A pump-driven evaporative cooling air conditioning system for a data center and its oil return method

Abstract

The present invention discloses a pump-driven evaporative cooling air conditioning system for a data center and its oil return method, which includes a first valve, a second valve, a third valve, an expansion valve, a gas-liquid separator, a compressor, an oil separator, a condenser, a regenerator, a low-pressure circulation accumulator and an evaporator. An evaporator inlet pipe is connected between the low-pressure circulation accumulator and the evaporator. One end of the main condenser pipeline is arranged on the low-pressure circulation accumulator, and the other end of the main condenser pipeline is successively provided with a compressor suction pipe and an oil return pipe after passing through the expansion valve, the regenerator, the condenser, the oil separator, the compressor, the gas-liquid separator and the second valve. In the present invention, the refrigerant oil automatically flows into the compressor through the oil return pipe, and the regenerator can gasify the refrigerant to prevent liquid slugging of the compressor when the liquid return amount is large. The refrigerant pump drives the flow of the refrigerant at the end, which is more conducive to bringing the lubricating oil attached to the evaporator return air pipe back to the low-pressure circulation accumulator, effectively solving the oil return problem at the unfavorable end.

Description

Technical Field

[0001] The present invention belongs to the technical field of air-conditioning refrigeration systems, and particularly provides a pump-driven evaporative cooling air-conditioning system for a data center and an oil return method thereof. Background Art

[0002] With the rapid development of 5G mobile communication, cloud computing, big data, etc., the number of data centers around the world has exceeded 8 million, consuming about 1.1% - 1.5% of the global electricity consumption. Therefore, the energy-saving demand of data centers is very urgent. Among the total energy consumption of data centers, the energy consumption of air-conditioning equipment accounts for about 40%. Traditional data center air-conditioning systems need to operate compressors throughout the year, and generally have the problem of high system energy consumption. The heat pipe and vapor compression composite air-conditioning system can comprehensively improve the system performance and is gradually applied to data center cooling projects.

[0003] However, in terms of the condenser cooling mode, many heat pipe and vapor compression composite computer room cooling systems still use air cooling, with low heat exchange efficiency. For the end system of a data center cooling system with a large number of evaporators arranged in a relatively dispersed manner, the liquid supply capacity of a compound air-conditioning system using a direct expansion liquid supply method is limited. The refrigerant pump forced liquid supply system is beneficial to evenly distribute the liquid to each evaporator and achieve sufficient cooling. However, under high pressure, the refrigerant and the refrigeration oil are limitedly soluble, and it is difficult for the oil separator to completely separate all the refrigeration oil in the refrigerant and refrigeration oil mixture at the compressor outlet. Therefore, after the high-pressure refrigerant passes through the throttle and enters the low-pressure circulation barrel, it often carries a part of the refrigeration oil. Since the inside of the low-pressure circulation barrel is in a low-temperature and low-pressure environment, at this time, fluorine and the refrigerant are partially miscible, and it is difficult to return the refrigeration oil. Continuously returning the refrigeration oil accumulated in the low-pressure circulation barrel to the compressor is an important prerequisite for the stable operation of the system. Summary of the Invention

[0004] To solve the above problems, the present invention provides a pump-driven evaporative cooling air-conditioning system for a data center and an oil return method thereof.

[0005] Embodiment 1

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows: A pump-driven evaporative cooling air conditioning system for a data center, comprising a first valve, a second valve, a third valve, an expansion valve, a gas-liquid separator, a compressor, an oil separator, a condenser, a regenerator, a low-pressure circulation accumulator, a refrigerant pump and an evaporator. An evaporator inlet pipe is connected between the low-pressure circulation accumulator and the evaporator. One end of an evaporator return pipe is provided on the evaporator, and the other end of the evaporator return pipe is arranged in the low-pressure circulation accumulator. One end of a condenser main pipe is provided on the low-pressure circulation accumulator. The other end of the condenser main pipe is sequentially provided with a compressor suction pipe and a return oil pipe after passing through the expansion valve, the regenerator, the condenser, the oil separator, the compressor, the gas-liquid separator and the second valve, and the compressor suction pipe is arranged in the low-pressure circulation accumulator. The return oil pipe passes through the regenerator and the third valve and is arranged in the low-pressure circulation accumulator. A condenser branch pipe is arranged outside the condenser main pipe. The two ends of the condenser branch pipe are respectively connected to the outside of the oil separator and the condenser main pipe outside the second valve, and a first valve is arranged on the condenser branch pipe. The compressor is connected to the oil separator through a pipeline.

