Chilled water heat recovery air conditioning system and use method thereof

Abstract

The present invention relates to a chilled water heat recovery air-conditioning system and a method for using the same. By adding a water source heat pump unit for heat recovery in a refrigeration room, the return water of the air-conditioning chilled water system is directly used as the heat source side of the water source heat pump unit to recover heat, thereby providing preheating for the building's domestic hot water system or directly heating tap water into usable domestic hot water. At the same time, the free cooling energy is returned to the chilled water system, thereby constructing an economical, healthy, green, environmentally friendly, and energy-saving chilled water heat recovery air-conditioning system coupled with a water source heat pump and a chiller, which is suitable for large public buildings, especially large hotels, hospitals, and other buildings that require cooling and domestic hot water throughout the year.

Description

Technical Field

[0001] The present invention relates to an air-conditioning system, and in particular to a chilled water heat recovery air-conditioning system and a use method thereof. Background Art

[0002] With the national goal of achieving carbon peak and carbon neutrality, effectively improving the energy efficiency of refrigeration rooms has become a key focus for HVAC industry practitioners. For large public buildings with year-round cooling and heating needs, improving the energy efficiency of refrigeration rooms requires not only optimizing equipment and piping, but also adopting efficient control systems. Efficiently coupling the building's cooling and heating systems is also a key approach to improving the energy efficiency of the room.

[0003] Large public buildings in hot summers and warm winters, or hot summers and cold winters, have distinct internal and external air conditioning system zones due to their large size and depth. The cooling and heating loads in the external zone fluctuate seasonally, with cooling in summer and heating in winter, while the internal zone experiences cooling year-round. Furthermore, large public buildings like hotels and hospitals require domestic hot water year-round, resulting in simultaneous cooling and heating needs throughout the building year.

[0004] During cooling, conventional air conditioning systems absorb waste heat from the target room through chilled water. This heat is then transferred to the cooling water system in the chiller's condenser and discharged to the outside through cooling towers and other equipment. A large amount of condensation heat is directly discharged into the atmosphere and lost, resulting in significant energy waste. This heat, in turn, raises the ambient temperature, causing severe thermal pollution. Recovering this heat and using it to meet the building's heating needs would not only reduce thermal pollution but also effectively lower the building's overall energy consumption, ultimately achieving energy conservation and emission reductions.

[0005] Traditional heat recovery air conditioning systems are primarily categorized as indirect or direct. Direct heat recovery systems are further divided into full and partial heat recovery. The indirect system uses heat from the condenser's water, which is around 37°C, to preheat domestic hot water. However, due to the increased equipment required, the outlet water temperature is low, resulting in low heat exchange efficiency. Consequently, the indirect system offers low economic benefits and a long payback period.

[0006] Full heat recovery directly utilizes the sensible and latent heat of the refrigerant vapor at the compressor outlet. Although the recovered heat is large, it will cause a relatively large pressure drop in the condenser, thereby reducing the efficiency of the chiller and increasing the chiller's power consumption, which reduces the overall energy saving of the building. Partial heat recovery only recovers the sensible heat of the refrigerant vapor at the compressor outlet. The recovery amount is not large, generally not exceeding 20% of the overall condensation heat, and the temperature of the hot water provided is not high. In addition, direct heat recovery systems, whether full or partial heat recovery, are greatly affected by the operating conditions of the chiller. When the heat recovery chiller is shut down for adjustment or maintenance, heat recovery cannot be performed. Moreover, to achieve continuous heat recovery, the heat recovery chiller must be used continuously, which increases the failure rate of the chiller, shortens its service life, and affects the stability of the building's cold source system. Summary of the Invention

[0007] The purpose of the present invention is to overcome the shortcomings of traditional heat recovery air-conditioning systems, further improve the energy efficiency of refrigeration rooms, reduce building energy consumption, and provide an economical, healthy, green, environmentally friendly, and energy-saving water source heat pump coupled with a chiller and a chiller, which is suitable for large public buildings, especially hotels, hospitals, etc., which require cooling and domestic hot water throughout the year. The system and its use method are suitable for large public buildings.

