Hot water recovery system of magnetic suspension water chilling unit and control method

Abstract

The invention relates to a magnetic suspension water chilling unit hot water recovery system and a control method, and belongs to the technical field of magnetic suspension water chilling units. The system comprises a magnetic suspension water chilling unit and a heat pump unit, the heat pump unit and an exhaust pipe of the magnetic suspension water chilling unit are connected in parallel to form a first branch circulation pipeline, the heat pump unit is used for absorbing condensation heat of a gaseous refrigerant, and then hot water at the set temperature is obtained through heating circulation; or, the heat pump unit is connected with the liquid supply pipe of the magnetic suspension water chilling unit in parallel to form a second branch circulation pipeline, the heat pump unit is used for absorbing the heat of the liquid refrigerant, and then hot water at the set temperature is obtained through heating circulation. According to the magnetic suspension water chilling unit, the heat pump unit is connected with the magnetic suspension water chilling unit in parallel to absorb condensation heat of the gaseous refrigerant or heat of the liquid refrigerant to obtain hot water at the set temperature, meanwhile, the condensation effect is enhanced, and the energy efficiency of the magnetic suspension water chilling unit is improved.

Description

Technical Field

[0001] The invention relates to a hot water recovery system and a control method for a magnetic suspension chiller, belonging to the technical field of magnetic suspension chillers. Background Art

[0002] Magnetic levitation chillers have the unique advantages of energy saving and high efficiency, low maintenance costs, and low vibration and noise, and are gradually gaining favor in the market.

[0003] At present, the condensation heat of most magnetic levitation chillers is not utilized, but is directly released into the outdoor environment through heat exchange equipment. A few chillers utilize part of the condensation heat by adding heat recovery heat exchangers, but can only produce hot water at a maximum of 30~35℃, which cannot meet the needs of certain application scenarios for higher-grade hot water.

[0004] How to further improve the hot water temperature of the heat recovery system to meet more application scenarios is of great significance to improving the comprehensive energy efficiency of the magnetic levitation chiller and improving the utilization rate of energy. Summary of the invention

[0005] The purpose of the present invention is to provide a hot water recovery system for a magnetic levitation chiller. By connecting a heat pump unit in parallel with the exhaust pipe or liquid supply pipe of the magnetic levitation chiller, the condensing evaporator of the heat pump unit absorbs heat from the exhaust pipe or liquid supply pipe of the magnetic levitation chiller, and hot water above 60°C can be produced, while the energy efficiency of the magnetic levitation chiller is improved.

[0006] Another object of the present invention is to provide a control method for a hot water recovery system of a magnetic levitation chiller.

[0007] The technical solution of the present invention is: A hot water recovery system for a magnetic levitation chiller comprises a magnetic levitation chiller and a heat pump unit. The magnetic suspension chiller comprises a magnetic suspension refrigeration compressor, a first condenser, a throttling device, an economizer and a first evaporator; the magnetic suspension refrigeration compressor, the first condenser, the throttling device, the economizer and the first evaporator are connected to form a main circulation pipeline; and an exhaust pipe is arranged between the magnetic suspension refrigeration compressor and the first condenser, and a liquid supply pipe is arranged between the first condenser and the economizer; The heat pump unit comprises a condenser evaporator, a heat pump unit compressor, a second condenser and a throttling device which are connected in sequence; The heat pump unit is connected in parallel with the exhaust pipe of the magnetic suspension chiller to form a first sub-circulation pipeline. The heat pump unit is used to absorb the condensation heat of the gaseous refrigerant, and then obtains hot water of the set temperature through a heating cycle; Alternatively, the heat pump unit is connected in parallel with the liquid supply pipe of the magnetic levitation chiller to form a second sub-circulation pipeline. The heat pump unit is used to absorb the heat of the liquid refrigerant and then obtain hot water of a set temperature through a heating cycle.

[0008] Preferably, according to the present invention, the refrigerant input end of the condenser evaporator is connected to the exhaust pipe through a branch exhaust pipe, a first three-way switch valve is provided on the branch exhaust pipe, and a branch of the first three-way switch valve is connected to the liquid supply pipe; The refrigerant output end of the condenser evaporator is connected to the first condenser through a liquid outlet pipe, and a second three-way switch valve is arranged on the liquid outlet pipe, and a branch of the second three-way switch valve is connected to the liquid supply pipe; By switching the first three-way switch valve and the second three-way switch valve, the heat pump unit and the exhaust pipe / liquid supply pipe of the magnetic suspension chiller are connected in parallel.

