Evaporative cooling precision air conditioner

Abstract

The present application relates to a kind of evaporative cooling precision air conditioner, it includes indoor air conditioning unit and evaporative condensing outdoor unit, indoor air conditioning unit includes compressor, evaporative heat exchange coil, first check valve, outdoor unit includes fluorine pump, evaporative condensing heat exchange coil, second check valve, compressor one end is connected with evaporative heat exchange coil one end by pipeline, evaporative heat exchange coil other end is connected with fluorine pump one end, fluorine pump other end is connected with evaporative condensing heat exchange coil one end by pipeline, evaporative condensing heat exchange coil other end is connected with the other end of compressor by pipeline, first check valve is connected with the both ends of compressor by pipeline in parallel, second check valve is connected with the both ends of fluorine pump by pipeline in parallel.It is compressor mode when outdoor temperature is greater than or equal to set temperature, it is fluorine pump mode when outdoor temperature is less than set temperature, by intelligent switching mode, it can meet the demand of high temperature refrigeration in summer while, energy efficiency is higher, energy saving and consumption reduction is obvious.

Description

Technical Field

[0001] This invention relates to the field of air conditioning and refrigeration technology, and specifically to a precision air conditioner for data centers using water evaporative cooling. Background Technology

[0002] After decades of development, precision air conditioning technology has matured in all aspects. Due to its ease of use, simple operation, and high reliability, it is widely used in small and medium-sized data centers or in environments with high temperature and humidity requirements. Most current precision air conditioners use mechanical refrigeration with compressors. To save energy, the load is increased in high-temperature climates and reduced in non-high-temperature climates, using compressor frequency conversion control to match the year-round cooling needs of the data center. However, this approach brings the following problems: First, the compressor has a large power consumption, resulting in significant power consumption throughout the year; second, continuous compressor operation leads to high compressor wear and tear, and more frequent malfunctions. Without fundamental innovation, its application scope will become increasingly narrow.

[0003] With the advancement of technology, the research and development of evaporative condensers has received increasing attention. By reducing the condensation temperature through evaporative cooling, the energy efficiency of the system can be significantly improved. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, the present invention aims to provide an evaporative cooling precision air conditioner, wherein the evaporative condensing outdoor unit can switch operating modes according to the outdoor ambient temperature. When the outdoor temperature is greater than or equal to the set natural cooling temperature, it operates in compressor cooling mode; when the outdoor temperature is less than the set natural cooling temperature, it switches to refrigerant pump operation mode. In refrigerant pump operation mode, the system mainly relies on evaporative cooling for cooling, which can significantly reduce energy consumption. At the same time, in summer, in compressor cooling mode, the evaporative cooling condensation method can significantly reduce the condensing temperature to about 30°C, which greatly improves the system's energy efficiency and results in significant energy saving and consumption reduction.

[0005] This invention also pre-cools the natural air entering the evaporative condensing outdoor unit, reducing the wet-bulb temperature of the air. After humidification, the temperature approaches the ambient dew point temperature, resulting in air and chilled water at near the ambient dew point temperature. The chilled water at near the ambient dew point temperature is then used to cool the external air, further reducing the temperature of the air entering the system, as well as the temperature of the humidified air and the circulating water. This lowers the evaporative cooling temperature on the surface of the evaporative condensing heat exchange coil, thereby reducing the refrigerant condensation temperature within the coil, improving system energy efficiency, and increasing the time available for utilizing natural cooling sources throughout the year.

[0006] The technical solutions of the embodiments of the present invention are as follows:

[0007] An evaporative cooling precision air conditioner includes an indoor air conditioning unit that cools and lowers the temperature of air on the heat source side and an evaporative condensing outdoor unit.

