Indirect evaporative cooling air conditioning system and control method thereof

Abstract

The present application relates to air conditioning technical field, specifically to an indirect evaporative cooling air conditioning system and a control method thereof, comprising a cabinet; a heat exchange core, a heat exchanger and an evaporator are arranged in the cabinet; an evaporative water pan in communication with the heat exchanger is arranged at the bottom of the evaporator; a bypass air duct is arranged between the return air cavity and the supply air cavity; and an adjusting damper is arranged in the bypass air duct. The evaporator is arranged in the supply air cavity, and the evaporative water pan at the bottom of the evaporator is in communication with the heat exchanger, so that the low-temperature condensed water generated by the evaporator can be recycled as a secondary cold source to perform secondary cooling and dehumidification on the supply air, thereby effectively reducing the overall energy consumption; in addition, the bypass air duct and the adjusting damper are arranged between the return air cavity and the supply air cavity, so that when the mixed air temperature is too low due to the secondary cooling and dehumidification, the adjusting damper can be opened to make part of the supply air without being cooled by the heat exchanger directly enter the mixed air cavity to mix with the airflow cooled and dehumidified by the heat exchanger, thereby improving the supply air temperature in the mixed air cavity.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, specifically to an indirect evaporative cooling air conditioning system and its control method. Background Technology

[0002] Indirect evaporative cooling technology uses a non-contact heat exchanger to transfer the cooling energy generated by direct evaporative cooling to the circulating air in the computer room, making full use of natural cold sources to achieve cooling. Compared with traditional air-cooled and chilled water systems, it has significant energy-saving advantages and has become the mainstream technology for next-generation data center temperature control systems. Typical indirect evaporative cooling air conditioning units are usually equipped with a compressor mechanical cooling supplement system, which can supplement cooling energy when the natural cold source is insufficient. The operating modes are divided into dry mode, wet mode, and mixed mode, which can adapt to the cooling needs of different seasons and climatic conditions.

[0003] However, current indirect evaporative cooling technology can only achieve temperature reduction with constant humidity, and cannot remove moisture from the air. To meet the constant temperature and humidity requirements of data center computer rooms, it is usually necessary to configure additional vapor compression dehumidification systems and humidifiers. However, vapor compression dehumidification relies on the compressor to cool the air below the dew point temperature to achieve dehumidification, which consumes a lot of energy. In high-temperature and high-humidity areas or during the rainy season, the compressor must prioritize the cooling load of the computer room and cannot cool the air to a sufficiently low dew point temperature, resulting in insufficient dehumidification. Under low-load conditions, the supply air temperature after being cooled by indirect evaporative cooling technology is already low, the evaporator has limited cooling margin, and the heat exchange efficiency drops significantly, making it difficult to achieve effective dehumidification. Ultimately, this leads to high humidity in the computer room supply air and the risk of condensation. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned shortcomings in the prior art by providing an indirect evaporative cooling air conditioning system and its control method.

[0005] The objective of this invention is achieved through the following technical solution: an indirect evaporative cooling air conditioning system, comprising a housing; a heat exchange core and a heat exchanger are provided inside the housing; the housing is provided with an air inlet chamber, an air outlet chamber, a return air chamber, a supply air chamber, and a mixing air chamber; the air inlet chamber is connected to the air outlet chamber through the heat exchange core; the return air chamber is connected to the supply air chamber through the heat exchange core; the supply air chamber is connected to the mixing air chamber through the heat exchanger. An evaporator is provided inside the air supply chamber; an evaporation water receiving tray is provided at the bottom of the evaporator; a regulating water valve is provided between one end of the heat exchanger and the evaporation water receiving tray; one end of the heat exchanger is connected to the evaporation water receiving tray through the regulating water valve; a blower is provided inside the air mixing chamber. A bypass ventilation duct is provided between the air mixing chamber and the air supply chamber; the bypass ventilation duct is equipped with a regulating air valve.

[0006] The present invention is further configured such that the air inlet chamber is provided with a spray pipe at the top of the heat exchange core; the air outlet chamber is provided with a spray water tank at the bottom of the heat exchange core; and the other end of the heat exchanger is connected to the spray water tank.

[0007] The invention is further configured such that a hot water exchange tank is provided inside the air mixing chamber; the other end of the heat exchanger is connected to the spray water tank via the hot water exchange tank; and a water supply valve is provided between the hot water exchange tank and the spray water tank. The heat exchanger is provided with a heat exchange water receiving tray at the bottom; the heat exchange water receiving tray is connected to the heat exchange water tank.

[0008] The present invention is further configured such that a sealing frame is provided inside the box; the sealing frame is sealed between the air supply chamber and the air mixing chamber; the bypass ventilation duct and the heat exchanger are both provided in the sealing frame; the air supply chamber is connected to the air mixing chamber through the heat exchanger or the bypass ventilation duct.

[0009] The present invention is further configured such that the heat exchanger is located in the middle of the sealing frame; the bypass ventilation duct is located at both ends of the sealing frame; the evaporator and the sealing frame are both inclined; and the evaporator and the sealing frame are arranged parallel to each other.