[0009] Preferably according to the present invention, both the branch exhaust pipe and the liquid outlet pipe are provided with a stop valve.

[0010] Preferably according to the present invention, the installation position of the condenser evaporator is higher than the installation position of the first condenser.

[0011] Preferably according to the present invention, the second condenser is a plate heat exchanger.

[0012] Preferably according to the present invention, the second condenser is provided with a cold water inlet pipe and a hot water outlet pipe, and an electric regulating valve is installed on the cold water inlet pipe.

[0013] On the other hand, the present invention provides a control method for a hot water recovery system of a magnetic levitation chiller, which is used to control the hot water recovery system of the magnetic levitation chiller, comprising: Start the magnetic levitation chiller; According to the condensation pressure P of the first condenser in the magnetic suspension chiller c The evaporation pressure P of the first evaporator e The ratio P c / P e To control the switching of the first three-way switch valve and the second three-way switch valve, thereby switching the working mode of the heat pump unit and recycling the waste heat of the magnetic levitation chiller.

[0014] According to the preferred embodiment of the invention, the system further comprises a first condenser pressure sensor and a first evaporator pressure sensor, which are respectively used to obtain the condensing pressure P of the first condenser. c The evaporation pressure P of the first evaporator e ; According to the condensation pressure P of the first condenser in the magnetic suspension chiller c The evaporation pressure P of the first evaporator e The ratio P c / P e To control the switch of the first three-way switch valve and the second three-way switch valve, so as to switch the working mode of the heat pump unit and recycle the waste heat of the magnetic suspension chiller, including: When P c / P e >CR1, CR1 represents the first-level pre-protection pressure ratio of the cooling liquid supply of the magnetic suspension refrigeration compressor. CR1 is determined by experiments based on the pressure ratio range of the safe operation of the magnetic suspension refrigeration compressor; open the first three-way switch valve so that the branch exhaust pipe is only connected to the exhaust pipe; open the second three-way switch valve so that the liquid outlet pipe is only connected to the first condenser; that is, the branch exhaust pipe is not connected to the liquid supply pipe, and the liquid outlet pipe is not connected to the liquid supply pipe; start the heat pump unit so that the heat pump unit is connected in parallel with the exhaust pipe; the heat pump unit starts to run, a part of the gaseous refrigerant circulates in the main circulation pipeline, and the other part of the gaseous refrigerant enters the first sub-circulation pipeline, condenses into liquid refrigerant in the condenser evaporator, and then flows into the first condenser through the liquid outlet pipe under the action of gravity, mixes with the refrigerant in the main circulation pipeline, and continues the refrigeration cycle; When CR2≤P c / P e ≤CR1, CR2 represents the secondary pre-protection pressure ratio of the cooling liquid supply of the magnetic suspension refrigeration compressor. CR2 is determined by experiments based on the pressure ratio range of the safe operation of the magnetic suspension refrigeration compressor. The heat dissipation of the first condenser is reduced to weaken the condensation effect of the magnetic suspension chiller to prevent P c / P e Continue to lower to ensure the cooling of the magnetic suspension refrigeration compressor. At this time, the heat pump unit continues to maintain the working mode in parallel with the exhaust pipe.

[0015] According to the preferred embodiment of the invention, according to the condensation pressure P of the first condenser in the magnetic suspension chiller c The evaporation pressure P of the first evaporator e The ratio P c / P e To control the switch of the first three-way switch valve and the second three-way switch valve, so as to switch the working mode of the heat pump unit and recycle the waste heat of the magnetic suspension chiller, including: When CR3≤P c / P e When CR2 is less than CR3, CR3 represents the minimum pressure ratio of the cooling liquid supply of the magnetic levitation refrigeration compressor. CR3 is determined through experiments based on the pressure ratio range of safe operation of the magnetic levitation refrigeration compressor. The first three-way switch valve is switched so that the branch exhaust pipe is only connected to the liquid supply pipe. The second three-way switch valve is switched so that the liquid outlet pipe is only connected to the liquid supply pipe, so that the heat pump unit is connected in parallel with the liquid supply pipe. The heat pump unit keeps running, a part of the liquid refrigerant circulates in the main circulation pipeline, and the other part of the liquid refrigerant enters the second branch circulation pipeline, and returns to the main circulation pipeline after further cooling in the condenser evaporator. The two parts of the refrigerant are mixed and enter the economizer through the throttling device to continue the refrigeration cycle.

