Liquid cooling system and cold storage oil return control method thereof

Abstract

The invention relates to the technical field of refrigeration, in particular to a liquid cooling system and a cold storage oil return control method thereof, and the liquid cooling system comprises a first cold source side system, a second cold source side system, a cooling side system and a heat exchanger; the heat exchanger is provided with a water path pipeline and a fluorine path pipeline; each of the first cold source side system and the second cold source side system comprises a compressor and a condenser; one end of the compressor is connected with one end of the condenser; and the other end of the condenser is connected with the other end of the compressor after passing through a fluorine pipeline. Whether low-load operation is carried out or not is judged according to the compressor frequency, the liquid supply temperature, the liquid return temperature and the difference value between the liquid supply temperature and the liquid return temperature, and all the compressors are prevented from running at low frequency by adjusting the running number of the compressors. And after quitting the cooling mode, judging whether the temperature of the water tank is within a specified range, entering a cold storage mode in time, and actively operating the oil return frequency of the compressor in the cold storage mode.

Description

Technical Field

[0001] The invention relates to the technical field of refrigeration, and in particular to a liquid cooling system and a cold storage and oil return control method thereof. Background Art

[0002] In the field of outdoor equipment cooling, both air cooling and liquid cooling technologies have been widely used. Air cooling equipment is often used for heat dissipation of various outdoor devices due to its simple structure and low cost, such as outdoor cabinets, communication base station heat dissipation and other scenarios. Its working principle is mainly to use fans to force air flow to take away the heat generated by the equipment. However, the efficiency of air cooling is limited, the outdoor environment is complex and changeable, and harsh conditions such as high temperature and high humidity will greatly weaken the air cooling effect, making it difficult to meet the growing heat dissipation needs of high-power equipment; secondly, the noise generated by the operation of the fan is relatively large, and the air inlet and outlet of the air cooling equipment are very easy to get dirty and blocked. Once blocked, the air circulation will be blocked, the heat dissipation efficiency will be greatly reduced, and it may even cause the equipment to be damaged due to overheating.

[0003] Traditional liquid cooling systems are mainly used in equipment that has higher requirements for heat dissipation and is more sensitive to temperature control accuracy, such as data center server cooling, new energy vehicle battery cooling, etc. In these scenarios, the liquid cooling system removes heat through the circulation of coolant, which can achieve more efficient heat dissipation. Among them, the common timed oil return strategy is to perform oil return operation after accumulating low-frequency operation for a certain period of time.

[0004] However, the timed oil return strategy of the traditional liquid cooling system also has serious defects. On the one hand, the reliability of oil return is low. Timed oil return is a passive oil return method. Under different working conditions, the setting of the oil return interval and the oil return operation time requires a lot of experimental verification to determine the appropriate value to ensure the reliability of oil return, which undoubtedly increases the R&D cost and time cost. On the other hand, the stability of the liquid supply temperature is poor. When the system runs at low load for a long time, if the oil return control is entered, it is very easy to cause the liquid supply temperature to be too high or too low, and the liquid supply temperature fluctuates widely and is unstable. Taking the cooling of new energy vehicle batteries as an example, the optimal operating temperature of mainstream batteries is between 20-35°C. If the liquid supply temperature of the liquid cooling system exceeds this range for a long time, it will directly affect the battery life, and may even cause the liquid cooling system to shut down, seriously affecting the normal operation of the equipment. Summary of the invention

[0005] The purpose of the present invention is to provide a liquid cooling system and a cold storage and oil return control method thereof in view of the above-mentioned deficiencies in the prior art.

[0006] The object of the present invention is achieved through the following technical solutions: A liquid cooling system comprises a first cold source side system, a second cold source side system, a cooling side system and a heat exchanger; the heat exchanger is provided with a water pipeline and a fluorine pipeline;

[0007] The first cold source side system and the second cold source side system both include a compressor and a condenser; one end of the compressor is connected to one end of the condenser; the other end of the condenser is connected to the other end of the compressor through a fluorine pipeline;

[0008] The cooling side system includes a water tank, a circulation pump, a cooling circuit and a bypass pipe; the cooling circuit includes a cooling valve and a heating device; one end of the water tank is connected to one end of the circulation pump; the other end of the circulation pump is connected to one end of the water pipe; the other end of the water pipe is connected to the other end of the water tank through a bypass pipe; the bypass pipe is provided with a bypass valve; the other end of the water pipe is connected to the other end of the water tank after passing through the heating device; the cooling valve is arranged between the other end of the water pipe and the heating device.