[0010] The present invention is further configured such that the indirect evaporative cooling air conditioning system includes a computer room temperature sensor for detecting the computer room temperature, a computer room humidity sensor for detecting the computer room humidity, a supply air temperature sensor for detecting the supply air temperature between the evaporator and the heat exchanger, a supply air humidity sensor for detecting the supply air humidity between the evaporator and the heat exchanger, a mixing air temperature sensor for detecting the mixing air temperature of the mixing chamber, a condensate temperature sensor for detecting the condensate temperature of the evaporative water collection pan, and a condensate flow sensor for detecting the condensate flow rate of the evaporative water collection pan.

[0011] A control method for an indirect evaporative cooling air conditioning system includes the following steps: S1. Real-time monitoring of computer room temperature, humidity, supply air temperature, supply air humidity, mixed air temperature, condensate temperature, and condensate flow rate; S2. Obtain the dew point temperature setpoint by measuring the computer room temperature and humidity, and the computer room dew point temperature. S3. Calculate the dehumidification requirement based on the supply air temperature; if the mixed air temperature is less than the dew point temperature setting or the dehumidification requirement is greater than the dehumidification requirement setting, then enter the anti-condensation mode; otherwise, proceed to step S4. S4. If the supply air temperature is greater than the first supply air setting value, the condensate flow rate is greater than the flow rate setting value, and the condensate temperature is less than the second supply air setting value, then enter the high temperature protection mode; otherwise, return to step S1. The second supply air setting value is less than the first supply air setting value, and the dew point temperature setting value is less than the second supply air setting value.

[0012] The present invention is further configured such that, in step S4, the high-temperature protection mode includes the following steps: A1. Open the regulating water valve; A2. The opening of the regulating water valve is controlled by the temperature difference between the supply air temperature and the third supply air setting value. The larger the temperature difference between the supply air temperature and the third supply air setting value, the larger the opening of the regulating water valve; the smaller the temperature difference between the supply air temperature and the third supply air setting value, the smaller the opening of the regulating water valve. The third supply air setting value is greater than the second supply air setting value and the third supply air setting value is less than the first supply air setting value. A3. Return to step A1 if any of the following conditions are met: When the supply air temperature is not greater than the first supply air setting value; When the condensate flow rate is not greater than the set flow rate; When the condensate temperature is not less than the second air supply setting value.

[0013] The present invention is further configured such that, in step S3, the anti-condensation mode includes a water valve adjustment step and an air valve adjustment step; The water valve adjustment process includes the following steps: B1. If the following conditions are met simultaneously: the dehumidification demand is greater than the dehumidification demand setting value, the condensate flow rate is greater than the flow rate setting value, and the condensate temperature is less than the second air supply setting value, then proceed to step B2. B2. Open the regulating water valve and control the opening degree of the regulating water valve according to the dehumidification demand. The greater the dehumidification demand, the greater the opening degree of the regulating water valve, and the smaller the dehumidification demand, the smaller the opening degree of the regulating water valve. After the first preset time, proceed to step B3. B3. Recheck the dehumidification demand, condensate flow rate, and condensate temperature. If the dehumidification demand is greater than the dehumidification demand setting, the condensate flow rate is greater than the flow rate setting, and the condensate temperature is less than the second air supply setting, then return to step B2; otherwise, close the regulating water valve. The damper adjustment process includes the following steps: C1. When the regulating water valve is opened, if the mixed air temperature is less than the lower limit air supply setting value, then proceed to step C2; the lower limit air supply setting value is greater than the dew point temperature setting value, and the lower limit air supply setting value is less than the second air supply setting value. C2. Open the regulating air valve. Control the opening of the regulating air valve by the temperature difference between the lower limit air supply setting value and the mixed air temperature. The larger the temperature difference between the lower limit air supply setting value and the mixed air temperature, the larger the opening of the regulating air valve. The smaller the temperature difference between the lower limit air supply setting value and the mixed air temperature, the smaller the opening of the regulating air valve. After the second preset time, proceed to step C3. C3. Detect the mixed air temperature. If the mixed air temperature is less than the lower limit of the supply air setting value, return to step C2; otherwise, close the regulating damper.