[0008] The indoor air conditioning unit includes an air conditioning shell, an air conditioning air inlet, a compressor, a first check valve, an evaporative heat exchange coil, a throttling valve, an air conditioning fan, an air conditioning air outlet, a temperature and humidity sensor, a controller, an indoor unit refrigerant outlet, an indoor unit refrigerant inlet, etc. The evaporative heat exchange coil is connected to the compressor and the throttling valve through pipes, and the first check valve is connected to the compressor in parallel through front and rear pipes.

[0009] The evaporative condensing outdoor unit includes a condensing outdoor unit casing, a refrigerant pump, a second check valve, an evaporative condensing heat exchange coil, a condensing fan, an outdoor unit air inlet, a spray module, packing, a surface cooler, an outdoor unit air outlet, a water collection pan, a circulating water pump, a water storage tank, a water replenishment device, a refrigerant inlet for the condensing outdoor unit, and a refrigerant outlet for the condensing outdoor unit. The refrigerant pump is connected to the evaporative condensing heat exchange coil via a pipe, and the second check valve is connected in parallel to both ends of the refrigerant pump via pipes. The outdoor unit air outlet is located at the top of the condensing outdoor unit casing, the outdoor unit air inlet is located on the lower side of the condensing outdoor unit casing, the condensing fan is installed on the outdoor unit air outlet, and the spray module and the evaporative condensing heat exchange coil are connected in parallel. The evaporative condensing heat exchange coil is placed below the condensing fan, the packing is placed below the evaporative condensing heat exchange coil, the surface cooler is placed below the packing, the outdoor unit air inlet is located beside the surface cooler, the water collection tray is placed below the packing, the water collection tray is connected to the water storage tank, the circulating water pump inlet is connected to the water storage tank through a pipe, the circulating water pump outlet is connected to the surface cooler inlet through a pipe, the surface cooler outlet is connected to the spray module through a pipe, the spray module consists of several nozzles that spray water onto the evaporative condensing heat exchange coil, and the water replenishment device is connected to the water storage tank through a pipe.

[0010] The indoor air conditioning unit and the evaporative condensing outdoor unit are connected by pipes. The refrigerant outlet of the indoor unit is connected to the refrigerant inlet of the condensing outdoor unit by pipes, and the refrigerant inlet of the indoor unit is connected to the outlet of the refrigerant pump by pipes.

[0011] Preferably, the evaporative condensing heat exchange coil is a radial finned tube heat exchanger, and the evaporative condensing heat exchange coil is arranged in a V-shape or an inverted V-shape; the fins on the evaporative condensing heat exchange coil are evenly distributed, completely covering and evenly dividing the airflow space inside the evaporative condensing heat exchange coil, and are arranged in a corrugated shape or in an alternating pattern along the airflow direction; the flow direction of the cooled fluid is arranged counter-currently to the airflow direction between the layers of the evaporative condensing heat exchange coil.

[0012] Preferably, the evaporative condensing outdoor unit is further provided with an automatic filtration and sewage discharge device, which is located between the circulating water pump and the surface cooler.

[0013] Preferably, the evaporative condensing outdoor unit is further equipped with an inlet air temperature and humidity sensor, an outlet air temperature sensor, a condensing temperature sensor, a condensing pressure sensor, and a control module. The control module can automatically adjust the load of the condensing fan and the load of the circulating water pump according to the outlet water temperature and the preset temperature target value, so that the condensing temperature and pressure reach the preset target value.

[0014] Preferably, the surface of the evaporative condensing heat exchange coil is provided with a hydrophilic coating containing infrared radiation heat dissipation material.

[0015] Preferably, the surface of the surface cooler is provided with a superhydrophobic coating containing infrared radiation heat dissipation material.

[0016] Preferably, the average particle size of the water droplets sprayed by the spray module is less than 1 mm.

[0017] Preferably, the surface cooler is a finned heat exchanger.

[0018] Preferably, the evaporative heat exchange coil is a finned heat exchange coil.

[0019] Preferably, the evaporative condensing outdoor unit further includes an air filter, which is installed at the air inlet of the outdoor unit.