[0008] The present invention is implemented through the following technical solution: a chilled water heat recovery air conditioning system. It includes a chiller 1, a water source heat pump unit 2, an outdoor heat exchange system 3, a domestic hot water heat exchange system 4, a first circulating pump 5, a second circulating pump 6, a third circulating pump 7, a chilled water collector 8, a chilled water manifold 9, an air conditioning chilled water system pressure constant device 10, several switching valves, and a pressure differential bypass valve group;

[0009] The chiller 1 includes a first condenser 11 and a first evaporator 12; the water source heat pump unit 2 includes a second condenser 21 and a second evaporator 22;

[0010] The water supply end of the first evaporator 12 is connected to the cold water distributor 9, and the cold water distributor 9 branches off a line connected to the cold water supply pipe at the end of the air conditioner; the cold water manifold 8 branches off a line connected to the cold water return pipe at the end of the air conditioner;

[0011] The cold water manifold 8 branches into three pipelines; the first pipeline is connected to the first circulation pump 5 and the first evaporator 12, and after heat exchange in the first evaporator 12, it becomes air-conditioning cold water supply and flows into the cold water manifold 9; the second pipeline is connected to the second circulation pump 6 and the second evaporator 22, and after heat exchange in the second evaporator 22, it is connected to the first circulation pump 5 and the first evaporator 12, and then after heat exchange in the first evaporator 12, it becomes air-conditioning cold water supply and flows into the cold water manifold 9; the third pipeline is connected to the third circulation pump 7 and the second evaporator 22, and after heat exchange in the second evaporator 22, it becomes air-conditioning cold water supply and flows into the cold water manifold 9; the switching valve is set on the main pipeline and the branch pipeline of the above three pipelines;

[0012] A bypass pipe is provided between the cold water manifold 8 and the cold water manifold 9, and a pressure differential bypass valve group is provided on the bypass pipe; the cold water manifold 8 is connected to the constant pressure device 10 of the air conditioning cold water system;

[0013] The first condenser 11 is connected to the outdoor heat exchange system 3 ; the second condenser 21 is connected to the domestic hot water side heat exchange system 4 .

[0014] A method for using a chilled water heat recovery air conditioning system, which is divided into summer and winter operating conditions:

[0015] The working process of summer working condition is as follows:

[0016] The chiller 1 is running, the water source heat pump 2 is running, the outdoor side heat exchange system 3 is running, the domestic hot water side heat exchange system 4 is running, the first circulation pump 5 is running, the second circulation pump 6 is running, the air conditioning cold water system constant pressure device 10 is running, and the third circulation pump 7 is turned off. By controlling the switching valve, the equipment in the first and second paths participates in the operation and circulation, and the equipment in the third path does not participate in the operation and circulation;

[0017] The workflow for winter conditions is as follows:

[0018] The water source heat pump 2 is running, the domestic hot water side heat exchange system 4 is running, the air conditioning cold water circulation pump 3 7 is running, the air conditioning cold water system constant pressure device 10 is running, the first circulation pump 1 5 is turned off, the second circulation pump 6 is turned off, and the chiller 1 is turned off. By controlling the switching valve, the equipment in the third route participates in the operation and circulation; the equipment in the first and second routes do not participate in the operation and circulation.

[0019] The overall design concept of the present invention is: to add a water source heat pump unit for heat recovery in the refrigeration room, and directly use the return water of the air-conditioning chilled water system as the heat source side of the water source heat pump unit to recover heat, provide preheating for the building's domestic hot water system or directly heat tap water into usable domestic hot water, and at the same time return the free cooling energy to the chilled water system, thereby constructing an economical, healthy, green, environmentally friendly, and energy-saving water source heat pump and chiller coupled chilled water heat recovery air-conditioning system suitable for large public buildings, especially large hotels, hospitals and other buildings that require cooling and domestic hot water throughout the year.

[0020] The advantages of the present invention are as follows:

[0021] 1. Compared to conventional air conditioning systems without heat recovery, adding a water-source heat pump unit for heat recovery in the refrigeration room recycles the condensation heat discharged into the atmosphere, reducing building heating energy consumption. At the same time, the generated free cooling energy is directly returned to the chilled water system, reducing the cooling load borne by the chiller. Furthermore, since the temperature difference between the supply and return water of the chiller is reduced, the unit's energy efficiency is greatly improved, significantly reducing the chiller's power consumption and reducing building cooling energy consumption. This provides high economic benefits and a short payback period.

[0022] 2. Compared to traditional condenser water heat recovery air conditioning systems, the water-source heat pump unit used for heat recovery is separate from the chiller. Heat recovery is not affected by the chiller's operating conditions, which increases the heat recovery period and reduces the building's annual energy consumption. The added water-source heat pump unit generates free cooling while providing heat. For buildings with high cooling requirements, such as five-star hotels, this can supplement cooling capacity in the event of a chiller failure or repair, thus increasing the cooling system's reliability.