[0009] The present invention is further configured such that an electronic expansion valve and a drying filter are provided between the other end of the condenser and the fluorine pipeline; and a fan is provided at the condenser.

[0010] The present invention is further configured such that a flow meter is provided between the other end of the water pipeline and the cooling valve.

[0011] The present invention is further configured such that a one-way valve and a cooling filter are provided between the other end of the water tank and the heating device.

[0012] The present invention is further configured such that a liquid return temperature sensor is provided at the other end of the water tank; the liquid return temperature sensor is used to measure the liquid return temperature of the cooling side system.

[0013] The present invention is further configured such that a liquid supply temperature sensor is provided at the other end of the water pipeline; the liquid supply temperature sensor is used to measure the liquid supply temperature of the cooling side system.

[0014] The present invention is further configured such that a water temperature sensor is provided in the water tank; the water temperature sensor is used to measure the temperature of the water tank.

[0015] A cold storage and oil return control method for a liquid cooling system comprises the following steps:

[0016] Step S1, in standby state, whether a start command is received, if yes, proceed to step A1, if no, proceed to step B1;

[0017] Step A1, enter cooling mode, and determine whether the ambient temperature is greater than the cooling start temperature setting value; if yes, proceed to step A11, if not, proceed to step A21;

[0018] Step A11, enter the dual compressor operation mode, determine whether all compressor frequencies are less than the first frequency setting value, if so, enter step A12;

[0019] Step A12, determine whether the difference between the supply liquid temperature and the return liquid temperature is less than the temperature difference setting value or whether the supply liquid temperature is less than the first temperature setting value, if yes, proceed to step A21, if no, return to step A11;

[0020] Step A21, enter the single compressor operation mode, determine whether the compressor frequency reaches the maximum frequency and whether the liquid supply temperature is greater than the second temperature setting value, if yes, proceed to step A11; if not, proceed to step A22;

[0021] Step A22, determining whether the compressor frequency is lower than the first frequency setting value and whether the liquid supply temperature is lower than the third temperature setting value, if not, returning to step A21, if yes, stopping the compressor until the liquid supply temperature is higher than the second temperature setting value and then returning to step A21;

[0022] Step B1, determine whether the water tank temperature is within the temperature setting interval, if so, return to step S1, if not, go to step B2;

[0023] Step B2: Enter the cold storage mode.

[0024] The present invention is further configured such that step B2 also includes: determining whether the ambient temperature is greater than the cold storage start temperature setting value; if so, entering the dual compressor operation mode, and the compressor operating oil return frequency setting value; if not, entering the single compressor operation mode, and the compressor operating oil return frequency setting value.

[0025] The present invention is further configured to include the following steps: Step B3, determine whether the water tank temperature is less than the cold storage closing temperature setting value, and if so, return to step S1.

[0026] Beneficial effects of the present invention: The present invention determines whether it is low-load operation by the compressor frequency, liquid supply temperature, liquid return temperature and the difference between the liquid supply temperature and the liquid return temperature, and avoids all compressors from running at low frequency by adjusting the number of compressors running. After exiting the cooling mode, it is determined whether the water tank temperature is within the specified range, and the cold storage mode is entered in time. In the cold storage mode, the compressor actively runs the oil return frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The invention is further described using the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the invention. A person skilled in the art can obtain other drawings based on the following drawings without creative work.

[0028] Figure 1 is a system flow chart of the present invention;

[0029] Figure 2 It is a structural principle diagram of the present invention;

[0030] Among them: 11. First cold source side system; 12. Second cold source side system; 2. Cooling side system; 3. Heat exchanger; 31. Water pipeline; 32. Fluorine pipeline; 33. Electronic expansion valve; 34. Dry filter; 35. Fan; 41. Compressor; 42. Condenser; 51. Water tank; 52. Circulation pump; 53. Bypass pipeline; 54. Cooling valve; 55. Heating equipment; 56. Flow meter; 57. One-way valve; 58. Cooling filter; 59. Bypass valve; 61. Return liquid temperature sensor; 62. Liquid supply temperature sensor; 63. Water temperature sensor. DETAILED DESCRIPTION

[0031] The present invention is further described in conjunction with the following examples.