[0020] Preferably, the evaporative condenser heat exchange coil is placed at an X-degree angle to the horizontal, and the packing is placed at an X-degree angle to the horizontal.

[0021] Preferably, the surface cooler is placed at an angle of 180-X degrees to the horizontal direction, and the length from the top to the bottom of the outdoor unit's air inlet is greater than the vertical length from the top to the bottom of the surface cooler.

[0022] Preferably, the evaporative heat exchange coil is placed at an X-degree angle to the horizontal direction.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] By setting up a compressor and a first check valve connected in parallel with the compressor, and by setting up a refrigerant pump and a second check valve connected in parallel with the refrigerant pump, a dual working mode is formed. It can switch the working mode according to the outdoor ambient temperature. When the outdoor temperature is greater than or equal to the set temperature, it is in compressor cooling mode. When the outdoor temperature is less than the set temperature, it switches to refrigerant pump operation mode. Through intelligent switching of working modes, it can meet the high-temperature cooling needs in summer while being more energy efficient and significantly saving energy and reducing consumption.

[0025] It also pre-cools the natural air entering the evaporative condensing outdoor unit by installing a surface cooler at the air inlet of the outdoor unit. The cooled air then convects and evaporates the spray water in the packing, causing the spray water to be cooled to near the ambient dew point temperature and flow into the water storage tank. After the air is pre-cooled, the water in the water storage tank is sprayed out through the spray module, which improves the evaporative condensing effect of the evaporative condensing heat exchange coil and thus reduces the operating energy consumption of the entire air conditioning system. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of an evaporative cooling precision air conditioner according to the present invention;

[0027] Figure 2 This is a schematic diagram of the evaporative condenser heat exchange coil in this invention;

[0028] 10. Condensing outdoor unit casing; 100. Evaporative condensing outdoor unit unit; 101. Outdoor unit air outlet; 102. Outdoor unit air inlet; 130. Coil; 140. Fins; 131. Liquid guiding section; 132. Connecting section; 11. Spray module; 12. Packing; 13. Surface cooler; 14. Circulating water pump; 15. Water storage tank; 16. Water collection tray; 17. Evaporative condensing heat exchange coil; 18. Condensing fan; 200. Indoor air conditioning unit; 21. Evaporative heat exchange coil; 22. Air conditioning fan; 23. Refrigerant pump; 24. Second check valve; 25. First check valve; 26. Compressor; 27. Air conditioning casing; 28. Throttling valve. Detailed Implementation

[0029] 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.

[0030] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to 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.

[0031] 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.

[0032] like Figure 1 As shown, Figure 1This is a schematic diagram of an evaporative cooling precision air conditioner according to the present invention; it includes an indoor air conditioning unit 200 that provides cooling capacity to cool the air on the heat source side and an evaporative condensing outdoor unit 100 that releases heat to the outside environment. Similar to a household air conditioner, the indoor air conditioning unit is located indoors, such as inside a data center server room, and cools the indoor hot air. The evaporative condensing outdoor unit is located outdoors, such as outside the data center server room, and cools the heat source medium in the indoor air conditioning unit after the original cold source medium has been exchanged for heat.

