Air conditioner cabinet and control method thereof

Abstract

The application discloses an air conditioner cabinet and a control method thereof, and relates to the technical field of air conditioner terminal equipment. The air conditioner cabinet comprises a shell and a two-stage heat exchanger. The shell is provided with an air return port, an air supply port, and an air duct connecting the air return port and the air supply port. The shell is provided with a first side wall and a second side wall which are opposite along a first direction. The first side wall is provided with the air return port, and the second side wall is provided with the air supply port. The two-stage heat exchanger is arranged in the air duct along the first direction. The two-stage heat exchanger is provided with a water inlet, a water outlet, and a heat exchange channel connecting the water inlet and the water outlet. The water inlet is arranged close to the second side wall, and the water outlet is arranged close to the first side wall. The flow direction of the cooling liquid in the heat exchange channel is opposite to the direction of the air flowing from the air return port to the air supply port in the air duct. Therefore, the problem that the heat exchange efficiency of the existing air conditioner cabinet is low and the energy consumption of the air supply and distribution is high under the condition of medium temperature and large temperature difference is solved.

Description

Technical Field

[0001] This invention relates to the field of air conditioning terminal equipment technology, and in particular to an air conditioning cabinet and its control method. Background Technology

[0002] With the acceleration of urbanization and the rapid development of public buildings, the proportion of building energy consumption in total social energy consumption is constantly increasing. Among them, air conditioning system energy consumption accounts for more than 50% of building energy consumption. However, traditional air conditioning terminal equipment has gradually revealed several technical limitations in actual operation. The supply and return water temperature difference of traditional air conditioning terminals is usually 5℃, resulting in a large water flow. The energy consumption of the distribution system accounts for about 30% to 40% of the total energy consumption of the air conditioning system. At the same time, traditional air conditioning cabinets mostly adopt a single-stage heat exchanger design. Under large temperature difference conditions, the temperature difference between the outlet water and the outlet air of the heat exchanger gradually decreases, resulting in a significant decrease in the heat exchange efficiency of the latter half of the heat exchanger and a low utilization rate per unit heat exchange area. In recent years, medium-temperature large temperature difference air conditioning technology has gradually attracted attention. Some research institutions have proposed the concept of a high-temperature chilled water temperature and humidity independent control system of 16 to 18℃. However, the terminals of this system mostly use dry fan coil units or radiant panels, which have not effectively solved the problem of matching the heat exchange performance of the air conditioning cabinet under medium-temperature large temperature difference conditions. While existing technologies offer solutions for combined air conditioning units designed for low-temperature, large-temperature-difference conditions, such as designs using honeycomb aluminum fins and internally threaded copper tube heat exchangers, these are primarily suitable for low-temperature environments and still utilize a single-stage heat exchanger structure. This makes it difficult to address the efficiency degradation in the latter half of the heat exchanger under large temperature differences. Therefore, developing an air conditioning unit specifically optimized for medium-temperature, large-temperature-difference conditions has significant technical and application value. Summary of the Invention

[0003] The main objective of this invention is to propose an air conditioning cabinet and its control method, which aims to solve the problems of low heat exchange efficiency and high energy consumption in the transmission and distribution of existing air conditioning cabinets under medium-temperature and large temperature difference conditions.

[0004] To achieve the above objectives, the present invention provides an air conditioning cabinet comprising: The housing has a return air inlet, an air supply inlet, and an air duct connecting the return air inlet and the air supply inlet. The housing has a first sidewall and a second sidewall opposite to each other along a first direction. The first sidewall is provided with the return air inlet, and the second sidewall is provided with the air supply inlet. A two-stage heat exchanger is arranged in the air duct along the first direction. The two-stage heat exchanger has an inlet, an outlet, and a heat exchange channel connecting the inlet and the outlet. The water inlet is located near the second side wall, and the water outlet is located near the first side wall, so that the flow direction of the coolant in the heat exchange channel is opposite to the direction of the air in the air duct flowing from the return air inlet to the supply air inlet.

[0005] In one embodiment, the two-stage heat exchanger includes a first-stage heat exchanger and a second-stage heat exchanger arranged sequentially along the first direction. The second-stage heat exchanger is disposed near the first sidewall and has the water inlet. The first-stage heat exchanger is disposed near the second sidewall and has the water outlet. The heat exchange area of ​​the first-stage heat exchanger is smaller than that of the second-stage heat exchanger.

[0006] In one embodiment, the first-stage heat exchanger has a first heat exchange tube and a plurality of first fins arranged on the first heat exchange tube. The second-stage heat exchanger has a second heat exchange tube and a plurality of second fins arranged on the second heat exchange tube; And / or, the first fin is a windowed fin; And / or, the second fin is a corrugated aluminum fin; And / or, the spacing between two adjacent first fins is greater than the spacing between two adjacent second fins; And / or, the wall thickness of the second heat exchange tube is greater than the wall thickness of the first heat exchange tube; And / or, both the first heat exchange tube and the heat exchange tube are made of internally threaded copper tubes.

[0007] In one embodiment, the air conditioning cabinet further includes: A valve, located in the heat exchange channel, is used to regulate the water flow rate through the heat exchange channel; A fan, located inside the air duct, is used to regulate the air volume supplied by the air duct; The controller is electrically connected to the valve and the fan, respectively, and is used to acquire the return air temperature, return air humidity, inlet water temperature, outlet water temperature and supply air temperature of the air conditioning unit, calculate the real-time dew point temperature based on the return air temperature and return air humidity, and adjust the opening of the valve to regulate the water flow through the two-stage heat exchanger based on the inlet water temperature and the outlet water temperature, so that the actual supply and return water temperature difference between the inlet water temperature and the outlet water temperature approaches the target temperature difference, or adjust the speed of the fan to make the supply air temperature higher than the real-time dew point temperature.

[0008] In one embodiment, the controller is specifically used for: The actual supply and return water temperature difference is calculated based on the inlet water temperature and the outlet water temperature, and the deviation between the actual supply and return water temperature difference and the target temperature difference is obtained. If the absolute value of the deviation is greater than a preset threshold, the water flow rate change rate and air volume change rate are obtained. If the rate of change of water flow is determined to be greater than the rate of change of air volume, the opening of the valve is adjusted so that the actual temperature difference approaches the target temperature difference. If the rate of change of water flow is determined to be no greater than the rate of change of air volume, the speed of the fan is adjusted until the air supply temperature is close to the real-time dew point temperature. Then, the upper limit of the fan speed is limited so that the air supply temperature is higher than the sum of the real-time dew point temperature and the upper limit of the preset temperature range.

[0009] In one embodiment, the air duct includes a return air section, a filter section, a heat exchange section, an air supply section, and a control section arranged sequentially along a first direction. The return air section is connected to the return air inlet, the filter section is provided with a two-stage filter, the heat exchange section is provided with the two-stage heat exchanger, the air supply section is provided with the fan and connected to the air supply inlet, and the control section is provided with the controller.

[0010] In one embodiment, the housing further has four connecting walls that connect the first sidewall and the second sidewall. The four connecting walls are connected to each other to form the air duct. Each connecting wall, the first sidewall, and the second sidewall has an outer wall panel, an inner wall panel, and a heat insulation layer disposed between the outer wall panel and the inner wall panel. And / or, a broken bridge gap is provided between the outer wall panel and the inner wall panel.

[0011] In one embodiment, the inner wall of the housing is provided with a guide channel for collecting condensate, and a water collection tray connected to the guide channel is provided below the guide channel. The water collection tray is connected to a drain pipe extending to the outside of the housing, and the drain pipe is used to discharge the condensate collected by the water collection tray to the outside of the housing.

[0012] In one embodiment, the cross-sectional shape of the guide channel is V-shaped; And / or, the width of the guide channel is not less than 6 mm and not more than 10 mm; And / or, the depth of the guide channel is not less than 4 mm and not more than 6 mm; And / or, the flow channel is formed at the bottom of the housing.

[0013] The present invention also proposes a control method for an air conditioning cabinet, applied to the air conditioning cabinet described above, the control method comprising: Obtain the return air temperature, return air humidity, inlet water temperature, outlet water temperature and supply air temperature of the air conditioning unit; Calculate the real-time dew point temperature based on the return air temperature and humidity. Based on the inlet and outlet water temperatures, adjust the valve opening to regulate the water flow through the two-stage heat exchanger, so that the actual supply and return water temperature difference between the inlet and outlet water temperatures approaches the target temperature difference; or, adjust the fan speed to make the supply air temperature higher than the real-time dew point temperature.