[0032] Depend on Figure 1 to Figure 2 It can be seen that the liquid cooling system described in this embodiment includes a first cold source side system 11, a second cold source side system 12, a cooling side system 2 and a heat exchanger 3; the heat exchanger 3 is provided with a water pipeline 31 and a fluorine pipeline 32;

[0033] The first cold source side system 11 and the second cold source side system 12 both include a compressor 41 and a condenser 42; one end of the compressor 41 is connected to one end of the condenser 42; the other end of the condenser 42 is connected to the other end of the compressor 41 through a fluorine path pipeline 32;

[0034] The cooling side system 2 includes a water tank 51, a circulation pump 52, a cooling circuit and a bypass pipe 53; the cooling circuit includes a cooling valve 54 and a heating device 55; one end of the water tank 51 is connected to one end of the circulation pump 52; the other end of the circulation pump 52 is connected to one end of the water pipe 31; the other end of the water pipe 31 is connected to the other end of the water tank 51 through the bypass pipe 53; the bypass pipe 53 is provided with a bypass valve 59; the other end of the water pipe 31 is connected to the other end of the water tank 51 after passing through the heating device 55; the cooling valve 54 is arranged between the other end of the water pipe 31 and the heating device 55.

[0035] Specifically, the liquid cooling system described in this embodiment, when in use, the compressor 41 of the cold source side system is started, and the cooling side system 2 is provided with cold capacity through the fluorine path pipe 32 of the heat exchanger 3; the cooling side system 2 has a cooling mode and a cold storage mode. When entering the cooling mode, the bypass valve 59 is closed and the cooling valve 54 is opened. At this time, a circulating water circuit is formed between the water tank 51, the circulating pump 52, the water pipeline 31, the cooling valve 54 and the heating device 55, and the heating device 55 is cooled by providing the cold capacity of the heat exchanger 3 to the heating device 55; when entering the cold storage mode, the bypass valve 59 is opened and the cooling valve 54 is closed. At this time, a circulating water circuit is formed between the water tank 51, the circulating pump 52, the water pipeline 31 and the bypass pipeline 53. After the compressor 41 is started, it runs at the set value of the return oil frequency, so that the cold source side system can actively store cold, which solves the problem that when the existing liquid cooling system switches from standby to the next startup, the cooling side liquid supply temperature is too high, resulting in a long waiting time, thereby improving the reliability of the cooling process of the liquid cooling system.

[0036] In the liquid cooling system described in this embodiment, an electronic expansion valve 33 and a drying filter 34 are provided between the other end of the condenser 42 and the fluorine path pipeline 32; and a fan 35 is provided at the condenser 42. In this embodiment, the electronic expansion valve 33 is provided to facilitate the adjustment of the flow of the first cold source side system 11 and the second cold source side system 12; the drying filter 34 is provided to filter impurities; and the fan 35 is provided to facilitate the discharge of heat from the condenser 42.

[0037] In the liquid cooling system described in this embodiment, a flow meter 56 is provided between the other end of the water pipe 31 and the cooling valve 54. The above arrangement facilitates understanding of the flow rate of the cooling circuit.

[0038] In the liquid cooling system described in this embodiment, a one-way valve 57 and a cooling filter 58 are provided between the other end of the water tank 51 and the heat generating device 55. The one-way valve 57 can prevent the liquid in the cooling circuit from flowing back, and the cooling filter 58 can filter the liquid in the cooling circuit.

[0039] In the liquid cooling system described in this embodiment, a return liquid temperature sensor 61 is provided at the other end of the water tank 51; the return liquid temperature sensor 61 is used to measure the return liquid temperature of the cooling side system 2. The above arrangement facilitates the measurement of the return liquid temperature, thereby facilitating the control of the working state of each compressor 41.

[0040] In the liquid cooling system described in this embodiment, a liquid supply temperature sensor 62 is provided at the other end of the water pipe 31; the liquid supply temperature sensor 62 is used to measure the liquid supply temperature of the cooling side system 2. The above arrangement facilitates the measurement of the liquid supply temperature, thereby facilitating the control of the working state of each compressor 41.

[0041] In the liquid cooling system described in this embodiment, a water temperature sensor 63 is provided in the water tank 51; the water temperature sensor 63 is used to measure the temperature of the water tank 51. The above arrangement facilitates the measurement of the temperature of the water tank 51, thereby facilitating the control of the working state of each compressor 41.