[0016] According to a preferred embodiment of the invention, the system further comprises a three-way regulating valve, a third pressure sensor and a temperature sensor. The three-way regulating valve is arranged on the liquid supply pipe, and the branch of the three-way regulating valve is connected with the branch of the first three-way switch valve; the third pressure sensor is arranged inside the economizer to obtain the internal pressure P of the economizer. m The temperature sensor is set in the liquid supply pipe to obtain the temperature T of the mixed liquid refrigerant in the main circulation pipeline and the second sub-circulation pipeline. h ; The working method further includes: obtaining the temperature T of the mixed liquid refrigerant in the main circulation pipeline and the second sub-circulation pipeline. h and the current internal pressure P of the economizer m The corresponding saturation temperature T m ; The temperature T of the mixed liquid refrigerant in the main circulation pipeline and the second sub-circulation pipeline is controlled by adjusting the opening of the three-way regulating valve in the liquid supply pipe. h , so that T m +T1≥T h ≥T m +T2; T1 and T2 are both experience values; When the load of the magnetic suspension chiller decreases and T h <T m When +T2, the branch of the three-way regulating valve and the heat pump unit are closed.

[0017] The beneficial effects of the present invention are: The present invention provides a hot water recovery system for a magnetic levitation chiller, in which a heat pump unit is connected in parallel with an exhaust pipe or a liquid supply pipe of the magnetic levitation chiller, and a condenser evaporator of the heat pump unit absorbs heat from the exhaust pipe or the liquid supply pipe of the magnetic levitation chiller, and can produce hot water above 60°C, while improving the energy efficiency of the magnetic levitation chiller. When the heat pump unit is connected in parallel with the exhaust pipe, the condenser evaporator in the heat pump unit absorbs part of the condensation heat of the magnetic levitation chiller, reducing the heat entering the first condenser, helping to enhance the condensation effect, reducing the condensation temperature and pressure, and improving the energy efficiency of the chiller. When the heat pump unit is connected in parallel with the liquid supply pipe, the condenser evaporator of the heat pump unit further cools and lowers the temperature of the liquid refrigerant flowing out of the condenser of the magnetic levitation chiller, increasing the supercooling degree of the liquid refrigerant before entering the throttling device, helping to increase the cooling capacity of the unit and improving the refrigeration energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the overall structure of a hot water recovery system for a magnetic levitation chiller provided by the present invention.

[0019] Figure 2This is a structural schematic diagram of a heat pump unit and an exhaust pipe in parallel in a hot water recovery system of a magnetic levitation chiller provided by the present invention.

[0020] Figure 3 This is a structural schematic diagram of a heat pump unit and a liquid supply pipe in parallel in a hot water recovery system of a magnetic levitation chiller provided by the present invention.

[0021] 1. The first evaporator, 2. The first condenser, 3. The magnetic suspension refrigeration compressor, 4. The economizer, 5. The heat pump unit compressor, 6. The condensing evaporator, 7. The second condenser, 8. The throttling device, 9. The filter cartridge, 10. The exhaust pipe, 11. The branch exhaust pipe, 12. The first three-way switch valve, 13. The liquid outlet pipe, 14. The liquid supply pipe, 15. The second three-way switch valve, 16. The three-way regulating valve, 17. The return air pipe, 18. The compressor intermediate air supply pipe, 19. The cold water inlet pipe, 20. The electric regulating valve, 21. The hot water outlet pipe, 22. The stop valve, 23. The temperature sensor. DETAILED DESCRIPTION

[0022] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention as detailed in the appended claims.