[0023] 3. Compared with traditional condenser water heat recovery air conditioning systems, water source heat pump units absorb heat from the refrigeration system while also returning the generated free cooling directly to the chilled water system, lowering the chilled water return temperature and, consequently, the cooling load borne by the chiller. Furthermore, since the temperature difference between the chiller's supply and return water is reduced, the unit's energy efficiency ratio is also significantly improved. As a result, the overall energy efficiency of the refrigeration room is significantly improved.

[0024] 4. Compared with the traditional condensing water heat recovery air conditioning system, the power consumption of the chiller is reduced, the heat dissipation of the unit is reduced, and thus the heat dissipation borne by the cooling water system is reduced. By reducing the cooling water circulation flow and other measures, the energy consumption of the refrigeration room can be further reduced.

[0025] 5. This system adds a water source heat pump unit for heat recovery and some switching valves, building a new type of economical, healthy, comfortable, green, environmentally friendly and energy-saving chilled water heat recovery air-conditioning system that couples a water source heat pump with a chiller. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of a chilled water heat recovery air conditioning system;

[0027] Figure 2 A schematic diagram of the summer operating conditions of a chilled water heat recovery air conditioning system;

[0028] Figure 3 A schematic diagram of the winter operating conditions of a chilled water heat recovery air conditioning system.

[0029] Explanation of reference numbers: 1 chiller, 11 first condenser, 12 first evaporator, 2 water source heat pump unit, 21 second condenser, 22 second evaporator, 3 outdoor side heat exchange system, 4 domestic hot water side heat exchange system, 5 first circulation pump, 6 second circulation pump, 7 third circulation pump, 8 cold water collector, 9 cold water manifold, 10 air conditioning cold water system constant pressure device, 31 first valve, 32 second valve, 33 third valve, 34 fourth valve, 35 fifth valve. DETAILED DESCRIPTION

[0030] The present invention is described in detail below with reference to the accompanying drawings:

[0031] like Figure 1 As shown: A chilled water heat recovery air conditioning system, which includes a chiller 1, a water source heat pump unit 2, an outdoor side heat exchange system 3, a domestic hot water side heat exchange system 4, a first circulating pump 5, a second circulating pump 6, a third circulating pump 7, a cold water collector 8, a cold water manifold 9, an air conditioning cold water system constant pressure device 10, a plurality of switching valves and a pressure differential bypass valve group;

[0032] The chiller 1 includes a first condenser 11 and a first evaporator 12; the water source heat pump unit 2 includes a second condenser 21 and a second evaporator 22;

[0033] The water supply end of the first evaporator 12 is connected to the cold water distributor 9, and the cold water distributor 9 branches off a line connected to the cold water supply pipe at the end of the air conditioner; the cold water manifold 8 branches off a line connected to the cold water return pipe at the end of the air conditioner;

[0034] The cold water manifold 8 branches into three pipelines; the first pipeline is connected to the first circulation pump 5 and the first evaporator 12, and after heat exchange in the first evaporator 12, it becomes air-conditioning cold water supply and flows into the cold water manifold 9; the second pipeline is connected to the second circulation pump 6 and the second evaporator 22, and after heat exchange in the second evaporator 22, it is connected to the first circulation pump 5 and the first evaporator 12, and then after heat exchange in the first evaporator 12, it becomes air-conditioning cold water supply and flows into the cold water manifold 9; the third pipeline is connected to the third circulation pump 7 and the second evaporator 22, and after heat exchange in the second evaporator 22, it becomes air-conditioning cold water supply and flows into the cold water manifold 9; the switching valve is set on the main pipeline and the branch pipeline of the above three pipelines;

[0035] A bypass pipe is provided between the cold water manifold 8 and the cold water manifold 9, and a pressure differential bypass valve group is provided on the bypass pipe; the cold water manifold 8 is connected to the constant pressure device 10 of the air conditioning cold water system;

[0036] The first condenser 11 is connected to the outdoor heat exchange system 3 ; the second condenser 21 is connected to the domestic hot water side heat exchange system 4 .

[0037] It should be noted that the switching valves installed on the three-way pipeline are distributed according to the requirements of the pipeline layout. Their main purpose is to ensure that the three-way pipeline can be opened and closed as required. The current case presents the layout of the switching valve positions based on the existing design scheme, and the actual design can be based on the specific pipeline layout.