[0042] The present embodiment provides a method for controlling cold storage and oil return of a liquid cooling system, comprising the following steps:

[0043] Step S1, in standby state, whether a start command is received, if yes, proceed to step A1, if no, proceed to step B1;

[0044] Step A1, enter cooling mode, and determine whether the ambient temperature is greater than the cooling start temperature setting value; if yes, proceed to step A11, if not, proceed to step A21;

[0045] Step A11, enter the dual compressor 41 operation mode, determine whether the frequencies of all compressors 41 are less than the first frequency setting value, if so, enter step A12;

[0046] Step A12, determine whether the difference between the supply liquid temperature and the return liquid temperature is less than the temperature difference setting value or whether the supply liquid temperature is less than the first temperature setting value, if yes, proceed to step A21, if no, return to step A11;

[0047] Step A21, enter the single compressor 41 operation mode, determine whether the frequency of the compressor 41 reaches the maximum frequency and whether the liquid supply temperature is greater than the second temperature setting value, if yes, go to step A11; if not, go to step A22;

[0048] Step A22, determining whether the frequency of the compressor 41 is lower than the first frequency setting value and whether the liquid supply temperature is lower than the third temperature setting value, if not, returning to step A21, if yes, stopping the compressor 41 until the liquid supply temperature is higher than the second temperature setting value and then returning to step A21;

[0049] Step B1, determine whether the temperature of the water tank 51 is within the temperature setting interval, if so, return to step S1, if not, go to step B2;

[0050] Step B2: Enter the cold storage mode.

[0051] The present embodiment describes a cold storage and oil return control method for a liquid cooling system, wherein step B2 further includes: determining whether the ambient temperature is greater than the cold storage start temperature setting value; if so, entering the dual compressor 41 operation mode, and the compressor 41 operating oil return frequency setting value; if not, entering the single compressor 41 operation mode, and the compressor 41 operating oil return frequency setting value.

[0052] The cold storage and oil return control method of a liquid cooling system described in this embodiment also includes the following steps: Step B3, determine whether the temperature of the water tank 51 is less than the cold storage closing temperature setting value, and if so, return to step S1.

[0053] Specifically, through the above-mentioned settings, during the operation of the unit in this embodiment, whether it is low-load operation is determined by the frequency of the compressor 41, the supply liquid temperature, the return liquid temperature, and the difference between the supply liquid temperature and the return liquid temperature. By adjusting the number of operating compressors 41, low-frequency operation of all compressors 41 can be avoided.

[0054] After exiting the cooling mode, it is determined whether the temperature of the water tank 51 is within a specified range, and the cold storage mode is entered in time. In the cold storage mode, the compressor 41 actively operates the oil return frequency.

[0055] Through the above arrangement, the low-frequency operation of the compressor 41 can be utilized in the standby state, and the active oil return function of the cold source side system and the active cold storage function of the cooling side system 2 can be realized at the same time, which solves the problems of the slow start of the compressor 41 caused by the low oil return reliability of the cold source system and the poor stability and long waiting time caused by the excessively high liquid supply temperature of the cooling side system 2 when the existing liquid cooling system is switched from standby to the next startup, thereby improving the reliability of the cooling process of the liquid cooling system and achieving the following effects:

[0056] Intelligent matching: The cooling mode and the cold storage mode are associated with different ambient temperatures to avoid the compressor 41 of the dual system being turned on and then turned off, and to reduce the problem of frequent start and stop of the compressor 41 of the cold source measurement system caused by system misjudgment.

[0057] Reliable oil return: In the cold storage mode, the compressor 41 runs at the oil return frequency setting value, actively returns oil at low frequency, increases the number of oil returns, avoids wear or damage of the compressor 41 due to lack of oil, and improves the reliability of the compressor 41.