[0023] Example 1 The present invention provides a hot water recovery system for a magnetic suspension chiller, such as Figure 1 , Figure 2 and Figure 3 As shown, it includes a magnetic levitation chiller and a heat pump unit. The magnetic suspension chiller comprises a magnetic suspension refrigeration compressor 3, a first condenser 2, a throttling device 8, an economizer 4 and a first evaporator 1; the magnetic suspension refrigeration compressor 3, the first condenser 2, the throttling device 8, the economizer 4 and the first evaporator 1 are connected to form a main circulation pipeline; and an exhaust pipe 10 is arranged between the magnetic suspension refrigeration compressor 3 and the first condenser 2, and a liquid supply pipe 14 is arranged between the first condenser 2 and the economizer 4; Specifically, a return air pipe 17 is provided between the magnetic suspension refrigeration compressor 3 and the first evaporator 1. A filter cartridge 9 and a throttling device 8 are also provided on the liquid supply pipe 14, a compressor intermediate air supply pipe 18 is provided between the economizer 4 and the magnetic suspension refrigeration compressor 3, and a throttling device 8 is provided between the economizer 4 and the evaporator.

[0024] The economizer 4 is a flash economizer; the throttling device 8 is a device for reducing the refrigerant pressure by throttling the refrigerant, for example, it can be an electronic expansion valve.

[0025] The heat pump unit comprises a condenser evaporator 6, a heat pump unit compressor 5, a second condenser 7 and a throttling device 8 which are connected in sequence; The heat pump unit is connected in parallel with the exhaust pipe 10 of the magnetic suspension chiller to form a first sub-circulation pipeline. The heat pump unit is used to absorb the condensation heat of the gaseous refrigerant and then obtain hot water of the set temperature through a heating cycle. Alternatively, the heat pump unit is connected in parallel with the liquid supply pipe 14 of the magnetic suspension chiller to form a second sub-circulation pipeline. The heat pump unit is used to absorb the heat of the liquid refrigerant and then obtain hot water of a set temperature through a heating cycle.

[0026] The magnetic levitation chiller of this embodiment further includes a compressor cooling system, which is not marked in the drawings.

[0027] Compared with using an independent heat pump unit to produce hot water, the system provided by the present invention provides a higher low-temperature heat source for the heat pump unit, the heating cycle energy efficiency is higher under the same water outlet temperature conditions, and the hot water temperature produced under the same pressure ratio conditions is also higher.

[0028] Example 2 The present invention provides a hot water recovery system for a magnetic suspension chiller, which differs from Embodiment 1 in that: The refrigerant input end of the condenser evaporator 6 is connected to the exhaust pipe 10 through a branch exhaust pipe 11, and a first three-way switch valve 12 is provided on the branch exhaust pipe 11, and a branch of the first three-way switch valve 12 is connected to a liquid supply pipe 14; The refrigerant output end of the condenser evaporator 6 is connected to the first condenser 2 through a liquid outlet pipe 13, and a second three-way switch valve 15 is provided on the liquid outlet pipe 13, and a branch of the second three-way switch valve 15 is connected to a liquid supply pipe 14; By switching the first three-way switch valve 12 and the second three-way switch valve 15, the heat pump unit and the exhaust pipe 10 / liquid supply pipe 14 of the magnetic suspension chiller are connected in parallel.

[0029] Example 3 The present invention provides a hot water recovery system for a magnetic suspension chiller, which differs from Embodiment 2 in that: The branch exhaust pipe 11 and the liquid outlet pipe 13 are both provided with a stop valve 22. When the heat pump unit is overhauled, it is convenient to disconnect it from the magnetic suspension chiller.

[0030] Example 4 The present invention provides a hot water recovery system for a magnetic suspension chiller, which differs from Embodiment 1 in that: In order to ensure that the liquid refrigerant coming out of the condenser evaporator 6 of the heat pump unit flows smoothly into the first condenser 2 of the chiller, the installation position of the condenser evaporator 6 is higher than the installation position of the first condenser 2 .

[0031] Example 5 The present invention provides a hot water recovery system for a magnetic suspension chiller, which differs from Embodiment 1 in that: The second condenser 7 is a plate heat exchanger. The plate heat exchanger has a compact structure, is conducive to the miniaturization of the heat pump unit, facilitates the integrated design of the entire heat recovery system, and saves installation space.

