Indirect evaporative air cooling device

Abstract

The present application relates to a kind of indirect evaporative air cooling device, the device includes shell, cooling coil, circulating water pump, circulating water evaporative cooling module, wet film, first water collecting tray, second water collecting tray, water storage tank, spray backwater tank, spray water pump, water supplement device, inner circulating fan, outer circulating fan, spraying device and heat exchanger being arranged in shell;It is pre-cooled by natural wind entering the device, and the cooled cold air is used to the cooling water in the wet film and the packing for convective evaporation cooling, so that the cooling water is cooled to the water close to ambient wet-bulb temperature.It is optimized by optimizing the process of cooling and evaporation, and the overall evaporation efficiency and cooling efficiency are greatly improved, and the device is also compact, compared with the existing multistage evaporative cooling unit, the volume and weight are greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of indirect evaporative air cooling technology, and more specifically to a dew point type indirect evaporative air cooling device with an air pre-cooling module. Background Technology

[0002] Evaporative cooling air conditioning technology is an environmentally friendly, efficient, and economical cooling method that can significantly reduce electricity consumption and greenhouse gas and CFC emissions, and is currently widely used in industrial plants. However, conventional direct evaporation devices can only cool air and circulating water to near the wet-bulb temperature, and the air humidity is relatively high, resulting in still relatively high temperatures during the hot summer months. Dew-point evaporative cooling units can better solve this problem, but currently, similar devices are bulky, not compact enough, very heavy, and have low overall efficiency. The main problems with this type of device are the lack of a systematic design between air precooling and evaporation, insufficient precooling water temperature, and low evaporation efficiency, all of which require improvement in overall efficiency and cooling capacity. Currently, mainstream indirect evaporative cooling devices can only cool hot air to near the wet-bulb temperature through natural cooling, typically wet-bulb temperature +(2-6)℃. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the present invention provides an indirect evaporative air cooling device with a pre-cooled water evaporative air cooling treatment module. By optimizing the cooling and evaporation process, the overall evaporation efficiency and cooling efficiency are greatly improved. The device is also relatively compact, significantly reducing its size and weight compared to existing multi-stage evaporative cooling units.

[0004] This invention pre-cools the air with cold water, and then the pre-cooled air continues to evaporate and cool through a direct evaporation module. During pre-cooling, the cold water is heated and then cooled in a separate counter-current evaporation heat exchange module. In this counter-current evaporation heat exchange module, the pre-cooled air that has passed through the direct evaporation module is directly used to cool the heated circulating water. This ensures that the temperature of the circulating water flowing into and out of the direct evaporation module is always the lowest in the entire system, approaching the dew point temperature of the outside air at low system loads. Using this air, close to the dew point temperature, to cool the external heat load during the indirect evaporation heat exchange process significantly improves the cooling effect during high-temperature periods in summer. The outlet air temperature can be lower than the wet-bulb temperature, and under normal conditions, it can achieve an effect 2-4°C higher than the dew point temperature at rated load. The air cleanliness after treatment by the direct evaporation module is greatly improved, avoiding scaling in the indirect evaporation module heat exchanger. Dust in the air is washed and deposited in the sedimentation and discharge module before being discharged from the system.

[0005] The technical solutions of the embodiments of the present invention are as follows:

[0006] An indirect evaporative air cooling device includes a housing, and inside the housing, a surface cooler, a circulating water pump, a circulating water evaporative cooling module, a wet film, a first water collection tray, a second water collection tray, a water storage tank, a spray return water tank, a spray water pump, a water replenishment device, an internal circulation fan, an external circulation fan, a spray device, and a heat exchanger. The housing is provided with an external circulation air inlet, an external circulation air outlet, an internal circulation air inlet, and an internal circulation air outlet. The external circulation air inlet is located on the side of the housing and connected to the surface cooler. The external circulation air outlet is located on the upper part of the housing and connected to the external circulation fan. The internal circulation air inlet is located on the upper side of the housing and connected to one end of the first channel of the heat exchanger. The internal circulation air outlet is located on the upper side of the housing and connected to one end of the first channel of the heat exchanger.

[0007] The internal circulation fan is located below the side of the housing and connected to the other end of the first channel of the heat exchanger. The internal circulation fan is located between the internal circulation outlet or the internal circulation inlet and the heat exchanger.