[0033] The evaporative cooling precision air conditioner of this invention is mainly used in data center computer rooms. The structure design of the indoor air conditioning unit usually adopts the top air intake and bottom air supply. Specifically, the indoor air conditioning unit 200 includes an air conditioning shell 27, an air conditioning air inlet, a compressor 26, a first check valve 25, an evaporative heat exchange coil 21, a throttling valve 28, an air conditioning fan 22, an air conditioning air outlet, a temperature and humidity sensor, a controller, an indoor refrigerant outlet, an indoor refrigerant inlet, etc. The evaporative heat exchange coil 21 is connected to the compressor 26 and the throttling valve 28 through pipes. The first check valve 25 is connected to the compressor 26 in parallel through front and rear pipes. The air conditioning fan 22 is located at the lower part of the air conditioning shell 27. The upper part of the air conditioning shell is the air inlet end, and the lower side of the air conditioning shell is the air supply end. Specifically, the evaporative condensing outdoor unit 100 includes a condensing outdoor unit casing 10, a refrigerant pump 23, a second check valve 24, an evaporative condensing heat exchange coil 17, a condensing fan 18, an outdoor unit air inlet 101, a spray module 11, packing 12, a surface cooler 13, an outdoor unit air outlet 102, a water collection tray 16, a circulating water pump 14, a water storage tank 15, a water replenishment device, a condensing outdoor unit refrigerant inlet, and a condensing outdoor unit refrigerant outlet. The refrigerant pump is connected to the evaporative condensing heat exchange coil via a pipe, and the second check valve is connected to both ends of the refrigerant pump in parallel via pipes. The indoor air conditioning unit and the evaporative condensing outdoor unit are connected via pipes, the indoor unit refrigerant outlet is connected to the condensing outdoor unit refrigerant inlet via a pipe, and the indoor unit refrigerant inlet is connected to the refrigerant pump outlet via a pipe.

[0034] Specifically, the spray module consists of several nozzles connected by pipes. The nozzles are evenly arranged and aligned with the evaporative condensing heat exchange coil. Preferably, the average particle size of the water droplets sprayed from the nozzles is less than 1 mm. The nozzles are preferably solid conical nozzles. By optimizing the spray nozzles and water pressure, the sprayed water is evenly sprayed onto the evaporative cooling heat exchanger in the form of small droplets with a particle size of less than 1 mm (preferably with an average particle size of 0.5 mm), rather than the traditional water jet spray or the traditional atomized spray. This spraying method ensures that the water droplets are evenly distributed on the surface of the evaporative condensing heat exchange coil and that the sprayed water exhibits a significant temperature gradient distribution in the direction of airflow. The sprayed water temperature is higher above the evaporative cooling heat exchanger and lower below the evaporative condensing heat exchange coil. Experiments show that when the particle size of the spray water is less than 0.5 mm, most of the spray particles are easily blown away by the wind; when the particle size of the spray water is greater than 1 mm, the spray water distribution will be uneven, and the evaporation rate will decrease due to the reduction in the total surface area of ​​the spray water balls.

[0035] Preferably, the evaporative condensing outdoor unit is also equipped with an inlet air temperature and humidity sensor, an outlet air temperature sensor, a condensing temperature sensor, a condensing pressure sensor, and a control module. The control module can automatically adjust the load of the condensing fan and the load of the circulating water pump according to the outlet water temperature and the preset temperature target value, so that the condensing temperature and pressure reach the preset target value.

[0036] For the entire evaporative cooling precision air conditioner, the specific cold source system consists of a compressor, evaporative heat exchange coil, refrigerant pump, evaporative condensing heat exchange coil, first check valve, second check valve, and throttling valve, forming a dual-mode cold source switching circulation system. The current operating mode is switched by controlling the opening and closing of the first check valve, compressor, second check valve, and refrigerant pump. Specifically, the control is as follows: When the first check valve is open, the compressor is off, the second check valve is closed, and the refrigerant pump is on, the refrigerant pump operates. The refrigerant pump drives the refrigerant to circulate in the evaporative condenser heat exchange coil and the evaporative heat exchange coil itself. The refrigerant exchanges heat with the indoor hot air in the evaporative heat exchange coil, causing its temperature to rise. The heated refrigerant then flows to the evaporative condenser heat exchange coil, where it exchanges heat with the outdoor cold air, causing its temperature to drop. This cycle repeats. When the first check valve is closed, the compressor is on, the second check valve is open, and the refrigerant pump is off, the compressor operates. Similar to a regular air conditioner, the compressor compresses the refrigerant and delivers it to the evaporative heat exchange coil. The refrigerant absorbs heat and is then delivered to the evaporative condenser heat exchange coil, where the outdoor cold air cools it down. This cycle repeats. The opening and closing of the first check valve, compressor, second check valve, and refrigerant pump are controlled by the controller based on the detected outdoor ambient temperature. When the outdoor temperature is greater than or equal to the set value, such as 31°C, the compressor operates in operation mode. When the outdoor temperature is less than the set value, the refrigerant pump operates in operation mode. Through intelligent switching between the two operating modes, the compressor operates in operation mode during the high temperatures of summer, and the indoor temperature can reach the cooling demand value. In other seasons, the refrigerant pump operates in operation mode. The refrigerant pump consumes less power than the compressor, which makes the air conditioning system consume less power.