[0032] Example 6 The present invention provides a hot water recovery system for a magnetic suspension chiller, which differs from Embodiment 1 in that: The second condenser 7 is provided with a cold water inlet pipe 19 and a hot water outlet pipe 21, and an electric regulating valve 20 is installed on the cold water inlet pipe 19. The hot water flow in the hot water outlet pipe 21 is changed by adjusting the opening of the electric regulating valve 20, and the temperature of the hot water in the hot water outlet pipe 21 is controlled to meet the set hot water temperature requirement. The electric regulating valve 20 can be an electric butterfly valve.

[0033] Example 7 The present invention provides a control method for a hot water recovery system of a magnetic levitation chiller, which is used to implement the control of the hot water recovery system of a magnetic levitation chiller in any one of Embodiments 1 to 6, comprising: Start the magnetic levitation chiller; According to the condensation pressure P of the first condenser 2 in the magnetic suspension chiller c The evaporation pressure P of the first evaporator 1 e The ratio P c / P e To control the opening and closing of the first three-way switch valve 12 and the second three-way switch valve 15, thereby switching the working mode of the heat pump unit and recycling the waste heat of the magnetic suspension chiller.

[0034] Example 8 The present invention provides a control method for a hot water recovery system of a magnetic suspension chiller, which differs from Embodiment 7 in that: The system also includes a first condenser pressure sensor and a first evaporator pressure sensor, which are used to obtain the condensing pressure P of the first condenser 2 respectively. c The evaporation pressure P of the first evaporator 1 e ; The first condenser 2 pressure sensor and the first evaporator 1 pressure sensor are not identified in the accompanying drawings.

[0035] According to the condensation pressure P of the first condenser 2 in the magnetic suspension chiller c The evaporation pressure P of the first evaporator 1e The ratio P c / P e To control the switch of the first three-way switch valve 12 and the second three-way switch valve 15, so as to switch the working mode of the heat pump unit, and recycle the waste heat of the magnetic suspension chiller. Figure 1 , Figure 2 and Figure 3 To illustrate, including: At this time, the connection relationship of the pipeline is as follows Figure 2 As shown, the circulation position of the refrigerant is as follows Figure 2 As shown by the arrow in the middle; when P c / P e >CR1, where CR1 represents the first-level pre-protection pressure ratio of the cooling liquid supply of the magnetic levitation refrigeration compressor 3, which is determined by experiments based on the pressure ratio range for safe operation of the magnetic levitation refrigeration compressor. For example, the preferred value of CR1 is between 1.75-1.85. Open the first three-way switch valve 12 so that the branch exhaust pipe 11 is only connected to the exhaust pipe 10; open the second three-way switch valve 15 so that the liquid outlet pipe 13 is only connected to the first condenser 2; that is, the branch exhaust pipe 11 and the liquid supply pipe 14 are not connected, and the liquid outlet pipe 13 and the liquid supply pipe 14 are not connected; start the heat pump unit so that the heat pump unit is connected in parallel with the exhaust pipe 10; the heat pump unit starts to run, a part of the gaseous refrigerant circulates in the main circulation pipeline, and the other part of the gaseous refrigerant enters the first sub-circulation pipeline, condenses into liquid refrigerant in the condenser evaporator 6, and then flows into the first condenser 2 through the liquid outlet pipe 13 under the action of gravity, mixes with the refrigerant in the main circulation pipeline, and continues the refrigeration cycle; The condenser evaporator 6 absorbs part of the condensation heat of the magnetic suspension chiller, reduces the heat entering the first condenser 2, helps to enhance the condensation effect, lowers the condensation temperature and pressure, and improves the energy efficiency of the chiller.

[0036] When CR2≤P c / P e ≤CR1, CR2 represents the secondary pre-protection pressure ratio of the cooling liquid of the magnetic suspension refrigeration compressor 3, which is determined by experiments based on the pressure ratio range of the safe operation of the magnetic suspension refrigeration compressor. For example, the preferred value of CR2 is between 1.65 and 1.7, then the heat dissipation of the first condenser 2 is reduced to weaken the condensation effect of the magnetic suspension chiller to prevent P c / P e Continue to reduce to ensure cooling of the magnetic suspension refrigeration compressor 3. At this time, the heat pump unit continues to maintain the working mode in parallel with the exhaust pipe 10. For example, the heat dissipation of the first condenser 2 can be reduced by reducing the flow of cooling water of the first condenser 2 or reducing the fan speed of the outdoor cooling tower.