[0014] The present invention is further configured such that, in step S3, the anti-condensation mode includes a fan adjustment step; the fan adjustment step includes the following steps: D1. If the mixed air temperature is not greater than the dew point temperature setting value, proceed to step D2. D2. Switch the PI speed adjustment target of the blower to the anti-condensation supply and return air temperature difference, and then proceed to step D3; D3. Initialize the current adjustment target value of the anti-condensation supply and return air temperature difference to equal the normal supply and return air temperature difference setting value; then lower the current adjustment target value of the anti-condensation supply and return air temperature difference to the preset temperature difference, and the blower adjusts the PI speed according to the lowered anti-condensation supply and return air temperature difference, and then proceed to step D4. D4. After the first preset time, the mixed air temperature is checked again; if the mixed air temperature is greater than the dew point temperature setting value, proceed to step D51; if the mixed air temperature is not greater than the dew point temperature setting value, proceed to step D61. D51. Adjust the current target value of the anti-condensation supply and return air temperature difference upward to the preset temperature difference. The blower adjusts the PI speed according to the adjusted anti-condensation supply and return air temperature difference, and then proceeds to step D52. D52. Determine whether the current adjustment target value of the anti-condensation supply and return air temperature difference after the adjustment is equal to the normal supply and return air temperature difference setting value. If so, the PI speed adjustment target of the supply fan is switched to the normal supply and return air temperature difference; otherwise, return to step D4. D61. Determine whether the current adjustment target value of the anti-condensation supply and return air temperature difference is equal to the lower limit value of the normal supply and return air temperature difference. If so, maintain the current adjustment target value of the anti-condensation supply and return air temperature difference and return to step D4. Otherwise, proceed to step D62. The lower limit value of the normal supply and return air temperature difference is less than the set value of the normal supply and return air temperature difference. D62. Lower the current target value of the anti-condensation supply and return air temperature difference to the preset temperature difference. The blower adjusts its speed according to the lowered anti-condensation supply and return air temperature difference, and then returns to step D4.

[0015] The beneficial effects of this invention are as follows: By installing an evaporator in the air supply cavity and connecting the evaporation water collection tray at the bottom of the evaporator to the heat exchanger, the low-temperature condensate generated by the evaporator can be recovered as a secondary cold source to perform secondary cooling and dehumidification of the supply air, thereby effectively reducing the overall energy consumption. In addition, by setting a bypass ventilation duct and regulating air valve between the return air cavity and the air supply cavity, when the mixed air temperature is too low due to secondary cooling and dehumidification, the regulating air valve can be opened to allow some of the supply air that has not been cooled by the heat exchanger to directly enter the mixed air cavity and mix with the airflow that has been cooled and dehumidified by the heat exchanger, thereby increasing the supply air temperature of the mixed air cavity. Attached Figure Description

[0016] 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.

[0017] Figure 1 This is a cross-sectional view of the indirect evaporative cooling air conditioning system of the present invention; Figure 2 yes Figure 1 A magnified view of part A in the middle; Figure 3 This is a schematic diagram of the structure of the evaporator and heat exchanger of the present invention. Figure 4 This is a schematic diagram of the structure of the evaporator and heat exchanger of the present invention from another perspective; Figure 5 This is a control flowchart of the control method of the present invention; Figure 6 This is the control flowchart of the high-temperature protection mode of the present invention; Figure 7 This is a control flowchart of the water valve adjustment steps of the present invention; Figure 8 This is a control flowchart of the damper adjustment steps of the present invention; Figure 9 This is a control flowchart of the fan adjustment steps of the present invention; The components are as follows: 1. Housing; 2. Heat exchange core; 3. Air inlet chamber; 31. Spray pipe; 4. Exhaust chamber; 41. Spray water tank; 5. Return air chamber; 6. Air supply chamber; 61. Evaporator; 62. Evaporation water tray; 7. Mixing chamber; 71. Blower; 8. Heat exchanger; 81. Hot water tank; 82. Heat exchange water tray; 83. Regulating water valve; 9. Sealing frame; 91. Bypass ventilation duct; 92. Regulating air valve. Detailed Implementation

[0018] The present invention will be further described in conjunction with the following embodiments.

[0019] Depend on Figures 1 to 4 As can be seen, the indirect evaporative cooling air conditioning system described in this embodiment includes a housing 1; the housing 1 is provided with a heat exchange core 2 and a heat exchanger 8; the housing 1 is provided with an air inlet chamber 3, an air outlet chamber 4, a return air chamber 5, a supply air chamber 6, and a mixing air chamber 7; the air inlet chamber 3 is connected to the air outlet chamber 4 through the heat exchange core 2; the return air chamber 5 is connected to the supply air chamber 6 through the heat exchange core 2; the supply air chamber 6 is connected to the mixing air chamber 7 through the heat exchanger 8; An evaporator 61 is provided inside the air supply chamber 6; an evaporation water receiving tray 62 is provided at the bottom of the evaporator 61; a regulating water valve 83 is provided between one end of the heat exchanger 8 and the evaporation water receiving tray 62; one end of the heat exchanger 8 is connected to the evaporation water receiving tray 62 through the regulating water valve 83; a blower 71 is provided inside the air mixing chamber 7. A bypass ventilation duct 91 is provided between the air mixing chamber 7 and the air supply chamber 6; the bypass ventilation duct 91 is provided with a regulating air valve 92.