[0007] Further, it further comprises a water level control valve, a blowdown valve, a packing, a water tank, a spray head, a water pump and a water guide pipe. The water tank is installed on the lower side of the inner cavity of the condenser, and the blowdown valve is communicated with the water tank. The water level control valve is assembled in the water tank, and the water level control valve is electrically connected to an external control device through a wire. The packing is assembled in the middle of the inner cavity of the condenser. The spray head is assembled on the upper side of the inner cavity of the condenser. The two ends of the water guide pipe are respectively connected to the water tank and the spray head, and the water pump is arranged on the water guide pipe. A fan is assembled on the upper side of the condenser.

[0008] Further, it further comprises a liquid level gauge, and the liquid level gauge is arranged on the low-pressure circulation accumulator.

[0009] Further, the type of the liquid level gauge is tuning fork vibration type, magnetic float type, pressure type, ultrasonic type, sonar wave type, magnetic flap type or radar type.

[0010] Further, the compressor suction pipe and the evaporator return pipe are both located on the upper side of the inner cavity of the low-pressure circulation accumulator. The return oil pipe is located on the lower side of the inner cavity of the low-pressure circulation accumulator, and return oil holes are uniformly arranged at the lower end of the return oil pipe.

[0011] Further, the type of the regenerator is plate heat exchanger, shell-and-tube heat exchanger, tube-shell heat exchanger, cross-flow heat exchanger or spiral plate heat exchanger.

[0012] Further, the type of the compressor is a lubricant-containing compressor such as a screw compressor, a scroll compressor, or a centrifugal compressor. The compressor is equipped with an oil level sensor, and the type of the oil level sensor is a photoelectric oil level sensor, a capacitive oil level sensor, or a differential pressure oil level sensor.

[0013] Embodiment 2

[0014] An oil return method for a pump-driven evaporative cooling air conditioning system for a data center is realized by using a pump-driven evaporative cooling air conditioning system for a data center as described in Embodiment 1. When the oil level in the compressor is lower than the safety value, the first valve is closed, the second valve, the third valve, and the expansion valve are opened, and the refrigerant pump is turned on. The refrigerant pump drives the refrigerant to flow, driving the lubricating oil accumulated on the inner wall of the evaporator to flow into the low-pressure circulation accumulator.

[0015] Multiple oil return holes on the oil return pipe uniformly absorb the lubricating oil and liquid refrigerant in the low-pressure circulation accumulator. After passing through the regenerator, the liquid refrigerant is vaporized. The gaseous refrigerant and the lubricating oil then flow into the main condenser pipeline. At the same time, the compressor suction pipe guides the gaseous refrigerant in the low-pressure circulation accumulator into the main condenser pipeline. The lubricating oil flows back into the compressor, and the gaseous refrigerant flows through the main condenser pipeline and the condenser, causing the lubricating oil accumulated on its inner wall to flow into the low-pressure circulation accumulator.

[0016] Embodiment 3

[0017] Hot air pipe mode. When the outdoor ambient temperature is relatively low, the second valve, the compressor, and the third valve are closed, the first valve and the refrigerant pump are turned on. The liquid refrigerant flows out of the low-pressure circulation accumulator and is driven by the refrigerant pump into the evaporator, exchanges heat with the indoor hot air and becomes a gas-liquid two-phase, then flows through the evaporator return pipe and returns to the low-pressure circulation accumulator. The gas-liquid two-phase refrigerant is separated in the low-pressure circulation accumulator. The gaseous refrigerant passes through the main condenser pipeline and the condenser, and exchanges heat at the condenser and becomes a liquid refrigerant, and finally flows back to the low-pressure circulation accumulator. In this mode, the frequency of the fluorine pump is adjusted according to the outlet air temperature of the cabinet, the frequency of the outdoor unit condenser fan is adjusted according to the evaporation temperature, and at the same time, it should be ensured that the evaporation pressure is not lower than a certain value.

