Cooling water temperature compensation control method

Abstract

The present invention belongs to the technical field of cooling equipment, and particularly relates to a control method for compensating the temperature of cooling water. When the cooling equipment is working, the control system monitors the outdoor wet-bulb temperature. When the current cold source is a cooling tower, if the outdoor wet-bulb temperature is higher than the safe operating temperature of the cooling tower, the control system immediately switches the cold source from the cooling tower to a chiller; when the current cold source is a chiller, if the outdoor wet-bulb temperature is lower than the safe operating temperature of the chiller, the control system performs cold source switching. The cold source switching conditions are reasonable, which can filter short-term external temperature fluctuations, thus ensuring the long-term stable operation of the cooling equipment in spring and autumn seasons, and can timely switch the cold source based on the external temperature, reducing energy consumption on the premise of ensuring the operation of the equipment.

Description

Technical Field

[0001] The present invention belongs to the technical field of cooling equipment, and particularly relates to a control method for compensating the temperature of cooling water. Background Art

[0002] When computers in a data center are working, a large amount of heat is generated. To maintain the normal operation of the computers, cooling equipment is required to cool down the computers. The cooling equipment usually uses a chiller and a cooling tower as the cold source. When the temperature is relatively low, using the cooling tower to cool down the computers can effectively reduce energy consumption; when the temperature is relatively high, the outlet water temperature of the cooling tower cannot meet the heat dissipation requirements, and the chiller is used to cool down the computers.

[0003] Currently, when using the cooling tower as the cold source, the outlet water temperature of the cooling tower is monitored. When the outlet water temperature of the cooling tower is higher than a certain set value, the cold source is switched to the chiller. However, when using this cold source switching method, the outside air temperature will fluctuate multiple times within a day in spring and autumn, and then the cold source switching conditions are met multiple times, resulting in too frequent switching of the cold source and affecting the efficient and stable operation of the cooling equipment. Summary of the Invention

[0004] The purpose of the present invention is to provide a control method for compensating the temperature of cooling water, which can avoid the frequent switching of the cold source caused by the temperature fluctuation in spring and autumn, and can timely realize the cold source switching from the cooling tower to the chiller when the outside air temperature meets the cold source switching conditions.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is: a control method for compensating the temperature of cooling water. When the cooling equipment is working, the control system monitors the outdoor wet-bulb temperature and determines whether to switch the cold source according to the outdoor wet-bulb temperature. Denote T0 as the safe working temperature of the cooling tower, T1 as the safe working temperature of the chiller, and T0 < T1;

[0006] Step A: When the current cold source is the cooling tower, if the outdoor wet-bulb temperature is greater than T0, the control system immediately switches the cold source from the cooling tower to the chiller according to Step A1 and Step A2, and enters Step B; where

[0007] Step A1: The control system turns on the chiller, and at the same time controls the pipeline valve to make the outlet water of the cooling tower flow through the chiller and exchange heat with the outlet water of the data center computer room load at the first heat exchanger and then return;

[0008] Step A2: When the temperature of the cooling water flowing through the chiller rises to the refrigeration start set value of the chiller, the chiller starts refrigeration. The control system controls the pipeline valve to make the outlet water of the data center computer room load exchange heat with the outlet water of the chiller at the second heat exchanger and then return, then disconnects the connection pipeline between the cooling tower and the first heat exchanger, and then closes the cooling tower;

[0009] Step B: When the current cold source is a chiller, if the outdoor wet-bulb temperature is less than T1, the control system switches the cold source to the cooling tower according to Step B1 and Step B2. After completing the cold source switching, it enters Step A; where

[0010] Step B1: Continue to apply the current cold source for a duration of t0, and detect the outdoor wet-bulb temperature after the duration of t0.

[0011] Step B2: If the outdoor wet-bulb temperature is greater than T0 after the duration of t0, enter Step B.

