Water-cooled machine room air conditioning system and control method thereof

Abstract

The application relates to the technical field of air conditioners, in particular to a water-cooled machine room air conditioning system and a control method thereof, which comprises a water inlet pipe, a water outlet pipe, a first four-way valve, a second four-way valve, a heat exchanger, a heat exchange coil, a refrigeration assembly and an air duct; the heat exchanger is provided with a first heat exchange channel and a second heat exchange channel; the refrigeration assembly is in communication with the first heat exchange channel; the refrigeration assembly comprises an evaporator; the evaporator and the heat exchange coil are arranged in the air duct; the first four-way valve and the second four-way valve are combined to switch, multiple different water flow states are realized, so that the water-cooled machine room air conditioning system can run in compression refrigeration mode, mixed refrigeration mode, coil refrigeration mode, first heat supplement refrigeration mode, second heat supplement refrigeration mode, compression dehumidification mode, mixed dehumidification mode, coil dehumidification mode, first heat supplement dehumidification mode and second heat supplement dehumidification mode and the like, different working conditions are adapted, and the overall energy consumption is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, specifically to a water-cooled computer room air conditioning system and its control method. Background Technology

[0002] With the rapid development of the digital economy, data centers, as the core carrier of information infrastructure, have experienced explosive growth in construction scale, leading to a sharp increase in operating energy consumption. Among these, the air conditioning system, as a key unit for ensuring the stable operation of server equipment, accounts for a high proportion of the total energy consumption of data centers. Therefore, reducing the energy consumption of air conditioning systems is an important task for achieving green and low-carbon operation of data centers.

[0003] Utilizing outdoor natural cold sources for cooling can effectively reduce the operating time of mechanical compression refrigeration, thereby reducing overall energy consumption. Currently, water-cooled computer room air conditioners adapted to natural cold sources are mainly divided into two categories: one is chilled water type computer room air conditioners, which exchange heat with the computer room air by directly flowing low-temperature chilled water through heat exchange coils without starting the compressor, and have extremely high energy efficiency ratio under low water temperature conditions; however, when the temperature of the natural cold source water rises, the cooling capacity of the chilled water coils will decrease sharply, failing to meet the cooling needs of the computer room, and may even lead to excessive supply air temperature, server equipment overheating and shutdown, and extremely poor operational reliability under high water temperature conditions.

[0004] Another type is water-cooled computer room air conditioning, which uses a mechanical compression refrigeration cycle and natural cold source water as the cooling medium for the condenser. Even under high water temperature conditions, it can still output cooling capacity stably. However, under low water temperature conditions, the compressor still needs to run continuously, and it cannot make full use of the free cooling capacity of the natural cold source, resulting in a low system energy efficiency ratio and limited energy-saving effect. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned shortcomings in the prior art by providing a water-cooled computer room air conditioning system and its control method.

[0006] The objective of this invention is achieved through the following technical solution: a water-cooled computer room air conditioning system, comprising an inlet pipe, an outlet pipe, a first four-way valve, a second four-way valve, a heat exchanger, a heat exchange coil, refrigeration components, and an air duct; The heat exchanger is provided with a first heat exchange channel and a second heat exchange channel; the refrigeration component is connected to the first heat exchange channel; the refrigeration component includes an evaporator; the evaporator and the heat exchange coil are both located in the air duct; The first four-way valve includes a first port, a second port, a third port, and a fourth port; when the first port and the second port are connected, the third port and the fourth port are connected; when the first port and the fourth port are connected, the second port and the third port are connected. The second four-way valve includes a fifth port, a sixth port, a seventh port, and an eighth port; when the fifth port and the sixth port are connected, the seventh port and the eighth port are connected; when the fifth port and the eighth port are connected, the sixth port and the seventh port are connected. The inlet pipe is connected to the first interface; the second interface is connected to one end of the second heat exchange channel; the third interface is connected to the fifth interface; the fourth interface is connected to one end of the heat exchange coil; the sixth interface is connected to the other end of the second heat exchange channel; the seventh interface is connected to the outlet pipe; and the eighth interface is connected to the other end of the heat exchange coil.

[0007] The present invention is further configured such that the refrigeration assembly further includes a compressor and an expansion valve; one end of the compressor is connected to one end of the evaporator; the other end of the evaporator is connected to one end of the expansion valve; the other end of the expansion valve is connected to one end of the first heat exchange channel; and the other end of the first heat exchange channel is connected to the other end of the compressor.

[0008] The present invention is further configured such that the water outlet pipe is equipped with an electrically controlled valve.

[0009] The present invention is further configured such that the air duct is equipped with a blower; the evaporator is located between the blower and the heat exchange coil.

[0010] The present invention is further configured such that the water inlet pipe is equipped with an water inlet temperature sensor for detecting the water inlet temperature; and the end of the air duct near the heat exchange coil is equipped with a return air temperature and humidity sensor for detecting the return air dry bulb temperature and humidity.

