32through Path2.

Path1may be bifurcated into Path3and Path4. The refrigerant flowing from the first passage ports230may enter Path1and may be directed to Path3shown inFIG.8of the drawings. Path3may direct refrigerant to flow into the refrigerant storage tank25through the liquid inlet251. Path4may connect Path1to the liquid outlet252of the refrigerant storage tank25, so that refrigerant coming from the liquid outlet252may flow through Path4and reach Path1.

The main heat exchange system2may further comprise a first unidirectional valve236connected between the first passage ports230of the second heat exchangers204and the first communicating port226of the first heat exchanger203. Specifically, the first unidirectional valve236may be connected in Path4and may be configured to restrict the flow of refrigerant in one predetermined direction. In this preferred embodiment, the first unidirectional valve236may be configured to allow refrigerant to flow only in a direction from the liquid outlet252of the refrigerant storage tank25toward the first passage ports230of the second heat exchangers204through Path4and Path1.

The main heat exchange system2may further comprise a filter238connected to the liquid outlet252of the refrigerant storage tank25in Path4. The filter238may be configured to filter unwanted substances from the refrigerant which pass through them. The refrigerant coming out from the liquid outlet252may sequentially pass through the filter238in Path4and Path1and eventually reach the first passage ports230of the second heat exchangers204.

The main heat exchange system2may further comprise an expansion valve239connected to the filter238in Path4. The expansion valve239may be configured to control and regulate the flow of the refrigerant passing through them. Thus, the refrigerant passing through Path4may be guided to flow through the filter238and the expansion valve239.

On the other hand, refrigerant coming out from the cooling outlet322of the cooling heat exchanger32may enter either Path5or Path6. This may be illustrated inFIG.8of the drawings. The main heat exchange system2may further comprise a second unidirectional valve237connected to the cooling outlet322and the liquid inlet251of the refrigerant storage tank25in Path5. The second unidirectional valve237may be configured to allow flow of refrigerant only in a direction from the cooling outlet322toward the liquid inlet251through Path5.

The main heat exchange system2may further comprise a first electrically-operated two-way valve27connected to the cooling outlet322and the third connecting port2333in Path6. The first electrically-operated two-way valve27may be selectively opened or closed to selectively allow refrigerant to pass therethrough. Refrigerant from the cooling outlet322may be selectively guided to flow through the first electrically-operated two-way valve27in Path6.

The main heat exchange system2may further comprise a second electrically- operated two-way valve28connected to the first passage ports230of the second heat exchangers204and the liquid inlet251of the refrigerant storage tank25in Path3. The second electrically-operated two-way valve28may be selectively opened or closed to selectively allow refrigerant to pass therethrough. Refrigerant from the first passage ports230may be selectively guided to flow through second electrically-operated two-way valve28and enter the liquid inlet251of the refrigerant storage tank25through Path3.

The main heat exchange system2may further comprise a third electrically-operated two-way valve290connected between the first passage ports230and the cooling inlet321of the cooling heat exchanger32in Path2. The third electrically-operated two-way valve290may be selectively opened or closed to selectively allow refrigerant to pass therethrough.

The main heat exchange system2may further comprise a third unidirectional valve240connected to the expansion valve239, the first unidirectional valve236and the first communicating port226of the first heat exchanger203through Path7as indicated inFIG.8of the drawings. The third unidirectional valve240may be configured to allow refrigerant to flow only in a direction from the expansion valve239in Path4toward the first communicating port226through Path7.

The main heat exchange system2may further comprise a fourth unidirectional valve264connected to the first communicating port226of the first heat exchanger203, and the liquid inlet251of the refrigerant storage tank25through Path8indicated inFIG.8of the drawings. The fourth unidirectional valve264may be configured to allow refrigerant to flow in a direction from the first communicating port226toward the liquid inlet251through Path8. The fourth unidirectional valve264may also be connected to the third unidirectional valve240in Path7, and the second unidirectional valve237in Path5which may connect to the cooling outlet322, and the first electrically-operated two-way valve27in parallel.

The heat distribution system may be arranged to retrieve the heat generated by the main heat exchange system2and distribute the heat to designated indoor spaces through at least one terminal device. One of such terminal devices may be a ventilating device. The ventilating device may be utilized for delivering ambient air to the indoor space when the central air conditioning and heat pump system is operated in the heat pump mode.

According to the preferred embodiment of the present invention, the cooling tower31may be installed to lower the temperature of refrigerant circulating in the cooling heat exchanger32.

The tower casing311may have a rectangular cross section having a top side3113, a bottom side and a plurality of peripheral sides3114. Obviously, the tower casing311may be embodied as having a wide variety of cross sections for suiting different operational environments.

The pump33may be connected between the water storage tank312and the water distributor313for circulating cooling water between the water storage tank312and the water distributor313.