[0014] In this invention, a two-stage heat exchanger is arranged along a first direction within the casing. The inlets of the two-stage heat exchangers are positioned close to the second sidewall with the air supply port, while the outlets are positioned close to the first sidewall with the return air port. This arrangement ensures that the flow direction of the coolant within the heat exchange channel is opposite to the direction of the air flow from the return air port to the air supply port within the duct. This configuration allows the coolant, which is cooler, to first flow through the area near the air supply port after entering the two-stage heat exchanger, exchanging heat with the cooler air to be supplied in that area. As the coolant flows towards the first sidewall near the return air port within the heat exchange channel, its temperature gradually increases. At this point, the heated coolant encounters and exchanges heat with the warmer air entering from the return air port. This ensures that a large temperature difference is maintained between the coolant and the air at all cross-sections throughout the heat exchange process, effectively avoiding the problem of reduced heat exchange efficiency in the latter half of the heat exchanger due to unidirectional or mixed flow in traditional single-stage heat exchangers. By making the flow direction of the coolant in the heat exchange channel opposite to the direction of the air flow from the return air inlet to the supply air outlet in the air duct, the counter-current heat exchange principle is fully utilized to tap the heat exchange potential under large temperature difference conditions, significantly improving the utilization rate of the unit heat exchange area. This enables the air conditioning cabinet to adapt to the heat exchange performance requirements under medium temperature and large temperature difference conditions, thereby helping to increase the supply and return water temperature difference and reduce the water flow and energy consumption of the distribution system. This improves the situation of low heat exchange efficiency and high distribution energy consumption of existing air conditioning cabinets under medium temperature and large temperature difference conditions. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of the air conditioning cabinet of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the structure of the air conditioning cabinet of the present invention. Figure 2 ; Figure 3 This is a schematic diagram illustrating the heat exchange temperature-enthalpy change principle of the air conditioning cabinet of the present invention. Figure 4 This is a schematic diagram of the circuit functional modules of the air conditioning cabinet of the present invention; Figure 5 This is a schematic diagram of the structure of the housing of the present invention; Figure 6 This is a schematic diagram of the structure of the guide channel, water collection tray and drain pipe of the present invention; Figure 7The flow chart of the control method for the air conditioning cabinet of the present invention Figure 1 ; Figure 8 The flow chart of the control method for the air conditioning cabinet of the present invention Figure 2 .

[0017] Explanation of icon numbers: 100. Air conditioning unit; 10. Shell; 101. Return air vent; 102. Supply air vent; 103. Air duct; 1031. Return air section; 1032. Filter section; 1033. Heat exchange section; 1034. Supply air section; 1035. Control section; 104. Guide channel; W, channel width; D, channel depth; 11. First side wall; 12. Second side wall; 13. Connecting wall; 111. Outer wall panel; 112. Inner wall panel; 113. Insulation layer; 1101. Thermal break gap; 12. 13. Water collection tray; 20. Drain pipe; 21. Two-stage heat exchanger; 21. First-stage heat exchanger; 211. First fin; 212. First heat exchange tube; 22. Second-stage heat exchanger; 221. Second fin; 222. Second heat exchange tube; 30. Valve; 40. Fan; 50. Controller; 60. Two-stage filter; 61. Primary filter; 62. Medium-efficiency filter; 71. Inlet main pipe; 72. Outlet main pipe; 81. First-stage distributor; 82. Second-stage distributor.

[0018] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] With the acceleration of urbanization and the rapid development of public buildings, the proportion of building energy consumption in total social energy consumption is constantly increasing. Among them, air conditioning system energy consumption accounts for more than 50% of building energy consumption. However, traditional air conditioning terminal equipment has gradually revealed several technical limitations in actual operation. The supply and return water temperature difference of traditional air conditioning terminals is usually 5℃, resulting in a large water flow. The energy consumption of the distribution system accounts for about 30% to 40% of the total energy consumption of the air conditioning system. At the same time, traditional air conditioning cabinets mostly adopt a single-stage heat exchanger design. Under large temperature difference conditions, the temperature difference between the outlet water and the outlet air of the heat exchanger gradually decreases, resulting in a significant decrease in the heat exchange efficiency of the latter half of the heat exchanger and a low utilization rate per unit heat exchange area. In recent years, medium-temperature large temperature difference air conditioning technology has gradually attracted attention. Some research institutions have proposed the concept of a high-temperature chilled water temperature and humidity independent control system of 16 to 18℃. However, the terminals of this system mostly use dry fan coil units or radiant panels, which have not effectively solved the problem of matching the heat exchange performance of the air conditioning cabinet under medium-temperature large temperature difference conditions. While existing technologies offer solutions for combined air conditioning units designed for low-temperature, large-temperature-difference conditions, such as designs using honeycomb aluminum fins and internally threaded copper tube heat exchangers, these are primarily suitable for low-temperature environments and still utilize a single-stage heat exchanger structure. This makes it difficult to address the efficiency degradation in the latter half of the heat exchanger under large temperature differences. Therefore, developing an air conditioning unit specifically optimized for medium-temperature, large-temperature-difference conditions has significant technical and application value.

[0021] This invention proposes an air conditioning cabinet 100.

[0022] Please see Figure 1 In one embodiment of the present invention, the air conditioning cabinet 100 includes: The housing 10 has a return air inlet 101, an air supply outlet 102, and an air duct 103 connecting the return air inlet 101 and the air supply outlet 102. The housing 10 has a first side wall 11 and a second side wall 12 opposite to each other in a first direction. The first side wall 11 is provided with the return air inlet 101, and the second side wall 12 is provided with the air supply outlet 102. Two-stage heat exchangers 20 are arranged in the air duct 103 along the first direction. The two-stage heat exchangers 20 have an inlet, an outlet, and a heat exchange channel connecting the inlet and the outlet. The inlet is located near the second side wall 12, and the outlet is located near the first side wall 11, so that the flow direction of the coolant in the heat exchange channel is opposite to the direction of the air in the air duct 103 flowing from the return air port 101 to the supply air port 102.

[0023] In this embodiment, the air conditioning cabinet 100 is a terminal processing device applied to the air conditioning system of public buildings, mainly used for cooling and dehumidifying indoor return air to meet environmental comfort requirements. The housing 10 serves as the main support structure and protective shell of the air conditioning cabinet 100, and has an internal air duct 103 that connects the return air inlet 101 and the air supply outlet 102, providing a closed and continuous flow path for directional air delivery. The housing 10 has a first side wall 11 and a second side wall 12 arranged opposite to each other along a first direction. The first side wall 11 is provided with a return air inlet 101, allowing the return air with a higher indoor temperature to smoothly enter the air duct 103; the second side wall 12 is provided with an air supply outlet 102, allowing the low-temperature air after heat exchange treatment to be evenly delivered to the indoor space, thereby realizing a unidirectional orderly flow of air from the first side wall 11 to the second side wall 12 within the housing 10.

[0024] To achieve efficient heat transfer and utilization under medium-temperature and large-temperature-difference operating conditions, the air conditioning unit 100 also includes a two-stage heat exchanger 20. The two-stage heat exchanger 20 is arranged along a first direction within the air duct 103, allowing the air flowing through the air duct 103 to fully exchange heat with the heat exchanger during its flow. The two-stage heat exchanger 20 has an inlet, an outlet, and a heat exchange channel connecting the inlet and outlet. Coolant supplied by an external cold source flows into the heat exchange channel through the inlet and exchanges heat with the air in the air duct 103 during its flow along the channel. The coolant, after absorbing heat and increasing its temperature, then flows out through the outlet to the external pipeline. The inlet is located near the second side wall 12, which means that the coolant with a lower temperature first enters the heat exchange area near the air outlet 102; while the outlet is located near the first side wall 11, which means that the coolant after absorbing heat and heating up is discharged from the side near the return air outlet 101. This makes the flow direction of the coolant in the heat exchange channel opposite to the direction of the air in the air duct 103 flowing from the return air outlet 101 to the air outlet 102, forming a counter-current heat exchange layout.