[0037] In the overall power consumption of the air conditioning system, the cooling efficiency of the evaporative condensing heat exchange coil is particularly important. Typically, evaporative condensing heat exchange coils are cooled by air or water. Air cooling is determined by the external ambient temperature, and the lower the ambient temperature, the better the effect. However, the climate is uncontrollable. Water cooling consumes a lot of water. To meet the cooling requirements of the evaporative condensing heat exchange coil in this invention, this invention adopts a dew point type indirect evaporative water cooling method.

[0038] Specifically, regarding the internal structure of the evaporative condensing outdoor unit, the outdoor unit's air outlet is located at the top of the condensing outdoor unit's casing, the outdoor unit's air inlet is located on the lower side of the condensing outdoor unit's casing, the condensing fan is installed on the outdoor unit's air outlet, the spray module and the evaporative condensing heat exchange coil are located below the condensing fan, the packing is located below the evaporative condensing heat exchange coil, the surface cooler is located below the packing, the outdoor unit's air inlet is located beside the surface cooler, the water collection tray is located below the packing, the water collection tray is connected to a water storage tank, the circulating water pump's inlet is connected to the water storage tank via a pipe, the circulating water pump's outlet is connected to the surface cooler's inlet via a pipe, the surface cooler's outlet is connected to the spray module via a pipe, the spray module consists of several nozzles that spray water onto the evaporative condensing heat exchange coil, and the water replenishment device is connected to the water storage tank via a pipe.

[0039] When the condenser fan is turned on, it draws in external natural air through the air inlet of the outdoor unit. The air is pre-cooled by the surface cooler to become cold air. When the circulating water pump is turned on, it draws cold water from the water tank and pre-cools the external natural air through the surface cooler. The water is then sprayed onto the evaporative condenser heat exchange coil by several nozzles in the spray module. After exchanging heat with the evaporative condenser heat exchange coil, the water flows into the packing. The pre-cooled cold air reaches the packing and convects with the spray water in the packing, resulting in an isenthalpic process. The spray water evaporates and cools down, resulting in spray water and cold air at near dew point temperature. The spray water is stored in the water tank through the water collection pan. The cold air flows out from the packing to perform secondary cooling on the evaporative condenser heat exchange coil and is finally discharged through the air outlet of the outdoor unit.

[0040] The actual experimental data are as follows: 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 maximum temperature of 31℃ and a relative humidity of 75% can be obtained. The 31℃ air enters the packing and undergoes convection evaporation with the water curtain in the packing. The water curtain in the packing sprays water onto the heat exchange coil. The spray water is transported from the surface cooler to the spray module. After exchanging heat with the 35℃ air, the 28℃ water in the surface cooler rises to 29℃. The 29℃ spray water sprays water onto the 40℃ heat exchange coil. After sufficient heat exchange, the water becomes 35.5℃ water and flows from the heat exchange coil into the packing. After pre-cooling, air at 31℃ and 75% relative humidity evaporates through convection with a 32.5℃ packing 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 31℃ and 75% relative humidity is 27℃. The minimum water curtain temperature can be controlled at 27℃. After cooling, the packing water curtain flows into the water storage tank, where it is cooled to 27℃. The 31℃ air, after humidification and cooling, becomes 30℃. The air with 100% relative humidity exchanges heat with the spray water flowing on the heat exchange coil, raising the air temperature to approximately 37℃. The RH is 85% when the air is discharged through the outdoor unit's air outlet.