[0008] One end of the second channel of the heat exchanger, together with the shell and the circulating water evaporation cooling module, forms an external circulation air outlet channel. The other end of the second channel of the heat exchanger, together with the shell, the first water collection tray, the second water collection tray, and the circulating water evaporation cooling module, forms an external circulation air inlet channel. The external circulation fan is located in the external circulation air outlet channel, and the surface cooler, the wet film, and the spray device are located in the external circulation air inlet channel.

[0009] The circulating water evaporative cooling module is located below the external circulation fan. The module includes evaporative cooling packing and a spray device, with the packing located below the spray device. The wet film is located below the circulating water evaporative cooling module. The surface cooler and the external circulation air inlet are located in front of the wet film. The wet film is placed at an angle. The first water collection tray is located below the wet film. The water storage tank is located below the first water collection tray. The first water collection tray is connected to the water storage tank via a pipe. The water replenishment device is connected to the water storage tank via a pipe. The inlet and outlet of the circulating water pump are respectively connected to the water storage tank and the external circulation fan via pipes. The inlet of the surface cooler is connected to the outlet of the surface cooler, and the spray device is located at the lower end of the air inlet of the second channel of the heat exchanger. The second water collection tray is located at the lower end of the spray device, and the spray return water tank is located below the second water collection tray. The second water collection tray is connected to the spray return water tank through a pipe. The first water collection tray, the circulating water pump, the water storage tank, the surface cooler, the spray device, the evaporative cooling packing, and the wet film together form a wet film circulating water system. The second channel of the heat exchanger, the spray device, the second water collection tray, the spray water pump, and the spray return water tank together form a spray circulating water system.

[0010] When the device is in operation, circulating water is pumped into the surface cooler by the circulating water pump, and then enters the circulating water evaporative cooling module through the pipeline. It is evenly sprayed above the evaporative cooling packing by the spraying device. After being cooled, the circulating water drips evenly onto the wet film, and then flows from the wet film into the water storage tank below.

[0011] The spray water pump draws water from the spray return water tank and pumps it into the spray device. The spray device sprays water onto the second channel of the heat exchanger. The spray water flows out along the second channel of the heat exchanger to the second water collection tray, and then flows back to the spray return water tank.

[0012] When the external circulation fan is turned on, outdoor air enters the external circulation air intake channel through the external circulation air inlet, is then pre-cooled by the surface cooler, humidified by the wet film to become cold air, and then delivered to the second channel of the heat exchanger to exchange heat with the hot air in the first channel of the heat exchanger, and is output to the external circulation air outlet channel and discharged through the external circulation air outlet.

[0013] When the internal circulation fan is turned on, hot air enters the first channel of the heat exchanger through the internal circulation air inlet and exchanges heat with the cold air in the second channel of the heat exchanger, and is discharged through the internal circulation air outlet.

[0014] Preferably, the surface cooler is a finned heat exchange surface cooler.

[0015] Preferably, the device further includes an air filter, which is installed at the external air intake.

[0016] Preferably, both the external circulation fan and the internal circulation fan are EC centrifugal fans.

[0017] Preferably, the device further includes a sedimentation and sludge discharge device, which is placed inside the water storage tank. The inlet of the sedimentation and sludge discharge device is connected to the first water collection tray through a pipe. Circulating water flows out from the first water collection tray into the sedimentation and sludge discharge device, where sludge is deposited. Clean circulating water flows into the water storage tank. The sedimentation and sludge discharge device is equipped with a sludge discharge valve to discharge sludge through timed sludge discharge.