[0025] Through the aforementioned counter-current heat exchange layout, the coolant and air flow in opposite directions throughout the two-stage heat exchanger 20. When the warmer air enters the air duct 103 from the return air inlet 101 on the first sidewall 11, it first encounters the coolant, which has already absorbed some heat and is at a relatively high temperature. Thanks to the air being at its highest temperature point throughout the entire process, the temperature difference loss caused by the coolant's temperature rise is effectively compensated, allowing a large heat exchange temperature difference to be maintained between the two, thus preventing the heat exchange driving force from prematurely decaying at the inlet. As the air continues to flow along the first direction towards the air outlet 102 on the second sidewall 12, the air temperature gradually decreases, while the coolant it encounters at this time is at its lowest temperature because it has just flowed in from the inlet near the second sidewall 12. Due to the advantage of the counter-current arrangement, a large heat exchange temperature difference is also maintained between the two. This design ensures that a large heat exchange temperature difference is maintained throughout the entire length of the air duct 103, thereby achieving efficient and uniform heat exchange performance. It effectively improves the problem of a significant decrease in heat exchange efficiency in the latter half of the stage of a traditional single-stage heat exchanger under large temperature difference conditions due to the gradual decrease in the terminal temperature difference. This significantly improves the utilization rate of the unit heat exchange area, enabling the air conditioning unit 100 to better adapt to the heat exchange performance matching requirements under medium-temperature and large temperature difference conditions. This, in turn, helps to increase the supply and return water temperature difference and reduce the water flow and energy consumption of the distribution system.

[0026] In the technical solution of the present invention, by setting two-stage heat exchangers 20 arranged along a first direction in the housing 10, and setting the water inlet of the two-stage heat exchangers 20 close to the second side wall 12 with the air outlet 102, and setting the water outlet of the two-stage heat exchangers 20 close to the first side wall 11 with the return air outlet 101, the flow direction of the coolant in the heat exchange channel is opposite to the direction of the air in the air duct 103 flowing from the return air outlet 101 to the air outlet 102. This configuration ensures that the coolant, which is cooler, first flows through the area near the air outlet 102 after entering the two-stage heat exchanger 20, where it exchanges heat with the cooler air to be delivered. As the coolant flows towards the first sidewall 11 near the return air outlet 101 within the heat exchange channel, its temperature gradually increases. At this point, the heated coolant meets the warmer air entering from the return air outlet 101 and exchanges heat with it. This allows the coolant and air to maintain a large temperature difference at all cross-sections throughout the heat exchange process, effectively avoiding the problem of reduced heat exchange efficiency in the latter half of the heat exchanger due to unidirectional or mixed flow in traditional single-stage heat exchangers. By making the flow direction of the coolant in the heat exchange channel opposite to the direction of the air in the air duct 103 flowing from the return air port 101 to the supply air port 102, the counter-current heat exchange principle is fully utilized to tap the heat exchange potential under large temperature difference conditions, significantly improving the utilization rate of the unit heat exchange area. This enables the air conditioning cabinet 100 to adapt to the heat exchange performance requirements under medium temperature and large temperature difference conditions, thereby helping to increase the supply and return water temperature difference and reduce the water flow and energy consumption of the distribution system. This improves the situation of low heat exchange efficiency and high distribution energy consumption of the existing air conditioning cabinet 100 under medium temperature and large temperature difference conditions.

[0027] like Figure 1 and Figure 2 As shown, in one embodiment, the two-stage heat exchanger 20 includes a first-stage heat exchanger 21 and a second-stage heat exchanger 22 arranged sequentially along a first direction. The second-stage heat exchanger 22 is disposed near the first sidewall 11 and has an inlet. The first-stage heat exchanger 21 is disposed near the second sidewall 12 and has an outlet. The heat exchange area of ​​the first-stage heat exchanger 21 is smaller than the heat exchange area of ​​the second-stage heat exchanger 22.

[0028] In this embodiment, the first-stage heat exchanger 21 and the second-stage heat exchanger 22 are arranged sequentially along a first direction inside the air duct 103. Air entering from the return air inlet 101 first flows through the first-stage heat exchanger 21 for preliminary heat exchange, and then flows through the second-stage heat exchanger 22 for further heat exchange, forming a staged air handling process. Cooling water flows sequentially through the second-stage heat exchanger 22 and the first-stage heat exchanger 21, circulating in series within the two heat exchangers 20, forming a counter-current heat exchange with the air. Figure 3As shown in the temperature-enthalpy diagram, cooling water with an inlet temperature of T1=16℃ first enters the second-stage heat exchanger 22, absorbs heat, and rises to an intermediate water temperature of T2=22℃. During this process, the air temperature drops from an intermediate temperature of Tb=23℃ to the supply air temperature of Tc=20℃, corresponding to a heat exchange of Q2. Subsequently, the cooling water, heated to T2=22℃, enters the first-stage heat exchanger 21 through the connecting pipe, continues to absorb heat, and rises to a return water temperature of T3=28℃. During this process, the air temperature drops from a return air temperature of Ta=30℃ to the aforementioned intermediate temperature of Tb=23℃, corresponding to a heat exchange of Q1. Since the first-stage heat exchanger 21 handles the untreated high-temperature return air, the heat exchange temperature difference between it and the cooling water is larger. In contrast, the second-stage heat exchanger 22 handles the pre-cooled air, and the heat exchange temperature difference between it and the cooling water is relatively smaller. Therefore, the heat exchange Q1 undertaken by the first-stage heat exchanger 21 is greater than the heat exchange Q2 undertaken by the second-stage heat exchanger 22. Compared to a single-stage heat exchanger design, this phased arrangement extends the contact process between air and cooling water, which helps alleviate the problem of a significant decrease in heat exchange efficiency in the latter half of the heat exchanger under large temperature difference conditions. At the same time, it allows the first-stage heat exchanger 21 and the second-stage heat exchanger 22 to share the heat exchange load, avoiding excessive heat exchange pressure on a single heat exchanger under large temperature difference conditions, thereby improving the utilization rate of the unit heat exchange area.

[0029] The aforementioned counter-current heat exchange layout ensures a consistently large temperature difference between the cooling water and air in each heat exchanger stage. Specifically, in the first-stage heat exchanger 21, although the cooling water temperature has risen to near the return water temperature T3 = 28℃, the air it encounters is at the highest return air temperature in the entire process, Ta = 30℃. This high air temperature effectively compensates for the temperature loss caused by the cooling water's temperature rise, maintaining a significant temperature difference between the two. Similarly, in the second-stage heat exchanger 22, although the air temperature has decreased to near the supply air temperature Tc = 20℃, the cooling water it encounters is at the lowest inlet water temperature in the entire process, T1 = 16℃. Thanks to the superior quality of the cold source in the counter-current arrangement, a large temperature difference is also maintained between the two. The aforementioned temperature difference distribution characteristics enable the cooling water to maintain a relatively reasonable temperature difference match with the air throughout the entire process of flowing through the two-stage heat exchanger 20. This effectively improves the situation where the outlet temperature difference gradually decreases and the heat exchange efficiency decreases under large temperature difference conditions in traditional single-stage heat exchangers. This allows the air conditioning cabinet 100 to make fuller use of the heat exchange temperature difference under medium-temperature and large temperature difference conditions.

[0030] The heat exchange area of ​​the second-stage heat exchanger 22 is larger than that of the first-stage heat exchanger 21. This area ratio is set based on the difference in heat exchange load borne by each stage of the heat exchanger during counter-current heat exchange. In the counter-current heat exchange layout, the second-stage heat exchanger 22 is located on the cooling water inlet side, where the cooling water temperature is low. However, the air exchanging heat with it has already undergone pretreatment by the first-stage heat exchanger 21, and its temperature is relatively low. The temperature difference between the two is small, therefore a larger heat exchange area is needed to maintain sufficient heat exchange capacity. The first-stage heat exchanger 21 is located on the cooling water outlet side. Although the cooling water temperature is somewhat higher, the air exchanging heat with it is the untreated return air at the highest temperature throughout the entire process. The maximum temperature of the air effectively compensates for the temperature difference loss caused by the rise in cooling water temperature, allowing a large temperature difference to still be maintained between the two. A smaller heat exchange area is sufficient to meet the heat exchange requirements. By setting the heat exchange area of ​​the second-stage heat exchanger 22 to be greater than that of the first-stage heat exchanger 21, the two-stage heat exchangers 20 can maintain a relatively matched heat exchange capacity in their respective operating ranges, avoiding the limitation of overall heat exchange efficiency due to insufficient heat exchange area of ​​a certain stage heat exchanger, thereby further improving the comprehensive heat exchange performance of the air conditioning cabinet 100 under medium temperature and large temperature difference conditions.

