A two-phase flow cooling system with multiple evaporation temperatures

Abstract

The present invention relates to a two-phase flow cooling system with multiple evaporation temperatures, comprising a two-phase flow cooling unit, a normal temperature circuit, a low temperature circuit and a compressor, wherein the normal temperature circuit comprises a normal temperature evaporator, the low temperature circuit comprises a thermal expansion valve and a low temperature evaporator, and the compressor is arranged at the return air main of the low temperature circuit; the cooling medium in the two-phase flow cooling unit enters the normal temperature circuit and the low temperature circuit respectively, the cooling medium entering the normal temperature circuit passes through the normal temperature evaporator and then returns to the two-phase flow cooling unit, the cooling medium entering the low temperature circuit is first throttled into a low temperature and low pressure medium by a thermal expansion valve, and then passes through the low temperature evaporator and the compressor in sequence and then returns to the two-phase flow cooling unit. Thus, a cooling circuit with multiple evaporation temperatures is provided for electronic equipment, which meets different heat dissipation requirements and greatly reduces the equipment quantity and complexity of the cooling system.

Description

Technical Field

[0001] The invention relates to the field of cooling technology, and in particular to a two-phase flow cooling system with multiple evaporation temperatures. Background Art

[0002] Two-phase flow cooling technology is a new type of electronic equipment cooling method. Its principle is to use a liquid supply pump to drive the liquid phase change medium into the cold plate of the electronic equipment. The phase change medium absorbs heat in the cold plate, evaporates into a gas-liquid mixture, and enters the heat exchanger. It is condensed into liquid by the external heat sink to form a cycle. Compared with traditional liquid cooling, two-phase flow cooling technology has the advantages of small flow, high heat exchange efficiency, and high energy efficiency ratio. However, for more complex electronic equipment, due to the differences in the structure, power density, and temperature resistance of each device, some electronic equipment needs a lower cooling temperature for heat dissipation, and the evaporation temperature of the two-phase flow cooling system is determined by the external heat sink temperature. In order to obtain a higher energy efficiency ratio, the heat sink usually uses ambient wind or cooling tower, which cannot provide a lower evaporation temperature. If a low-temperature chiller is used to cool this part of the electronic equipment, a set of equipment will require different cooling systems for cooling, there are many types of cooling equipment, the reliability of the cooling system is reduced, and the weight and power consumption are greatly increased. Summary of the invention

[0003] In order to solve the existing technical problems, the present invention provides a two-phase flow cooling system with multiple evaporation temperatures.

[0004] The specific contents of the present invention are as follows: A two-phase flow cooling system with multiple evaporation temperatures, comprising a two-phase flow cooling unit, a normal temperature circuit, a low temperature circuit and a compressor, wherein the normal temperature circuit comprises a normal temperature evaporator, the low temperature circuit comprises a thermal expansion valve and a low temperature evaporator, and the compressor is arranged at the return air main of the low temperature circuit; the cooling medium in the two-phase flow cooling unit enters the normal temperature circuit and the low temperature circuit respectively, the cooling medium entering the normal temperature circuit passes through the normal temperature evaporator and then returns to the two-phase flow cooling unit, and the cooling medium entering the low temperature circuit passes through the thermal expansion valve, the low temperature evaporator and the compressor in turn and then returns to the two-phase flow cooling unit.

[0005] Furthermore, the temperature sensing package of the thermal expansion valve is arranged at the exhaust port of the low-temperature evaporator.

[0006] Furthermore, a solenoid valve is provided in the liquid supply pipe of the low-temperature circuit. The solenoid valve is arranged at the front end of the thermal expansion valve. The cooling medium of the two-phase flow cooling unit enters the low-temperature circuit through the solenoid valve.

[0007] Furthermore, it comprises a plurality of low temperature circuits, and the exhaust ports of the low temperature circuits are all connected to the suction ends of the compressors.

[0008] Furthermore, the two-phase flow cooling unit includes a heat exchanger, a liquid storage tank and a liquid supply pump. The heat exchanger condenses the cooling medium entering the two-phase flow cooling unit and discharges it into the liquid storage tank. The liquid supply pump pumps the cooling supply liquid in the liquid storage tank into the cooling system supply pipe.

[0009] Furthermore, the liquid supply pipe of the normal temperature circuit and the liquid supply pipe of the low temperature circuit are both connected to the liquid supply pipe of the cooling system, the compressor is located in the return air main pipe of the low temperature circuit, the exhaust end of the compressor and the return liquid port of the normal temperature circuit are both connected to the cooling system return liquid pipe, and the cooling system return liquid pipe is connected to the heat exchanger.

[0010] Furthermore, the cooling medium adopts Freon R134a, and both the low-temperature evaporator and the normal-temperature evaporator adopt cold plates.