[0020] Specifically, in the indirect evaporative cooling air conditioning system described in this embodiment, after the hot return air from the computer room enters the return air cavity 5, it first flows through the heat exchange core 2 and undergoes non-contact heat exchange with the outdoor fresh air introduced into the air inlet cavity 3 to achieve preliminary cooling before entering the air supply cavity 6. When the compressor is running, the evaporator 61 in the air supply cavity 6 further cools the airflow. The low-temperature condensate generated on the surface of the evaporator 61 is collected in the evaporation water collection pan 62 at the bottom and sent to the heat exchanger 8 after the flow rate is controlled by the regulating water valve 83. When the airflow in the air supply cavity 6 flows through the heat exchanger 8, it exchanges heat with the low-temperature condensate in the heat exchanger 8. The water vapor in the air condenses upon encountering the condensate, achieving secondary cooling and dehumidification. The dehumidified airflow enters the mixing air cavity 7 and is sent into the computer room by the blower 71. When the dehumidification of the heat exchanger 8 causes the mixed air temperature to be too low, the regulating air valve 92 of the bypass ventilation duct 91 is opened, allowing some of the supply air that has not been cooled by the heat exchanger 8 to directly enter the mixing air cavity 7 and mix with the low-temperature dehumidified airflow to raise the temperature.

[0021] In this embodiment, the condensate generated by the evaporator 61 is used as a secondary cold source, which can achieve dehumidification without additional power consumption, effectively reducing the compressor running time and reducing cooling energy consumption. In addition, the mixed air temperature is dynamically adjusted by the bypass ventilation duct 91, which can avoid the mixed air from being too cold without electric heating or waste heat compensation, effectively eliminating the risk of condensation in the mixed air cavity 7 and the machine room.

[0022] In addition, in this embodiment, a water pump can be installed between one end of the heat exchanger 8 and the evaporation water receiving pan 62 to provide power for the flow of condensate in the evaporation water receiving pan 62. During this process, the water pump can maintain a constant power, and the flow rate of condensate between the heat exchanger 8 and the evaporation water receiving pan 62 can be adjusted by controlling the opening of the regulating water valve 83.

[0023] In this embodiment, an indirect evaporative cooling air conditioning system is described. The air inlet chamber 3 has a spray pipe 31 at the top of the heat exchange core 2; the exhaust chamber 4 has a spray water tank 41 at the bottom of the heat exchange core 2; and the other end of the heat exchanger 8 is connected to the spray water tank 41. Specifically, when the outdoor dry-bulb temperature is high, the system switches to wet mode. Water in the spray water tank 41 is sprayed onto the surface of the heat exchange core 2 through the spray pipe 31. The water evaporates and absorbs heat, lowering the temperature of the heat exchange core 2 and enhancing the heat exchange effect between the return air and fresh air. Additionally, the condensate after being heated by the heat exchanger 8 is directly returned to the spray water tank 41 through a pipeline for reuse as supplementary water for the spray system.

[0024] This embodiment describes an indirect evaporative cooling air conditioning system. The mixing chamber 7 contains a hot water tank 81. The other end of the heat exchanger 8 is connected to a spray water tank 41 via the hot water tank 81. A water supply valve is provided between the hot water tank 81 and the spray water tank 41. A heat exchange water receiving tray 82 is located at the bottom of the heat exchanger 8 and is connected to the hot water tank 81. Specifically, when airflow passes through the heat exchanger 8 for dehumidification, water droplets condensed on the surface of the heat exchanger 8 drip into the heat exchange water receiving tray 82 at the bottom and flow into the hot water tank 81 through a pipeline. Simultaneously, the condensate after heat exchange in the heat exchanger 8 also flows into the hot water tank 81 for temporary storage and sedimentation. When the water level in the spray water tank 41 falls below a set threshold, the water supply valve is opened to replenish the clean condensate stored in the hot water tank 81 into the spray water tank 41, achieving closed-loop utilization of water resources.

[0025] This embodiment describes an indirect evaporative cooling air conditioning system, in which a sealing frame 9 is provided inside the housing 1; the sealing frame 9 is sealed between the air supply chamber 6 and the mixing chamber 7; the bypass ventilation duct 91 and the heat exchanger 8 are both located within the sealing frame 9; the air supply chamber 6 is connected to the mixing chamber 7 through the heat exchanger 8 or the bypass ventilation duct 91. Specifically, the sealing frame 9 completely isolates the air supply chamber 6 from the mixing chamber 7, and the airflow in the air supply chamber 6 can only enter the mixing chamber 7 through the heat exchanger 8 or the bypass ventilation duct 91, with no other short-circuit channels, thus avoiding uneven temperature and humidity and local condensation problems in the machine room caused by local airflow short circuits.

[0026] In this embodiment, an indirect evaporative cooling air conditioning system is described, wherein the heat exchanger 8 is located in the middle of the sealing frame 9; the bypass ventilation duct 91 is located at both ends of the sealing frame 9; the evaporator 61 and the sealing frame 9 are both inclined; and the evaporator 61 and the sealing frame 9 are arranged parallel to each other. Specifically, the heat exchanger 8 is centrally located, and the bypass ventilation ducts 91 are symmetrically distributed at both ends, so that the bypass airflow and the low-temperature airflow from the heat exchanger 8 can be quickly and evenly mixed in the mixing chamber 7; the evaporator 61 and the sealing frame 9 are inclined, so that the condensate and dew generated on their surfaces can flow smoothly into the bottom evaporation water receiving pan 62 and the heat exchange water receiving pan 82 under the action of gravity.