[0018] Compared to existing technologies, the advantages of this invention are as follows: By pre-cooling the external air through a surface cooler at the front end of the wet film air inlet, the external air temperature is lowered. The cooled air is then humidified and cooled again through the wet film to obtain cold air and circulating water close to the dew point temperature. This ensures that the temperature of the circulating water flowing into and out of the direct evaporation module is always the lowest in the entire system, approaching the dew point temperature of the external air at low system loads. Using this air close to the dew point temperature to cool the external heat load during the indirect evaporation heat exchange process significantly improves the cooling effect during high-temperature periods in summer. The outlet air temperature can be lower than the wet-bulb temperature, typically achieving an effect 2-4°C higher than the dew point temperature under rated load. The air cleanliness after treatment by the direct evaporation module is greatly improved, avoiding scaling on the indirect evaporation module heat exchanger. Dust in the air is washed and deposited in the settling and discharge module before being discharged from the system. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of an indirect evaporative air cooling device according to the present invention;

[0020] 104. Internal circulation air inlet; 105. Internal circulation air outlet; 106. External circulation air outlet; 107. External circulation air inlet; 11. Surface cooler; 12. Circulating water pump; 131. Evaporative cooling packing; 132. Spray device; 14. Wet film; 16. Water storage tank; 17. Internal circulation fan; 18. External circulation fan; 19. Heat exchanger; 20. Spray device; 21. Settling and sewage discharge device; 22. Spray return water tank; 23. Spray water pump; 24. First water collection tray; 25. Second water collection tray. Detailed Implementation

[0021] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0022] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0024] like Figure 1 As shown, Figure 1 This is a schematic diagram of an indirect evaporative air cooling device according to the present invention. The indirect evaporative air cooling device includes a housing, and inside the housing are a surface cooler 11, a circulating water pump 12, a circulating water evaporative cooling module, a wet film 14, a first water collection tray 24, a second water collection tray 25, a water storage tank 16, a spray return water tank 22, a spray water pump 23, a water replenishment device, an internal circulation fan 17, an external circulation fan 18, a spray device 20, and a heat exchanger 19. The housing serves as a supporting carrier for the functional components of the device. Specifically, the housing is provided with an external circulation air inlet 107, an external circulation air outlet 106, an internal circulation air inlet 104, and an internal circulation air outlet 105. The external circulation air inlet is located on the side of the housing and connected to the surface cooler, while the external circulation air outlet is located on the upper part of the housing and connected to the external circulation... The fan has an internal circulation air inlet located on the upper side of the casing and connected to one end of the first channel of the heat exchanger. The internal circulation air outlet is located on the lower side of the casing and connected to the other end of the first channel of the heat exchanger. The internal circulation fan is located between the internal circulation air outlet or the internal circulation air inlet and the heat exchanger. To make the entire device structure more compact and smaller in size, preferably, the internal circulation fan 17 is an EC centrifugal fan. One end of the second channel of the heat exchanger, together with the casing and the circulating water evaporative cooling module, forms an external circulation air outlet channel. The other end of the second channel of the heat exchanger, together with the casing, the first water collection tray 24, the second water collection tray 25, and the circulating water evaporative cooling module, forms an external circulation air inlet channel. The external circulation fan is located in the external circulation air outlet channel. The surface cooler, wet film, and spray device are located in the external circulation air inlet channel. The circulating water evaporative cooling module is located below the external circulation fan 18. To meet the functional requirements of the device structure, preferably, the external circulation fan is an EC centrifugal fan.

[0025] In this invention, the circulating water evaporative cooling module evaporates and cools the circulating water heated from the surface cooler. Specifically, the circulating water evaporative cooling module includes an evaporative cooling packing 131 and a spray device 132, with the evaporative cooling packing 131 located below the spray device 132. In this invention, the wet film serves as a direct evaporative cooling module, located below the circulating water evaporative cooling module. The first water collection tray 24 is located below the wet film 14, and the water storage tank 16 is located below the first water collection tray 24. The first water collection tray is connected to the water storage tank via a pipe, and the water replenishment device is connected to the water storage tank 16 via a pipe. The surface cooler 11 and the external circulation air inlet 107 are located in front of the wet film 14, which is placed at an angle. The circulating water pump... The inlet and outlet of the heat exchanger are connected to the water storage tank and the inlet of the surface cooler 11 via pipes, respectively. The outlet of the surface cooler 11 is connected to the spray device 132. The spray device sprays the water delivered from the surface cooler evenly onto the evaporative cooling packing. The spray device is located at the lower end of the air inlet of the second channel of the heat exchanger, the second water collection tray is located at the lower end of the spray device, and the spray return water tank is located below the second water collection tray. The second water collection tray is connected to the spray return water tank via pipes. The first water collection tray, the circulating water pump, the water storage tank, the surface cooler, the spray device, the evaporative cooling packing, and the wet film together form a wet film circulating water system. The second channel of the heat exchanger, the spray device, the second water collection tray, the spray water pump, and the spray return water tank together form a spray circulating water system.

