Magnetic levitation water chiller hot water recovery system and control method

Abstract

The present application relates to a kind of magnetic levitation water chiller hot water recovery system and control method, belong to magnetic levitation water chiller technical field.System includes magnetic levitation water chiller and heat pump unit, heat pump unit and the exhaust pipe of magnetic levitation water chiller parallel formation first sub-circulation pipe, heat pump unit is used to absorb the condensation heat of gaseous refrigerant, then, through heating cycle, the hot water of set temperature is obtained;Or, heat pump unit and the liquid supply pipe of magnetic levitation water chiller parallel formation second sub-circulation pipe, heat pump unit is used to absorb the heat of liquid refrigerant, then, through heating cycle, the hot water of set temperature is obtained.In the present application, heat pump unit is obtained by gaseous refrigerant condensation heat or liquid refrigerant heat to absorb the hot water of set temperature by parallel with magnetic levitation water chiller, while enhancing condensing effect, improve the energy efficiency of magnetic levitation water chiller.

Description

Technical Field

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

[0002] Magnetic levitation chillers have the unique advantages of energy saving, 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 and is directly released to the outdoor environment through heat exchange equipment. A few chillers utilize part of the condensation heat by adding heat recovery heat exchangers, and can only produce hot water at a maximum temperature 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 energy utilization. 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 condenser 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:

[0008] A hot water recovery system for a magnetic levitation chiller, comprising a magnetic levitation chiller and a heat pump unit.

[0009] The magnetic levitation chiller includes a magnetic levitation refrigeration compressor, a first condenser, a throttling device, an economizer, and a first evaporator; the magnetic levitation 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 provided between the magnetic levitation refrigeration compressor and the first condenser, and a liquid supply pipe is provided between the first condenser and the economizer;

[0010] The heat pump unit includes a condenser evaporator, a heat pump unit compressor, a second condenser and a throttling device connected in sequence;

[0011] The heat pump unit and the exhaust pipe of the magnetic levitation chiller are connected in parallel to form the 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 the heating cycle;

[0012] 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 the set temperature through a heating cycle.

[0013] According to a preferred embodiment of 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;

[0014] 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;

[0015] 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 levitation chiller are connected in parallel.

[0016] Preferably, according to the present invention, both the branch exhaust pipe and the liquid outlet pipe are provided with a shut-off valve.

[0017] According to the present invention, preferably, the installation position of the condenser evaporator is higher than the installation position of the first condenser.

[0018] According to the present invention, preferably, the second condenser is a plate heat exchanger.

[0019] 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.

[0020] In another aspect, 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:

[0021] Start the magnetic levitation chiller;

[0022] According to the condensing pressure P of the first condenser in the magnetic levitation chiller c The evaporation pressure P of the first evaporator e The ratio P c / P e To control the opening and closing 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.

[0023] According to the preferred embodiment of the present invention, the system further 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 ;

[0024] According to the condensing pressure P of the first condenser in the magnetic levitation chillerc The evaporation pressure P of the first evaporator e The ratio P c / P e To control the opening and closing 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, including:

[0025] When P c / P e >CR1, CR1 represents the first-level pre-protection pressure ratio of the cooling liquid supply of the magnetic levitation refrigeration compressor. CR1 is determined through experiments based on the pressure ratio range of safe operation of the magnetic levitation 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 and the liquid supply pipe are not connected, and the liquid outlet pipe and the liquid supply pipe are not connected; start the heat pump unit so that the heat pump unit is connected in parallel with the exhaust pipe; when the heat pump unit starts running, 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;

[0026] When CR2≤P c / P e When CR1 is less than or equal to CR2, CR2 represents the secondary pre-protection pressure ratio of the cooling liquid supply of the magnetic levitation refrigeration compressor. CR2 is determined by experiments based on the pressure ratio range for safe operation of the magnetic levitation refrigeration compressor. The heat dissipation of the first condenser is reduced to weaken the condensing effect of the magnetic levitation 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.

[0027] According to the preferred embodiment of the present invention, the condensing pressure P of the first condenser in the magnetic suspension chiller is c The evaporation pressure P of the first evaporator e The ratio P c / P e To control the opening and closing 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, including:

[0028] When CR3≤P c / P eWhen 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 for safe operation of the magnetic levitation refrigeration compressor. The first three-way switch valve is switched so that the branch exhaust pipe is connected only to the liquid supply pipe. The second three-way switch valve is switched so that the liquid outlet pipe is connected only 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, with a portion of the liquid refrigerant circulating in the main circulation pipeline and the other portion of the liquid refrigerant entering the second branch circulation pipeline, and returning to the main circulation pipeline after further cooling in the condenser evaporator. The two portions of refrigerant are mixed and enter the economizer through the throttling device to continue the refrigeration cycle.