[0011] A control method for a water-cooled computer room air conditioning system includes the following steps: S1. If the cooling demand is less than the preset value for the first cooling cycle, proceed to step S2; otherwise, proceed to step A1. A1. If the inlet water temperature is less than the difference between the return air dry bulb temperature and the preset value of the first inlet water temperature difference, proceed to step A2; otherwise, start the compression refrigeration mode. A2. If the inlet water temperature is less than the difference between the return air dry bulb temperature and the preset value of the first cooling temperature difference, then the coil cooling mode is turned on; otherwise, the mixed cooling mode is turned on. S2. If the cooling demand is not less than the second cooling entry preset value, proceed to step B1; if the first cooling entry preset value is greater than the second cooling entry preset value. B1. If the inlet water temperature is less than the sum of the return air dry bulb temperature and the second inlet water temperature difference preset value, proceed to step B2; otherwise, start the first supplementary heating and cooling mode. B2. If the inlet water temperature is less than the difference between the return air dry bulb temperature and the second preset cooling temperature difference, the coil cooling mode is activated; otherwise, the second supplementary heating cooling mode is activated. The first preset cooling temperature difference is greater than the second preset cooling temperature difference.

[0012] The present invention is further configured such that, in step S2, if the cooling demand is less than the second cooling entry preset value, then proceed to step S3; S3. If the dehumidification demand is less than the first dehumidification preset value, proceed to step S4; otherwise, proceed to step C1. C1. If the inlet water temperature is not higher than the return air dew point temperature, the mixed dehumidification mode will be turned on; otherwise, the compression dehumidification mode will be turned on. S4. If the dehumidification requirement is not less than the second dehumidification preset value, proceed to step D1; the first dehumidification preset value is greater than the second dehumidification preset value. D1. If the inlet water temperature is less than the sum of the return air dry bulb temperature and the third inlet water temperature difference preset value, proceed to step D2; otherwise, activate the first heat replenishment and dehumidification mode. D2. If the inlet water temperature is not higher than the return air dew point temperature, the coil dehumidification mode will be turned on; otherwise, the second supplementary heating dehumidification mode will be turned on.

[0013] The present invention is further configured such that, in step S4, if the dehumidification demand is less than the second dehumidification preset value, then the standby mode is activated.

[0014] The present invention is further configured such that, in the compression refrigeration mode, the first interface is connected to the second interface, the third interface is connected to the fourth interface, the fifth interface is connected to the eighth interface, and the sixth interface is connected to the seventh interface; the refrigeration component is activated. In the hybrid cooling mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the eighth interface, the sixth interface is connected to the seventh interface, and the cooling component is activated. In coil cooling mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the sixth interface, and the seventh interface is connected to the eighth interface; the cooling component stops working. In the first heating and cooling mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the eighth interface, and the sixth interface is connected to the seventh interface; the cooling component is activated. In the second heating and cooling mode, the first interface is connected to the second interface, the third interface is connected to the fourth interface, the fifth interface is connected to the sixth interface, and the seventh interface is connected to the eighth interface; the cooling component is activated.

[0015] The present invention is further configured such that, in the compression dehumidification mode, the first interface is connected to the second interface, the third interface is connected to the fourth interface, the fifth interface is connected to the eighth interface, and the sixth interface is connected to the seventh interface; the refrigeration component is activated. In the hybrid dehumidification mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the eighth interface, and the sixth interface is connected to the seventh interface; the refrigeration component is activated. In coil dehumidification mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the sixth interface, and the seventh interface is connected to the eighth interface; the refrigeration component stops working. In the first heating and dehumidification mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the eighth interface, and the sixth interface is connected to the seventh interface; the refrigeration component is activated. In the second heating and dehumidification mode, the first interface is connected to the second interface, the third interface is connected to the fourth interface, the fifth interface is connected to the sixth interface, and the seventh interface is connected to the eighth interface; the refrigeration component is activated.

[0016] The beneficial effects of this invention are as follows: By combining and switching the first four-way valve and the second four-way valve, this invention can achieve various different water flow direction states, thereby enabling the water-cooled computer room air conditioning system to operate in various modes such as compression refrigeration mode, mixed refrigeration mode, coil refrigeration mode, first supplementary heating refrigeration mode, second supplementary heating refrigeration mode, compression dehumidification mode, mixed dehumidification mode, coil dehumidification mode, first supplementary heating dehumidification mode, and second supplementary heating dehumidification mode, adapting to different operating conditions and effectively reducing overall energy consumption. Attached Figure Description

[0017] The invention will be further illustrated with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the invention. For those skilled in the art, other drawings can be obtained based on the following drawings without any creative effort.

[0018] Figure 1 This is a system schematic diagram of the water-cooled computer room air conditioning system of the present invention; Figure 2 This is a control flowchart of the control method of the present invention; The components include: 1. Inlet pipe; 11. Inlet water temperature sensor; 2. Outlet pipe; 21. Electrically controlled valve; 3. First four-way valve; 4. Heat exchanger; 41. First heat exchange channel; 42. Second heat exchange channel; 5. Heat exchange coil; 6. Air duct; 61. Supply fan; 62. Return air temperature and humidity sensor; 71. Evaporator; 72. Compressor; 73. Expansion valve; 8. Second four-way valve. Detailed Implementation

[0019] The present invention will be further described in conjunction with the following embodiments.