[0026] The wet film circulating water system and the spray circulating water system are two independent water systems. The wet film circulating water system plays the role of pre-cooling, humidifying and washing the air. When the outside air passes through the surface cooler and the wet film, the dust mixed with the water in the wet film flows into the wet film circulating water storage tank after the sewage is discharged, which can solve the problem of dust mixed with the outside air. The spray circulating water system is a closed circulation system, which is not affected by external pollution and avoids the problems of nozzle clogging of the spray device and scale buildup in the heat exchanger that affect heat exchange.

[0027] The entire air circulation system is connected as follows:

[0028] like Figure 1As shown, A-A1 represents the flow path of outdoor air in the external circulation channel. The external circulation inlet, surface cooler, wet film, spray device, second channel of heat exchanger, external circulation fan, and external circulation outlet are connected in sequence to form the external circulation channel. A-A2 represents the flow path of outdoor air cooling circulating water. The external circulation inlet, surface cooler, wet film, evaporative cooling packing, spray device, external circulation fan, and external circulation outlet are connected in sequence to form the circulating water cooling channel. BB represents the flow path of indoor air in the internal circulation channel. The internal circulation inlet, first channel of heat exchange, internal circulation fan, and internal circulation outlet are connected in sequence to form the internal circulation channel. When the indirect evaporative air cooling device is working, outdoor air enters the external circulation channel from the external circulation inlet and passes through the surface cooler. After being cooled, the air enters the wet film, where it is humidified and cooled on the surface. An external circulation fan draws in some of the pre-cooled outside air, creating counter-current convection with the circulating water in the evaporative cooling packing, thus cooling the circulating water. Another portion of the pre-cooled outside air enters the heat exchanger, where it undergoes evaporative cooling and heat transfer, cooling the internal circulating hot air. The heated outdoor air is then blown out through the external circulation outlet by the external circulation fan. Meanwhile, hot air enters the internal circulation channel from the internal circulation inlet, is cooled on the surface of the indirect evaporative heat exchanger, and is then blown into the room through the internal circulation outlet by the internal circulation fan. Outdoor air is heated in the external circulation channel before being discharged. Throughout the entire cooling process, only outdoor air acts as the cold source, exchanging heat with the indoor hot air. Simultaneously, the pre-cooled, humidified, and cooled outdoor air enters the evaporative cooling packing, where it undergoes convective evaporation with the heated circulating water, cooling the circulating water so that the temperature of the circulating water flowing onto the wet film is close to the dew point temperature. In this embodiment, outdoor air refers to the air that enters the room through the external circulation air inlet, and hot air refers to the air that enters the room through the internal circulation air inlet.

[0029] The above is an introduction to the structure and connection relationships of the indirect evaporative air cooling device. The following section details the operational steps of the indirect evaporative air cooling device under a specific working condition:

[0030] Air with an external temperature of 35℃ and a relative humidity of 60% is pre-cooled by a 28℃ surface cooler, undergoing an isohumid cooling process. By controlling the water velocity and air intake of the surface cooler, air with a minimum temperature of 31℃ and a relative humidity of 75% can be obtained. The 31℃ air enters the wet film and undergoes convection evaporation with the water curtain in the wet film. The water curtain in the wet film is formed by the circulating water in the water tank spraying onto the evaporative cooling packing and flowing onto the wet film. The circulating water is transported from the surface cooler to the spraying device. After exchanging heat with the 35℃ air, the 28℃ circulating water in the surface cooler rises to 29℃. The 29℃ circulating water sprays onto the evaporative cooling packing, and after the packing and air undergo convection evaporation, it becomes 32.5℃ water and flows from the evaporative cooling packing into the wet film. After pre-cooling, air at 31℃ and 75% relative humidity evaporates through convection with a 32.5℃ wet film water curtain, humidifying and cooling the air. By controlling the flow rate of the water curtain, the air intake speed, and the convection contact area, the relative humidity is humidified to over 96%, approaching 100%. At this point, the water curtain temperature is close to the wet-bulb temperature. The wet-bulb temperature corresponding to 31℃ and 75% relative humidity is 27℃. The minimum water curtain temperature can be controlled at 27℃. After cooling, the wet film water curtain flows into the water storage tank. The packing water curtain cools to 27℃. The 31℃ air becomes 30℃ after humidification and cooling. Part of the air with 100% relative humidity enters the second channel of the heat exchanger and exchanges heat with the 37℃ hot air in the first channel of the heat exchanger before being discharged through the external circulation outlet. The other part enters the circulating water evaporation cooling module and exchanges heat with the circulating water through convection evaporation before being discharged through the external circulation outlet. The 27℃ circulating water is circulated and transported to the surface cooler to pre-cool the external air. The indirect evaporative air cooling device of the present invention can cool 37°C hot air to 33.5°C by heat exchange.