[0041] Compared to pre-cooling without a surface cooler: when air with an external temperature of 35°C and a relative humidity of 60% enters the equipment directly, the condensing temperature of the heat exchange coil will rise to 41°C, the air temperature at the outdoor unit outlet will rise to approximately 38.5°C, and 55% RH will be discharged.

[0042] The above comparison shows that by installing a surface cooler after the air enters through the outdoor unit's air inlet to pre-cool the air, the air temperature decreases and the humidity increases, resulting in a decrease in the wet-bulb temperature. By controlling the fan speed, the water flow rate in the packing, and the contact area between the air and water, the water flowing out of the packing can be brought close to the dew point temperature, resulting in a lower raw water temperature. This leads to a greater temperature difference with the heat exchange coil. The greater the temperature difference, the more heat is carried away by the sprayed water, resulting in a better cooling effect on the refrigerant and making the air conditioning more energy-efficient.

[0043] To maximize the pre-cooling contact area and extend the pre-cooling time between the outside air and the surface cooler, thereby achieving a greater temperature difference for pre-cooling the outside air, the surface cooler is preferably a finned heat exchanger. Preferably, a superhydrophobic coating with added infrared radiation heat dissipation material is applied to the surface of the surface cooler. In this embodiment, this coating contains nano-polymer organosilicon components and transition metal oxides such as cobalt, nickel, and manganese. Such a coating improves the heat exchange efficiency of the surface cooler, thereby enhancing the overall cooling capacity of the evaporative condensing outdoor unit.

[0044] To maximize the contact area and extend the contact time between air and the evaporative condensing heat exchange coils, thereby improving heat exchange efficiency, the evaporative condensing heat exchange coils are preferably radially finned heat exchange coils, arranged in a V-shape or inverted V-shape. The fins on the evaporative condensing heat exchange coils are evenly distributed, completely covering and uniformly dividing the airflow space inside the coils, and are arranged in a corrugated or staggered pattern along the airflow direction. The flow direction of the cooled fluid is counter-current to the airflow direction between the layers of the evaporative condensing heat exchange coils. Figure 2 As shown, the radial finned tube heat exchanger consists of coils 130 and fins 140. Coils 130 are composed of a liquid guiding section 131 and a connecting section 132. The connecting sections 132 connect the liquid guiding sections vertically in an S-shape, forming rows of vertical coils. This ensures that the fluid being cooled in each row of vertical coils flows from top to bottom, allowing the fluid being cooled and the air entering the radial finned tubes to exchange heat in a counter-current manner, resulting in high heat exchange efficiency. Conventionally, the liquid guiding section 131 and the connecting section 132 of the coil are connected in an S-shape in the horizontal direction, causing the fluid being cooled and the air entering the radial finned tubes to exchange heat in a cross-flow manner, resulting in low heat exchange efficiency.

[0045] In this embodiment, the fins 140 of the radial finned tube heat exchanger are corrugated along the airflow direction (not shown in the figure, but those skilled in the art can understand this from...). Figure 2 Straight fins (inferred to be corrugated fins) are arranged either in a staggered or corrugated-staggered pattern. In radial finned tube heat exchangers, the fins are corrugated along the airflow direction, which, compared to the conventional straight fins, increases the contact area between the air and the fins, thus improving heat exchange efficiency. In radial finned tube heat exchangers, the fins are staggered along the airflow direction, which, compared to the conventional arrangement, increases airflow turbulence and improves heat exchange efficiency. In particular, with a staggered arrangement, one row of fins can extend into the space between adjacent rows, increasing the overall fin area and enhancing airflow turbulence, thereby increasing the heat exchanger's efficiency.