[0018] Embodiment 4

[0019] Evaporative cooling heat pipe mode. When the outdoor ambient temperature is relatively low and the air-cooled heat pipe mode cannot meet the heat load, based on Embodiment 3, the water pump is turned on. The liquid refrigerant flows out from the low-pressure circulation accumulator and is driven by the refrigerant pump into the evaporator, exchanges heat with the indoor hot air and becomes a gas-liquid two-phase, then flows through the evaporator return pipe and returns to the low-pressure circulation accumulator. The gas-liquid two-phase refrigerant is separated in the low-pressure circulation accumulator. The gaseous refrigerant passes through the condenser. In the condenser, the water pump is turned on to drive the water in the water tank to flow through the water guide pipe to the spray head, and the sprayed water falls onto the main condenser pipeline in the condenser to achieve water cooling. At the same time, air cooling is achieved through the fan. With the cooperation of water cooling and air cooling, the gaseous refrigerant exchanges heat and becomes a liquid refrigerant, and finally flows back to the low-pressure circulation accumulator. When ending this mode, the water pump should be turned off and the drain valve should be opened to drain the water in the water tank. In this mode, the frequency of the fluorine pump is adjusted according to the cabinet outlet air temperature, the frequency of the outdoor unit condenser fan is adjusted according to the evaporation temperature, and at the same time, it should be ensured that the evaporation pressure is not lower than a certain value.

[0020] Embodiment 5

[0021] Air-cooled vapor compression mode. When the outdoor ambient temperature is relatively high, the first valve and the third valve are closed, and the second valve, the compressor and the refrigerant pump are turned on. The liquid refrigerant flows out from the low-pressure circulation accumulator and is driven by the refrigerant pump into the evaporator, exchanges heat with the indoor hot air in the evaporator and becomes a gas-liquid two-phase, then returns to the low-pressure circulation accumulator. The gaseous refrigerant in the low-pressure circulation accumulator sequentially passes through the gas-liquid separator, the compressor, the oil separator and enters the condenser for heat exchange, and then flows back to the low-pressure circulation accumulator after throttling through the expansion valve. In this mode, the frequency of the fluorine pump is adjusted according to the cabinet outlet air temperature, the frequency of the outdoor unit compressor is adjusted according to the evaporation temperature, the frequency of the condenser fan is adjusted according to the condensation temperature, and the opening degree of the expansion valve is adjusted according to the liquid level.

[0022] Embodiment 6

[0023] Evaporative cooling vapor compression mode. When the outdoor ambient temperature is relatively high and the air-cooled vapor compression mode cannot meet the heat load, based on Embodiment 5, the water pump is turned on. The liquid refrigerant flows out from the low-pressure circulation accumulator, is driven by the refrigerant pump and enters the evaporator. After heat exchange with the indoor hot air in the evaporator, it becomes a gas-liquid two-phase, and then returns to the low-pressure circulation accumulator. The gaseous refrigerant in the low-pressure circulation accumulator sequentially passes through the gas-liquid separator, the compressor, and the oil separator and enters the condenser. In the condenser, the water pump is turned on to drive the water in the water tank to flow through the water guide pipe to the spray head, and the sprayed water falls on the main condenser pipeline in the condenser to achieve water cooling. At the same time, air cooling is achieved through the fan. Under the cooperation of water cooling and air cooling, the gaseous refrigerant exchanges heat and becomes a liquid refrigerant, and then flows back to the low-pressure circulation accumulator after throttling through the expansion valve. When ending this mode, the water pump should be turned off, and at the same time, the drain valve is opened to drain the water. In this mode, the frequency of the fluorine pump is adjusted according to the cabinet outlet air temperature, the frequency of the outdoor unit compressor is adjusted according to the evaporation temperature, the frequency of the condenser fan is adjusted according to the condensation temperature, and the opening degree of the expansion valve is adjusted according to the liquid level.