[0020] Depend on Figure 1 As can be seen, the water-cooled computer room air conditioning system described in this embodiment includes an inlet pipe 1, an outlet pipe 2, a first four-way valve 3, a second four-way valve 8, a heat exchanger 4, a heat exchange coil 5, a refrigeration component, and an air duct 6. The heat exchanger 4 is provided with a first heat exchange channel 41 and a second heat exchange channel 42; the refrigeration component is connected to the first heat exchange channel 41; the refrigeration component includes an evaporator 71; the evaporator 71 and the heat exchange coil 5 are both located in the air duct 6. The first four-way valve 3 includes a first port, a second port, a third port, and a fourth port; when the first port and the second port are connected, the third port and the fourth port are connected; when the first port and the fourth port are connected, the second port and the third port are connected. The second four-way valve 8 includes a fifth port, a sixth port, a seventh port, and an eighth port; when the fifth port and the sixth port are connected, the seventh port and the eighth port are connected; when the fifth port and the eighth port are connected, the sixth port and the seventh port are connected. The inlet pipe 1 is connected to the first interface; the second interface is connected to one end of the second heat exchange channel 42; the third interface is connected to the fifth interface; the fourth interface is connected to one end of the heat exchange coil 5; the sixth interface is connected to the other end of the second heat exchange channel 42; the seventh interface is connected to the outlet pipe 2; and the eighth interface is connected to the other end of the heat exchange coil 5.

[0021] Specifically, in the water-cooled computer room air conditioning system described in this embodiment, cooling water enters the first port of the first four-way valve 3 from the inlet pipe 1. Through the four valve port combinations of the first four-way valve 3 and the second four-way valve 8, four independent cooling water flow paths can be switched out: First cooling water flow path: Cooling water flows into the second heat exchange channel 42 of heat exchanger 4 after passing through the first and second ports of the first four-way valve 3, and then is discharged from the outlet pipe 2 after passing through the sixth and seventh ports of the second four-way valve 8. Second cooling water flow path: Cooling water flows into heat exchange coil 5 after passing through the first and fourth ports of the first four-way valve 3, then flows into the second heat exchange channel 42 of heat exchanger 4 through the eighth and fifth ports of the second four-way valve 8 and the third and second ports of the first four-way valve 3, and finally flows out from the outlet pipe 2 after passing through the sixth and seventh ports of the second four-way valve 8. The third cooling water flow path: After passing through the first and fourth ports of the first four-way valve 3, the cooling water flows into the heat exchange coil 5, and then through the eighth and seventh ports of the second four-way valve 8 before being discharged from the outlet pipe 2. Fourth cooling water flow path: After passing through the first and second ports of the first four-way valve 3, the cooling water flows into the second heat exchange channel 42 of the heat exchanger 4, then through the sixth and fifth ports of the second four-way valve 8, and the third and fourth ports of the first four-way valve 3, it flows into the heat exchange coil 5, and finally through the eighth and seventh ports of the second four-way valve 8, it is discharged from the outlet pipe 2.

[0022] This embodiment enables the water-cooled computer room air conditioning system to operate in various modes, including compression refrigeration mode, mixed refrigeration mode, coil refrigeration mode, first supplementary heating refrigeration mode, second supplementary heating refrigeration mode, compression dehumidification mode, mixed dehumidification mode, coil dehumidification mode, first supplementary heating dehumidification mode, and second supplementary heating dehumidification mode, adapting to different operating conditions and effectively reducing overall energy consumption.

[0023] The water-cooled computer room air conditioning system described in this embodiment includes a compressor 72 and an expansion valve 73 as part of the refrigeration components. One end of the compressor 72 is connected to one end of the evaporator 71. The other end of the evaporator 71 is connected to one end of the expansion valve 73. The other end of the expansion valve 73 is connected to one end of the first heat exchange channel 41. The other end of the first heat exchange channel 41 is connected to the other end of the compressor 72. Specifically, when the refrigeration unit starts, the compressor 72 compresses the low-temperature, low-pressure gaseous refrigerant in the evaporator 71 into a high-temperature, high-pressure gaseous refrigerant, which is then sent into the first heat exchange channel 41 of the heat exchanger 4. The high-temperature, high-pressure refrigerant exchanges heat with the cooling water flowing in the second heat exchange channel 42 in the first heat exchange channel 41, releasing condensation heat and becoming a high-pressure liquid refrigerant. The high-pressure liquid refrigerant is throttled and depressurized by the expansion valve 73, transforming into a low-temperature, low-pressure gas-liquid two-phase mixture before entering the evaporator 71. The low-temperature, low-pressure refrigerant absorbs heat from the air in the air duct 6 in the evaporator 71, evaporates into a gaseous refrigerant, and is drawn back into the compressor 72, completing the closed-loop mechanical compression refrigeration cycle.

[0024] In this embodiment, a water-cooled computer room air conditioning system is described, wherein the water outlet pipe 2 is equipped with an electrically controlled valve 21. This configuration facilitates the control of the cooling water flow rate.