[0031] like Figure 1 and Figure 2 As shown, in one embodiment, the first-stage heat exchanger 21 has a first heat exchange tube 212 and a plurality of first fins 211 arranged on the first heat exchange tube 212; The second-stage heat exchanger 22 has a second heat exchange tube 222 and a plurality of second fins 221 arranged on the second heat exchange tube 222; And / or, the first fin 211 is a windowed fin; And / or, the second fin 221 is a corrugated aluminum fin; And / or, the spacing between two adjacent first fins 211 is greater than the spacing between two adjacent second fins 221; And / or, the wall thickness of the second heat exchange tube 222 is greater than the wall thickness of the first heat exchange tube 212; And / or, both the first heat exchange tube 212 and the heat exchange tube are made of internally threaded copper tubes.

[0032] In this embodiment, cooling water enters through the main inlet pipe 71, is evenly distributed by the first-stage water distributor 81, and flows into the first heat exchange tube 212 of the first-stage heat exchanger 21, where it exchanges heat with the first fins 211 of the first-stage heat exchanger 21. The first fins 211 are window-type fins, and the spacing between two adjacent window-type fins is 2.0–2.5 mm. That is, the spacing between two adjacent window-type fins can be any one of 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, and 2.5 mm, or other values ​​within this range, and is not specifically limited here. In this embodiment, the spacing between two adjacent window-type fins is 2.3 mm. This spacing helps to reduce the flow resistance of air flowing through the first-stage heat exchanger 21, allowing the untreated high-temperature return air to pass smoothly and maintaining a high air velocity to enhance convective heat transfer. The first heat exchange tube 212 is a φ9.52 mm internally threaded copper tube with a wall thickness of 0.35 mm. By employing 2.3mm spaced finned tubes and a 0.35mm thick first heat exchange tube 212, the heat exchange area of ​​the first-stage heat exchanger 21 can reach 180m². Cooling water that has completed initial heat exchange enters the second heat exchange tube 222 of the second-stage heat exchanger 22 via connecting pipes, where it undergoes deep cooling with the second fins 221 of the second-stage heat exchanger 22. The second fins 221 are corrugated aluminum fins, with a spacing of 1.8–2.2mm between adjacent corrugated fins. That is, the spacing between adjacent corrugated fins can be any one of 1.8mm, 1.9mm, 2.0mm, 2.1mm, or 2.2mm, or other values ​​within this range; no specific limitation is imposed here. In this embodiment, the spacing between adjacent corrugated fins is 2.0mm, which is smaller than the spacing between adjacent finned tubes. When the air temperature decreases and the volumetric flow rate decreases after pre-cooling by the first-stage heat exchanger 21, the smaller fin spacing helps increase the heat exchange surface area per unit volume, thereby compensating for the decrease in heat exchange driving force caused by the reduced temperature difference. The second heat exchange tube 222 also uses a φ9.52mm internally threaded copper tube, but its wall thickness is 0.4mm, which is greater than the wall thickness of the first heat exchange tube 212. Since the second-stage heat exchanger 22 is located close to the main water inlet pipe 71, it bears the higher inlet pressure from the external water supply system, and the thicker tube wall helps to improve its structural strength and pressure resistance reliability. By using corrugated fins with a spacing of 2.0mm and a second heat exchange tube 222 with a wall thickness of 0.4mm, the heat exchange area of ​​the second-stage heat exchanger 22 can reach 210m², which is 15–20% larger than the heat exchange area of ​​the first-stage heat exchanger 21, specifically an increase of 16.7%. The increase in area is adapted to the requirement that the second-stage heat exchanger 22 bears a larger heat exchange load in the counter-flow arrangement, so that the two-stage heat exchangers 20 can maintain a relatively balanced heat exchange capacity throughout the entire process.The return water in the heat exchange tubes of the second-stage heat exchanger 22 is collected by the second-stage water collector 82 and discharged through the outlet main pipe 72, thereby realizing the series counter-current circulation of cooling water in the first-stage heat exchanger 21 and the second-stage heat exchanger 22.

[0033] In addition, the water volume and air volume regulation of the existing air conditioning cabinet 100 usually adopt independent control loops. Under large temperature difference conditions, the two have a strong coupling relationship. The adjustment of a single parameter is easy to cause fluctuations in the other parameter, making it difficult to achieve stable operation with large temperature difference.

[0034] To improve this problem, such as Figure 1 and Figure 4 As shown, in one embodiment, the air conditioning cabinet 100 further includes: Valve 30 is located in the heat exchange channel and is used to regulate the water flow rate through the heat exchange channel; Fan 40 is installed in air duct 103 and is used to regulate the air supply volume of air duct 103; The controller 50 is electrically connected to the valve 30 and the fan 40 respectively. It is used to obtain the return air temperature, return air humidity, inlet water temperature, outlet water temperature and supply air temperature of the air conditioning cabinet 100, calculate the real-time dew point temperature based on the return air temperature and return air humidity, and adjust the opening of the valve 30 according to the inlet water temperature and outlet water temperature to adjust the water flow through the two-stage heat exchanger 20 so that the actual supply and return water temperature difference between the inlet water temperature and the outlet water temperature approaches the target temperature difference, or adjust the speed of the fan 40 so that the supply air temperature is higher than the real-time dew point temperature.

[0035] In this embodiment, to adjust the water flow rate through the two-stage heat exchanger 20 and achieve target temperature difference control, the air conditioning cabinet 100 is also equipped with a valve 30. This valve 30 is installed on the pipeline between the two-stage heat exchanger 20 and acts as a flow regulation component, controlling the flow rate of the coolant through the two-stage heat exchanger 20 by changing its opening degree. When the actual supply and return water temperature difference between the inlet and outlet water temperatures deviates from the target temperature difference, the water flow rate can be changed by adjusting the opening degree of the valve 30, allowing the actual supply and return water temperature difference to gradually approach the target temperature difference. For example, when the actual supply and return water temperature difference is less than the target temperature difference, the opening of valve 30 can be appropriately reduced to decrease the water flow rate, prolonging the residence time of the coolant in the two-stage heat exchanger 20, thereby increasing the outlet water temperature and increasing the actual supply and return water temperature difference to approach the target temperature difference. When the actual supply and return water temperature difference is greater than the target temperature difference, the opening of valve 30 can be appropriately increased to increase the water flow rate, shortening the residence time of the coolant in the two-stage heat exchanger 20, thereby decreasing the outlet water temperature and decreasing the actual supply and return water temperature difference to approach the target temperature difference. This setting helps reduce the energy consumption generated by high-flow-rate transmission, while allowing the air conditioning unit 100 to adapt to the operating requirements of different loads.

[0036] To regulate the airflow through the duct 103, the air conditioning unit 100 is also equipped with a fan 40. This fan 40, installed within the duct 103, acts as an aerodynamic component, adjusting the airflow through the duct 103 by changing its rotational speed. With the fan 40 installed, the air conditioning unit 100 can adjust the airflow according to actual needs, adapting to air handling requirements under different operating conditions. When the indoor load changes, the airflow can be adjusted by changing the fan 40's rotational speed, ensuring a more reasonable match between the supply air temperature and the indoor temperature, avoiding energy waste or reduced comfort caused by excessive or insufficient airflow. Simultaneously, the fan 40 can work in conjunction with the two-stage heat exchanger 20, maintaining a suitable airflow velocity as the air passes through it, ensuring sufficient heat exchange.

[0037] To achieve coordinated regulation of water and air volume, the air conditioning unit 100 is also equipped with a controller 50. This controller 50, as the core of the system control, is electrically connected to the valve 30 and the fan 40, respectively, and is used to collect real-time data on the return air temperature, return air humidity, inlet water temperature, outlet water temperature, and supply air temperature of the air conditioning unit 100. The controller 50 can calculate the real-time dew point temperature based on the return air temperature and humidity; this parameter characterizes the critical point for condensation under the current air conditions. The controller 50 uses the inlet and outlet water temperatures as the core control basis. Based on their actual changes, it selectively adjusts the opening of valve 30 or the speed of fan 40. When the actual supply and return water temperature difference deviates from the target temperature difference, the controller 50 prioritizes adjusting the valve 30 opening to change the water flow through the two-stage heat exchanger 20, bringing the actual supply and return water temperature difference closer to the target temperature difference. This reduces energy consumption from large-flow water transport while meeting heat exchange requirements. Simultaneously, the counter-current arrangement of the two-stage heat exchanger 20 improves the problem of decreased heat exchange efficiency in the latter half of the heat exchanger under large temperature difference conditions. When changes in the inlet and outlet water temperatures indicate a risk of the supply air temperature falling below the real-time dew point temperature, the controller 50 adjusts the fan 40 speed to change the air volume, maintaining the supply air temperature within a safe range above the real-time dew point temperature, thus preventing condensation inside the duct 103 or at the air outlet 102. Because water flow and air volume are strongly coupled under large temperature difference conditions, traditional independent control loops struggle to maintain stable operation. In this embodiment, the controller 50 selectively and collaboratively adjusts the valve 30 opening and fan 40 speed based on the inlet and outlet water temperatures. This ensures a more coordinated match between water and air volume, effectively reducing fluctuations in one parameter caused by adjusting another. This facilitates stable operation under large temperature differences, thereby improving the overall performance of the air conditioning unit 100 under medium-temperature, large-temperature-difference conditions.