[0038] In this case, there are five switching valves, namely the first valve 31, the second valve 32, the third valve 33, the fourth valve 34, and the fifth valve 35. The first valve is set between the cold water collector 8 and the first circulation pump 5 of the first circuit, the second valve 32 is set between the cold water collector 8 and the second circulation pump 5 of the second circuit, the third valve 33 is set between the second circulation pump 5 and the first evaporator 12 of the second circuit, the fourth valve 34 is set between the cold water collector 8 and the third circulation pump 6 of the third circuit, and the fifth valve is set between the second evaporator 22 and the cold water distributor 9 of the third circuit (here a branch pipe is provided between the second evaporator 22 and the cold water distributor 9, which is connected in parallel with the second circulation pump 5 and the first evaporator 12, and the fifth valve is set on the branch pipe).

[0039] The outdoor heat exchange system 3 includes an outdoor heat exchange pipe connected to the outdoor medium and a medium storage device. By selecting the outdoor heat exchange medium, the corresponding outdoor heat exchange system 3 is set:

[0040] a In areas where there is sufficient groundwater, suitable water quality and temperature, and direct groundwater extraction is permitted, the outdoor heat exchange system 3 can directly extract groundwater as the heat exchange medium;

[0041] b. In areas where surface water is sufficient, of suitable quality and temperature, and where direct surface water extraction is permitted, the outdoor heat exchange system 3 can directly extract surface water as the heat exchange medium;

[0042] c. In areas where water is insufficient, water quality and temperature are unsuitable, and direct access to water is prohibited, the outdoor heat exchange pipe is an underground pipe, the medium storage device is a cooling tower, and the outdoor heat exchange system 3 adopts a combination of underground pipes and cooling towers;

[0043] The outdoor heat exchange pipe described in d is a pipe, the medium storage device is a cooling tower, and the outdoor side heat exchange system connected to the chiller 1 can adopt a cooling tower or directly adopt outdoor air.

[0044] Furthermore, the domestic hot water side heat exchange system 4 includes a heat storage device, a circulating water pump and a heat exchange device, wherein the heat storage device can be a hot water storage tank, and the heat exchange device can be a water-water heat exchanger.

[0045] Furthermore, the air-conditioning cold water system constant pressure device 10 is any one of an expansion tank constant pressure, an air pressure tank constant pressure, and a variable frequency water replenishment constant pressure.

[0046] The number of the cold water supply pipe and return pipe connected to the air conditioner terminal is at least one.

[0047] Furthermore, the first circulation pump 5 , the second circulation pump 6 , and the third circulation pump 7 are all air-conditioning cold water circulation pumps.

[0048] like Figure 2 、 3 Shown: A method of using a chilled water heat recovery air conditioning system, which is divided into summer and winter operating conditions:

[0049] like Figure 2 As shown: The working process of summer working condition is as follows:

[0050] The chiller 1 is running, the water source heat pump 2 is running, the outdoor heat exchange system 3 is running, the domestic hot water heat exchange system 4 is running, the first circulation pump 5 is running, the second circulation pump 6 is running, the air conditioning cold water system constant pressure device 10 is running, and the third circulation pump 7 is turned off; by controlling the switching valve, the equipment in the first and second circuits participate in the operation and circulation, and the equipment in the third circuit does not participate in the operation and circulation;

[0051] like Figure 3 As shown: The working process of winter working condition is as follows:

[0052] The water source heat pump 2 is running, the domestic hot water side heat exchange system 4 is running, the air conditioning cold water circulation pump 3 7 is running, the air conditioning cold water system constant pressure device 10 is running, the first circulation pump 1 5 is turned off, the second circulation pump 6 is turned off, and the chiller 1 is turned off; by controlling the switching valve, the equipment in the third route participates in the operation and circulation; the equipment in the first and second routes do not participate in the operation and circulation.

[0053] Combining the specific switching valve position of this case and the attached drawings, we can see the specific switching conditions of the switching valve during each working condition;

[0054] The summer working principle diagram is as follows Figure 2 As shown:

[0055] The chiller 1 is running, the water source heat pump 2 is running, the outdoor heat exchange system 3 is running, the domestic hot water heat exchange system 4 is running, the first air-conditioning cold water circulation pump 5 is running, the second air-conditioning cold water circulation pump 6 is running, and the air-conditioning cold water system constant pressure device 10 is running. The first valve 31, the second valve 32, and the third valve 33 of the switching valve are open, the fourth valve 34 is closed, and the fifth valve 35 is closed.