[0025] This embodiment describes a water-cooled computer room air conditioning system, in which a blower 61 is provided in the air duct 6; and an evaporator 71 is located between the blower 61 and the heat exchange coil 5. Specifically, after the blower 61 starts, a negative pressure is formed in the air duct 6, and the computer room return air is drawn in from the end of the air duct 6 near the heat exchange coil 5. It first flows through the heat exchange coil 5 and undergoes a first heat exchange with the cooling water in the heat exchange coil 5 to achieve pre-cooling or heat replenishment treatment. The pre-treated air continues to flow along the air duct 6 and undergoes a second heat exchange with the low-temperature refrigerant in the evaporator 71 to complete deep cooling or dehumidification. Finally, the clean air, after temperature and humidity adjustment, is pressurized by the blower 61 and sent into the computer room.

[0026] In this embodiment, a water-cooled computer room air conditioning system is provided, wherein the water inlet pipe 1 is equipped with an inlet water temperature sensor 11 for detecting the inlet water temperature; and the air duct 6 is equipped with a return air temperature and humidity sensor 62 for detecting the return air dry bulb temperature at one end near the heat exchange coil 5.

[0027] Depend on Figure 2 As can be seen, the control method for a water-cooled computer room air conditioning system described in this embodiment includes the following steps: S1. If the cooling demand is less than the first cooling threshold preset value, proceed to step S2; otherwise, proceed to step A1. An example of the first cooling threshold preset value is 200%. A1. If the inlet water temperature is less than the difference between the return air dry bulb temperature and the preset value of the first inlet water temperature difference, proceed to step A2; otherwise, activate the compression refrigeration mode. An example of the preset value of the first inlet water temperature difference is 3℃. A2. If the inlet water temperature is less than the difference between the return air dry bulb temperature and the first cooling temperature difference preset value, the coil cooling mode will be turned on; otherwise, the mixed cooling mode will be turned on. The first cooling temperature difference preset value is 8℃. S2. If the cooling demand is not less than the second cooling input preset value, proceed to step B1; the first cooling input preset value is greater than the second cooling input preset value; wherein the second cooling input preset value is 50% (for example). B1. If the inlet water temperature is less than the sum of the return air dry bulb temperature and the second inlet water temperature difference preset value, proceed to step B2; otherwise, activate the first supplementary heating and cooling mode. The example of the second inlet water temperature difference preset value is 2℃. B2. If the inlet water temperature is less than the difference between the return air dry bulb temperature and the second preset cooling temperature difference, the coil cooling mode is activated; otherwise, the second supplementary heating cooling mode is activated. The first preset cooling temperature difference is greater than the second preset cooling temperature difference. For example, the second preset cooling temperature difference is 6℃.

[0028] Specifically, the control method of the water-cooled computer room air conditioning system described in this embodiment first divides the cooling condition into two levels: high load (cooling demand ≥ 200%) and low load (50% ≤ cooling demand < 200%) by comparing the cooling demand with the first and second preset cooling thresholds; then, by combining the difference between the inlet water temperature and the return air dry-bulb temperature, the availability of the natural cold source is determined, and the optimal cooling mode is automatically matched.

[0029] In the control method of the water-cooled computer room air conditioning system described in this embodiment, if the cooling demand is less than the second cooling preset value in step S2, then proceed to step S3. S3. If the dehumidification demand is less than the first dehumidification preset value, proceed to step S4; otherwise, proceed to step C1. An example of the first dehumidification preset value is 300%. C1. If the inlet water temperature is not higher than the return air dew point temperature, the mixed dehumidification mode will be turned on; otherwise, the compression dehumidification mode will be turned on. S4. If the dehumidification requirement is not less than the second dehumidification preset value, proceed to step D1; the first dehumidification preset value is greater than the second dehumidification preset value; wherein the second dehumidification preset value is 30% (example). D1. If the inlet water temperature is less than the sum of the return air dry bulb temperature and the third inlet water temperature difference preset value, proceed to step D2; otherwise, activate the first heat replenishment and dehumidification mode. The example of the third inlet water temperature difference preset value is 2℃. D2. If the inlet water temperature is not higher than the return air dew point temperature, the coil dehumidification mode will be turned on; otherwise, the second supplementary heating dehumidification mode will be turned on.

[0030] Specifically, in the control method of the water-cooled computer room air conditioning system described in this embodiment, when the cooling demand is less than 50%, the system automatically switches to dehumidification priority judgment, dividing the dehumidification condition into two levels: high humidity load (dehumidification demand ≥ 300%) and low humidity load (30% ≤ dehumidification demand < 300%). By comparing the inlet water temperature and the return air dew point temperature, the dehumidification capacity of the heat exchange coil 5 is determined, and the corresponding dehumidification mode is matched.

[0031] In the control method of the water-cooled computer room air conditioning system described in this embodiment, in step S4, if the dehumidification demand is less than the second dehumidification preset value, then the standby mode is activated. In the standby mode, the electronically controlled valve 21 is closed, the compressor 72 stops working, and the blower 61 runs at the standby speed. Specifically, when the cooling demand is <50% and the dehumidification demand is <30%, the temperature and humidity of the computer room meet the operating requirements of the server equipment, the system enters the standby state, and only the blower 61 is kept running at a low speed to maintain the basic ventilation volume of the computer room.