[0012] If the outdoor wet-bulb temperature is less than or equal to T0 after the duration of t0, the control system turns on the cooling tower, and controls the pipeline valves to make the water outlet of the cooling tower and the data center computer room load exchange heat at the first heat exchanger and then return the water, then disconnects the connecting pipeline between the chiller and the second heat exchanger, and then shuts down the chiller.

[0013] If the outdoor wet-bulb temperature is greater than T0 and less than T1 after the duration of t0, enter Step B1.

[0014] Compared with the prior art, the present invention has the following technical effects: The cold source switching conditions are reasonable, which can filter short-term temperature fluctuations in the outside world, thereby ensuring the long-term stable operation of the cooling equipment in spring and autumn seasons, and can switch the cold source in a timely manner based on the outside temperature, reducing energy consumption on the premise of ensuring the operation of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The following briefly describes the content expressed by each drawing in this specification and the marks in the drawings:

[0016] Figure 1 is a schematic diagram of the present invention;

[0017] Figure 2 is a schematic diagram of the working or compensation state of this chilled water tower;

[0018] Figure 3 is a schematic diagram of the working state of this chiller for refrigeration and the chilled water tower for auxiliary heat dissipation;

[0019] Figure 4 is a schematic diagram of the working state of this chiller for separate refrigeration;

[0020] Figure 5 、 6 is a schematic diagram of the control method of the present invention.

[0021] In the figure: 10. Computer room load, 20. Cooling tower, 30. Chiller, 40. First heat exchanger, 50. Second heat exchanger, C1. Valve 1, C2. Valve 2, C3. Direct pipeline 1, R1. Valve 4, R2. Valve 5, R3. Direct pipeline 2. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following further elaborates on the specific implementation manners of the present invention in detail by describing embodiments in conjunction with the accompanying drawings.

[0023] A cooling water temperature compensation control method. When the cooling equipment is operating, the control system monitors the outdoor wet-bulb temperature and determines whether to switch the cold source based on the outdoor wet-bulb temperature. Denote T0 as the safe operating temperature of the cooling tower and T1 as the safe operating temperature of the chiller, and T0 < T1.

[0024] Step A: When the current cold source is the cooling tower 20, if the outdoor wet-bulb temperature is greater than T0, the control system immediately switches the cold source from the cooling tower 20 to the chiller 30 and enters Step B.

[0025] It should be noted that when using the outdoor wet-bulb temperature as the cold source switching condition, there may be a situation where the measured outdoor air temperature meets the cold source switching condition, but the outlet water temperature of the cooling tower is lower than the refrigeration startup condition of the chiller, resulting in the inability of the chiller to start the refrigeration program. Changing the refrigeration startup condition of the chiller is difficult and costly. If the cold source is not switched until the outlet water temperature of the cooling tower rises to the refrigeration startup set value of the chiller, it may cause overheating in the data center and reduce the operating efficiency of the computer. Therefore, the following steps are adopted to switch the cold source from the cooling tower 20 to the chiller 30:

[0026] Step A1: As shown in the attached Figure 2 figure, the control system turns on the chiller 30 and simultaneously controls the pipeline valve to make the outlet water of the cooling tower 20 flow through the chiller 30 and exchange heat with the outlet water of the data center computer room load 10 at the heat exchanger 40 and then return.

[0027] Step A2: As shown in the attached Figure 3 、 4 figure, when the cooling water temperature flowing through the chiller 30 rises to the refrigeration startup set value of the chiller, the chiller 30 starts refrigeration. The control system controls the pipeline valve to make the outlet water of the data center computer room load 10 exchange heat with the outlet water of the chiller 30 at the heat exchanger 50 and then return, then disconnects the connecting pipeline between the cooling tower 20 and the heat exchanger 40, and then closes the cooling tower 20.