[0037] Example 9 The present invention provides a control method for a hot water recovery system of a magnetic suspension chiller, which differs from Embodiment 7 in that: According to the condensation pressure P of the first condenser in the magnetic suspension chiller c The evaporation pressure P of the first evaporator e The ratio P c / P e To control the switch of the first three-way switch valve and the second three-way switch valve, so as to switch the working mode of the heat pump unit and recycle the waste heat of the magnetic suspension chiller, including: When CR3≤P c / P e When CR2 is less than CR3, CR3 represents the minimum pressure ratio value of the cooling liquid supply of the magnetic suspension refrigeration compressor 3, which is determined by experiments based on the pressure ratio range of the safe operation of the magnetic suspension refrigeration compressor. For example, the preferred value of CR3 is between 1.55 and 1.6. At this time, the connection relationship of the pipeline is as follows: Figure 3 As shown, the circulation position of the refrigerant is as follows Figure 3 As shown by the middle arrow; switch the first three-way switch valve 12 so that the branch exhaust pipe 11 is connected only to the liquid supply pipe 14; switch the second three-way switch valve 15 so that the liquid outlet pipe 13 is connected only to the liquid supply pipe 14; that is, the branch exhaust pipe 11 is not connected to the exhaust pipe 10, and the liquid outlet pipe 13 is not connected to the first condenser 2, so that the heat pump unit is connected in parallel with the liquid supply pipe 14, and the heat pump unit keeps running, a part of the liquid refrigerant circulates in the main circulation pipeline, and the other part of the liquid refrigerant enters the second sub-circulation pipeline, and is further cooled in the condenser evaporator 6, and the liquid refrigerant obtains a greater degree of subcooling, and then flows back to the main circulation pipeline to mix with the main refrigerant. After the two parts of the refrigerant are mixed, they pass through the filter cartridge 9 and the throttling device 8 and enter the economizer 4 to continue the refrigeration cycle.

[0038] Among them, P c / P e The value is calculated every minute.

[0039] The condenser evaporator 6 of the heat pump unit further cools down the liquid refrigerant coming out of the first condenser 2, increasing the supercooling degree of the liquid refrigerant before entering the throttling device 8, which helps to increase the cooling capacity of the unit and improve the refrigeration energy efficiency.

[0040] Example 10 The present invention provides a control method for a hot water recovery system of a magnetic suspension chiller, which differs from Embodiment 9 in that: The system further includes a three-way regulating valve 16, a third pressure sensor and a temperature sensor 23. The three-way regulating valve 16 is arranged on the liquid supply pipe 14, and the branch of the three-way regulating valve 16 is connected to the branch of the first three-way switch valve 12; the third pressure sensor is arranged inside the economizer 4, and is used to obtain the internal pressure P of the economizer 4. m The temperature sensor 23 is used to obtain the temperature T of the mixed liquid refrigerant in the main circulation pipeline and the second sub-circulation pipeline. h Specifically, the temperature sensor 23 may be disposed at a position where the liquid refrigerant in the liquid outlet pipe 13 is mixed with the liquid supply pipe 14; the third pressure sensor is not shown in the accompanying drawings.

[0041] The working method also includes: Get the temperature T of the mixed liquid refrigerant in the main circulation pipeline and the second sub-circulation pipeline h and the current internal pressure P of economizer 4 m The corresponding saturation temperature T m ;P m The corresponding saturation temperature T m Available from existing data.

[0042] The temperature T of the mixed liquid refrigerant in the main circulation pipeline and the second sub-circulation pipeline is controlled by adjusting the opening of the three-way regulating valve 16 in the liquid supply pipe 14. h , so that T m +T1≥T h ≥T m +T2; T1 and T2 are both empirical values, for example, the preferred value of T1 is 6°C, and the preferred value of T2 is 3°C.

[0043] When the load of the magnetic suspension chiller decreases and T h <T m At +T2, the branch of the three-way regulating valve 16 and the heat pump unit are closed.