[0046] Preferably, a hydrophilic coating containing infrared radiation heat dissipation material is applied to the surface of the radial finned tube heat exchanger. In this embodiment, this coating contains nano-silica or nano-alumina, and transition metal oxides such as cobalt, nickel, and manganese. Such a coating improves the heat exchange efficiency of the radial finned tube heat exchanger, while also better adsorbing water droplets to form a water film, increasing the evaporation efficiency of the sprayed water, and overall improving the cooling capacity of the evaporative condensing outdoor unit.

[0047] To prevent dust and impurities from entering the evaporative condensing outdoor unit unit and polluting the internal environment, preferably, the evaporative condensing outdoor unit unit also includes an air filter, which is installed at the air inlet of the outdoor unit.

[0048] Impurities inevitably appear in water, and over time, they can easily form scale inside the surface cooler and on the surface of the evaporative condensing heat exchange coil, clogging the surface cooler and reducing its heat exchange efficiency. To solve this problem, preferably, the evaporative condensing outdoor unit also includes an automatic filter and drain device. This device is located between the circulating water pump and the surface cooler, with one end connected to the outlet of the circulating water pump and the other end connected to the inlet of the surface cooler. The raw water is filtered before entering the surface cooler.

[0049] To maximize the contact surface area between the evaporative condensing heat exchange coil and the packing within the fixed-size condensing outdoor unit casing and the air, preferably, the evaporative condensing heat exchange coil is placed at an X-degree angle to the horizontal, and the packing is placed at an angle of 180-X degrees to the horizontal. The lower end of the evaporative condensing heat exchange coil and the upper end of the packing are joined at a small distance. In actual design, once the tilt angle and the space of the condensing outdoor unit casing are determined, the evaporative condensing heat exchange coil and packing of the appropriate size can be designed.

[0050] To ensure that the pre-cooled air flows more concentratedly into the packing, the surface cooler and packing should be placed parallel to each other. Preferably, the surface cooler is placed at an angle of 180-X degrees to the horizontal, and the length from the top to the bottom of the outdoor unit's air inlet is greater than the vertical length from the top to the bottom of the surface cooler. This greater length of the outdoor unit's air inlet allows each section of the surface cooler to pre-cool the incoming air, achieving a larger pre-cooling airflow.

[0051] Similarly, indoor air conditioners are usually taller than wide. In order to obtain a larger heat exchange area, the evaporative heat exchange coil is preferably placed at an X-degree angle to the horizontal direction.

[0052] This invention establishes a dual-operating mode by setting up a compressor and a first check valve connected in parallel with the compressor, and by setting up a refrigerant pump and a second check valve connected in parallel with the refrigerant pump. It can switch operating modes according to the outdoor ambient temperature. When the outdoor temperature is greater than or equal to the set temperature, it operates in compressor cooling mode; when the outdoor temperature is less than the set temperature, it switches to refrigerant pump operating mode. Through intelligent switching of operating modes, it can meet the high-temperature cooling needs in summer while achieving higher energy efficiency and significant energy saving and consumption reduction.

[0053] This invention pre-cools the outside air by installing a surface cooler before it enters the condenser unit casing and exchanges heat with the spray water in the packing. This lowers the outside air temperature, and the cooled air exchanges heat with the spray water in the packing to obtain spray water with a lower outlet temperature. The lower outlet temperature of the spray water increases the temperature difference between it and the evaporative condenser heat exchange coil, further reducing the temperature of the refrigerant in the evaporative condenser heat exchange coil. By placing the surface cooler, packing, and evaporative condenser heat exchange coil at an X-degree angle to the horizontal, the contact area between the air and the surface cooler, packing, and evaporative condenser heat exchange coil is increased, resulting in more complete heat exchange, convection, and evaporative evaporation between the air and these components.

[0054] 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.