[0027] This embodiment describes an indirect evaporative cooling air conditioning system, which further includes a room temperature sensor for detecting room temperature, a room humidity sensor for detecting room humidity, a supply air temperature sensor for detecting the supply air temperature between the evaporator 61 and the heat exchanger 8, a supply air humidity sensor for detecting the supply air humidity between the evaporator 61 and the heat exchanger 8, a mixing air temperature sensor for detecting the mixing air temperature in the mixing chamber 7, a condensate temperature sensor for detecting the condensate temperature in the evaporative water collection pan 62, and a condensate flow sensor for detecting the condensate flow rate in the evaporative water collection pan 62. Specifically, this embodiment uses each sensor to collect environmental and operating parameters at corresponding locations in real time and transmits the data to the controller. The controller calculates the dew point temperature based on the room temperature and humidity, and combines this with parameters such as supply air temperature and humidity, mixing air temperature, condensate temperature, and condensate flow rate to determine the current operating condition of the system. It automatically triggers an anti-condensation mode or an anti-high temperature mode and controls the opening of the regulating water valve 83, the opening of the regulating air valve 92, and the speed of the supply fan 71.

[0028] Depend on Figures 5 to 9 As can be seen, the control method for an indirect evaporative cooling air conditioning system described in this embodiment includes the following steps: S1. Real-time monitoring of computer room temperature, humidity, supply air temperature, supply air humidity, mixed air temperature, condensate temperature, and condensate flow rate; S2. Calculate the computer room dew point temperature by measuring the computer room temperature and humidity. Obtain the dew point temperature setpoint value by measuring the computer room dew point temperature. An example value for the dew point temperature setpoint value is the computer room dew point temperature + 0.5℃. S3. Calculate the dehumidification requirement based on the supply air temperature; if the mixed air temperature is lower than the dew point temperature setting or the dehumidification requirement is greater than the dehumidification requirement setting, then enter the anti-condensation mode; otherwise, proceed to step S4. The example value for the dehumidification requirement setting is 10%. S4. If the following conditions are met simultaneously: the supply air temperature is greater than the first supply air setting value, the condensate flow rate is greater than the flow rate setting value, and the condensate temperature is less than the second supply air setting value, then enter the high temperature protection mode; otherwise, return to step S1. The second supply air setting value is less than the first supply air setting value, and the dew point temperature setting value is less than the second supply air setting value. An example value for the first supply air setting value is 27°C. An example value for the second supply air setting value is 24°C. An example value for the flow rate setting value is 0.5L / min.

[0029] Specifically, the control method of the indirect evaporative cooling air conditioning system described in this embodiment first determines whether there is a risk of condensation by detecting multi-dimensional parameters, prioritizing the safety of the equipment in the computer room; under the premise that there is no risk of condensation, idle condensate is used for pre-cooling and cooling, effectively improving energy-saving capabilities; the dew point temperature setpoint is calculated based on the actual dew point temperature of the computer room plus a safety margin, and the dehumidification demand is quantified by the difference between the current supply air humidity and the set humidity, ensuring that the triggering conditions are accurately matched with the actual operating conditions.

[0030] This embodiment resolves the contradiction between sacrificing dehumidification for cooling and causing excessive cooling by dehumidification, thus achieving the dual effects of preventing condensation and saving energy.

[0031] The control method for an indirect evaporative cooling air conditioning system described in this embodiment includes the following steps in step S4: A1. Open the regulating water valve 83; A2. The opening of the regulating water valve 83 is controlled by the temperature difference between the supply air temperature and the third supply air setting value. The larger the temperature difference between the supply air temperature and the third supply air setting value, the larger the opening of the regulating water valve 83; the smaller the temperature difference between the supply air temperature and the third supply air setting value, the smaller the opening of the regulating water valve 83. The third supply air setting value is greater than the second supply air setting value and less than the first supply air setting value. An example value for the third supply air setting value is 25.5℃. A3. Return to step A1 if any of the following conditions are met: When the supply air temperature is not greater than the first supply air setting value; When the condensate flow rate is not greater than the set flow rate; When the condensate temperature is not less than the second air supply setting value.

[0032] Specifically, the control method of the indirect evaporative cooling air conditioning system described in this embodiment utilizes the idle condensate generated by the evaporator 61 as a cold source in the high-temperature protection mode. When there is no risk of condensation and the supply air temperature is too high, the flow rate of condensate is controlled by adjusting the opening of the water valve 83 to pre-cool the supply air, thereby achieving auxiliary cooling and reducing the number of compressor starts and running time. Furthermore, it can automatically stop when there is insufficient condensate, the supply air temperature is too low, or the condensate temperature is too high, to avoid affecting the normal operation of the system.