[0044] This system provides two different solutions. When the heat pump unit is connected in parallel with the exhaust pipe 10, the cooling capacity is increased and the energy efficiency of the chiller is improved from the perspective of reducing the condensing temperature and pressure of the chiller and reducing the power consumption of the compressor; when the heat pump unit is connected in parallel with the liquid supply pipe 14, the energy efficiency of the chiller is improved only from the perspective of increasing the liquid supply supercooling and cooling capacity of the chiller without reducing the pressure ratio and the power consumption of the compressor. The first method can make use of more waste heat of the chiller. Therefore, when certain conditions are met, the working mode of the heat pump unit in parallel with the exhaust pipe 10 is preferentially adopted to maximize the operating energy efficiency of the magnetic levitation chiller; when the working mode of the exhaust pipe 10 is not available, the working mode of the heat pump unit in parallel with the liquid supply pipe 14 is switched to expand the working range of the heat pump unit, and the waste heat of the chiller is used to the maximum extent to produce domestic hot water, thereby improving the comprehensive energy efficiency of the magnetic levitation chiller and the system.

[0045] The above description shows and describes the preferred implementation of the present application, but as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other implementations, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the object concept of this article through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not depart from the spirit and scope of the present application, and should be within the scope of protection of the claims attached to the present application.

Claims

1. A hot water recovery system for a magnetic levitation chiller, characterized in that: Including magnetic levitation chillers and heat pump units, The magnetic suspension chiller comprises a magnetic suspension refrigeration compressor, a first condenser, a throttling device, an economizer and a first evaporator; the magnetic suspension refrigeration compressor, the first condenser, the throttling device, the economizer and the first evaporator are connected to form a main circulation pipeline; and an exhaust pipe is arranged between the magnetic suspension refrigeration compressor and the first condenser, and a liquid supply pipe is arranged between the first condenser and the economizer; The heat pump unit comprises a condenser evaporator, a heat pump unit compressor, a second condenser and a throttling device which are connected in sequence; The heat pump unit is connected in parallel with the exhaust pipe of the magnetic suspension chiller to form a first sub-circulation pipeline. The heat pump unit is used to absorb the condensation heat of the gaseous refrigerant, and then obtains hot water of the set temperature through a heating cycle; Alternatively, the heat pump unit is connected in parallel with the liquid supply pipe of the magnetic levitation chiller to form a second sub-circulation pipeline. The heat pump unit is used to absorb the heat of the liquid refrigerant and then obtain hot water of a set temperature through a heating cycle.

2. A hot water recovery system for a magnetic levitation chiller according to claim 1, characterized in that: The refrigerant input end of the condenser evaporator is connected to the exhaust pipe through a branch exhaust pipe, a first three-way switch valve is provided on the branch exhaust pipe, and a branch of the first three-way switch valve is connected to the liquid supply pipe; the refrigerant output end of the condenser evaporator is connected to the first condenser through a liquid outlet pipe, and a second three-way switch valve is provided on the liquid outlet pipe, and a branch of the second three-way switch valve is connected to the liquid supply pipe; by switching the first three-way switch valve and the second three-way switch valve, the exhaust pipe / liquid supply pipe of the heat pump unit and the magnetic levitation chiller are connected in parallel.

3. A hot water recovery system for a magnetic levitation chiller according to claim 2, characterized in that: Both the branch exhaust pipe and the liquid outlet pipe are provided with stop valves.

4. A hot water recovery system for a magnetic levitation chiller according to claim 1, characterized in that: The installation position of the condenser evaporator is higher than the installation position of the first condenser.

5. The hot water recovery system of a magnetic levitation chiller according to claim 1, characterized in that: The second condenser is a plate heat exchanger.

6. A hot water recovery system for a magnetic levitation chiller according to claim 1, characterized in that: The second condenser is provided with a cold water inlet pipe and a hot water outlet pipe, and an electric regulating valve is installed on the cold water inlet pipe.

7. A control method for a hot water recovery system of a magnetic levitation chiller, characterized in that: The control for realizing the hot water recovery system of the magnetic suspension chiller according to any one of claims 2 to 6 comprises: Start the magnetic levitation chiller; According to the condensation pressure P of the first condenser in the magnetic suspension chiller c The evaporation pressure P of the first evaporator e The ratio P c / P e To control the switching of the first three-way switch valve and the second three-way switch valve, thereby switching the working mode of the heat pump unit and recycling the waste heat of the magnetic levitation chiller.