[0024] The beneficial effects of using the present invention are as follows:

[0025] 1. When the environmental temperature is relatively low, the refrigerant pump is turned on to operate the heat pipe mode, which can make full use of the natural cold source for cooling, saving the energy consumption of the compressor and having good energy-saving effects.

[0026] 2. When the air-cooled heat pipe mode cannot meet the refrigeration demand, the evaporative cooling mode is operated, increasing the applicable range of the heat pipe mode and further achieving energy saving.

[0027] 3. When the environmental temperature is relatively high, the compressor and the refrigerant pump are turned on simultaneously to operate the vapor compression mode, providing sufficient cooling capacity for the indoor.

[0028] 4. The refrigerant pump liquid supply method is conducive to uniform liquid distribution among multiple evaporators. The head of the pump can effectively overcome the frictional resistance during the refrigerant flow process, preventing insufficient liquid supply to each evaporator at the end.

[0029] 5. Solve the problem of oil return in the refrigerant pump liquid supply system. The refrigerant oil automatically flows into the compressor through the oil return pipe, and the regenerator can vaporize the refrigerant to prevent liquid slugging of the compressor when the liquid return volume is large. The refrigerant pump drives the refrigerant flow at the end, which is more conducive to bringing the lubricating oil attached to the evaporator return air pipe back to the low-pressure circulation accumulator, effectively solving the oil return problem at the unfavorable end. Description of the Drawings

[0030] Figure 1 It is the system diagram of the present invention.

[0031] The reference numerals include: 1, the first valve; 2, the second valve; 3, the water level control valve; 4, the sewage valve; 5, the third valve; 6, the expansion valve; 7, the gas-liquid separator; 8, the compressor; 9, the oil separator; 10, the condenser; 11, the packing; 12, the water tank; 13, the water pump; 14, the regenerator; 15, the low-pressure circulation accumulator; 16, the liquid level gauge; 17, the refrigerant pump; 18, the evaporator; 19, the compressor suction pipe; 20, the evaporator return pipe; 21, the oil return pipe; 22, the water guide pipe; 23, the main condenser pipeline; 24, the branch condenser pipeline; 25, the evaporator inlet pipe. Specific Embodiment

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] Embodiment 1

[0034] Referring to Figure 1 , a pump-driven evaporative cooling air conditioning system for a data center, includes the first valve 1, the second valve 2, the third valve 5, the expansion valve 6, the gas-liquid separator 7, the compressor 8, the oil separator 9, the condenser 10, the regenerator 14, the low-pressure circulation accumulator 15, the refrigerant pump 17 and the evaporator 18. There is an evaporator inlet pipe 25 communicating between the low-pressure circulation accumulator 15 and the evaporator 18. One end of the evaporator return pipe 20 is provided on the evaporator 18, and the other end of the evaporator return pipe 20 is arranged inside the low-pressure circulation accumulator 15. One end of the main condenser pipeline 23 is provided on the low-pressure circulation accumulator 15. The other end of the main condenser pipeline 23 passes through the expansion valve 6, the regenerator 14, the condenser 10, the oil separator 9, the compressor 8, the gas-liquid separator 7 and the second valve 2 in sequence, and then the compressor suction pipe 19 and the oil return pipe 21 are provided. The compressor suction pipe 19 is arranged inside the low-pressure circulation accumulator 15. The oil return pipe 21 passes through the regenerator 14 and the third valve 5 and is arranged inside the low-pressure circulation accumulator 15. The main condenser pipeline 23 is provided with a branch condenser pipeline 24 on the outside. The two ends of the branch condenser pipeline 24 are respectively communicated to the outside of the oil separator 9 and the main condenser pipeline 23 outside the second valve 2, and a first valve 1 is provided on the branch condenser pipeline 24. The compressor 8 and the oil separator 9 are connected by a pipeline.