[0056] Winter working principle diagram Figure 3 As shown:

[0057] The water source heat pump 2 is running, the domestic hot water side heat exchange system 4 is running, the third air-conditioning cold water circulation pump 7 is running, the air-conditioning cold water system constant pressure device 10 is running, the first valve 31 in the switching valve, the second valve 32 in the switching valve and the third valve 33 in the switching valve are closed, the fourth valve 34 is closed and the fifth valve 35 is opened.

[0058] The following is a specific application of a chilled water heat recovery air conditioning system (the overall layout and connection relationship of the system are not disclosed to the public):

[0059] The application is located in Quanzhou City, with a total construction area of approximately 70,475m 2 , with 35 floors above ground and two floors in the basement, the main functions of the building are apartments and hotels. The hotel area is approximately 49,901m 2 The first to sixth floors are the hotel podium, which mainly houses the lobby, conference rooms, banquet hall, all-day dining restaurant, etc. The nineteenth to thirty-fifth floors are the hotel guest rooms, which mainly house the guest rooms, swimming pool, SPA, etc. The hotel part uses a centralized air-conditioning system.

[0060] Air conditioning calculation parameters are based on the Xiamen region. Summer air conditioning is calculated based on a dry-bulb temperature of 33.5°C and a wet-bulb temperature of 27.5°C; winter air conditioning is calculated based on a dry-bulb temperature of 6.6°C and a relative humidity of 79%. The hotel's air conditioning cooling load is approximately 5,000 kW, and the heating load is approximately 3,700 kW.

[0061] The hotel's air conditioning system utilizes a combination of centrifugal chillers and screw chillers, housed in a basement-level chiller room. A water-source heat pump unit is installed within the chiller room, reducing the chilled water return temperature to improve the chiller's energy efficiency while also providing preheating or heat for the hotel's domestic hot water system.

[0062] The specific configuration of the hotel's air-conditioning system in this project is as follows:

[0063] 1 Chiller:

[0064] Variable frequency centrifugal chillers, each with a rated cooling capacity of 1760KW, two in total;

[0065] Fixed-frequency screw chiller, rated cooling capacity of 1232KW per unit, 1 unit in total;

[0066] 2 Water source heat pump unit:

[0067] The rated cooling capacity of each unit is 800KW, and there is 1 unit in total;

[0068] 3. Outdoor heat exchange system: The outdoor heat exchange system of the chiller adopts the traditional cooling tower system:

[0069] Rated flow rate of a single cooling tower is 450m 3 / h, 2 units in total; rated flow rate of a single cooling tower is 300m 3 / h, 1 unit in total;

[0070] 4. Domestic hot water side heat exchange system:

[0071] Closed water storage tank, effective volume 3m 3 , 1 in total; single unit flow rate 150m 3 / h circulating water pump, head 15m, 2 units in total, 1 in use and 1 in reserve; 1 plate heat exchanger;

[0072] 5. First circulation pump:

[0073] Single flow rate 350m 3 / h, lift 30m, 3 units in total, 2 in use and 1 in reserve;

[0074] Single flow rate 250m 3 / h, lift 30m, 2 units in total, 1 in use and 1 in reserve;

[0075] 6. Second circulation pump:

[0076] Single flow rate 150m 3 / h, lift 10m, 2 units in total, 1 in use and 1 in reserve;

[0077] 7. The third circulation pump:

[0078] Single flow rate 150m 3 / h, lift 25m, 2 units in total, 1 in use and 1 in reserve;

[0079] 8. First-stage cold water collector: D700xL6200;

[0080] 9. First-stage cold water manifold: D7000xL6200;

[0081] 10. Air conditioning cold water system constant pressure device: variable frequency water replenishment constant pressure device;

[0082] 31, 32, 33, 33, 35 switching valves: There are 5 valves in total.

[0083] Although the present invention is illustrated and described using specific embodiments and their alternatives, it should be understood that various changes and modifications can be implemented without departing from the spirit and scope of the present invention. Therefore, it should be understood that the present invention is not limited in any sense except by the limitations of the appended claims and their equivalents.