[0011] The beneficial effects of the present invention are as follows: a low-temperature circuit is added to the two-phase flow cooling system, and a thermal expansion valve is used to throttle the normal-temperature working medium into a low-temperature and low-pressure working medium, thereby providing the electronic equipment with a liquid supply temperature that meets the requirements, eliminating the low-temperature refrigeration water system, greatly reducing the amount and complexity of the cooling system equipment, reducing the volume, weight, and energy consumption of the cooling system, and improving the system reliability; the original low-temperature refrigeration water heat exchange process of the electronic equipment is changed from single-phase heat transfer to phase change heat transfer, thereby improving the heat transfer efficiency and reducing the volume and weight of the heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The specific implementation of the present invention will be further explained below in conjunction with the accompanying drawings.

[0013] Figure 1 A schematic diagram of a two-phase flow cooling system with multiple evaporation temperatures according to the present invention;

[0014] Figure 2 A pressure-enthalpy diagram was run for the system of the present invention. DETAILED DESCRIPTION

[0015] like Figure 1 As shown, this embodiment discloses a two-phase flow cooling system with multiple evaporation temperatures, including a two-phase flow cooling unit 1, a normal temperature circuit, a low temperature circuit and a compressor 5.

[0016] The two-phase flow cooling unit 1 includes a heat exchanger, a liquid storage tank and a liquid supply pump. The heat exchanger condenses the cooling medium entering the two-phase flow cooling unit 1 and discharges it into the liquid storage tank. The liquid supply pump pumps the cooling medium in the liquid storage tank into the cooling system liquid supply pipe.

[0017] The normal temperature loop includes a normal temperature evaporator 6. The supercooled liquid flowing out of the two-phase flow cooling unit 1 enters the normal temperature loop liquid supply pipe through the cooling system liquid supply pipe, and then enters the normal temperature evaporator 6 to absorb heat and evaporate. The normal temperature evaporator 6 supplies the normal temperature cooling equipment. The return liquid port of the normal temperature evaporator 6 is connected to the cooling system return liquid pipe, and the cooling system return liquid pipe is connected to the heat exchanger, and the cooling medium of the normal temperature loop enters the two-phase flow cooling unit 1.

[0018] The low-temperature circuit includes a thermal expansion valve 3 and a low-temperature evaporator 4. The cooling medium enters the low-temperature circuit liquid supply pipe from the cooling system liquid supply pipe. The thermal expansion valve 3 throttles the liquid medium flowing into the low-temperature circuit. The throttled medium flashes from the supercooled liquid to a low-temperature, low-pressure saturated gas-liquid mixture and enters the low-temperature evaporator 4. The low-temperature evaporator 4 is located after the thermal expansion valve 3. The throttled low-temperature, low-pressure medium absorbs the heat of the electronic equipment through the low-temperature evaporator 4 and evaporates into a low-pressure superheated gas.

[0019] The temperature sensing package of the thermal expansion valve 3 is located at the exhaust port of the low-temperature evaporator 4. The opening of the expansion valve is adjusted by detecting the exhaust port temperature to prevent excessive liquid from entering the low-temperature evaporator 4 and causing liquid hammer in the compressor 5.

[0020] In this embodiment, there are multiple low-temperature circuits, and a solenoid valve 2 is provided in front of one or more low-temperature circuits. The solenoid valve 2 is located in the low-temperature circuit liquid supply pipe and is provided at the front end of the thermal expansion valve 3. When the heating device is not working, the phase change medium is cut off to prevent the liquid from entering the compressor 5. The corresponding solenoid valve 2 can be opened or closed according to the cooling requirements of the heating device, thereby controlling the operation of the corresponding low-temperature circuit.

[0021] The compressor 5 is located in the return gas main of the low-temperature circuit, and the air intake port is connected to the exhaust port of each low-temperature evaporator 4, compressing the low-pressure superheated gas discharged from each low-temperature evaporator 4 into high-temperature and high-pressure gas; the exhaust port of the compressor 5 is connected to the liquid return pipe of the cooling system, and the pressurized high-temperature and high-pressure gas is discharged into the liquid return pipe of the cooling system, merged with the liquid return of the normal temperature circuit, and entered the two-phase flow cooling unit 1 to complete a cycle.

[0022] In this application, the low temperature circuit and the normal temperature circuit are connected through the same two-phase flow cooling unit 1, sharing the liquid supply pump and the heat exchanger, and the main circulation of the cooling system is realized by pump drive, and the compression cycle is combined with the pump drive cycle, which solves the problem of the existing pump drive two-phase circulation without low temperature circuit. In this embodiment, the liquid supply temperature in the low temperature circuit and the normal temperature circuit is different, and the pressure enthalpy diagram of its operation is as follows Figure 2 shown.

[0023] Curve 1-2 is the supercooled liquid entering the liquid supply pipe through the boosting effect of the working fluid pump, curve 2-3-4 is the normal temperature circuit, the supercooled liquid enters the normal temperature evaporator 6, and absorbs heat and evaporates. Curve 2-3-4'-5'-6'-4 is the low temperature circuit, where curve 3-4' is the supercooled liquid flashing through the thermal expansion valve 3 to become a low temperature and low pressure gas-liquid mixture, curve 4'-5' is the low temperature gas-liquid mixture evaporating into superheated gas in the low temperature evaporator 4, curve 5'-6' is the low pressure gas being compressed by the compressor 5 to become high pressure gas, curve 6'-4 is the high pressure gas of the compressor 5 entering the system return pipe and mixing with the return liquid of the normal temperature circuit, and curve 4-1 is the system return liquid condensing into supercooled liquid under the action of the heat exchanger, and re-entering the liquid supply pump to complete a cycle.