[0038] like Figure 1 and Figure 4 As shown, in one embodiment, the controller 50 is specifically used for: Calculate the actual supply and return water temperature difference based on the inlet and outlet water temperatures, and obtain the deviation between the actual supply and return water temperature difference and the target temperature difference; If the absolute value of the deviation is greater than a preset threshold, obtain the rate of change of water flow and the rate of change of air volume. If the rate of change of water flow is greater than the rate of change of air volume, adjust the opening of valve 30 to make the actual temperature difference approach the target temperature difference. If the rate of change of water flow is determined to be no greater than the rate of change of air volume, adjust the speed of fan 40 until the supply air temperature is close to the real-time dew point temperature, then limit the upper limit of the speed of fan 40 so that the supply air temperature is higher than the sum of the real-time dew point temperature and the upper limit of the preset temperature range.

[0039] In this embodiment, the controller 50 performs periodic closed-loop control of the operating status of the air conditioning unit 100. The specific execution process includes multiple stages such as data acquisition, deviation calculation, dominant factor identification, water or air volume adjustment, and safety protection. The controller 50 first collects the inlet water temperature T_in, return water temperature T_out, and water flow rate G_w, and calculates the actual supply and return water temperature difference ΔT based on the inlet water temperature T_in and return water temperature T_out. This actual supply and return water temperature difference ΔT is equal to the return water temperature T_out minus the inlet water temperature T_in. Subsequently, the controller 50 compares the actual supply and return water temperature difference ΔT with the target temperature difference ΔT_set, and calculates the temperature difference deviation e. This temperature difference deviation e is equal to the target temperature difference ΔT_set minus the actual supply and return water temperature difference ΔT, used to quantify the degree of deviation between the current heat exchange state and the ideal state. When determining the source of deviation, if the absolute value of the temperature difference deviation e is greater than the preset threshold of 1℃, and the rate of change of water flow is greater than the rate of change of air flow, it is determined that the water-side deviation is dominant, and the water flow is adjusted first; otherwise, it is determined that the air-side deviation is dominant, and the air flow is adjusted first. For the case where the water-side deviation is dominant, the water-side control loop inside the controller 50 outputs a control signal to the valve 30 through a PID control algorithm. By changing the opening of the valve 30, the water flow through the two-stage heat exchanger 20 is adjusted, so that the actual supply and return water temperature difference approaches the target temperature difference, achieving precise matching of the water-side heat exchange capacity. For the case where the air-side deviation is dominant, the air-side control loop inside the controller 50 outputs a control signal to the frequency converter through a PID control algorithm. The frequency converter adjusts the speed of the fan 40 to change the airflow through the duct 103, so that the air-side heat exchange conditions adapt to load changes. During this process, the controller 50 uses the real-time dew point temperature Td as a feedforward compensation parameter in the airflow regulation stage. When the supply air temperature T_supply approaches the real-time dew point temperature Td, the upper limit of the fan speed 40 is limited to maintain the supply air temperature T_supply at a level not lower than the real-time dew point temperature Td plus 1.5℃. This 1.5℃ falls within the preset temperature range of 1.0–2.0℃, thereby preventing the supply air temperature from being too low and causing condensation in the air duct 103 or at the air outlet 102. After completing any of the above regulation operations, the controller 50 records the current operating data and updates the load prediction model. After a 30-second delay, it returns to the steps of collecting the inlet water temperature T_in, return water temperature T_out, and water flow rate G_w, forming a continuous closed-loop control cycle. This delay setting can both prevent system oscillation caused by excessively frequent adjustment actions and reserve sufficient response time for the heat exchange process, enabling the air conditioning cabinet 100 to maintain a relatively stable operating state under medium temperature and large temperature difference conditions, and to maximize heat exchange efficiency and energy utilization while meeting the anti-condensation safety requirements.

[0040] like Figure 1 and Figure 4As shown, in one embodiment, the controller 50 supports Modbus RTU / TCP and BACnet communication protocols and can be connected to a building equipment management system. It has a data storage cycle of ≥1 year and supports remote monitoring and remote firmware upgrades.

[0041] like Figure 1 and Figure 4 As shown, in one embodiment, the air duct 103 includes a return air section 1031, a filter section 1032, a heat exchange section 1033, an air supply section 1034, and a control section 1035 arranged sequentially along a first direction. The return air section 1031 is connected to the return air outlet 101, the filter section 1032 is provided with a two-stage filter 60, the heat exchange section 1033 is provided with a two-stage heat exchanger 20, the air supply section 1034 is provided with a fan 40 and is connected to the air supply outlet 102, and the control section 1035 is provided with a controller 50.

[0042] In this embodiment, the airflow organization path inside the air conditioning unit 100 is arranged sequentially in a first direction, forming a complete air duct 103 structure consisting of a return air section 1031, a filter section 1032, a heat exchange section 1033, a supply air section 1034, and a control section 1035. The return air section 1031, as the airflow inlet area, is connected to the return air outlet 101 and is responsible for introducing indoor return air into the air duct 103. The airflow then enters the filter section 1032, where a two-stage filter 60 is configured to perform graded purification treatment on the introduced air to remove particulate matter and impurities from the air, reducing the dust accumulation load on the subsequent heat exchange section 1033. The filtered air flows into the heat exchange section 1033, where a two-stage heat exchanger 20 is installed to perform heat exchange treatment on the air, thereby regulating the air temperature. The air that has undergone heat exchange continues to flow into the air supply section 1034. A fan 40 installed in the air supply section 1034 provides power for the airflow and delivers the treated air to the target area via the air outlet 102. A controller 50 is installed in the control section 1035. Placing the controller 50 in the control section 1035 helps to shorten the electrical connection path between the controller 50 and the fan 40, reducing line loss and improving the reliability of signal transmission. Furthermore, the airflow through the duct 103 can be used to cool the controller 50, preventing it from overheating or being affected by excessively high ambient temperatures, thus ensuring stable operation. Each functional section is connected sequentially along the first direction, so that the air can complete the operations of introduction, purification, heat exchange and delivery in an orderly manner as it flows through the return air section 1031, the filter section 1032, the heat exchange section 1033 and the supply air section 1034. At the same time, the controller 50 in the control section 1035 can manage the speed of the fan 40 and the operating status of the heat exchanger in real time, so that the overall structure of the air conditioning cabinet 100 is compact and the functional areas are clearly defined, which is conducive to improving air handling efficiency and operational stability.

[0043] like Figure 1 and Figure 4As shown, in one embodiment, the two-stage filter 60 disposed within the filter section 1032 includes a pre-filter 61 and a medium-efficiency filter 62 arranged sequentially along a first direction. The pre-filter 61 is a G4-grade bag filter with a filtration efficiency greater than or equal to 90%, determined by gravimetric analysis, primarily used to intercept larger dust and impurities. The medium-efficiency filter 62 is an F7-grade bag filter with a filtration efficiency greater than or equal to 80%, determined by colorimetric analysis, used to further remove finer particles from the air. Both the pre-filter 61 and the medium-efficiency filter 62 adopt a drawer-type installation structure for easy daily maintenance and replacement. Each filter is equipped with a differential pressure sensor to monitor changes in airflow resistance before and after the filter in real time. When the differential pressure sensor detects that the resistance of the primary filter 61 and / or the secondary filter 62 exceeds twice the initial value, the air conditioning unit 100 issues a replacement reminder, prompting maintenance personnel to clean or replace the corresponding filters in a timely manner to maintain a suitable airflow within the duct 103 and prevent airflow reduction or increased energy consumption due to filter blockage. Through the graded configuration and status monitoring of the two-stage filters 60, the air conditioning unit 100 can ensure the cleanliness of the supplied air while making the operation and maintenance of the filter section 1032 more convenient and controllable. This helps extend the service life of the two-stage heat exchangers 20 and maintain the stable operating performance of the entire unit under medium-temperature and large-temperature-difference conditions.