[0058] The liquid supply temperature is stable: oil return is only performed during the standby process to ensure that the cooling process will not enter the oil return logic and the liquid supply temperature will not be affected. According to the difference between the liquid supply temperature and the liquid return temperature or after judging the liquid supply temperature, the load of the compressor 41 is intelligently matched to increase or decrease the load, so that the liquid supply temperature is more stable and the cooling of the cooling side system 2 is quickly realized.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A liquid cooling system, characterized in that: It comprises a first cold source side system (11), a second cold source side system (12), a cooling side system (2) and a heat exchanger (3); the heat exchanger (3) is provided with a water pipeline (31) and a fluorine pipeline (32); The first cold source side system (11) and the second cold source side system (12) both comprise a compressor (41) and a condenser (42); one end of the compressor (41) is connected to one end of the condenser (42); the other end of the condenser (42) is connected to the other end of the compressor (41) through a fluorine path pipeline (32); The cooling side system (2) comprises a water tank (51), a circulation pump (52), a cooling circuit and a bypass pipe (53); the cooling circuit comprises a cooling valve (54) and a heating device (55); one end of the water tank (51) is connected to one end of the circulation pump (52); the other end of the circulation pump (52) is connected to one end of the water pipe (31); the other end of the water pipe (31) is connected to the other end of the water tank (51) through the bypass pipe (53); the bypass pipe (53) is provided with a bypass valve (59); the other end of the water pipe (31) is connected to the other end of the water tank (51) after passing through the heating device (55); the cooling valve (54) is provided between the other end of the water pipe (31) and the heating device (55).

2. A liquid cooling system according to claim 1, characterized in that: An electronic expansion valve (33) and a drying filter (34) are provided between the other end of the condenser (42) and the fluorine-circuit pipeline (32); and a fan (35) is provided at the condenser (42).

3. A liquid cooling system according to claim 1, characterized in that: A flow meter (56) is provided between the other end of the water pipe (31) and the cooling valve (54).

4. A liquid cooling system according to claim 1, characterized in that: A one-way valve (57) and a cooling filter (58) are provided between the other end of the water tank (51) and the heating device (55).

5. A liquid cooling system according to claim 1, characterized in that: A liquid return temperature sensor (61) is provided at the other end of the water tank (51); the liquid return temperature sensor (61) is used to measure the liquid return temperature of the cooling side system (2).

6. A liquid cooling system according to claim 1, characterized in that: A liquid supply temperature sensor (62) is provided at the other end of the water pipeline (31); the liquid supply temperature sensor (62) is used to measure the liquid supply temperature of the cooling side system (2).

7. A liquid cooling system according to claim 1, characterized in that: A water temperature sensor (63) is provided in the water tank (51); the water temperature sensor (63) is used to measure the temperature of the water tank (51).

8. A cold storage and oil return control method for a liquid cooling system according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step S1, in standby state, whether a start command is received, if yes, proceed to step A1, if no, proceed to step B1; Step A1, enter cooling mode, and determine whether the ambient temperature is greater than the cooling start temperature setting value; if yes, proceed to step A11, if not, proceed to step A21; Step A11, entering the dual compressor (41) operation mode, determining whether the frequencies of all compressors (41) are less than the first frequency setting value, and if so, proceeding to step A12; Step A12, determine whether the difference between the supply liquid temperature and the return liquid temperature is less than the temperature difference setting value or whether the supply liquid temperature is less than the first temperature setting value, if yes, proceed to step A21, if no, return to step A11; Step A21, entering the single compressor (41) operation mode, determining whether the frequency of the compressor (41) reaches the maximum frequency and whether the liquid supply temperature is greater than the second temperature setting value, if yes, proceeding to step A11; if no, proceeding to step A22; Step A22, determining whether the frequency of the compressor (41) is lower than the first frequency setting value and whether the liquid supply temperature is lower than the third temperature setting value, if not, returning to step A21, if yes, stopping the compressor (41) until the liquid supply temperature is higher than the second temperature setting value and then returning to step A21; Step B1, determine whether the temperature of the water tank (51) is within the temperature setting interval, if so, return to step S1, if not, proceed to step B2; Step B2: Enter the cold storage mode.

9. The cold storage and oil return control method of a liquid cooling system according to claim 8, characterized in that: The step B2 further comprises: determining whether the ambient temperature is greater than the cold storage start temperature setting value; if so, entering the dual compressor (41) operation mode, and the compressor (41) operating at the oil return frequency setting value; if not, entering the single compressor (41) operation mode, and the compressor (41) operating at the oil return frequency setting value.

10. The cold storage and oil return control method of a liquid cooling system according to claim 9, characterized in that: The following steps are also included: Step B3, determine whether the temperature of the water tank (51) is less than the cold storage closing temperature setting value, if so, return to step S1.

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