[0035] Both the main condenser pipeline 23 and the oil return pipe 21 pass through the regenerator 14 to realize the heat exchange between the refrigerant at the outlet of the condenser 12 and the liquid refrigerant in the oil return pipe 21, vaporize the liquid refrigerant, and make the oil return work proceed smoothly.

[0036] Specifically, it further includes a water level control valve 3, a sewage valve 4, a packing 11, a water tank 12, a spray head, a water pump 13 and a water conduit 22. The water tank 12 is installed on the lower side of the inner cavity of the condenser 10, and the sewage valve 4 is communicated with the water tank 12. The water level control valve 3 is assembled in the water tank 12, and the water level control valve 3 is electrically connected to an external control device through a wire. The packing 11 is assembled in the middle of the inner cavity of the condenser 10. The spray head is assembled on the upper side of the inner cavity of the condenser 10. The two ends of the water conduit 22 are respectively connected to the water tank 12 and the spray head, and the water pump 13 is arranged on the water conduit 22. A fan is assembled on the upper side of the condenser 10.

[0037] At the condenser 10, air cooling and water cooling can be carried out simultaneously for efficient heat exchange.

[0038] Specifically, it further includes a liquid level gauge 16, and the liquid level gauge 16 is arranged on the low-pressure circulation accumulator 15.

[0039] Specifically, the type of the liquid level gauge 16 is a tuning fork vibration type, a magnetic float type, a pressure type, an ultrasonic type, a sonar wave type, a magnetic turning plate type or a radar type. The liquid level gauge 16 is used to monitor the liquid level in the low-pressure circulation accumulator 15.

[0040] Specifically, both the compressor suction pipe 19 and the evaporator return pipe 20 are located on the upper side of the inner cavity of the low-pressure circulation accumulator 15, and the oil return pipe 21 is located on the lower side of the inner cavity of the low-pressure circulation accumulator 15, and oil return holes are evenly opened at the lower end of the oil return pipe 21.

[0041] The compressor suction pipe 19 and the evaporator return pipe 20 convey gaseous refrigerant, and the oil return pipe 21 evenly absorbs the refrigeration oil and the liquid refrigerant in the low-pressure circulation accumulator 15 through the oil return holes for oil recovery.

[0042] Specifically, the type of the regenerator 14 is a plate heat exchanger, a shell-and-tube heat exchanger, a tube-shell heat exchanger, a cross-flow heat exchanger or a spiral plate heat exchanger, which is used for heat exchange with the liquid refrigerant to turn it into gaseous refrigerant.

[0043] Specifically, the type of the compressor 8 is a compressor containing lubricating oil such as a screw type, a scroll type or a centrifugal type. The compressor 8 is equipped with an oil level sensor, and the type of the oil level sensor is an optoelectronic oil level sensor, a capacitive oil level sensor or a differential pressure oil level sensor.

[0044] Embodiment 2

[0045] The oil return method of a pump-driven evaporative cooling air conditioning system for a data center is realized by using a pump-driven evaporative cooling air conditioning system for a data center as described in Embodiment 1. When the oil level in the compressor 8 is lower than the safety value, the first valve 1 is closed, the second valve 2, the third valve 5 and the expansion valve 6 are opened, and the refrigerant pump 17 is turned on. The refrigerant pump 17 drives the refrigerant to flow, driving the lubricating oil accumulated on the inner wall of the evaporator 18 to flow into the low-pressure circulation accumulator 15;

[0046] Multiple oil return holes on the oil return pipe 21 evenly absorb the lubricating oil and liquid refrigerant in the low-pressure circulation accumulator 15. After passing through the regenerator 14, the liquid refrigerant is vaporized. The gaseous refrigerant and the lubricating oil will then flow into the condenser main pipeline 23. At the same time, the compressor suction pipe 19 guides the gaseous refrigerant in the low-pressure circulation accumulator 15 into the condenser main pipeline 23. The lubricating oil flows back into the compressor 8, and the gaseous refrigerant flows through the condenser main pipeline 23 and the condenser 10, and the lubricating oil accumulated on its inner wall flows into the low-pressure circulation accumulator 15.