[0044] like Figure 1 and Figure 4 As shown, in one embodiment, the return air section 1031 and the filter section 1032, the filter section 1032 and the heat exchange section 1033, the heat exchange section 1033 and the air supply section 1034, and the air supply section 1034 and the control section 1035 are respectively connected by flanges, and the mating surfaces are provided with anti-collision elastic sealing strips.

[0045] In this embodiment, adjacent connection points between the return air section 1031 and the filter section 1032, between the filter section 1032 and the heat exchange section 1033, between the heat exchange section 1033 and the air supply section 1034, and between the air supply section 1034 and the control section 1035 are all fastened together by flanges. The flange connection method facilitates the on-site assembly and subsequent disassembly and maintenance of the return air section 1031, the filter section 1032, the heat exchange section 1033, the air supply section 1034, and the control section 1035. At the flange-connected joints between the return air section 1031 and the filter section 1032, the filter section 1032 and the heat exchange section 1033, the heat exchange section 1033 and the supply air section 1034, and the supply air section 1034 and the control section 1035, anti-reverse elastic sealing strips are installed. Under the flange tightening force, these anti-reverse elastic sealing strips elastically deform and fill the microscopic gaps between the joints, reducing the risk of air leakage from the connections of the return air section 1031, filter section 1032, heat exchange section 1033, supply air section 1034, and control section 1035. These anti-reverse elastic sealing strips also have the ability to resist reverse airflow impact, and are not prone to rolling over or dislodging under the influence of internal air pressure fluctuations or reverse airflow generated during start-up and shutdown of the air conditioning unit 100, maintaining the stability of the joint seal. The combined use of flange connections and anti-rebound elastic sealing strips creates a continuous airtight barrier at the connection interfaces between the return air section 1031, filter section 1032, heat exchange section 1033, air supply section 1034, and control section 1035. This reduces the possibility of untreated air infiltration or treated air leakage, helps maintain the pressure balance and orderly airflow organization of the internal air duct 103 of the air conditioning unit 100, and reduces energy loss and operating noise caused by air leakage.

[0046] Furthermore, when the air conditioning unit 100 operates under medium-temperature water supply conditions, the water supply temperature of 14–18℃ is close to or slightly higher than the indoor air dew point temperature, which easily leads to condensation on the inner wall surface and heat exchanger surface of the existing air conditioning unit 100. However, the existing air conditioning unit 100 lacks an effective active anti-condensation structure design to deal with this type of condensation problem, making it difficult to eliminate condensate in a timely manner, thereby affecting the normal operation and reliability of the air conditioning unit 100.

[0047] To improve this problem, such as Figure 1 and Figure 5 As shown, in one embodiment, the housing 10 also has four connecting walls 13 that connect the first side wall 11 and the second side wall 12. The four connecting walls 13 are connected to each other to form an air duct 103. The connecting walls 13, the first side wall 11 and the second side wall 12 each have an outer wall panel 111, an inner wall panel 112 and a heat insulation layer 113 disposed between the outer wall panel 111 and the inner wall panel 112. And / or, a thermal break gap 1101 is provided between the outer wall panel 111 and the inner wall panel 112.

[0048] In this embodiment, the connecting wall 13, the first side wall 11, and the second side wall 12 all adopt a composite panel structure. This composite panel structure includes an outer wall panel 111 with a wall thickness of 1.2 mm, an inner wall panel 112 with a wall thickness of 0.8 mm, and an insulation layer 113 composed of a 25 mm thick rubber and plastic insulation material. The outer wall panel 111 with a wall thickness of 1.2 mm was selected instead of a thinner specification because the outer wall panel 111, as the outermost layer of the shell 10, needs to withstand the mechanical impact during transportation and installation as well as the external load during long-term operation. If the wall thickness is less than 1.2 mm, it is easy to deform and cause sealing failure, while exceeding 1.2 mm will significantly increase the weight of the whole machine without significantly improving the thermal insulation performance. The inner wall panel 112 is selected with a wall thickness of 0.8 mm because the inner wall panel 112 is in direct contact with the airflow in the air duct 103. If it is too thick, it will increase the heat capacity and cause the temperature response to lag. If it is too thin, it will be difficult to resist the resonance noise caused by the vibration of the fan 40. 0.8 mm is just right to achieve a balance between suppressing vibration and maintaining thermal inertia. The insulation layer 113 uses 25mm thick rubber-plastic insulation material, calculated based on the typical heat transfer coefficient between the inner surface of the shell 10 and the external environment under medium-temperature and large-temperature-difference conditions. When the thickness is less than 25mm, the temperature of the outer surface of the shell 10 easily drops below the dew point in a high-humidity environment, causing condensation. When the thickness is greater than 25mm, the marginal insulation effect decreases and the effective flow area of ​​the air duct 103 is squeezed, affecting the air volume and heat exchange efficiency. The thermal break gap 1101 between the outer wall panel 111 and the inner wall panel 112 has a width of 10mm and a depth of 5mm, where the width can be selected within the range of 5–15mm and the depth can be selected within the range of 3–8mm. This size combination is not arbitrarily set: if the width of the thermal break gap 1101 is less than 5mm, the processing tolerance may cause the outer wall panel 111 and the inner wall panel 112 to make local contact and form residual thermal bridges; if the width is greater than 15mm, it will weaken the overall bending stiffness of the panel and cause the shell 10 to undergo slight deformation during negative pressure operation; if the depth is less than 3mm, heat flow can still be conducted through the metal substrate at the bottom of the gap; if the depth is greater than 8mm, it will compress the effective filling space of the insulation layer 113, thus reducing the overall heat insulation effect. The combination of 10mm width and 5mm depth ensures that the thermal bridge path is fully interrupted, while maintaining the structural integrity of the composite panel and the continuous coverage of the insulation layer 113, so that the shell 10 can meet the anti-condensation requirements while taking into account lightweight and manufacturing feasibility. The above parameter combination is an optimized solution determined for the specific needs of the air conditioning cabinet 100 to operate stably for a long time in a medium-temperature, large-temperature-difference, and high-humidity environment. Conventional general designs often only focus on a single thermal insulation index or structural strength, without comprehensively considering multiple constraints such as vibration suppression, thermal response speed, processing tolerance and space occupation of the air duct 103. Therefore, it is difficult to directly derive the specific numerical configuration in this embodiment.

[0049] like Figure 1 and Figure 6As shown, in one embodiment, the inner wall of the housing 10 is provided with a guide channel 104 for collecting condensate water. Below the guide channel 104, there is a water collection tray 12 connected to the guide channel 104. The water collection tray 12 is connected to a drain pipe 13 extending to the outside of the housing 10. The drain pipe 13 is used to discharge the condensate water collected by the water collection tray 12 to the outside of the housing 10.

[0050] In this embodiment, when condensation occurs on the inner wall surface of the housing 10 due to temperature difference during the operation of the air conditioning unit 100, the condensation adhering to the inner wall surface flows downward along the inner wall under gravity and flows into the guide channel 104. The guide channel 104 collects and guides the dispersed condensation, preventing it from flowing disorderly on the inner wall surface or dripping onto other components inside the air duct 103. The water collection tray 12 connected below the guide channel 104 receives the condensation collected by the guide channel 104, temporarily storing the condensation in the water collection tray 12 to prevent direct splashing or leakage. The drain pipe 13 connected to the water collection tray 12 continuously discharges the temporarily stored condensation in the water collection tray 12 to the outside of the housing 10, maintaining the liquid level in the water collection tray 12 within a reasonable range and preventing condensation from overflowing or remaining for a long time and breeding microorganisms. The guide channel 104, the water collection tray 12, and the drain pipe 13 are connected in sequence to form a complete condensate discharge path, so that the condensate generated on the inner wall of the shell 10 can be collected in an orderly manner and discharged in a timely manner, reducing the risk of condensate corrosion to the internal electrical components and heat exchange parts of the air conditioning cabinet 100, and reducing the possibility of odor or mold growth caused by water accumulation, which is conducive to maintaining the cleanliness and operational reliability of the internal environment of the air conditioning cabinet 100.

[0051] like Figure 6 As shown, in one embodiment, the cross-sectional shape of the guide channel 104 is V-shaped; And / or, the width W of the guide channel 104 is not less than 6 mm and not more than 10 mm; And / or, the groove depth D of the guide groove 104 is not less than 4 mm and not more than 6 mm; And / or, the flow channel 104 is formed at the bottom of the housing 10.