[0032] In the control method of the water-cooled computer room air conditioning system described in this embodiment, in the compression refrigeration mode, the first interface is connected to the second interface, the third interface is connected to the fourth interface, the fifth interface is connected to the eighth interface, and the sixth interface is connected to the seventh interface; the refrigeration component is started. Specifically, when the cooling load is high (≥200%) and the inlet water temperature is ≥ the return air dry bulb temperature -3℃, the natural cold source water temperature is too high and cannot provide effective cooling capacity. At this time, the cooling water only flows through the second heat exchange channel 42 of the heat exchanger 4, and the heat exchange coil 5 is bypassed to form an independent closed loop. The refrigeration components operate at full power and bear the entire cooling load through mechanical compression cycle. At this time, the cooling water path is: inlet pipe 1 - first interface - second interface - second heat exchange channel 42 - sixth interface - seventh interface - outlet pipe 2. At this time, the cooling water does not flow through the heat exchange coil 5, and the water in the heat exchange coil 5 is stagnant. The compressor 72 starts, and the control system adjusts the operating frequency of the compressor 72 according to the real-time cooling load demand. The blower 61 starts, and the control system adjusts the speed of the blower 61 according to the cooling load and the deviation of the blower temperature.

[0033] In the hybrid cooling mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the eighth interface, the sixth interface is connected to the seventh interface, and the cooling component is activated. Specifically, when the cooling load is high (≥200%) and the return air dry-bulb temperature is -8℃ ≤ inlet water temperature < return air dry-bulb temperature -3℃, the natural cold source can provide part of the cooling capacity. At this time, the cooling water first flows through the heat exchange coil 5 to pre-cool the return air, absorbing some of the heat in the air, and then enters the heat exchanger 4 to cool the refrigerant in the refrigeration cycle. The refrigeration components operate to bear the remaining cooling load. At this time, the cooling water path is: inlet pipe 1 - first interface - fourth interface - heat exchange coil 5 - eighth interface - fifth interface - third interface - second interface - second heat exchange channel. Pipe 42 - Sixth Interface - Seventh Interface - Water Outlet Pipe 2; At this time, compressor 72 starts, and the control system adjusts the operating frequency of compressor 72 according to the remaining cooling load after pre-cooling of heat exchange coil 5; blower 61 starts, and the speed is adjusted according to the total cooling load. The return air of the machine room first flows through heat exchange coil 5 and has the first heat exchange with the low temperature cooling water in heat exchange coil 5. After the air is pre-cooled, it continues to flow through evaporator 71 and has the second heat exchange with the low temperature refrigerant in evaporator 71. After the air has completed deep cooling, it is pressurized by blower 61 and sent into the machine room.

[0034] In coil cooling mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the sixth interface, and the seventh interface is connected to the eighth interface; the cooling component stops working. Specifically, when the cooling load is high (≥200%) and the inlet water temperature is < return air dry-bulb temperature -8℃, or when the cooling load is low (50% ≤ cooling demand < 200%) and the inlet water temperature is < return air dry-bulb temperature -6℃, the natural cold source can meet the cooling needs of the computer room. In this case, the cooling water only flows through the heat exchange coil 5, and the heat exchanger 4 is bypassed to form an independent closed loop. The refrigeration components are completely shut off, and cooling is achieved solely through the natural cold source. The cooling water path is: inlet pipe 1 - first interface - fourth interface - heat exchange coil 5 - eighth interface - seventh interface - outlet pipe 2. Cooling water does not flow through heat exchanger 4, and the water in heat exchanger 4 remains still; compressor 72 completely stops running, expansion valve 73 closes, and refrigerant circulation is interrupted; blower 61 starts, and the control system adjusts the speed of blower 61 individually according to the deviation between the return air temperature of the machine room and the set temperature; the return air of the machine room only flows through heat exchange coil 5 for heat exchange, and after being cooled down, it flows directly through evaporator 71 (without heat exchange function) and is then pressurized by blower 61 and sent into the machine room; by adjusting the speed of blower 61 and the opening of electric control valve 21, the temperature of the machine room is controlled to achieve pure natural cold source cooling.

[0035] In the first heating and cooling mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the eighth interface, and the sixth interface is connected to the seventh interface; the cooling component is activated. Specifically, when the cooling load is low (50% ≤ cooling demand < 200%) and the inlet water temperature ≥ return air dry-bulb temperature + 2℃, the natural cold source cannot provide cooling but can be used for supplemental heating. The cooling water first flows through the heat exchange coil 5 to directly supplement the return air, raising the return air temperature, and then enters the heat exchanger 4 to cool the refrigerant in the cooling cycle. The refrigeration components then operate to bear the cooling load. At this time, the cooling water path is: inlet pipe 1 - first interface - fourth interface - heat exchange coil 5 - eighth interface - fifth interface - third interface - second interface - second heat exchange channel 42 - sixth interface - seventh interface. Water outlet pipe 2; at this time, compressor 72 starts, and the control system adjusts the operating frequency according to the actual cooling load after heat replenishment; blower 61 starts, and the speed is adjusted according to the total load. The return air from the machine room first flows through heat exchange coil 5 and exchanges heat with the high-temperature cooling water in heat exchange coil 5. The air that has been heated by heat replenishment flows through evaporator 71 and exchanges heat with the low-temperature refrigerant in evaporator 71. It is cooled to the set temperature and then pressurized by blower 61 and sent into the machine room. The heat replenishment process effectively prevents condensation caused by the low supply air temperature and stabilizes the operating conditions of compressor 72.