[0047] The above mode is the oil return mode, in which the liquid refrigerant is heated and vaporized by the refrigerant on the high-temperature side in the regenerator 14 to prevent liquid slugging of the compressor 8.

[0048] If the oil return amount is large, the third valve 5 can be adjusted to increase the oil return amount and improve the oil return speed. The refrigerant pump 17 drives the refrigerant to flow, driving the oil accumulated on the pipe wall to flow back to the low-pressure circulation accumulator 15, which can effectively solve the problem of oil return at the end.

[0049] In this mode, the expansion valve 6 controls the liquid level to be maintained within a certain height range. When the oil return mode is running, the compressor 8 gradually increases its frequency until the oil level alarm disappears and then continues to run normally.

[0050] Embodiment 3

[0051] When the outdoor ambient temperature is relatively low, the second valve 2, the compressor 8 and the third valve 5 are closed, the first valve 1 and the refrigerant pump 17 are turned on. The liquid refrigerant flows out of the low-pressure circulation accumulator 15 and is driven by the refrigerant pump 17 into the evaporator 18, exchanges heat with the indoor hot air and becomes a gas-liquid two-phase, then flows through the evaporator return pipe 20 and returns to the low-pressure circulation accumulator 15. The gas-liquid two-phase refrigerant is separated in the low-pressure circulation accumulator 15. The gaseous refrigerant passes through the condenser main pipeline 23 through the condenser 10, and exchanges heat at the condenser 10 and becomes a liquid refrigerant, and finally flows back to the low-pressure circulation accumulator 15.

[0052] The above mode is the air-cooled heat pipe mode. In this mode, the frequency of the fluorine pump is adjusted according to the outlet air temperature of the cabinet, and the frequency of the outdoor unit condenser fan is adjusted according to the evaporation temperature. At the same time, it should be ensured that the evaporation pressure is not lower than a certain value.

[0053] Embodiment 4

[0054] When the outdoor ambient temperature is relatively low and the air-cooled heat pipe mode cannot meet the heat load, on the basis of Embodiment 3, the water pump 13 is turned on. The liquid refrigerant flows out from the low-pressure circulation accumulator 15, is driven by the refrigerant pump 17 and enters the evaporator 18, exchanges heat with the indoor hot air and becomes a gas-liquid two-phase, then flows through the evaporator return pipe 20 and returns to the low-pressure circulation accumulator 15. The gas-liquid two-phase refrigerant is separated in the low-pressure circulation accumulator 15. The gaseous refrigerant passes through the condenser 10. Inside the condenser 10, the water pump 13 is turned on to drive the water in the water tank 12 to flow through the water guide pipe 22 to the spray head, and the sprayed water falls onto the main condenser pipeline 23 in the condenser 10 to achieve water cooling. At the same time, air cooling is achieved through the fan. With the cooperation of water cooling and air cooling, the gaseous refrigerant exchanges heat and becomes a liquid refrigerant, and finally flows back to the low-pressure circulation accumulator 15.

[0055] The above mode is the evaporative cooling heat pipe mode. When ending this mode, the water pump 13 should be turned off and the drain valve 4 should be opened to drain the water in the water tank 12.

[0056] In this mode, the frequency of the fluorine pump is adjusted according to the cabinet outlet air temperature, the frequency of the outdoor unit condenser fan is adjusted according to the evaporation temperature, and at the same time, the evaporation pressure should be ensured not to be lower than a certain value.