[0055] 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. A precision air conditioner with evaporative cooling, characterized in that: The evaporative cooling precision air conditioner includes an indoor air conditioning unit that cools the air on the heat source side and an evaporative condensing outdoor unit. The indoor air conditioning unit includes an air conditioning shell, an air conditioning air inlet, a compressor, a first check valve, an evaporative heat exchange coil, a throttling valve, an air conditioning fan, an air conditioning air outlet, a temperature and humidity sensor, a controller, an indoor unit refrigerant outlet, and an indoor unit refrigerant inlet. The evaporative heat exchange coil is connected to the compressor and the throttling valve through pipes, and the first check valve is connected to the compressor in parallel through front and rear pipes. The evaporative condensing outdoor unit includes a condensing outdoor unit casing, a refrigerant pump, a second check valve, an evaporative condensing heat exchange coil, a condensing fan, an outdoor unit air inlet, a spray module, packing, a surface cooler, an outdoor unit air outlet, a water collection pan, a circulating water pump, a water storage tank, a water replenishment device, a refrigerant inlet for the condensing outdoor unit, and a refrigerant outlet for the condensing outdoor unit. The refrigerant pump is connected to the evaporative condensing heat exchange coil via a pipe, and the second check valve is connected in parallel to both ends of the refrigerant pump via pipes. The outdoor unit air outlet is located at the top of the condensing outdoor unit casing, the outdoor unit air inlet is located on the lower side of the condensing outdoor unit casing, the condensing fan is installed on the outdoor unit air outlet, and the spray module and the evaporative condensing heat exchange coil are connected in parallel. The evaporative condensing heat exchange coil is placed below the condensing fan, the packing is placed below the evaporative condensing heat exchange coil, the surface cooler is placed below the packing, the outdoor unit air inlet is located beside the surface cooler, the water collection tray is placed below the packing, the water collection tray is connected to the water storage tank, the circulating water pump inlet is connected to the water storage tank through a pipe, the circulating water pump outlet is connected to the surface cooler inlet through a pipe, the surface cooler outlet is connected to the spray module through a pipe, the spray module consists of several nozzles that spray water onto the evaporative condensing heat exchange coil, and the water replenishment device is connected to the water storage tank through a pipe. The indoor air conditioning unit and the evaporative condensing outdoor unit are connected by pipes. The refrigerant outlet of the indoor unit is connected to the refrigerant inlet of the condensing outdoor unit by pipes. The refrigerant inlet of the indoor unit is connected to the outlet of the refrigerant pump by pipes. The evaporative condensing outdoor unit is also equipped with an inlet air temperature and humidity sensor, an outlet air temperature sensor, a condensing temperature sensor, a condensing pressure sensor, and a control module. The control module can automatically adjust the load of the condensing fan and the circulating water pump according to the outlet water temperature and the preset temperature target value, so that the condensing temperature and pressure reach the preset target value.

2. The evaporative cooling precision air conditioner according to claim 1, characterized in that: The evaporative condensing heat exchange coil is a radial finned tube heat exchanger, and the evaporative condensing heat exchange coil is arranged in a "V" shape or an inverted "V" shape; the fins on the evaporative condensing heat exchange coil are evenly distributed, completely covering and evenly dividing the airflow space inside the evaporative condensing heat exchange coil, and are arranged in a corrugated shape or in an alternating pattern along the airflow direction; the flow direction of the cooled fluid is counter-current relative to the airflow direction between the layers of the evaporative condensing heat exchange coil.

3. The evaporative cooling precision air conditioner according to claim 1, characterized in that: The evaporative condensing outdoor unit is also equipped with an automatic filtration and sewage discharge device, which is located between the circulating water pump and the surface cooler.

4. The evaporative cooling precision air conditioner according to claim 1, characterized in that: The surface of the evaporative condenser heat exchange coil is coated with a hydrophilic coating containing infrared radiation heat dissipation material.

5. The evaporative cooling precision air conditioner according to claim 1, characterized in that: The surface of the surface cooler is coated with a superhydrophobic coating containing infrared radiation heat dissipation material.

6. The evaporative cooling precision air conditioner according to claim 1, characterized in that: The average diameter of the water droplets sprayed by the spray module is less than 1 mm.

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