[0036] In the second heating and cooling mode, the first interface is connected to the second interface, the third interface is connected to the fourth interface, the fifth interface is connected to the sixth interface, and the seventh interface is connected to the eighth interface; the cooling component is activated.

[0037] Specifically, when the cooling load is low (50% ≤ cooling demand < 200%) and the return air dry-bulb temperature is -6℃ ≤ inlet water temperature < return air dry-bulb temperature +2℃, the natural cold source cannot provide effective cooling. At this time, the cooling water first flows through heat exchanger 4 to absorb the condensation heat of the refrigeration cycle and raise its temperature, and then enters heat exchange coil 5 to supplement the return air with residual heat. The refrigeration components operate to bear the cooling load. At this time, the cooling water path is: inlet pipe 1 - first interface - second interface - second heat exchange channel 42 - sixth interface - fifth interface - third interface - fourth interface - heat exchange coil 5 - eighth interface. Interface - Seventh Interface - Water Outlet Pipe 2; At this time, the compressor 72 starts, and the control system adjusts the operating frequency according to the actual cooling load after heat replenishment; the blower 61 starts, and the speed is adjusted according to the total load. The return air of the machine room first flows through the heat exchange coil 5 and exchanges heat with the high-temperature water in the heat exchange coil 5 that has absorbed the condensation heat. The air that has been heated by the heat replenishment flows through the evaporator 71 and is cooled to the set temperature before being pressurized by the blower 61 and sent into the machine room. This mode realizes the recovery and utilization of the system's waste heat, and at the same time solves the problems of air supply condensation and large temperature and humidity fluctuations under low load.

[0038] In the control method of the water-cooled computer room air conditioning system described in this embodiment, in the compression dehumidification mode, the first interface is connected to the second interface, the third interface is connected to the fourth interface, the fifth interface is connected to the eighth interface, the sixth interface is connected to the seventh interface, and the refrigeration component is started. When there is a high humidity load (dehumidification requirement ≥300%) and the inlet water temperature is greater than the return air dew point temperature, the natural cold source water temperature is higher than the air dew point temperature and cannot provide effective dehumidification capacity. The cooling water only flows through the heat exchanger 4, the heat exchange coil 5 is bypassed, the refrigeration components operate, and the moisture in the air is condensed and precipitated on the low-temperature surface of the evaporator 71, bearing the entire dehumidification load. At this time, the cooling water path is the same as the cooling water path in the compression refrigeration mode. At this time, the compressor 72 starts, and the control system adjusts the operating frequency of the compressor 72 according to the real-time dehumidification load requirement (the deviation between the return air humidity of the machine room and the set humidity). The blower 61 starts and operates at low speed to prolong the contact time between the air and the evaporator 71 and improve the dehumidification efficiency. When the return air of the machine room flows through the heat exchange coil 5 (without heat exchange) and then flows through the evaporator 71, the water vapor in the air condenses into water on the surface of the evaporator 71 and is discharged. The air that has been cooled and dehumidified is pressurized by the blower 61 and sent into the machine room.

[0039] In the hybrid dehumidification mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the eighth interface, and the sixth interface is connected to the seventh interface; the refrigeration component is activated. When there is a high humidity load (dehumidification requirement ≥300%) and the inlet water temperature is ≤ the return air dew point temperature, the natural cold source can provide part of the dehumidification capacity. At this time, the cooling water first flows through the heat exchange coil 5, and uses the low temperature water to condense and precipitate some of the moisture in the air for pre-dehumidification, and then enters the heat exchanger 4 to cool the refrigerant. The refrigeration components operate to bear the remaining dehumidification load. At this time, the cooling water path is the same as the cooling water path in the mixed refrigeration mode. At this time, the compressor 72 starts, and the control system adjusts the operating frequency according to the remaining dehumidification load after the heat exchange coil 5 pre-dehumidifies. The blower 61 starts and operates at medium and low speed. The return air of the machine room first flows through the heat exchange coil 5, and some of the water vapor in the air condenses and precipitates on the surface of the coil. After the pre-dehumidification is completed, the air flows through the evaporator 71, and the remaining moisture condenses and precipitates on the surface of the evaporator 71. After the deep dehumidification is completed, the air is pressurized by the blower 61 and sent into the machine room. The two-stage dehumidification structure effectively improves the dehumidification energy efficiency ratio.