[0031] Compared to pre-cooling without a surface cooler: Air with an external temperature of 35℃ and a relative humidity of 60% directly enters the wet film and evaporative cooling packing, and convection occurs with the water curtain in the wet film. The water curtain in the wet film is sprayed with circulating water onto the evaporative cooling packing. The circulating water is transported to the spraying device by the surface cooler, and after evaporation with the air, it flows from the evaporative packing into the wet film. The circulating water is in a water storage tank. The 28℃ circulating water absorbs heat through evaporation with the air in the evaporative cooling packing, and then becomes water at about 32℃ before flowing into the wet film. Air at 35℃ and 60% relative humidity evaporates through convection with a 32℃ wet film water curtain, humidifying and cooling the air. By controlling the flow rate of the water curtain, the air intake speed, and the convection contact area, the relative humidity is increased to over 96%, approaching 100%. At this point, the water curtain temperature is close to the wet-bulb temperature. The wet-bulb temperature corresponding to 35℃ and 60% relative humidity is 28℃. The minimum temperature of the water curtain can be controlled at 28℃. After the wet film water curtain cools to 28℃, it flows into the water storage tank. The 35℃ air becomes 33℃ after humidification and cooling. Part of the air with 100% relative humidity enters the second channel of the heat exchanger and exchanges heat with the 37℃ hot air in the first channel of the heat exchanger before being discharged through the external circulation outlet. The other part enters the circulating water evaporation cooling module and exchanges heat with the circulating water through convection evaporation before being discharged through the external circulation outlet. The 28℃ circulating water is circulated and transported to the surface cooler to pre-cool the external air. An air cooling device without a pre-cooling unit can cool 37°C hot air down to 35°C by heat exchange, which increases power consumption by 15% compared to an indirect evaporative air cooling device with a pre-cooling unit.

[0032] The above comparison shows that by installing a surface cooler at the external circulation air inlet to pre-cool the incoming air, the air temperature decreases and the humidity increases, resulting in a decrease in the wet-bulb temperature. By controlling the external circulation fan speed, the packing water flow rate, and the contact area between the air and water, the water flowing out of the wet film can be brought close to the wet-bulb temperature. Since the wet-bulb temperature is lower after pre-cooling, the resulting water temperature is also lower. The external air is then pre-cooled by the surface cooler with the lower water temperature, resulting in colder air at an even lower temperature.

[0033] During operation, circulating water is pumped into the surface cooler by the circulating water pump, and then enters the circulating water evaporative cooling module through pipelines. It is evenly sprayed above the evaporative cooling packing by the spray device. After being cooled, the circulating water drips evenly onto the wet film and then flows from the wet film into the water storage tank below. The spray water pump draws water from the spray return water tank and pumps it into the spray device. The spray device sprays water onto the second channel of the heat exchanger. The spray water flows out along the second channel of the heat exchanger to the second water collection tray and then flows back to the spray return water tank. When the external circulation fan is turned on, outdoor air enters the external circulation air intake channel through the external circulation air inlet, is pre-cooled by the surface cooler, humidified by the wet film to become cold air, and then delivered to the second channel of the heat exchanger to exchange heat with the hot air in the first channel of the heat exchanger. It is then output to the external circulation air outlet channel and discharged through the external circulation air outlet. When the internal circulation fan is turned on, hot air enters the first channel of the heat exchanger through the internal circulation air inlet to exchange heat with the cold air in the second channel of the heat exchanger and is discharged through the internal circulation air outlet. To fulfill the functional requirements of the device structure, the internal circulation fan is preferably an EC centrifugal fan.