[0033] In the control method of the indirect evaporative cooling air conditioning system described in this embodiment, the anti-condensation mode in step S3 includes a water valve adjustment step and an air valve adjustment step. The water valve adjustment process includes the following steps: B1. If the following conditions are met simultaneously: the dehumidification demand is greater than the dehumidification demand setting value, the condensate flow rate is greater than the flow rate setting value, and the condensate temperature is less than the second air supply setting value, then proceed to step B2. B2. Open the regulating water valve 83. The opening of the regulating water valve 83 is controlled by the dehumidification demand. The greater the dehumidification demand, the greater the opening of the regulating water valve 83. The smaller the dehumidification demand, the smaller the opening of the regulating water valve 83. After the first preset time, proceed to step B3. The example value of the first preset time is 30 seconds. B3. Re-check the dehumidification demand, condensate flow rate, and condensate temperature. If the dehumidification demand is greater than the dehumidification demand setting, the condensate flow rate is greater than the flow rate setting, and the condensate temperature is less than the second air supply setting, then return to step B2; otherwise, close the regulating water valve 83. Specifically, this embodiment prioritizes the use of condensate for dehumidification. By adjusting the condensate flow rate, the dehumidification intensity is controlled, so that the dehumidification amount is dynamically matched with the actual dehumidification needs of the computer room, thereby reducing dehumidification energy consumption. In addition, a cyclic detection mechanism ensures the continuity and stability of the dehumidification process. When the condensate conditions are not met, the process automatically stops to avoid ineffective operation.

[0034] The damper adjustment process includes the following steps: C1. When the regulating water valve 83 is opened, if the mixed air temperature is less than the lower limit air supply setting value, then proceed to step C2; the lower limit air supply setting value is greater than the dew point temperature setting value, and the lower limit air supply setting value is less than the second air supply setting value; wherein the example value of the lower limit air supply setting value is the computer room dew point temperature + 1.5℃. C2. Open the regulating damper 92. Control the opening of the regulating damper 92 by the temperature difference between the lower limit air supply setting value and the mixed air temperature. The larger the temperature difference between the lower limit air supply setting value and the mixed air temperature, the larger the opening of the regulating damper 92. The smaller the temperature difference between the lower limit air supply setting value and the mixed air temperature, the smaller the opening of the regulating damper 92. After the second preset time, proceed to step C3. An example value for the second preset time is 20 seconds. C3. Detect the mixed air temperature. If the mixed air temperature is less than the lower limit of the supply air setting value, return to step C2; otherwise, close the regulating air valve 92.

[0035] Specifically, the air valve regulation is a temperature compensation method designed to address the problem of excessively cold mixed air temperature caused by condensate dehumidification. It improves the mixed air temperature by mixing the bypass air that is not cooled by the heat exchanger 8 with the low-temperature dehumidification airflow. In addition, it adopts a proportional regulation method to dynamically adjust the bypass air volume according to the temperature difference between the lower limit of the air supply setting and the mixed air temperature, so as to achieve smooth regulation of the air supply temperature without the need for additional energy-consuming electric heating or waste heat compensation devices.

[0036] The control method for an indirect evaporative cooling air conditioning system described in this embodiment includes a fan adjustment step in step S3; the fan adjustment step includes the following steps: D1. If the mixed air temperature is not greater than the dew point temperature setting value, proceed to step D2. D2. Switch the PI speed adjustment target of the blower 71 to the anti-condensation supply and return air temperature difference, and then proceed to step D3; D3. Initialize the current adjustment target value of the anti-condensation supply and return air temperature difference to equal the normal supply and return air temperature difference setting value; then lower the current adjustment target value of the anti-condensation supply and return air temperature difference to the preset temperature difference. The blower 71 adjusts the PI speed according to the lowered anti-condensation supply and return air temperature difference, and then proceeds to step D4. The example value of the normal supply and return air temperature difference setting value is 8℃. D4. After the first preset time, the mixed air temperature is checked again; if the mixed air temperature is greater than the dew point temperature setting value, proceed to step D51; if the mixed air temperature is not greater than the dew point temperature setting value, proceed to step D61. D51. Adjust the current target value of the anti-condensation supply and return air temperature difference upward to the preset temperature difference. The blower 71 adjusts the PI speed according to the adjusted anti-condensation supply and return air temperature difference, and then proceeds to step D52. D52. Determine whether the current adjustment target value of the anti-condensation supply and return air temperature difference after the adjustment is equal to the normal supply and return air temperature difference setting value. If so, the PI speed adjustment target of the blower 71 is switched to the normal supply and return air temperature difference; otherwise, return to step D4. D61. Determine whether the current adjustment target value of the anti-condensation supply and return air temperature difference is equal to the lower limit value of the normal supply and return air temperature difference. If so, maintain the current adjustment target value of the anti-condensation supply and return air temperature difference and return to step D4; otherwise, proceed to step D62. The lower limit value of the normal supply and return air temperature difference is less than the set value of the normal supply and return air temperature difference, wherein the example value of the lower limit value of the normal supply and return air temperature difference is 5℃. D62. Lower the current target value of the anti-condensation supply and return air temperature difference to the preset temperature difference. The blower 71 adjusts the PI speed according to the lowered anti-condensation supply and return air temperature difference, and then returns to step D4.