[0040] In coil dehumidification mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the sixth interface, and the seventh interface is connected to the eighth interface; the refrigeration component stops working. When the humidity load is low (30% ≤ dehumidification requirement < 300%) and the inlet water temperature ≤ return air dew point temperature, the natural cold source can fully meet the dehumidification requirements of the computer room. At this time, the cooling water only flows through the heat exchange coil 5, the heat exchanger 4 is bypassed, the refrigeration components are completely shut down, and dehumidification is achieved by directly condensing the moisture in the air with the low-temperature cooling water. At this time, the cooling water path is the same as the cooling water path in the coil cooling mode. At this time, the compressor 72 completely stops running, the expansion valve 73 is closed, the refrigerant circulation is interrupted, the system has no mechanical compression energy consumption, and dehumidification is achieved solely by the low-temperature cooling water. The blower 61 starts and operates at low speed. The return air of the computer room only flows through the heat exchange coil 5. When the cooling water temperature is lower than the return air dew point temperature, the water vapor in the air condenses and precipitates on the surface of the coil. The air dehumidified by the natural cold source is sent into the computer room through the evaporator 71 (without heat exchange) and the blower 61. By adjusting the speed of the blower 61 and the water flow rate, the humidity of the computer room is precisely controlled.

[0041] In the first heating and dehumidification mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the eighth interface, and the sixth interface is connected to the seventh interface; the refrigeration component is activated. When the humidity load is low (30% ≤ dehumidification requirement < 300%) and the inlet water temperature is ≥ return air dry bulb temperature + 2℃, the natural cold source cannot dehumidify but can be used for supplementary heating. At this time, the cooling water first flows through the heat exchange coil 5 to directly supplement the return air and raise the return air temperature before entering the heat exchanger 4 to cool the refrigerant. The refrigeration components operate to bear the dehumidification load. At this time, the cooling water path is the same as the cooling water path in the first supplementary heating and cooling mode. At this time, the compressor 72 starts, and the control system adjusts the operating frequency according to the actual dehumidification load after supplementary heating. The blower 61 starts and operates at a medium-low speed. The return air of the machine room first flows through the heat exchange coil 5 to be supplemented and heated. The heated air flows through the evaporator 71, and the water vapor in the air condenses and precipitates. The dehumidified air is pressurized by the blower 61 and sent into the machine room. The supplementary heating process effectively improves the supply air temperature and ensures the comfort of the machine room environment.

[0042] In the second heating and dehumidification mode, the first interface is connected to the second interface, the third interface is connected to the fourth interface, the fifth interface is connected to the sixth interface, and the seventh interface is connected to the eighth interface; the refrigeration component is activated.

[0043] When the humidity load is low (30% ≤ dehumidification requirement < 300%) and the return air dew point temperature < inlet water temperature < return air dry bulb temperature + 2℃, the natural cold source cannot provide effective dehumidification. At this time, the cooling water first flows through the heat exchanger 4 to absorb the condensation heat of the refrigeration cycle and raise its temperature, and then enters the heat exchange coil 5 to supplement the return air with residual heat. The refrigeration components operate to bear the dehumidification load. At this time, the cooling water path is the same as the cooling water path in the second supplementary heating refrigeration mode. At this time, the compressor 72 starts, and the control system adjusts the operating frequency according to the actual dehumidification load after supplementary heating. The blower 61 starts and operates at a medium and low speed. The return air of the machine room first flows through the heat exchange coil 5 and is heated by the condensation residual heat. The heated air flows through the evaporator 71 for dehumidification. The dehumidified air is pressurized by the blower 61 and sent into the machine room. This mode solves the contradiction between dehumidification and excessively low supply air temperature under low humidity load and keeps the relative humidity of the machine room stably controlled within a reasonable range.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A water-cooled computer room air conditioning system, characterized in that: It includes an inlet pipe (1), an outlet pipe (2), a first four-way valve (3), a second four-way valve (8), a heat exchanger (4), a heat exchange coil (5), refrigeration components, and an air duct (6); The heat exchanger (4) is provided with a first heat exchange channel (41) and a second heat exchange channel (42); the refrigeration component is connected to the first heat exchange channel (41); the refrigeration component includes an evaporator (71); the evaporator (71) and the heat exchange coil (5) are both located in the air duct (6); The first four-way valve (3) includes a first port, a second port, a third port and a fourth port; when the first port and the second port are connected, the third port and the fourth port are connected; when the first port and the fourth port are connected, the second port and the third port are connected. The second four-way valve (8) includes a fifth port, a sixth port, a seventh port, and an eighth port; when the fifth port is connected to the sixth port, the seventh port is connected to the eighth port; when the fifth port is connected to the eighth port, the sixth port is connected to the seventh port. The inlet pipe (1) is connected to the first interface; the second interface is connected to one end of the second heat exchange channel (42); the third interface is connected to the fifth interface; the fourth interface is connected to one end of the heat exchange coil (5); the sixth interface is connected to the other end of the second heat exchange channel (42); the seventh interface is connected to the outlet pipe (2); and the eighth interface is connected to the other end of the heat exchange coil (5).