[0028] Step B: When the current cold source is the chiller 30, if the outdoor wet-bulb temperature is less than T1, the control system performs cold source switching according to Step B1 and Step B2. After completing the cold source switching, it enters Step A. Among them,

[0029] Step B1: Continue to use the current cold source for a duration of t0, and detect the outdoor wet-bulb temperature after the duration of t0;

[0030] Step B2: If the outdoor wet-bulb temperature is greater than T0 within the duration of t0, enter Step B;

[0031] If the outdoor wet-bulb temperature is less than or equal to T0 after a time period of t0, the control system turns on the cooling tower 20, controls the pipeline valves to make the water discharged from the cooling tower 20 and the load 10 of the data center computer room exchange heat at the first heat exchanger 40 and then return, then disconnects the connecting pipeline between the chiller 30 and the second heat exchanger 50, and then turns off the chiller 30.

[0032] If the outdoor wet-bulb temperature is greater than T0 and less than T1 after a time period of t0, proceed to step B1.

[0033] It should be noted here that the so-called safe operating temperature refers to the outdoor wet-bulb temperature at which the heat dissipation effect of the load 10 of the computer room can meet the stable operation of the data center when a certain cold source is applied. That is, when the outdoor wet-bulb temperature is not higher than T0, applying the cooling tower 20 as the cold source has a good heat dissipation effect on the load 10 of the computer room and can ensure the stable operation of the data center; when the outdoor wet-bulb temperature is not lower than T1, applying the chiller 30 as the cold source can only meet the requirements for heat dissipation of the load 10 of the computer room; when the outdoor wet-bulb temperature is lower than T1 and higher than T0, applying the chiller 30 as the cold source has a relatively high energy consumption, and applying the cooling tower 20 as the cold source has a risk that the heat dissipation effect does not meet the requirements.

[0034] To ensure the stable and reliable operation of the data center, if the outdoor wet-bulb temperature rises from a low temperature to the safe operating temperature of the cooling tower 20, the cold source is switched, and the cold source is switched from the cooling tower 20 to the chiller 30. If the outdoor wet-bulb temperature drops from a high temperature to the safe operating temperature of the chiller 30, first continue to use the chiller 30 as the cold source and observe for a time period of t0. If after the t0 observation period, the outdoor wet-bulb temperature drops to the safe operating temperature of the cooling tower 20, then the cold source is switched, so that the temperature fluctuations within the t0 time range can be filtered, thus avoiding frequent switching of the cold source. To further reduce energy consumption, in step B2, if the outdoor wet-bulb temperature drops to T0 within the t0 time period, the cold source can be switched, and the cold source is switched from the chiller 30 to the cooling tower 20. The duration t0 of the observation period is preferably 2h ≤ t0 ≤ 14h. In this embodiment, t0 is 4h or 12h.

[0035] To reduce energy consumption, denote T2 as the auxiliary heat dissipation operating temperature of the cooling tower 20. After disconnecting the connecting pipeline between the cooling tower 20 and the first heat exchanger 40 in step A2, the following steps are used to turn off the cooling tower 20: judge the outlet water temperature of the cooling tower 20. If the outlet water temperature of the cooling tower 20 is less than or equal to T2, use the cooling tower 20 to dissipate heat from the chiller 30, that is, the attached Figure 3 shown working mode; once the outlet water temperature of the cooling tower 20 is greater than T2, disconnect the connection between the cooling tower 20 and the chiller 30 and turn off the cooling tower 20, that is, the attached Figure 4The working mode shown. In fact, in step B, that is, when the chiller 30 is used as the cold source, the cooling tower 20 can also be used to dissipate heat from the chiller 30 when the outlet water temperature of the cooling tower 20 is less than or equal to T2.

[0036] In another embodiment, to simplify the cold source switching condition, step B can adopt the following method. When the current cold source is the chiller 30, if the outdoor wet bulb temperature is less than T0, the control system will switch the cold source from the chiller 30 to the cooling tower 20 and enter step A. As shown in the attached Figure 5 figure, the outdoor wet bulb temperature is monitored, and the cold source is switched from the chiller 30 to the cooling tower 20 at time t2.