[0037] Specifically, in the control method of the indirect evaporative cooling air conditioning system described in this embodiment, when the mixed air temperature is still close to the dew point temperature after the regulating water valve 83 and regulating air valve 92 are activated, the anti-condensation supply and return air temperature difference control target is iteratively lowered to increase the speed of the supply fan 71, shorten the contact time between the airflow and the surface of the heat exchanger 8, and suppress water vapor condensation on the surface. This embodiment adopts a gradual adjustment method for the supply fan 71 to avoid system fluctuations caused by sudden changes in the speed of the supply fan 71, and at the same time sets an adjustment lower limit to prevent the supply fan 71 from being overloaded.

[0038] 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. An indirect evaporative cooling air conditioning system, characterized in that: The device includes a housing (1); the housing (1) contains a heat exchange core (2) and a heat exchanger (8); the housing (1) contains an air inlet chamber (3), an air outlet chamber (4), a return air chamber (5), a supply air chamber (6), and a mixing air chamber (7); the air inlet chamber (3) is connected to the air outlet chamber (4) through the heat exchange core (2); the return air chamber (5) is connected to the supply air chamber (6) through the heat exchange core (2); the supply air chamber (6) is connected to the mixing air chamber (7) through the heat exchanger (8); An evaporator (61) is provided inside the air supply chamber (6); an evaporation water receiving tray (62) is provided at the bottom of the evaporator (61); a regulating water valve (83) is provided between one end of the heat exchanger (8) and the evaporation water receiving tray (62); one end of the heat exchanger (8) is connected to the evaporation water receiving tray (62) through the regulating water valve (83); a blower (71) is provided inside the air mixing chamber (7); A bypass ventilation duct (91) is provided between the air mixing chamber (7) and the air supply chamber (6); the bypass ventilation duct (91) is provided with a regulating air valve (92).

2. The indirect evaporative cooling air conditioning system according to claim 1, characterized in that: The air inlet chamber (3) is provided with a spray pipe (31) at the top of the heat exchange core (2); the air outlet chamber (4) is provided with a spray water tank (41) at the bottom of the heat exchange core (2); the other end of the heat exchanger (8) is connected to the spray water tank (41).

3. The indirect evaporative cooling air conditioning system according to claim 2, characterized in that: The mixing chamber (7) is equipped with a hot water tank (81); the other end of the heat exchanger (8) is connected to the spray tank (41) through the hot water tank (81); a water supply valve is provided between the hot water tank (81) and the spray tank (41); The heat exchanger (8) is provided with a heat exchange water receiving tray (82) at the bottom; the heat exchange water receiving tray (82) is connected to the heat exchange water tank (81).

4. The indirect evaporative cooling air conditioning system according to claim 1, characterized in that: The housing (1) is provided with a sealing frame (9); the sealing frame (9) is sealed between the air supply chamber (6) and the air mixing chamber (7); the bypass ventilation duct (91) and the heat exchanger (8) are both provided in the sealing frame (9); the air supply chamber (6) is connected to the air mixing chamber (7) through the heat exchanger (8) or the bypass ventilation duct (91).

5. The indirect evaporative cooling air conditioning system according to claim 4, characterized in that: The heat exchanger (8) is located in the middle of the sealing frame (9); the bypass ventilation duct (91) is located at both ends of the sealing frame (9); the evaporator (61) and the sealing frame (9) are both inclined; the evaporator (61) and the sealing frame (9) are arranged in parallel.

6. The indirect evaporative cooling air conditioning system according to claim 1, characterized in that: The indirect evaporative cooling air conditioning system also includes a computer room temperature sensor for detecting the computer room temperature, a computer room humidity sensor for detecting the computer room humidity, a supply air temperature sensor for detecting the supply air temperature between the evaporator (61) and the heat exchanger (8), a supply air humidity sensor for detecting the supply air humidity between the evaporator (61) and the heat exchanger (8), a mixing air temperature sensor for detecting the mixing air temperature of the mixing chamber (7), a condensate temperature sensor for detecting the condensate temperature of the evaporative water receiving pan (62), and a condensate flow sensor for detecting the condensate flow rate of the evaporative water receiving pan (62).

7. A control method for an indirect evaporative cooling air conditioning system according to any one of claims 1-6, characterized in that: Includes the following steps: S1. Real-time monitoring of computer room temperature, humidity, supply air temperature, supply air humidity, mixed air temperature, condensate temperature, and condensate flow rate; S2. Obtain the dew point temperature setpoint by measuring the computer room temperature and humidity, and the computer room dew point temperature. S3. Calculate the dehumidification requirement based on the supply air temperature; if the mixed air temperature is less than the dew point temperature setting or the dehumidification requirement is greater than the dehumidification requirement setting, then enter the anti-condensation mode; otherwise, proceed to step S4. S4. If the supply air temperature is greater than the first supply air setting value, the condensate flow rate is greater than the flow rate setting value, and the condensate temperature is less than the second supply air setting value, then enter the high temperature protection mode; otherwise, return to step S1. The second supply air setting value is less than the first supply air setting value, and the dew point temperature setting value is less than the second supply air setting value.