[0029] 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.

[0030] 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 ;

[0031] The working method further includes: obtaining the temperature T of the liquid refrigerant after mixing 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 ;

[0032] 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;

[0033] When the load of the magnetic levitation chiller decreases and T h <T m At +T2, the branch of the three-way regulating valve and the heat pump unit are closed.

[0034] The beneficial effects of the present invention are:

[0035] The present invention provides a hot water recovery system for a magnetic levitation chiller. A heat pump unit is connected in parallel with the exhaust pipe or liquid supply pipe of the magnetic levitation chiller. The heat pump unit's condenser evaporator absorbs heat from the exhaust pipe or liquid supply pipe of the magnetic levitation chiller, producing 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 a portion of the condensation heat from the magnetic levitation chiller, reducing the amount of heat entering the first condenser, helping to enhance the condensation effect, lowering 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 the liquid refrigerant flowing out of the condenser of the magnetic levitation chiller, increasing the supercooling of the liquid refrigerant before entering the throttling device, helping to increase the cooling capacity of the unit and improve refrigeration energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] 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.

[0037] Figure 2 This is a structural schematic diagram of a heat pump unit and an exhaust pipe connected in parallel in a hot water recovery system of a magnetic levitation chiller provided by the present invention.

[0038] Figure 3 This is a structural schematic diagram of a heat pump unit and a liquid supply pipe connected in parallel in a hot water recovery system of a magnetic levitation chiller provided by the present invention.

[0039] 1. First evaporator, 2. First condenser, 3. Magnetic levitation refrigeration compressor, 4. Economizer, 5. Heat pump unit compressor, 6. Condenser evaporator, 7. Second condenser, 8. Throttling device, 9. Filter cartridge, 10. Exhaust pipe, 11. Branch exhaust pipe, 12. First three-way switch valve, 13. Liquid outlet pipe, 14. Liquid supply pipe, 15. Second three-way switch valve, 16. Three-way regulating valve, 17. Return air pipe, 18. Compressor intermediate air supply pipe, 19. Cold water inlet pipe, 20. Electric regulating valve, 21. Hot water outlet pipe, 22. Stop valve, 23. Temperature sensor. DETAILED DESCRIPTION

[0040] Exemplary embodiments will be described in detail herein, examples of which are illustrated in the accompanying drawings. In the following description, when referring to the drawings, like numbers in different figures represent like or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present invention, as detailed in the appended claims.

[0041] Example 1

[0042] The present invention provides a hot water recovery system for a magnetic levitation chiller, such as Figure 1 、 Figure 2 and Figure 3 As shown, it includes a magnetic levitation chiller and a heat pump unit.

[0043] The magnetic levitation chiller includes a magnetic levitation refrigeration compressor 3, a first condenser 2, a throttling device 8, an economizer 4, and a first evaporator 1. The magnetic levitation 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. In addition, an exhaust pipe 10 is provided between the magnetic levitation refrigeration compressor 3 and the first condenser 2, and a liquid supply pipe 14 is provided between the first condenser 2 and the economizer 4.

[0044] Specifically, a return air pipe 17 is provided between the magnetic suspension refrigeration compressor 3 and the first evaporator 1.

[0045] 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. A throttling device 8 is provided between the economizer 4 and the evaporator.

[0046] The economizer 4 is a flash economizer; the throttling device 8 is a device for reducing the refrigerant pressure by throttling the refrigerant, and may be, for example, an electronic expansion valve.

[0047] The heat pump unit includes a condenser evaporator 6, a heat pump unit compressor 5, a second condenser 7 and a throttling device 8 which are connected in sequence;

[0048] The heat pump unit is connected in parallel with the exhaust pipe 10 of the magnetic levitation 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.

[0049] Alternatively, the heat pump unit is connected in parallel with the liquid supply pipe 14 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 the set temperature through a heating cycle.

[0050] The magnetic levitation chiller of this embodiment further includes a compressor cooling system, which is not marked in the drawings.

[0051] 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 generated under the same pressure ratio conditions is also higher.

[0052] Example 2

[0053] The present invention provides a hot water recovery system for a magnetic levitation chiller, which differs from Example 1 in that:

[0054] The refrigerant input end of the condenser evaporator 6 is connected to the exhaust pipe 10 through a branch exhaust pipe 11. A first three-way switch valve 12 is provided on the branch exhaust pipe 11. The branch of the first three-way switch valve 12 is connected to the liquid supply pipe 14.