[0037] The pipeline of this embodiment is as shown in the attached Figure 1 figure. The outlet water of the machine room load 10 exchanges heat with the outlet water of the cooling tower 20 at the first heat exchanger 40 and exchanges heat with the outlet water of the chiller 30 at the second heat exchanger 50. The cooling tower 20, the chiller 30, and the first heat exchanger 40 are arranged in series on the same circuit and the on-off of the cooling tower 20 and the first heat exchanger 40 is controlled by valves. The machine room load 10, the first heat exchanger 40, and the second heat exchanger 50 are arranged in series on the same circuit and the on-off of the machine room load 10 and the first heat exchanger 40 is controlled by valves. The specific pipeline layout is as follows: a first valve C1 and a second valve C2 are sequentially provided at the outlet end of the cooling tower 20. The first valve C1 is connected between the outlet of the cooling tower 20 and the inlet of the first heat exchanger 40, and the second valve C2 is connected between the outlet of the first heat exchanger 40 and the return water inlet of the cooling tower 20. A direct pipeline C3 is provided between the first valve C1 and the second valve C2. A fourth valve R1 and a fifth valve R2 are sequentially provided at the outlet end of the machine room load 10. The fourth valve R1 is connected between the outlet of the machine room load 10 and the inlet of the first heat exchanger 40, and the fifth valve R2 is connected between the outlet of the first heat exchanger 40 and the return water inlet of the machine room load 10. A direct pipeline R3 is provided between the fourth valve R1 and the fifth valve R2. In this way, when and only when the first and second valves C1, C2 disconnect the direct pipeline C3 and connect the cooling tower 20 and the first heat exchanger 40, and the fourth and fifth valves R1, R2 disconnect the direct pipeline R3 and connect the machine room load 10 and the first heat exchanger 40, the outlet water of the cooling tower 20 exchanges heat with the outlet water of the machine room load 10 at the first heat exchanger 40. After the chiller 30 cools down, control the valves so that the first and second valves C1, C2 connect the direct pipeline C3 or the fourth and fifth valves R1, R2 connect the direct pipeline R3, and the outlet water of the machine room load 10 will exchange heat with the outlet water of the chiller 30 at the second heat exchanger 50.

[0038] In the embodiment shown in the attached drawings, the chiller 30 is located upstream of the first heat exchanger 40. In this way, the chiller 30 will be turned on only after the cooling water in the loop is heated to the set temperature, thus ensuring the stable operation of the chiller 30. To facilitate the switching of the cold source in spring and autumn, when the cooling tower 20 is used as the cold source, the method as shown in the attached Figure 2The operating mode shown. The cooling water temperature at the outlet of Heat Exchanger 1 40 in the cooling water circuit is relatively high. If the chiller 30 is installed downstream of Heat Exchanger 1 40 and upstream of the return water end of the cooling tower 20, the refrigeration program of the chiller 30 can be started more quickly. However, since there is still cooling water with a temperature lower than the set temperature in the circuit, if the temperature of the cooling water flowing through the chiller 30 is lower than the set temperature after the refrigeration program of the chiller 30 is started, it may cause the chiller 30 to stop refrigerating, affecting the working stability of the chiller 30.

[0039] When the cold source is switched from the cooling tower 20 to the chiller, the outlet water temperature of the cooling tower 20 is higher than the outlet water temperature of the chiller 30. In the embodiment shown in the drawings, Heat Exchanger 2 50 is located downstream of Heat Exchanger 1 40. In this way, Figure 2 In the operating mode shown, before the chiller 30 is turned on and operates stably, the outlet water of the computer room load 10 is first pre-cooled at Heat Exchanger 1 40 and then further heat-exchanged at Heat Exchanger 2 50, which can ensure the heat dissipation effect and further ensure the reliability of the computer during the cold source switching process. If Heat Exchanger 2 50 is installed upstream of Heat Exchanger 1 40, Figure 2 In the operating mode shown, after the chiller 30 is turned on, the outlet water of the computer room load 10 is first heat-exchanged at Heat Exchanger 2 50. If the temperature of the water of the computer room load after heat exchange is lower than the outlet water temperature of the cooling tower 20, at Heat Exchanger 1 40, it will instead cause the temperature of the water of the computer room load to rise, thereby affecting the heat dissipation effect of the computer room load 10.