[0024] In this embodiment, the cooling medium is Freon R134a, and both the low-temperature evaporator 4 and the normal-temperature evaporator 6 use cold plates.

[0025] The specific operation results are as follows: the two-phase flow cooling unit 1 provides power and terminal heat exchange for the cooling system, the liquid supply pressure is about 15 kg, and the return liquid pressure is about 9 kg. Figure 1 The gas-liquid mixture coming back from the electronic equipment is cooled by the two-phase flow cooling unit 1 (not shown). The highest water temperature of the cooling tower is 32°C, and the temperature of the supercooled Freon after cooling is about 40°C. Under the action of the two-phase flow cooling unit 1, the supercooled Freon is divided into two paths. One path enters the normal temperature evaporator 6 to cool the electronic equipment. The evaporation temperature is about 40°C and the evaporation pressure is about 9 kg. The other path is a low-temperature circuit, which passes through the solenoid valve 2 and enters the low-temperature evaporator 4. Under the throttling action of the thermal expansion valve 3, the 40°C liquid R134a flashes into a gas-liquid mixture of 5°C, and the pressure is reduced to about 2.5 kg. After heat exchange in the low-temperature evaporator 4, the 5°C gas-liquid mixture evaporates into a superheated gas of 10°C and enters the compressor 5. After the compressor 5 is pressurized, the gas pressure is increased to about 10 kg. At this time, the normal temperature circuit return liquid pressure is about 9 kg. The high-pressure gas enters the system return liquid pipe and returns to the two-phase flow cooling unit 1 to complete a cycle.

[0026] The cooling system of the present application uses the throttling effect of the thermal expansion valve 3 to provide low-temperature cooling medium for electronic equipment, and uses the pressurization effect of the compressor 5 to discharge the low-pressure gas that has completed the heat exchange into the system return liquid pipeline, completing the system cycle, meeting the cooling temperature requirements of different electronic equipment, removing the low-temperature water system in the system, and inheriting the advantages of phase change heat transfer technology, improving the heat exchange efficiency of the low-temperature circuit, and ultimately greatly reducing the amount and complexity of the cooling system equipment, reducing the volume and weight of the cooling system, power consumption, and improving system reliability. The original low-temperature refrigeration water heat exchange process of the electronic equipment changes from single-phase heat transfer to phase change heat transfer, which greatly improves the heat transfer efficiency and reduces the volume and weight of the heat exchanger.

[0027] Many specific details are described in the above description to facilitate a full understanding of the present invention. However, the above description is only a preferred embodiment of the present invention. The present invention can be implemented in many other ways different from those described herein, so the present invention is not limited to the specific implementation disclosed above. At the same time, any person familiar with the art can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A two-phase flow cooling system with multiple evaporation temperatures, characterized in that: It includes a two-phase flow cooling unit, a normal temperature circuit, a low temperature circuit and a compressor. The normal temperature circuit includes a normal temperature evaporator, the low temperature circuit includes a thermal expansion valve and a low temperature evaporator, and the compressor is arranged at the return air main of the low temperature circuit; the cooling medium in the two-phase flow cooling unit enters the normal temperature circuit and the low temperature circuit respectively, the cooling medium entering the normal temperature circuit passes through the normal temperature evaporator and then returns to the two-phase flow cooling unit, and the cooling medium entering the low temperature circuit passes through the thermal expansion valve, the low temperature evaporator and the compressor in sequence and then returns to the two-phase flow cooling unit; the temperature sensing package of the thermal expansion valve is arranged at the exhaust port of the low temperature evaporator; the liquid supply pipe of the low temperature circuit is provided with an electromagnetic valve, and the electromagnetic valve is arranged at the thermal expansion valve. At the front end of the valve, the cooling medium of the two-phase flow cooling unit enters the low-temperature circuit through the solenoid valve; it includes several low-temperature circuits, and the exhaust ports of the low-temperature circuits are all connected to the suction end of the compressor; the two-phase flow cooling unit includes a heat exchanger, a liquid storage tank and a liquid supply pump, the heat exchanger condenses the cooling medium entering the two-phase flow cooling unit and discharges it into the liquid storage tank, and the liquid supply pump pumps the cooling supply liquid in the liquid storage tank into the cooling system supply pipe; the normal temperature circuit supply pipe and the low temperature circuit supply pipe are both connected to the cooling system supply pipe, the compressor is located in the return air main pipe of the low temperature circuit, the exhaust end of the compressor and the return liquid port of the normal temperature circuit are both connected to the cooling system return pipe, and the cooling system return pipe is connected to the heat exchanger.

2. The two-phase flow cooling system with multiple evaporation temperatures according to claim 1 is characterized in that: The cooling medium is Freon R134a, and both the low-temperature evaporator and the normal-temperature evaporator use cold plates.

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