[0055] 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 the liquid supply pipe 14;

[0056] 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.

[0057] Example 3

[0058] The present invention provides a hot water recovery system for a magnetic levitation chiller, which differs from Example 2 in that:

[0059] 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.

[0060] Example 4

[0061] The present invention provides a hot water recovery system for a magnetic levitation chiller, which differs from Example 1 in that:

[0062] 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 that of the first condenser 2 .

[0063] Example 5

[0064] The present invention provides a hot water recovery system for a magnetic levitation chiller, which differs from Example 1 in that:

[0065] The second condenser 7 is a plate heat exchanger. The plate heat exchanger has a compact structure, which is conducive to the miniaturization of the heat pump unit, facilitates the integrated design of the entire heat recovery system, and saves installation space.

[0066] Example 6

[0067] The present invention provides a hot water recovery system for a magnetic levitation chiller, which differs from Example 1 in that:

[0068] The second condenser 7 is equipped with a cold water inlet pipe 19 and a hot water outlet pipe 21. An electric regulating valve 20 is installed on the cold water inlet pipe 19. Adjusting the opening of the electric regulating valve 20 changes the flow rate of hot water in the hot water outlet pipe 21, thereby controlling the temperature of the hot water in the hot water outlet pipe 21 to meet the desired hot water temperature. The electric regulating valve 20 can be an electric butterfly valve.

[0069] Example 7

[0070] 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 the magnetic levitation chiller according to any one of embodiments 1 to 6, comprising:

[0071] Start the magnetic levitation chiller;

[0072] According to the condensation pressure P of the first condenser 2 in the magnetic levitation 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 levitation chiller.

[0073] Example 8

[0074] The present invention provides a control method for a hot water recovery system of a magnetic levitation chiller, which differs from Example 7 in that:

[0075] 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 marked in the drawings.

[0076] According to the condensation pressure P of the first condenser 2 in the magnetic levitation chiller c The evaporation pressure P of the first evaporator 1 e 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, thereby switching the working mode of the heat pump unit, and recycling the waste heat of the magnetic suspension chiller. Figure 1 、 Figure 2 and Figure 3 To illustrate, including:

[0077] 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 Pc / 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 and 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;

[0078] The condenser evaporator 6 absorbs part of the condensation heat of the magnetic levitation chiller, reducing the heat entering the first condenser 2, which helps to enhance the condensation effect, reduce the condensation temperature and pressure, and improve the energy efficiency of the chiller.

[0079] When CR2≤P c / P e When CR1 is less than CR2, CR2 represents the secondary pre-protection pressure ratio of the cooling liquid of the magnetic suspension refrigeration compressor 3. It 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. In this case, the heat dissipation of the first condenser 2 is reduced to weaken the condensing effect of the magnetic suspension chiller to prevent P c / P e The temperature continues to decrease to ensure cooling of the magnetic suspension refrigeration compressor 3. At this time, the heat pump unit continues to maintain the parallel operation mode 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 to the first condenser 2 or reducing the fan speed of the outdoor cooling tower.

[0080] Example 9

[0081] The present invention provides a control method for a hot water recovery system of a magnetic levitation chiller, which differs from Example 7 in that:

[0082] According to the condensing pressure P of the first condenser in the magnetic levitation chiller c The evaporation pressure P of the first evaporator e The ratio P c / P eTo control the opening and closing 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, including:

[0083] 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 3. It 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 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. The liquid refrigerant obtains a greater degree of supercooling, 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.

[0084] Among them, P c / P e The value is calculated every minute.

[0085] The condenser evaporator 6 of the heat pump unit further cools 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.

[0086] Example 10

[0087] The present invention provides a control method for a hot water recovery system of a magnetic levitation chiller, which differs from Example 9 in that:

[0088] The system also 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. hSpecifically, the temperature sensor 23 can be set at the position after the liquid refrigerant in the liquid outlet pipe 13 is mixed with the liquid supply pipe 14; the third pressure sensor is not marked in the drawings.

[0089] The working method further comprises:

[0090] 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 based on existing data.

[0091] 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.

[0092] When the load of the magnetic levitation 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.

[0093] 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 subcooling and cooling capacity of the chiller, without reducing the pressure ratio and the power consumption of the compressor. The first method can make greater use of the 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 preferably 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, maximize the use of the waste heat of the chiller to produce domestic hot water, and improve the comprehensive energy efficiency of the magnetic levitation chiller and the system.

[0094] The foregoing description shows and describes preferred embodiments of the present application. However, as previously mentioned, it should be understood that the present application is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Rather, the present application may be used in various other combinations, modifications, and environments, and may be modified within the contemplation of the present invention through the teachings above or through techniques or knowledge in the relevant field. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present application shall be within the scope of protection of the appended claims.