As shown inFIG.8of the drawings, the tower casing311may further comprise a water screening member315provided above the water distributor313for preventing water from accidentally reaching the fan314. The water screening member315may also be arranged to guide or reflect water to flow toward the cooling heat exchanger32so as to ensure enough water is supplied to the cooling heat exchanger32for performing heat exchange with the refrigerant flowing therein.

The main heat exchange system2may further comprise a temperature sensor280provided at the liquid outlet252of the refrigerant storage tank25for detecting a temperature of the refrigerant flowing through the liquid outlet252. The operation mode of the present invention may depend on the temperature detected by the temperature sensor280.

The operation of the present invention is as follows: the central air conditioning and heat pump system described above involves a refrigerant flowing cycle and a water flowing cycle. The refrigerant may flow through the various components of the main heat exchange system2while the water may flow through the various components of the cooling arrangement3.

When the central air conditioning and heat pump system is in the comprehensive air conditioning mode, it is configured to generate cool air to designated indoor spaces. A refrigerant cycle starts from the compressor202. Superheated or vaporous refrigerant may be arranged to leave the compressor202through the compressor outlet207. The communicative valve233may be switched to the air conditioning switching mode. Moreover, the third electrically-operated two-way valve290may be opened, while the first electrically-operated two-way valve27and the second electrically-operated two-way valve28may be closed. The refrigerant leaving the compressor202may pass through the first connecting port2331of the communicative valve233, the second connecting port2332, and enter the second heat exchangers204through the second passage ports231. The refrigerant may then perform heat exchange with a coolant such as ambient air so as to release heat to ambient air (air-cooled).

The refrigerant may then be guided to exit the second heat exchangers204through the first passage ports230. The refrigerant leaving the second heat exchangers204may then be guided to flow through the third electrically-operated two-way valve290in Path2and enter the cooling heat exchanger32through the cooling inlet321. The refrigerant may be prevented from entering path1by the second electrically-operated two-way valve28and the first unidirectional valve236at this time. The refrigerant may be arranged to further release heat to the cooling water circulating in the cooling tower31. The heat released to the cooling water may be carried away by the ambient air drawn from the cooling tower air inlet3111.

The refrigerant leaving the cooling heat exchanger32through the cooling outlet322may then be guided to pass the second unidirectional valve237in Path5and pass through the liquid inlet251and enter the refrigerant storage tank25. The refrigerant may then leave the refrigerant storage tank25through the liquid outlet252and pass through the filter238, the expansion valve239in Path4and the third unidirectional valve240in Path7and eventually enter the first heat exchanger203through the first communicating port226. The refrigerant entering the first heat exchanger203may then be arranged to perform heat exchange with another heat exchange medium circulating in the heat distribution system so as to absorb heat from therefrom. The refrigerant may then be guided to leave the first heat exchanger203through the second communicating port227. The refrigerant may then be guided to flow through the fourth connecting port2334and the third connecting port2333of the communicative valve233and eventually flow back to the compressor202through the compressor inlet208. This completes one refrigerant cycle for the comprehensive air conditioning mode.

It is worth mentioning that the cooling heat exchanger32may be utilized for further cooling the temperature of the refrigerant through heat exchange with the cooling water coming from the water distributor313. The pump33may pump cooling water to circulate between the water distributor313and the water storage tank312. Specifically, cooling water in the water storage tank312may be pumped to the water distributor313for spraying on the cooling heat exchanger32. The cooing water may then perform heat exchange with the refrigerant circulating in the cooling heat exchanger32. After that, the cooling water having absorbed heat from the refrigerant may enter a cooling zone316as a space formed between the cooling heat exchanger32and the water storage tank312so that ambient air drawn from the cooling tower air inlet3111may be able to perform heat exchange with the cooling water. The cooling water will then be cooled down and collected in the water storage tank312for performing another cooling cycle.

From the above descriptions, one skilled in the art may appreciate that the refrigerant circulating in the main heat exchange system2of the present invention may be cooled by either the second heat exchangers204, the cooling heat exchanger32, or both. In the event that water supply is interrupted, the fan314and the pump33may be turned off so that the refrigerant will only be cooled by the second heat exchangers204.

Note that the comprehensive air conditioning mode implies that the refrigerant circulating in the main heat exchange system2may be cooled by water (cooling tower31) as well as air (second heat exchangers204).

When the temperature detected by the temperature sensor280falls below a predetermined threshold, the refrigerant may only be cooled by the second heat exchangers204. This mode of operation may be referred to as air-cooled air conditioning mode. When the central air conditioning and heat pump system is in the air-cooled air conditioning mode, it is also configured to generate cool air to designated indoor spaces. A refrigerant cycle starts from the compressor202. Superheated or vaporous refrigerant may be arranged to leave the compressor202through the compressor outlet207. The communicative valve233may be switched to the air conditioning switching mode. Moreover, the third electrically-operated two-way valve290may be closed, the first electrically-operated two-way valve27may be closed and the second electrically-operated two-way valve28may be opened. The refrigerant leaving the compressor202may pass through the first connecting port2331of the communicative valve233, the second connecting port2332, and enter the second heat exchangers204through the second passage ports231. The refrigerant may then perform heat exchange with a coolant such as ambient air so as to release heat to ambient air.