[0057] Embodiment 5

[0058] When the outdoor ambient temperature is relatively high, the first valve 1 and the third valve 5 are closed, and the second valve 2, the compressor 8 and the refrigerant pump 17 are turned on. The liquid refrigerant flows out from the low-pressure circulation accumulator 15, is driven by the refrigerant pump 17 and enters the evaporator 18, exchanges heat with the indoor hot air in the evaporator 18 and becomes a gas-liquid two-phase, then returns to the low-pressure circulation accumulator 15. The gaseous refrigerant in the low-pressure circulation accumulator 15 sequentially passes through the gas-liquid separator 7, the compressor 8, the oil separator 9 and enters the condenser 10 for heat exchange, and then flows back to the low-pressure circulation accumulator 15 after throttling through the expansion valve 6.

[0059] The above mode is the air-cooled vapor compression mode. In this mode, the frequency of the fluorine pump is adjusted according to the cabinet outlet air temperature, the frequency of the outdoor unit compressor is adjusted according to the evaporation temperature, the frequency of the condenser fan is adjusted according to the condensation temperature, and the opening of the expansion valve is adjusted according to the liquid level.

[0060] Embodiment 6

[0061] When the outdoor ambient temperature is relatively high and the air-cooled vapor compression mode cannot meet the heat load, on the basis of Embodiment Five, the water pump 13 is turned on. The liquid refrigerant flows out of the low-pressure circulation accumulator 15, is driven by the refrigerant pump 17 and enters the evaporator 18. After exchanging heat with the indoor hot air in the evaporator 18, it becomes a gas-liquid two-phase, and then returns to the low-pressure circulation accumulator 15. The gaseous refrigerant in the low-pressure circulation accumulator 15 sequentially passes through the gas-liquid separator 7, the compressor 8, and the oil separator 9 and enters the condenser 10. In the condenser 10, the water pump 13 is turned on to drive the water in the water tank 12 to flow through the water guide pipe 22 to the spray head, and the sprayed water falls on the main condenser pipeline 23 in the condenser 10 to achieve water cooling. At the same time, air cooling is achieved through the fan. With the cooperation of water cooling and air cooling, the gaseous refrigerant exchanges heat and becomes a liquid refrigerant, and then flows back to the low-pressure circulation accumulator 15 after throttling through the expansion valve 6.

[0062] The above mode is the evaporative cooling vapor compression mode. When ending this mode, the water pump 13 should be turned off, and at the same time, the drain valve 4 should be opened to drain the water in the water tank 12.

[0063] In this mode, the frequency of the fluorine pump is adjusted according to the cabinet outlet air temperature, the frequency of the outdoor unit compressor 8 is adjusted according to the evaporation temperature, the frequency of the condenser 10 fan is adjusted according to the condensation temperature, and the opening of the expansion valve 6 is adjusted according to the liquid level.

[0064] The above content is only the preferred embodiment of the present invention. For those of ordinary skill in the art, according to the idea of the present invention, many changes can be made in the specific implementation manner and application scope. As long as these changes do not depart from the concept of the present invention, they all belong to the protection scope of the present invention.