[0034] During the operation of the indirect evaporative air cooling device, circulating water close to the dew point temperature is pumped into the surface cooler by the circulating water pump. The surface cooler pre-cools and exchanges heat with the outside air, causing the circulating water temperature to rise. The circulating water in the surface cooler then enters the circulating water evaporative cooling module through the pipe and is evenly sprayed on the evaporative cooling packing by the spraying device. After being cooled, the circulating water drips evenly onto the wet film and then flows from the wet film into the first water storage tank below.

[0035] The indirect evaporative air cooling device of the present invention can be directly used for natural heat dissipation in data center computer rooms. Since the temperature of the cold air at the wet film is close to the dew point temperature, the heat exchange efficiency in the heat exchanger is higher, which is more energy-efficient for the overall power consumption of the data center.

[0036] Pre-cooled outside air enters the wet membrane and undergoes an isenthalpic humidification process with the circulating water in the wet membrane, which lowers the temperature of the circulating water in the wet membrane to the dew point temperature, thus obtaining circulating water and cold air close to the dew point temperature. In this way, the cold air close to the dew point temperature is used in the second channel of the heat exchanger to exchange heat with the hot air in the first channel of the heat exchanger, thereby cooling the machine room that generates hot air. Since the temperature of the cold air is lower than that of traditional indirect evaporation cold air, the cooling effect is better and the power consumption is lower.

[0037] By installing a spray device at the inlet of the first channel, which sprays the first channel before the pre-cooled air enters the first channel, evaporative cooling is increased, further improving the heat exchange efficiency of hot air in the heat exchanger.

[0038] To maximize the pre-cooling efficiency of the air intake, preferably, the length from the top to the bottom of the external circulation air intake is equal to the vertical length from the top to the bottom of the surface cooler; the length from the top to the bottom of the external circulation air intake is equal to the vertical length from the top to the bottom of the wet film.

[0039] To prevent dust and impurities from entering the device and polluting the internal environment, it is preferable to install an air filter at the air inlet.

[0040] In order to increase the pre-cooling contact area and time between the outside air and the surface cooler, and to achieve a greater temperature difference in the pre-cooling of the outside air, the surface cooler is preferably a finned heat exchanger.

[0041] To prevent impurities in the water from clogging the surface cooler, the evaporative cooling air device preferably also includes a water filter, with its two ends connected to the outlet of the circulating water pump and the inlet of the surface cooler via water pipes.

[0042] To prevent impurities carried by external air from flowing into the water storage tank along with the water curtain on the wet film and causing fouling, the device preferably also includes a sedimentation and sludge discharge device 21. The sedimentation and sludge discharge device is placed inside the water storage tank. The inlet of the sedimentation and sludge discharge device is connected to the first water collection tray through a pipe. Circulating water flows out from the first water collection tray into the sedimentation and sludge discharge device. Sludge settles in the sedimentation and sludge discharge device, and clean circulating water flows into the water storage tank. The sedimentation and sludge discharge device is equipped with a sludge discharge valve to discharge sludge through timed sludge discharge.

[0043] In this embodiment, both the evaporative cooling packing and the wet film increase the contact area and time between water and air. In this embodiment, the packing can be replaced by a wet film.

[0044] This invention pre-cools the outside air by setting a surface cooler at the front end of the wet film air inlet, thereby reducing the temperature of the outside air. The cooled air is then humidified and cooled by the wet film to obtain even colder air at a lower temperature.

[0045] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0046] The above embodiments merely illustrate preferred implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention should be determined by the appended claims.