[0040] When the outdoor wet bulb temperature is higher than T0, if the outlet water temperature of the cooling tower 20 is lower than the refrigeration start temperature of the chiller 30, adopt the operating mode as shown in Figure 2 the drawings. Valve 1 C1 connects the outlet of the cooling tower 20 and the inlet of Heat Exchanger 1 40, and Valve 2 C2 connects the outlet of Heat Exchanger 1 40 and the return water inlet of the cooling tower 20. At the same time, Valve 4 R1 in the computer room circuit connects the outlet of the computer room load 10 and the inlet of Heat Exchanger 1 40, and Valve 5 R2 connects the outlet of Heat Exchanger 1 40 and the return water inlet of the computer room load 10. In this way, the outlet water of the cooling tower 20 can quickly increase in temperature after heat exchange with the water of the computer room load at Heat Exchanger 1 40, and then quickly start the chiller 30 connected in series on the same circuit. In fact, when the cooling equipment uses the cooling tower 20 as the cold source in spring and autumn, the operating mode as shown in Figure 2The working mode shown is such that when the outdoor wet-bulb temperature is higher than T0, the water temperature of the cooling water in the cooling circuit must be higher than the refrigeration start-up temperature of the chiller 30, and the refrigeration program of the chiller 30 can be started without switching the working mode. In the actual application process, to ensure the cooling effect of the data center during the maintenance and repair of the cooling equipment, the cooling equipment usually has two or more cooling tower groups and chiller groups. The cooling towers in the cooling tower group are arranged in parallel, and the chillers in the chiller group are arranged in parallel. In the embodiment shown in the accompanying drawings, the cooling tower 20 and the chiller 30 connected in series in the same circuit are the currently working cooling tower 20 and chiller 30, and the staff can still repair the standby cooling tower 20 and chiller 30.

[0041] After the chiller 30 starts refrigeration and operates stably, first control the valves four and five R1 and R2 to connect the direct pipeline two R3, and disconnect the pipeline connecting the computer room load circuit and the heat exchanger one 40, that is, the valve four R1 connects the water outlet of the computer room load 10 and the valve five R2, and the valve five R2 connects the valve four R1 and the inlet of the heat exchanger two 50; then control the valves one and two C1 and C2 to connect the direct pipeline one C3, and disconnect the pipeline connecting the cooling circuit and the heat exchanger one 40, that is, the valve one C1 connects the water outlet of the cooling tower 20 and the valve two C2, and the valve two C2 connects the valve one C1 and the return water port of the cooling tower 20, so that the cooling tower 20 can be used to dissipate heat from the chiller 30 to further reduce energy consumption. Specifically, when implementing, let T2 be the auxiliary heat dissipation working temperature of the cooling tower 20 and T2 is greater than the refrigeration start-up temperature of the chiller, judge the water outlet temperature of the cooling tower 20. When the water outlet temperature of the cooling tower 20 is less than or equal to T2, apply the operation mode as shown in the appendix Figure 3 shown. In the cooling water circuit, the cooling tower 20 and the chiller 30 are connected in series, and the cooling tower 20 dissipates heat from the chiller 30; when the water outlet temperature of the cooling tower 20 is greater than T2, apply the operation mode as shown in the appendix Figure 4 shown, the cooling tower 20 stops working, and the chiller 30 adopts other heat dissipation modes.

[0042] In other embodiments, it is also possible to directly apply the operation mode as shown in the appendix after the chiller 30 starts refrigeration and operates stably. Figure 4 shown.