Claims

1. A pump-driven evaporative cooling air conditioning system for a data center, characterized in that: It includes a first valve (1), a second valve (2), a third valve (5), an expansion valve (6), a gas-liquid separator (7), a compressor (8), an oil separator (9), a condenser (10), a regenerator (14), a low-pressure circulation accumulator (15), a refrigerant pump (17) and an evaporator (18). There is an evaporator inlet pipe (25) communicating between the low-pressure circulation accumulator (15) and the evaporator (18). One end of an evaporator return pipe (20) is arranged on the evaporator (18), and the other end of the evaporator return pipe (20) is arranged inside the low-pressure circulation accumulator (15). One end of a condenser main pipeline (23) is arranged on the low-pressure circulation accumulator (15). The other end of the condenser main pipeline (23) sequentially passes through the expansion valve (6), the regenerator (14), the condenser (10), the oil separator (9), the compressor (8), the gas-liquid separator (7) and the second valve (2), and then a compressor suction pipe (19) and an oil return pipe (21) are arranged. The compressor suction pipe (19) is arranged inside the low-pressure circulation accumulator (15). The oil return pipe (21) passes through the regenerator (14) and the third valve (5) and is arranged inside the low-pressure circulation accumulator (15). A condenser branch pipeline (24) is arranged outside the condenser main pipeline (23). Both ends of the condenser branch pipeline (24) are respectively communicated to the condenser main pipeline (23) outside the oil separator (9) and outside the second valve (2), and a first valve (1) is arranged on the condenser branch pipeline (24). The compressor (8) and the oil separator (9) are communicated through a pipeline; Both the compressor suction pipe (19) and the evaporator return pipe (20) are located on the upper side of the inner cavity of the low-pressure circulation accumulator (15). The oil return pipe (21) is located on the lower side of the inner cavity of the low-pressure circulation accumulator (15), and oil return holes are evenly opened at the lower end of the oil return pipe (21); When the oil level in the compressor (8) is lower than the safety value, the first valve (1) is closed, the second valve (2), the third valve (5) and the expansion valve (6) are opened, the refrigerant pump (17) is opened, and the refrigerant pump (17) drives the refrigerant to flow, driving the lubricating oil accumulated on the inner wall of the evaporator (18) to flow into the low-pressure circulation accumulator (15); Multiple oil return holes on the oil return pipe (21) evenly absorb the lubricating oil and liquid refrigerant in the low-pressure circulation accumulator (15). The liquid refrigerant is vaporized through the regenerator (14). The gaseous refrigerant and the lubricating oil will then flow into the condenser main pipeline (23). At the same time, the compressor suction pipe (19) guides the gaseous refrigerant in the low-pressure circulation accumulator (15) into the condenser main pipeline (23). The lubricating oil flows back into the compressor (8). The gaseous refrigerant flows through the condenser main pipeline (23) and the condenser (10) to flow the lubricating oil accumulated on its inner wall into the low-pressure circulation accumulator (15).

2. The pump-driven evaporative cooling air conditioning system for a data center according to claim 1, wherein: It further includes a water level control valve (3), a blowdown valve (4), a packing (11), a water tank (12), a spray head, a water pump (13) and a water conduit (22). The water tank (12) is installed on the lower side of the inner cavity of the condenser (10), and the blowdown valve (4) is communicated with the water tank (12). The water level control valve (3) is assembled in the water tank (12), and the water level control valve (3) is electrically connected to an external control device through a wire. The packing (11) is assembled in the middle of the inner cavity of the condenser (10). The spray head is assembled on the upper side of the inner cavity of the condenser (10). Both ends of the water conduit (22) are respectively connected to the water tank (12) and the spray head, and the water pump (13) is arranged on the water conduit (22). A fan is assembled on the upper side of the condenser (10).

3. The pump-driven evaporative cooling air conditioning system for a data center according to claim 1, wherein: It further includes a liquid level gauge (16), and the liquid level gauge (16) is arranged on the low-pressure circulation accumulator (15).

4. The pump-driven evaporative cooling air conditioning system for a data center according to claim 3, characterized in that: The type of the liquid level gauge (16) is a tuning fork vibration type, a magnetic float type, a pressure type, an ultrasonic type, a sonar wave type, a magnetic flap type or a radar type.

5. The pump-driven evaporative cooling air conditioning system for a data center according to claim 1, wherein: The type of the regenerator (14) is a plate heat exchanger, a shell-and-tube heat exchanger, a tube-and-shell heat exchanger, a cross-flow heat exchanger or a spiral plate heat exchanger.

6. The pump-driven evaporative cooling air conditioning system for a data center according to claim 1, characterized in that: The type of the compressor (8) is a screw type, a scroll type or a centrifugal type compressor containing lubricating oil. The compressor (8) is equipped with an oil level sensor, and the type of the oil level sensor is an optoelectronic oil level sensor, a capacitive oil level sensor or a differential pressure type oil level sensor.

7. An oil return method for a pump-driven evaporative cooling air conditioning system for a data center is realized by using a pump-driven evaporative cooling air conditioning system for a data center as described in claim 1.

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