Claims

1. A hot water recovery system for a magnetic levitation chiller, characterized in that: It includes a magnetic levitation chiller and a heat pump unit. The magnetic levitation chiller includes a magnetic levitation refrigeration compressor, a first condenser, a throttling device, an economizer and a first evaporator; the magnetic levitation 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 provided between the magnetic levitation refrigeration compressor and the first condenser, and a liquid supply pipe is provided between the first condenser and the economizer. The heat pump unit includes a condensing evaporator, a heat pump unit compressor, a second condenser and a throttling device connected in sequence. The refrigerant input end of the condensing evaporator is connected to the exhaust pipe through a branch exhaust pipe, and a first three-way switch valve is provided on the branch exhaust pipe, and the branch of the first three-way switch valve is connected to the liquid supply pipe; the refrigerant output end of the condensing 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 the 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. The system is configured according to the condensing pressure P of the first condenser c The evaporation pressure P of the first evaporator e The ratio Pc / Pe dynamically switches the working mode of the heat pump unit: When Pc / Pe > CR1, the heat pump unit and the exhaust pipe of the magnetic levitation chiller are connected in parallel to form the 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 the heating cycle; CR1 represents the first-level pre-protection pressure ratio of the cooling liquid supply of the magnetic levitation refrigeration compressor, which is determined by experiments based on the pressure ratio range of the safe operation of the magnetic levitation refrigeration compressor; when CR2≤P c / P e When CR1 is less than or equal to CR2, the heat dissipation of the first condenser is reduced. CR2 represents the secondary pre-protection pressure ratio of the cooling liquid supply of the magnetic levitation refrigeration compressor, which is determined through experiments based on the pressure ratio range for safe operation of the magnetic levitation refrigeration compressor. When CR3≤Pc / Pe<CR2, the liquid supply pipes of the heat pump unit and the magnetic levitation chiller are connected in parallel to form a second sub-circulation pipeline, and the heat pump unit is used to absorb the heat of the liquid refrigerant and then obtain hot water at a set temperature through a heating cycle; CR3 represents the minimum pressure ratio of the cooling liquid supply of the magnetic levitation refrigeration compressor, and is determined through experiments based on the pressure ratio range for the safe operation of the magnetic levitation refrigeration compressor.

2. A hot water recovery system for a magnetic levitation chiller according to claim 1, characterized in that: Stop valves are provided on both the branch exhaust pipe and the liquid outlet pipe.

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

4. 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.

5. The hot water recovery system of 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 control valve is installed on the cold water inlet pipe.

6. A control method for a hot water recovery system of a magnetic levitation chiller, characterized in that: For controlling the magnetic levitation chiller hot water recovery system according to any one of claims 2-5, it includes: Start the magnetic levitation chiller. According to the condensing pressure P of the first condenser in the magnetic levitation chiller c The evaporation pressure P of the first evaporator e The ratio P c / P e To control the opening and closing 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.

7. The control method of a hot water recovery system of a magnetic levitation chiller according to claim 6, 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 condensing pressure P of the first condenser in the magnetic levitation chiller c The evaporation pressure P of the first evaporator e The ratio P c / P e To control the opening and closing 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, including: When P c / P e When CR1 is higher than CR1, the first three-way switch valve is opened, so that the branch exhaust pipe is connected only to the exhaust pipe; the second three-way switch valve is opened, so that the liquid outlet pipe is connected only to the first condenser, so that the heat pump unit and the exhaust pipe are connected in parallel; the heat pump unit starts to operate, 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, the heat dissipation of the first condenser is reduced.

8. The control method of a hot water recovery system of a magnetic levitation chiller according to claim 6, characterized in that: According to the condensing pressure P of the first condenser in the magnetic levitation chiller c The evaporation pressure P of the first evaporator e The ratio P c / P e To control the opening and closing 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, including: When CR3≤P c / P e When CR<CR2, the first three-way switch valve is switched so that the branch exhaust pipe is connected only to the liquid supply pipe; the second three-way switch valve is switched so that the liquid outlet pipe is connected only to the liquid supply pipe, so that the heat pump unit and the liquid supply pipe are connected in parallel; 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 refrigerant are mixed and enter the economizer through the throttling device to continue the refrigeration cycle.

9. The control method of a hot water recovery system of a magnetic levitation chiller according to claim 8, 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 control 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 levitation chiller decreases and T h <T m At +T2, the branch of the three-way regulating valve and the heat pump unit are closed.

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