8. The control method of a hot water recovery system of a magnetic levitation chiller according to claim 7, characterized in that: The system also includes a first condenser pressure sensor and a first evaporator pressure sensor, which are respectively used to obtain the condensing pressure P of the first condenser. c The evaporation pressure P of the first evaporator e ; According to the condensation pressure P of the first condenser in the magnetic suspension chiller c The evaporation pressure P of the first evaporator e The ratio P c / P e To control the switch of the first three-way switch valve and the second three-way switch valve, so as to switch the working mode of the heat pump unit and recycle the waste heat of the magnetic suspension chiller, including: When P c / P e >CR1, CR1 represents the first-level pre-protection pressure ratio of the cooling liquid supply of the magnetic suspension refrigeration compressor, which is determined through experiments based on the pressure ratio range of the safe operation of the magnetic suspension refrigeration compressor; open the first three-way switch valve so that the branch exhaust pipe is only connected to the exhaust pipe; open the second three-way switch valve so that the liquid outlet pipe is only connected to the first condenser, so that the heat pump unit is connected in parallel with the exhaust pipe; the heat pump unit starts to run, a part of the gaseous refrigerant circulates in the main circulation pipeline, and the other part of the gaseous refrigerant enters the first branch circulation pipeline, condenses into liquid refrigerant in the condenser evaporator, and then flows into the first condenser through the liquid outlet pipe under the action of gravity, mixes with the refrigerant in the main circulation pipeline, and continues the refrigeration cycle; When CR2≤P c / P e When ≤CR1, CR2 represents the secondary pre-protection pressure ratio of the cooling liquid supply of the magnetic suspension refrigeration compressor, which is determined through experiments based on the pressure ratio range for safe operation of the magnetic suspension refrigeration compressor, and the heat dissipation of the first condenser is reduced.

9. The control method of a hot water recovery system of a magnetic levitation chiller according to claim 7, characterized in that: According to the condensation pressure P of the first condenser in the magnetic suspension chiller c The evaporation pressure P of the first evaporator e The ratio P c / P e To control the switch of the first three-way switch valve and the second three-way switch valve, so as to switch the working mode of the heat pump unit and recycle the waste heat of the magnetic suspension chiller, including: When CR3≤P c / P e When CR2 is less than CR3, CR3 represents the minimum pressure ratio of the cooling liquid supply of the magnetic levitation refrigeration compressor, which is determined through experiments based on the pressure ratio range of safe operation of the magnetic levitation refrigeration compressor; the first three-way switch valve is switched so that the branch exhaust pipe is only connected to the liquid supply pipe; the second three-way switch valve is switched so that the liquid outlet pipe is only connected to the liquid supply pipe, so that the heat pump unit is connected in parallel with the liquid supply pipe; the heat pump unit keeps running, a part of the liquid refrigerant circulates in the main circulation pipeline, and the other part of the liquid refrigerant enters the second branch circulation pipeline, and returns to the main circulation pipeline after further cooling in the condenser evaporator. The two parts of the refrigerant are mixed and enter the economizer through the throttling device to continue the refrigeration cycle.

10. A control method for a hot water recovery system of a magnetic levitation chiller according to claim 9, characterized in that: The system also includes a three-way regulating valve, a third pressure sensor and a temperature sensor. The three-way regulating valve is arranged on the liquid supply pipe, and the branch of the three-way regulating valve is connected to the branch of the first three-way switch valve; the third pressure sensor is arranged inside the economizer to obtain the internal pressure P of the economizer. m The temperature sensor is set in the liquid supply pipe to obtain the temperature T of the mixed liquid refrigerant in the main circulation pipeline and the second sub-circulation pipeline. h ; The working method further includes: obtaining the temperature T of the mixed liquid refrigerant in the main circulation pipeline and the second sub-circulation pipeline. h and the current internal pressure P of the economizer m The corresponding saturation temperature T m ; By adjusting the opening of the three-way regulating valve in the liquid supply pipe, the temperature T of the mixed liquid refrigerant in the main circulation pipeline and the second sub-circulation pipeline is controlled h , so that T m +T1≥T h ≥T m +T2, T1 and T2 are both experience values; When the load of the magnetic suspension chiller decreases and T h <T m When +T2, the branch of the three-way regulating valve and the heat pump unit are closed.

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