[0052] In this embodiment, the guide channel 104 adopts a V-shaped cross-section. This V-shaped cross-section utilizes the structural characteristic of the two inclined surfaces converging towards the center, allowing the condensed water falling into the guide channel 104 to naturally flow towards the bottom of the channel under gravity, reducing the residue and adhesion of condensed water on the sidewalls of the guide channel 104. The width W of the guide channel 104 is limited to a range of not less than 6 mm and not more than 10 mm. When the width W is less than 6 mm, the guide channel 104 is prone to blockage due to processing deviations or long-term dust accumulation, affecting the smooth flow of condensed water. When the width W is greater than 10 mm, the condensed water spreads too widely within the guide channel 104, reducing the flow rate and hindering the rapid collection and discharge of condensed water. The depth D of the guide channel 104 is limited to a range of not less than 4 mm and not more than 6 mm. If the depth D is less than 4 mm, the water-holding capacity of the guide channel 104 is insufficient, and overflow is likely to occur when the condensate volume is large. If the depth D is greater than 6 mm, it will excessively encroach on the structural space at the bottom of the shell 10 and increase the difficulty of cleaning and maintenance. The guide channel 104 is located at the bottom of the shell 10 because the bottom of the shell 10 is the natural collection area of ​​condensate under gravity. Setting the guide channel 104 at this location can follow the downward trend of condensate, efficiently collect the condensate flowing down the inner wall of the shell 10, and prevent condensate from accumulating in other parts of the shell 10 or dripping onto internal functional components. The coordinated combination of the V-shaped cross-section, the range of the channel width W, the range of the channel depth D, and the bottom installation position gives the guide channel 104 suitable guiding capacity and anti-clogging performance within a limited space, which is beneficial to improving the reliability of condensate collection and discharge efficiency.

[0053] The present invention also proposes a control method for an air conditioning cabinet 100. The specific structure of the air conditioning cabinet 100 is as described in the above embodiments. Since the control method of the air conditioning cabinet 100 adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0054] Based on the above hardware structure, such as Figure 7 As shown, the control method of the air conditioning cabinet 100 includes: S100: Obtain the return air temperature, return air humidity, inlet water temperature, outlet water temperature and supply air temperature of the air conditioning unit; S200: Calculate the real-time dew point temperature based on the return air temperature and return air humidity; S300: Adjust the valve opening according to the inlet and outlet water temperatures to regulate the water flow through the two-stage heat exchanger so that the actual supply and return water temperature difference between the inlet and outlet water temperatures approaches the target temperature difference; or, adjust the fan speed so that the supply air temperature is higher than the real-time dew point temperature.

[0055] In this embodiment, a return air temperature and humidity sensor can be installed at the return air inlet 101. During the operation of the air conditioning cabinet 100, the return air temperature and humidity entering the air conditioning cabinet 100 can be detected by the return air temperature and humidity sensor. The obtained return air temperature and humidity are used as direct input parameters for calculating the real-time dew point temperature, which are used to characterize the current thermal and humidity state of the return air and determine the lower limit threshold for preventing condensation in the supply air. The air conditioning unit 100 also includes an inlet main pipe 71 and an outlet main pipe 72. The inlet main pipe 71 is connected to the water inlet, and the outlet main pipe 72 is connected to the water outlet. An inlet water temperature sensor is installed on the inlet main pipe 71 to detect the inlet water temperature flowing into the two-stage heat exchanger 20. An outlet water temperature sensor is installed on the outlet main pipe 72 to detect the outlet water temperature flowing out of the two-stage heat exchanger 20. The difference between the inlet water temperature and the outlet water temperature reflects the amount of heat exchange in the two-stage heat exchanger 20 during actual operation and the degree of water-side load matching. It is the core basis for judging whether the actual supply and return water temperature difference deviates from the target temperature difference. A water flow sensor can be installed on the connecting pipe between the two heat exchangers 20 in the air duct 103. The water flow sensor detects the water flow rate through the two heat exchangers 20. This water flow data can intuitively show the actual response state of the water flow rate through the two heat exchangers 20 after the valve 30 opening is adjusted, and help verify whether the control effect of the valve 30 opening change on the water flow rate meets expectations. The above sensor placement and detection method are only illustrative and are not a limitation on the sensor installation form or number. The return air temperature and humidity sensor, inlet water temperature sensor, outlet water temperature sensor, and water flow sensor collect parameters such as return air temperature, return air humidity, inlet water temperature, outlet water temperature, and water flow rate, which together constitute the data source for state perception and feedback regulation in the control method of air conditioning cabinet 100.

[0056] The controller 50 of the air conditioning unit 100 can calculate the real-time dew point temperature based on the return air temperature and humidity. This parameter represents the critical point for condensation under the current air conditions. The controller 50 uses the inlet water temperature and outlet water temperature as the core control basis. Based on the actual changes of these two temperatures, it selectively performs operations to adjust the opening of the valve 30 or the speed of the fan 40. When the actual supply and return water temperature difference between the inlet and outlet water temperatures deviates from the target temperature difference, the controller 50 prioritizes adjusting the opening of the valve 30 to change the water flow rate through the two-stage heat exchanger 20, so that the actual supply and return water temperature difference approaches the target temperature difference. This reduces the energy consumption generated by the large flow rate of water transport while meeting the heat exchange requirements. At the same time, in conjunction with the counter-current arrangement of the two-stage heat exchanger 20, it improves the problem of decreased heat exchange efficiency in the latter half of the heat exchanger under large temperature difference conditions. When changes in the inlet and outlet water temperatures indicate a risk that the supply air temperature may fall below the real-time dew point, the controller 50 adjusts the fan 40 speed to change the air volume, maintaining the supply air temperature within a safe range above the real-time dew point, thus preventing condensation inside the duct 103 or at the air outlet 102. Because water flow and air volume are strongly coupled under large temperature difference conditions, traditional independent control loops struggle to maintain stable operation. In this embodiment, the controller 50 selectively and collaboratively adjusts the valve 30 opening and fan 40 speed based on the inlet and outlet water temperatures, resulting in a more coordinated match between water and air volume. This effectively reduces the problem of fluctuations in one parameter caused by adjusting a single parameter, facilitating stable operation under large temperature differences and improving the overall performance of the air conditioning unit 100 under medium-temperature, large-temperature-difference conditions.

[0057] In one embodiment, step S200 is specifically calculated using the following formula: ; ; in, For real-time dew point temperature, Return air temperature, Let represent the return air humidity, a be a dimensionless constant, and b be the temperature fitting constant.

[0058] In this embodiment, the dimensionless constant 'a' is set to 17.27, and the temperature fitting constant 'b' is set to 237.7℃. These values ​​are empirical fitting results based on the nonlinear relationship between water vapor saturation pressure and temperature, used to accurately calculate the real-time dew point temperature by substituting the return air temperature and return air humidity into the aforementioned formula. The dimensionless constant 'a' participates in the calculation as a proportionality coefficient, affecting the sensitivity of the real-time dew point temperature to changes in return air humidity. The temperature fitting constant 'b' participates in the calculation of the denominator in degrees Celsius, correcting the deviation between the return air temperature and the water vapor saturation characteristics over a wide temperature range, making the calculated real-time dew point temperature closer to the actual air thermodynamic state. When the return air temperature and humidity collected by the return air temperature and humidity sensor are input to the controller 50, the controller 50 performs calculations according to the aforementioned formula, which includes the dimensionless constant a equal to 17.27 and the temperature fitting constant b equal to 237.7℃, and outputs the corresponding real-time dew point temperature value. This real-time dew point temperature value is then used to determine whether the supply air temperature needs to be adjusted to prevent condensation, thereby providing a quantitative reference for subsequent control decisions to adjust the speed of the fan 40 or the opening of the valve 30.

[0059] like Figure 8 As shown, in one embodiment, step S300 specifically includes: S310. Calculate the actual supply and return water temperature difference based on the inlet water temperature and the outlet water temperature, and obtain the deviation between the actual supply and return water temperature difference and the target temperature difference. S320. When the absolute value of the deviation is greater than the preset threshold, obtain the water flow rate change rate and the air volume change rate. S330. When it is determined that the rate of change of water flow is greater than the rate of change of air volume, adjust the valve opening to make the actual temperature difference approach the target temperature difference. S340. When the rate of change of water flow is determined to be no greater than the rate of change of air volume, adjust the speed of the fan until the air supply temperature is close to the real-time dew point temperature, then limit the upper limit of the fan speed so that the air supply temperature is higher than the sum of the real-time dew point temperature and the upper limit of the preset temperature range.