Claims

1. A cooling water temperature compensation control method, characterized in that: When the cooling equipment is working, the control system monitors the outdoor wet-bulb temperature and determines whether to switch the cold source according to the outdoor wet-bulb temperature. Denote T0 as the safe operating temperature of the cooling tower and T1 as the safe operating temperature of the chiller, and T0 < T1; Step A: When the current cold source is the cooling tower (20), if the outdoor wet-bulb temperature is greater than T0, the control system immediately switches the cold source from the cooling tower (20) to the chiller (30) according to Step A1 and Step A2, and enters Step B; where, Step A1: The control system turns on the chiller (30), and at the same time controls the pipeline valve to make the water outlet of the cooling tower (20) flow through the chiller (30) and exchange heat with the water outlet of the data center computer room load (10) at the first heat exchanger (40) and then return the water; Step A2: When the temperature of the cooling water flowing through the chiller (30) rises to the chiller refrigeration start set value, the chiller (30) starts refrigeration. The control system controls the pipeline valve to make the water outlet of the data center computer room load (10) exchange heat with the water outlet of the chiller (30) at the second heat exchanger (50) and then return the water, then disconnects the connecting pipeline between the cooling tower (20) and the first heat exchanger (40), and then turns off the cooling tower (20); Step B: When the current cold source is the chiller (30), if the outdoor wet-bulb temperature is less than T1, the control system switches the cold source from the chiller (30) to the cooling tower (20) according to Step B1 and Step B2. After completing the cold source switch, it enters Step A; where, Step B1: Continue to apply the current cold source for t0 duration, and detect the outdoor wet-bulb temperature after t0 duration; Step B2: If the outdoor wet-bulb temperature is greater than T0 within t0 duration, enter Step B; If the outdoor wet-bulb temperature is less than or equal to T0 after t0 duration, the control system turns on the cooling tower (20), and controls the pipeline valve to make the cooling tower (20) exchange heat with the water outlet of the data center computer room load (10) at the first heat exchanger (40) and then return the water, then disconnects the connecting pipeline between the chiller (30) and the second heat exchanger (50), and then turns off the chiller (30); If the outdoor wet-bulb temperature is greater than T0 and less than T1 after t0 duration, enter Step B1.

2. The cooling water temperature compensation control method according to claim 1, wherein: Denote T2 as the auxiliary heat dissipation operating temperature of the cooling tower (20). After disconnecting the connecting pipeline between the cooling tower (20) and the first heat exchanger (40) in Step A2 above, the following steps are used to turn off the cooling tower (20), Judge the water outlet temperature of the cooling tower (20). If the water outlet temperature of the cooling tower (20) is less than or equal to T2, use the cooling tower (20) to dissipate heat for the chiller (30); once the water outlet temperature of the cooling tower (20) is greater than T2, disconnect the connection between the cooling tower (20) and the chiller (30) and turn off the cooling tower (20).

3. The cooling water temperature compensation control method according to claim 1, characterized in that: In Step B2 above, if the outdoor wet-bulb temperature drops to T0 within t0 duration, the control system turns on the cooling tower (20), and controls the pipeline valve to make the cooling tower (20) exchange heat with the water outlet of the data center computer room load (10) at the first heat exchanger (40) and then return the water, then disconnects the connecting pipeline between the chiller (30) and the second heat exchanger (50), and then turns off the chiller (30).

4. The cooling water temperature compensation control method according to claim 1 or 2, characterized in that: The described step B is that when the current cold source is the chiller (30), if the outdoor wet bulb temperature is less than T0, the control system switches the cold source from the chiller (30) to the cooling tower (20) and enters step A.

5. The cooling water temperature compensation control method according to claim 1, characterized in that: In the described step B1, 2h ≤ t0 ≤ 14h.

6. The cooling water temperature compensation control method according to claim 5, wherein: In the described step B1, t0 is 4h or 12h.

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