The refrigerant may then be guided to exit the second heat exchangers204through the first passage ports230. The refrigerant leaving the second heat exchangers204may then be guided to flow through Path1and enter Path3and flow through the first electrically-operated two-way valve28. The refrigerant may be prevented from entering the cooling heat exchanger32at this time because the third electrically-operated two-way valve290is closed.

The refrigerant pass through the second electrically-operated two-way valve28may be arranged to pass through the liquid inlet251and enter the refrigerant storage tank25. The refrigerant may then leave the refrigerant storage tank25through the liquid outlet252and pass through the filter238, the expansion valve239in Path4and the third unidirectional valve240in Path7and eventually enter the first heat exchanger203through the first communicating port226. The refrigerant entering the first heat exchanger203may then be arranged to perform heat exchange with another heat exchange medium circulating in the heat distribution system so as to absorb heat from therefrom. The refrigerant may then be guided to leave the first heat exchanger203through the second communicating port227. The refrigerant may then be guided to flow through the fourth connecting port2334and the third connecting port2333of the communicative valve233and eventually flow back to the compressor202through the compressor inlet208. This completes one refrigerant cycle for the air-cooled air conditioning mode. In this refrigerant cycle, the refrigerant may be solely cooled by the ambient air passing through the second heat exchangers204.

When the central air conditioning and heat pump system is in the heat pump mode, it is configured to generate heat to designated indoor spaces. The corresponding refrigerant cycle also starts from the compressor202. Superheated or vaporous refrigerant may be arranged to leave the compressor202through the compressor outlet207. The communicative valve233may be switched to heat pump switching mode. Moreover, the first through third electrically-operated two-way valve27,28,290may all be closed.

The refrigerant leaving the compressor202may pass through the first connecting port2331, the fourth connecting port2334, and enter the first heat exchanger203through the second communicating port227. The refrigerant may then perform heat exchange with the heat distribution system so as to release heat to the heat exchange medium circulating in the first heat exchanger203. The refrigerant may be converted into liquid state after releasing heat. The refrigerant may then be guided to exit the first heat exchanger203through the first communicating port226. The refrigerant leaving the first heat exchanger203may then be guided to flow through the fourth unidirectional valve240in Path8and pass through the liquid inlet251and enter the refrigerant storage tank25. Refrigerant may be prevented from reaching the cooling heat exchanger32because of the second unidirectional valve237.

When the central air conditioning and heat pump system is in the heat pump mode, the fan314and the pump33may be turned off. In addition, the cooling water may be discharged out of the cooling tower31. The refrigerant will then be guided to leave the refrigerant storage tank25through the liquid outlet252and pass through the filter238, the expansion valve239connected in Path4, and may be guided to pass through the first unidirectional valve236. The refrigerant may then be guided to reach the second heat exchangers204through the corresponding first passage ports230for absorbing heat from the ambient air. The refrigerant may then exit the second heat exchangers204through the second passage ports231and may be guided to flow through the second connecting port2332of the communicative valve233, the third connecting port2333, and eventually go back to the compressor202through the compressor inlet208. This completes one refrigerant cycle in the heat pump mode.

The central air conditioning and heat pump system may further operate in a defrosting mode. The defrosting mode may be utilized to remove frost which may be formed on the second heat exchanger204when the central air conditioning and heat pump system is operated in the heat pump mode. In the defrosting mode, the corresponding refrigerant cycle also starts from the compressor202. Superheated or vaporous refrigerant may be arranged to leave the compressor202through the compressor outlet207. The communicative valve233may be switched to the air conditioning switching mode. Moreover, the first and the third electrically-operated two-way valve27,290may be closed, while the second electrically-operated two-way valve28may be opened.

The refrigerant leaving the compressor202may pass through the first connecting port2331, the second connecting port2332, and enter the second heat exchangers204through the second passage ports231for releasing heat to defrost the second heat exchangers204. The refrigerant may exit the second heat exchangers204through the first passage ports230and may be guided to pass through the second electrically-operated two-way valve28in Path3and enter the refrigerant storage tank25through the liquid inlet251. The refrigerant may then leave the refrigerant storage tank25through the liquid outlet252and pass through the filter238and the expansion valve239connected in Path4. The refrigerant may then be guided to pass through the third unidirectional valve240in Path7and enter the first heat exchanger203through the first communicating port226. The refrigerant leaving the first heat exchanger203through the second communicating port227may then be guided to flow through the fourth connecting port2334of the communicative valve233, the third connecting port2333, and eventually go back to the compressor202through the compressor inlet208. This completes one refrigerant cycle in the defrosting mode.

The present invention, while illustrated and described in terms of the preferred embodiments and several alternatives, is not limited to the particular description contained in this specification. Additional alternative or equivalent components could also be used to practice the present invention.