Claims

1. An indirect evaporative air cooling device, characterized in that: The device includes a housing, and inside the housing are a surface cooler, a circulating water pump, a circulating water evaporative cooling module, a wet film, a first water collection tray, a second water collection tray, a water storage tank, a spray return water tank, a spray water pump, a water replenishment device, an internal circulation fan, an external circulation fan, a spray device, and a heat exchanger. The housing is provided with an external circulation air inlet, an external circulation air outlet, an internal circulation air inlet, and an internal circulation air outlet. The external circulation air inlet is located on the side of the housing and is connected to the surface cooler. The external circulation air outlet is located on the upper part of the housing and is connected to the external circulation fan. The internal circulation air inlet is located on the upper side of the housing and is connected to one end of the first channel of the heat exchanger. The internal circulation air outlet is located on the lower side of the housing and is connected to the other end of the first channel of the heat exchanger. The internal circulation fan is located between the internal circulation air outlet or the internal circulation air inlet and the heat exchanger. One end of the second channel of the heat exchanger, together with the shell and the circulating water evaporation cooling module, forms an external circulation air outlet channel. The other end of the second channel of the heat exchanger, together with the shell, the first water collection tray, the second water collection tray, and the circulating water evaporation cooling module, forms an external circulation air inlet channel. The external circulation fan is located in the external circulation air outlet channel, and the surface cooler, the wet film, and the spray device are located in the external circulation air inlet channel. The circulating water evaporative cooling module is located below the external circulation fan. The module includes evaporative cooling packing and a spray device, with the packing located below the spray device. The wet film is located below the circulating water evaporative cooling module. The surface cooler and the external circulation air inlet are located in front of the wet film. The wet film is placed at an angle. The first water collection tray is located below the wet film. The water storage tank is located below the first water collection tray. The first water collection tray is connected to the water storage tank via a pipe. The water replenishment device is connected to the water storage tank via a pipe. The inlet and outlet of the circulating water pump are respectively connected to the water storage tank and the external circulation fan via pipes. The inlet of the surface cooler is connected to the outlet of the surface cooler, and the spray device is located at the lower end of the air inlet of the second channel of the heat exchanger. The second water collection tray is located at the lower end of the spray device, and the spray return water tank is located below the second water collection tray. The second water collection tray is connected to the spray return water tank through a pipe. The first water collection tray, the circulating water pump, the water storage tank, the surface cooler, the spray device, the evaporative cooling packing, and the wet film together form a wet film circulating water system. The second channel of the heat exchanger, the spray device, the second water collection tray, the spray water pump, and the spray return water tank together form a spray circulating water system. When the device is in operation, circulating water is pumped into the surface cooler by the circulating water pump, and then enters the circulating water evaporative cooling module through the pipeline. It is evenly sprayed above the evaporative cooling packing by the spraying device. After being cooled, the circulating water drips evenly onto the wet film, and then flows from the wet film into the water storage tank below. The spray water pump draws water from the spray return water tank and pumps it into the spray device. The spray device sprays water onto the second channel of the heat exchanger. The spray water flows out along the second channel of the heat exchanger to the second water collection tray, and then flows back to the spray return water tank. When the external circulation fan is turned on, outdoor air enters the external circulation air intake channel through the external circulation air inlet, is then pre-cooled by the surface cooler, humidified by the wet film to become cold air, and then delivered to the second channel of the heat exchanger to exchange heat with the hot air in the first channel of the heat exchanger, and is output to the external circulation air outlet channel and discharged through the external circulation air outlet. When the internal circulation fan is turned on, hot air enters the first channel of the heat exchanger through the internal circulation air inlet and exchanges heat with the cold air in the second channel of the heat exchanger, and is discharged through the internal circulation air outlet.

2. The indirect evaporative air cooling device according to claim 1, characterized in that: The surface cooler is a finned heat exchange surface cooler.

3. The indirect evaporative air cooling device according to claim 1, characterized in that: The device also includes an air filter, which is installed at the external air intake.

4. The indirect evaporative air cooling device according to claim 1, characterized in that: Both the external circulation fan and the internal circulation fan are EC centrifugal fans.

5. The indirect evaporative air cooling device according to claim 1, characterized in that: The device also includes a sedimentation and sludge discharge device, which is placed inside the water storage tank. The inlet of the sedimentation and sludge discharge device is connected to the first water collection tray through a pipe. Circulating water flows out from the first water collection tray into the sedimentation and sludge discharge device, where sludge is deposited and clean circulating water flows into the water storage tank. The sedimentation and sludge discharge device is equipped with a sludge discharge valve, which discharges sludge through timed sludge discharge.

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