[0060] In this embodiment, the controller 50 performs periodic closed-loop control of the operating status of the air conditioning unit 100. The specific execution process includes multiple stages such as data acquisition, deviation calculation, dominant factor identification, water or air volume adjustment, and safety protection. The controller 50 first collects the inlet water temperature T_in, return water temperature T_out, and water flow rate G_w, and calculates the actual supply and return water temperature difference ΔT based on the inlet water temperature T_in and return water temperature T_out. This actual supply and return water temperature difference ΔT is equal to the return water temperature T_out minus the inlet water temperature T_in. Subsequently, the controller 50 compares the actual supply and return water temperature difference ΔT with the target temperature difference ΔT_set, and calculates the temperature difference deviation e. This temperature difference deviation e is equal to the target temperature difference ΔT_set minus the actual supply and return water temperature difference ΔT, used to quantify the degree of deviation between the current heat exchange state and the ideal state. When determining the source of deviation, if the absolute value of the temperature difference deviation e is greater than the preset threshold of 1℃, and the rate of change of water flow is greater than the rate of change of air flow, it is determined that the water-side deviation is dominant, and the water flow is adjusted first; otherwise, it is determined that the air-side deviation is dominant, and the air flow is adjusted first. For the case where the water-side deviation is dominant, the water-side control loop inside the controller 50 outputs a control signal to the valve 30 through a PID control algorithm. By changing the opening of the valve 30, the water flow through the two-stage heat exchanger 20 is adjusted, so that the actual supply and return water temperature difference approaches the target temperature difference, achieving precise matching of the water-side heat exchange capacity. For the case where the air-side deviation is dominant, the air-side control loop inside the controller 50 outputs a control signal to the frequency converter through a PID control algorithm. The frequency converter adjusts the speed of the fan 40 to change the airflow through the duct 103, so that the air-side heat exchange conditions adapt to load changes. During this process, the controller 50 uses the real-time dew point temperature Td as a feedforward compensation parameter in the airflow regulation stage. When the supply air temperature T_supply approaches the real-time dew point temperature Td, the upper limit of the fan speed 40 is limited to maintain the supply air temperature T_supply at a level not lower than the real-time dew point temperature Td plus 1.5℃. This 1.5℃ falls within the preset temperature range of 1.0–2.0℃, thereby preventing the supply air temperature from being too low and causing condensation in the air duct 103 or at the air outlet 102. After completing any of the above regulation operations, the controller 50 records the current operating data and updates the load prediction model. After a 30-second delay, it returns to the steps of collecting the inlet water temperature T_in, return water temperature T_out, and water flow rate G_w, forming a continuous closed-loop control cycle. This delay setting can both prevent system oscillation caused by excessively frequent adjustment actions and reserve sufficient response time for the heat exchange process, enabling the air conditioning cabinet 100 to maintain a relatively stable operating state under medium temperature and large temperature difference conditions, and to maximize heat exchange efficiency and energy utilization while meeting the anti-condensation safety requirements.

[0061] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An air conditioning cabinet, characterized in that, include: The housing has a return air inlet, an air supply inlet, and an air duct connecting the return air inlet and the air supply inlet. The housing has a first sidewall and a second sidewall opposite to each other along a first direction. The first sidewall is provided with the return air inlet, and the second sidewall is provided with the air supply inlet. A two-stage heat exchanger is arranged in the air duct along the first direction. The two-stage heat exchanger has an inlet, an outlet, and a heat exchange channel connecting the inlet and the outlet. The water inlet is located near the second side wall, and the water outlet is located near the first side wall, so that the flow direction of the coolant in the heat exchange channel is opposite to the direction of the air in the air duct flowing from the return air inlet to the supply air inlet.

2. The air conditioning cabinet as described in claim 1, characterized in that, The two-stage heat exchanger includes a first-stage heat exchanger and a second-stage heat exchanger arranged sequentially along the first direction. The second-stage heat exchanger is located close to the first sidewall and has the water inlet. The first-stage heat exchanger is located close to the second sidewall and has the water outlet. The heat exchange area of ​​the first-stage heat exchanger is smaller than that of the second-stage heat exchanger.

3. The air conditioning cabinet as described in claim 2, characterized in that, The first stage heat exchanger has a first heat exchange tube and a plurality of first fins arranged on the first heat exchange tube; The second-stage heat exchanger has a second heat exchange tube and a plurality of second fins arranged on the second heat exchange tube; And / or, the first fin is a windowed fin; And / or, the second fin is a corrugated aluminum fin; And / or, the spacing between two adjacent first fins is greater than the spacing between two adjacent second fins; And / or, the wall thickness of the second heat exchange tube is greater than the wall thickness of the first heat exchange tube; And / or, both the first heat exchange tube and the heat exchange tube are made of internally threaded copper tubes.

4. The air conditioning cabinet as described in claim 1, characterized in that, The air conditioning unit also includes: A valve, located in the heat exchange channel, is used to regulate the water flow rate through the heat exchange channel; A fan, installed inside the air duct, is used to regulate the air volume supplied by the air duct; The controller is electrically connected to the valve and the fan, respectively, and is used to acquire the return air temperature, return air humidity, inlet water temperature, outlet water temperature and supply air temperature of the air conditioning unit, calculate the real-time dew point temperature based on the return air temperature and return air humidity, and adjust the opening of the valve to regulate the water flow through the two-stage heat exchanger based on the inlet water temperature and the outlet water temperature, so that the actual supply and return water temperature difference between the inlet water temperature and the outlet water temperature approaches the target temperature difference, or adjust the speed of the fan to make the supply air temperature higher than the real-time dew point temperature.

5. The air conditioning cabinet as described in claim 4, characterized in that, The controller is specifically used for: The actual supply and return water temperature difference is calculated based on the inlet water temperature and the outlet water temperature, and the deviation between the actual supply and return water temperature difference and the target temperature difference is obtained. If the absolute value of the deviation is greater than a preset threshold, the water flow rate change rate and air volume change rate are obtained. If the rate of change of water flow is determined to be greater than the rate of change of air volume, the opening of the valve is adjusted so that the actual temperature difference approaches the target temperature difference. If the rate of change of water flow is determined to be no greater than the rate of change of air volume, the speed of the fan is adjusted until the air supply temperature is close to the real-time dew point temperature. Then, the upper limit of the fan speed is limited so that the air supply temperature is higher than the sum of the real-time dew point temperature and the upper limit of the preset temperature range.

6. The air conditioning cabinet as described in claim 4, characterized in that, The air duct includes a return air section, a filter section, a heat exchange section, an air supply section, and a control section arranged sequentially along a first direction. The return air section is connected to the return air inlet. The filter section is equipped with a two-stage filter. The heat exchange section is equipped with the two-stage heat exchangers. The air supply section is equipped with the fan and connected to the air supply inlet. The control section is equipped with the controller.

7. The air conditioning cabinet as described in any one of claims 1 to 6, characterized in that, The housing also has four connecting walls that connect the first side wall and the second side wall. The four connecting walls are connected to each other to form the air duct. Each connecting wall, the first side wall and the second side wall has an outer wall panel, an inner wall panel and a heat insulation layer disposed between the outer wall panel and the inner wall panel. And / or, a broken bridge gap is provided between the outer wall panel and the inner wall panel.

8. The air conditioning cabinet as described in any one of claims 1 to 6, characterized in that, The inner wall of the housing is provided with a guide channel for collecting condensate. Below the guide channel is a water collection tray connected to the guide channel. The water collection tray is connected to a drain pipe extending to the outside of the housing. The drain pipe is used to discharge the condensate collected by the water collection tray to the outside of the housing.

9. The air conditioning cabinet as described in claim 8, characterized in that, The cross-sectional shape of the flow guide channel is V-shaped; And / or, the width of the guide channel is not less than 6 mm and not more than 10 mm; And / or, the depth of the guide channel is not less than 4 mm and not more than 6 mm; And / or, the flow channel is formed at the bottom of the housing.

10. A control method for an air conditioning cabinet, characterized in that, The control method for the air conditioning cabinet, as described in any one of claims 1 to 9, comprises: Obtain the return air temperature, return air humidity, inlet water temperature, outlet water temperature and supply air temperature of the air conditioning unit; Calculate the real-time dew point temperature based on the return air temperature and humidity. Based on the inlet and outlet water temperatures, adjust the valve opening to regulate the water flow through the two-stage heat exchanger, so that the actual supply and return water temperature difference between the inlet and outlet water temperatures approaches the target temperature difference; or, adjust the fan speed to make the supply air temperature higher than the real-time dew point temperature.

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