8. The control method according to claim 7, characterized in that: In step S4, the high-temperature protection mode includes the following steps: A1. Open the regulating water valve (83); A2. The opening of the regulating water valve (83) is controlled by the temperature difference between the supply air temperature and the third supply air setting value. The larger the temperature difference between the supply air temperature and the third supply air setting value, the larger the opening of the regulating water valve (83) is, and the smaller the temperature difference between the supply air temperature and the third supply air setting value, the smaller the opening of the regulating water valve (83) is. The third supply air setting value is greater than the second supply air setting value, and the third supply air setting value is less than the first supply air setting value. A3. Return to step A1 if any of the following conditions are met: When the supply air temperature is not greater than the first supply air setting value; When the condensate flow rate is not greater than the set flow rate; When the condensate temperature is not less than the second air supply setting value.

9. The control method according to claim 7, characterized in that: In step S3, the anti-condensation mode includes a water valve adjustment step and an air valve adjustment step; The water valve adjustment process includes the following steps: B1. If the following conditions are met simultaneously: the dehumidification demand is greater than the dehumidification demand setting value, the condensate flow rate is greater than the flow rate setting value, and the condensate temperature is less than the second air supply setting value, then proceed to step B2. B2. Open the regulating water valve (83). The opening degree of the regulating water valve (83) is controlled by adjusting the dehumidification demand. The greater the dehumidification demand, the greater the opening degree of the regulating water valve (83). The smaller the dehumidification demand, the smaller the opening degree of the regulating water valve (83). After the first preset time, proceed to step B3. B3. Check the dehumidification demand, condensate flow rate and condensate temperature again. If the dehumidification demand is greater than the dehumidification demand setting value, the condensate flow rate is greater than the flow rate setting value and the condensate temperature is less than the second air supply setting value at the same time, return to step B2; otherwise, close the regulating water valve (83). The damper adjustment process includes the following steps: C1. When the regulating water valve (83) is opened, if the mixed air temperature is less than the lower limit air supply setting value, then proceed to step C2; the lower limit air supply setting value is greater than the dew point temperature setting value, and the lower limit air supply setting value is less than the second air supply setting value. C2. Open the regulating air valve (92). Control the opening of the regulating air valve (92) by the temperature difference between the lower limit air supply setting value and the mixed air temperature. The larger the temperature difference between the lower limit air supply setting value and the mixed air temperature, the larger the opening of the regulating air valve (92). The smaller the temperature difference between the lower limit air supply setting value and the mixed air temperature, the smaller the opening of the regulating air valve (92). After the second preset time, proceed to step C3. C3. Detect the mixed air temperature. If the mixed air temperature is less than the lower limit of the supply air setting value, return to step C2; otherwise, close the regulating air valve (92).

10. The control method according to claim 7, characterized in that: In step S3, the anti-condensation mode includes a fan adjustment step; the fan adjustment step includes the following steps: D1. If the mixed air temperature is not greater than the dew point temperature setting value, proceed to step D2. D2. The PI speed adjustment target of the blower (71) is switched to the anti-condensation supply and return air temperature difference, and then proceed to step D3. D3. Initialize the current adjustment target value of the anti-condensation supply and return air temperature difference to equal the normal supply and return air temperature difference setting value; then lower the current adjustment target value of the anti-condensation supply and return air temperature difference to the preset temperature difference, and the blower (71) adjusts the PI speed according to the lowered anti-condensation supply and return air temperature difference, and then proceeds to step D4. D4. After the first preset time, the mixed air temperature is checked again; if the mixed air temperature is greater than the dew point temperature setting value, proceed to step D51; if the mixed air temperature is not greater than the dew point temperature setting value, proceed to step D61. D51. Adjust the current target value of the anti-condensation supply and return air temperature difference upward to the preset temperature difference. The blower (71) adjusts the PI speed according to the adjusted anti-condensation supply and return air temperature difference, and then proceeds to step D52. D52. Determine whether the current adjustment target value of the anti-condensation supply and return air temperature difference after the adjustment is equal to the normal supply and return air temperature difference setting value. If so, the PI speed adjustment target of the blower (71) is switched to the normal supply and return air temperature difference. Otherwise, return to step D4. D61. Determine whether the current adjustment target value of the anti-condensation supply and return air temperature difference is equal to the lower limit value of the normal supply and return air temperature difference. If so, maintain the current adjustment target value of the anti-condensation supply and return air temperature difference and return to step D4. Otherwise, proceed to step D62. The lower limit value of the normal supply and return air temperature difference is less than the set value of the normal supply and return air temperature difference. D62. The current target value of the anti-condensation supply and return air temperature difference is lowered by the preset temperature difference. The blower (71) adjusts the PI speed according to the lowered anti-condensation supply and return air temperature difference, and then returns to step D4.

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