2. The water-cooled computer room air conditioning system according to claim 1, characterized in that: The refrigeration assembly also includes a compressor (72) and an expansion valve (73); one end of the compressor (72) is connected to one end of the evaporator (71); the other end of the evaporator (71) is connected to one end of the expansion valve (73); the other end of the expansion valve (73) is connected to one end of the first heat exchange channel (41); the other end of the first heat exchange channel (41) is connected to the other end of the compressor (72).

3. The water-cooled computer room air conditioning system according to claim 1, characterized in that: The water outlet pipe (2) is equipped with an electrically controlled valve (21).

4. The water-cooled computer room air conditioning system according to claim 1, characterized in that: The air duct (6) is equipped with a blower (61); the evaporator (71) is located between the blower (61) and the heat exchange coil (5).

5. A water-cooled computer room air conditioning system according to claim 4, characterized in that: The water inlet pipe (1) is equipped with a water inlet temperature sensor (11) for detecting the water inlet temperature; the air duct (6) is equipped with a return air temperature and humidity sensor (62) for detecting the return air dry bulb temperature and humidity at one end near the heat exchange coil (5).

6. A control method for a water-cooled computer room air conditioning system according to any one of claims 1-5, characterized in that: Includes the following steps: S1. If the cooling demand is less than the preset value for the first cooling cycle, proceed to step S2; otherwise, proceed to step A1. A1. If the inlet water temperature is less than the difference between the return air dry bulb temperature and the preset value of the first inlet water temperature difference, proceed to step A2; otherwise, start the compression refrigeration mode. A2. If the inlet water temperature is less than the difference between the return air dry bulb temperature and the preset value of the first cooling temperature difference, then the coil cooling mode is turned on; otherwise, the mixed cooling mode is turned on. S2. If the cooling demand is not less than the second cooling entry preset value, proceed to step B1; if the first cooling entry preset value is greater than the second cooling entry preset value. B1. If the inlet water temperature is less than the sum of the return air dry bulb temperature and the second inlet water temperature difference preset value, proceed to step B2; otherwise, start the first supplementary heating and cooling mode. B2. If the inlet water temperature is less than the difference between the return air dry bulb temperature and the second preset cooling temperature difference, the coil cooling mode is activated; otherwise, the second supplementary heating cooling mode is activated. The first preset cooling temperature difference is greater than the second preset cooling temperature difference.

7. The control method according to claim 6, characterized in that: In step S2, if the cooling demand is less than the second cooling entry preset value, then proceed to step S3; S3. If the dehumidification demand is less than the first dehumidification preset value, proceed to step S4; otherwise, proceed to step C1. C1. If the inlet water temperature is not higher than the return air dew point temperature, the mixed dehumidification mode will be turned on; otherwise, the compression dehumidification mode will be turned on. S4. If the dehumidification requirement is not less than the second dehumidification preset value, proceed to step D1; the first dehumidification preset value is greater than the second dehumidification preset value. D1. If the inlet water temperature is less than the sum of the return air dry bulb temperature and the third inlet water temperature difference preset value, proceed to step D2; otherwise, activate the first heat replenishment and dehumidification mode. D2. If the inlet water temperature is not higher than the return air dew point temperature, the coil dehumidification mode will be turned on; otherwise, the second supplementary heating dehumidification mode will be turned on.

8. The control method according to claim 7, characterized in that: In step S4, if the dehumidification demand is less than the second dehumidification preset value, then the standby mode is activated.

9. The control method according to claim 6, characterized in that: In compression refrigeration mode, the first interface is connected to the second interface, the third interface is connected to the fourth interface, the fifth interface is connected to the eighth interface, and the sixth interface is connected to the seventh interface; the refrigeration component is activated. In the hybrid cooling mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the eighth interface, the sixth interface is connected to the seventh interface, and the cooling component is activated. In coil cooling mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the sixth interface, and the seventh interface is connected to the eighth interface; the cooling component stops working. In the first heating and cooling mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the eighth interface, and the sixth interface is connected to the seventh interface; the cooling component is activated. In the second heating and cooling mode, the first interface is connected to the second interface, the third interface is connected to the fourth interface, the fifth interface is connected to the sixth interface, and the seventh interface is connected to the eighth interface; the cooling component is activated.

10. The control method according to claim 7, characterized in that: In compression dehumidification mode, the first interface is connected to the second interface, the third interface is connected to the fourth interface, the fifth interface is connected to the eighth interface, and the sixth interface is connected to the seventh interface; the refrigeration component is activated. In the hybrid dehumidification mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the eighth interface, and the sixth interface is connected to the seventh interface; the refrigeration component is activated. In coil dehumidification mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the sixth interface, and the seventh interface is connected to the eighth interface; the refrigeration component stops working. In the first heating and dehumidification mode, the first interface is connected to the fourth interface, the second interface is connected to the third interface, the fifth interface is connected to the eighth interface, and the sixth interface is connected to the seventh interface; the refrigeration component is activated. In the second heating and dehumidification mode, the first interface is connected to the second interface, the third interface is connected to the fourth interface, the fifth interface is connected to the sixth interface, and the seventh interface is connected to the eighth interface; the refrigeration component is activated.

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