Claims

1. A chilled water heat recovery air conditioning system, characterized by: It includes a chiller (1), a water source heat pump unit (2), an outdoor side heat exchange system (3), a domestic hot water side heat exchange system (4), a first circulation pump (5), a second circulation pump (6), a third circulation pump (7), a cold water collector (8), a cold water manifold (9), an air conditioning cold water system constant pressure device (10), a plurality of switching valves and a pressure difference bypass valve group; Wherein, the chiller (1) comprises a first condenser (11) and a first evaporator (12); the water source heat pump unit (2) comprises a second condenser (21) and a second evaporator (22); The water supply end of the first evaporator (12) is connected to the cold water distributor (9), and the cold water distributor (9) branches off a line connected to the cold water supply pipe at the end of the air conditioner; the cold water collector (8) branches off a line connected to the cold water return pipe at the end of the air conditioner; The cold water collector (8) branches into three pipelines; the first pipeline is connected to the first circulation pump (5) and the first evaporator (12), and after heat exchange in the first evaporator (12), it becomes air-conditioning cold water supply and then flows into the cold water distributor (9); the second pipeline is connected to the second circulation pump (6) and the second evaporator (22), and after heat exchange in the second evaporator (22), it is connected to the first circulation pump (5) and the first evaporator (12), and then after heat exchange in the first evaporator (12), it becomes air-conditioning cold water supply and flows into the cold water distributor (9); the third pipeline is connected to the third circulation pump (7) and the second evaporator (22), and after heat exchange in the second evaporator (22), it becomes air-conditioning cold water supply and flows into the cold water distributor (9); the switching valve is provided on the main pipeline and the branch pipeline of the above three pipelines; A bypass pipe is provided between the cold water collector (8) and the cold water distributor (9), and a pressure differential bypass valve group is provided on the bypass pipe; the cold water collector (8) is connected to the air conditioning cold water system constant pressure device (10); The first condenser (11) is connected to the outdoor side heat exchange system (3); the second condenser (21) is connected to the domestic hot water side heat exchange system (4); The air-conditioning cold water system constant pressure device (10) is any one of an expansion tank constant pressure, an air pressure tank constant pressure, and a variable frequency water supply constant pressure; The first circulation pump (5), the second circulation pump (6), and the third circulation pump (7) are all air-conditioning cold water circulation pumps.

2. A chilled water heat recovery air conditioning system according to claim 1, characterized in that: The outdoor heat exchange system (3) includes an outdoor heat exchange pipe connected to the outdoor medium and a medium storage device. By selecting the outdoor heat exchange medium, the corresponding outdoor heat exchange system (3) is set: (a) In areas where groundwater is sufficient, of suitable quality and temperature, and where direct extraction of groundwater is permitted, the outdoor heat exchange system (3) can use direct extraction of groundwater as the heat exchange medium; (b) In areas where the surface water is sufficient, the water quality and temperature are suitable, and direct surface water extraction is permitted, the outdoor heat exchange system (3) can use direct surface water as the heat exchange medium; (c) In areas where water is insufficient, water quality and temperature are unsuitable, and direct access to water is prohibited, the outdoor heat exchange pipe is an underground pipe, the medium storage device is a cooling tower, and the outdoor heat exchange system (3) adopts a combination of underground pipes and cooling towers; The outdoor heat exchange pipe described in (d) is a pipe, the medium storage device is a cooling tower, and the outdoor heat exchange system connected to the chiller (1) can adopt a cooling tower or directly adopt outdoor air.

3. The chilled water heat recovery air conditioning system according to claim 1, characterized in that: The domestic hot water side heat exchange system (4) includes a heat storage device, a circulating water pump and a heat exchange device, wherein the heat storage device can be a heat storage tank, and the heat exchange device can be a water-water heat exchanger.

4. The method for using a chilled water heat recovery air conditioning system according to any one of claims 1 to 3, characterized in that: It is divided into summer working conditions and winter working conditions: The working process of summer working condition is as follows: The chiller (1) is running, the water source heat pump unit (2) is running, the outdoor side heat exchange system (3) is running, the domestic hot water side heat exchange system (4) is running, the first circulation pump (5) is running, the second circulation pump (6) is running, the air conditioning cold water system constant pressure device (10) is running, and the third circulation pump (7) is turned off. By controlling the switching valve, the equipment in the first and second paths participates in the operation and circulation, and the equipment in the third path does not participate in the operation and circulation; The workflow for winter conditions is as follows: The water source heat pump unit (2) is in operation, the domestic hot water side heat exchange system (4) is in operation, the third circulation pump (7) is in operation, the air conditioning cold water system constant pressure device (10) is in operation, the first circulation pump (5) is shut down, the second circulation pump (6) is shut down, and the chiller (1) is shut down. By controlling the switching valve, the equipment in the third path participates in the operation and circulation; the equipment in the first path and the second path do not participate in the operation and circulation.

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