Cross flow closed cooling tower with radial finned tube heat exchanger

Abstract

The application relates to a cross-flow closed cooling tower which comprises a shell, a fan, a wet membrane, a first water distributor, a second water distributor, an evaporative cooling heat exchanger, a water collecting tray, a water storage tank, a water pump and a primary cooling unit. The fan is located at the top of the shell, the wet membrane is located right behind the air inlet of the shell, the evaporative cooling heat exchanger is located right behind the wet membrane, the first water distributor is located above the wet membrane to distribute circulating water to the wet membrane, the second water distributor is located above the evaporative cooling heat exchanger to distribute circulating water to the evaporative cooling heat exchanger, the water collecting tray collects the circulating water flowing from the wet membrane and the evaporative cooling heat exchanger and delivers the circulating water to the water storage tank. The closed cooling tower adopts the wet membrane plus plate exchange for primary cooling and the wet membrane plus cross-flow radial finned tube evaporative cooling heat exchanger for secondary cooling. The mode can greatly increase the evaporative heat transfer contact area, so that the cooled fluid and the wet bulb temperature can be more closely approximated, and the dew point temperature can be more closely approximated in the case of pre-cooling.

Description

Technical Field

[0001] This invention relates to the field of evaporative cooling and heat transfer technology, specifically to a crossflow closed-loop cooling tower employing a radial finned tube heat exchanger. Background Technology

[0002] Closed-circuit cooling towers offer numerous advantages, including cleanliness, water conservation, energy efficiency, and the ability to directly supply cooling to the end-point. However, they also suffer from drawbacks such as high cost, large size, and bulkiness. These disadvantages stem from the low evaporation and heat exchange efficiencies of the shell-and-tube heat exchangers used in conventional closed-circuit cooling towers. The low efficiency is due to the typically insufficient surface area of ​​shell-and-tube heat exchangers. Even with the addition of fins to the heat exchange tubes, the water distribution on the fins is difficult to achieve uniformity, and only a small amount of air contacts the fins, often resulting in low evaporation and heat exchange efficiencies. Using a wet film combined with plate heat exchange can significantly improve evaporative cooling and increase cooling capacity; however, reducing the temperature difference between the cooled fluid and the circulating cooling water to within 2°C drastically increases investment. While radial finned tubes offer good heat transfer, increasing cooling capacity also significantly increases investment. This invention provides a cross-flow radial finned tube evaporative cooling heat exchanger for secondary cooling of fluids initially cooled by a wet film combined with plate heat exchange, thereby achieving a lower temperature approximation between the cooled fluid and the wet-bulb temperature in a low-cost manner. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, this invention provides a closed-loop cooling tower that uses a wet film heat exchanger for primary cooling and a wet film combined with a cross-flow radial finned tube evaporative cooling heat exchanger for secondary cooling. This method significantly increases the evaporative heat transfer contact area, not only enhancing the evaporative cooling process but also allowing the cross-flow flow to lower the temperature of the downstream spray circulating water to the required level. The two cooling circulating water sections enter different water tanks: the high-temperature cooling circulation section performs primary cooling, and the low-temperature cooling circulation section performs secondary cooling. This achieves a closer approximation between the cooled fluid and the wet-bulb temperature, and with pre-cooling, it can even approach the dew point temperature. The radial finned tubes of the evaporative cooling heat exchanger are arranged in series from top to bottom, with spray water flowing in from the top and air entering cross-flow from the finned tube extension direction.

[0004] The technical solutions of the embodiments of the present invention are as follows:

[0005] A crossflow closed-loop cooling tower includes a shell and a fan, a wet film, a first water distributor, a second water distributor, an evaporative cooling heat exchanger, a water collection tray, a water storage tank, a water pump, and a primary cooling unit disposed within the shell. The fan is located at the top of the shell, the wet film is located directly behind the air inlet of the shell, and the evaporative cooling heat exchanger is located directly behind the wet film. The first water distributor is located above the wet film and distributes circulating water to the wet film. The second water distributor is located above the evaporative cooling heat exchanger and distributes circulating water to the evaporative cooling heat exchanger. The water collection tray is located below the wet film and the evaporative cooling heat exchanger, and the water storage tank is located below the water collection tray. The water collection tray collects the circulating water flowing from the wet film and the evaporative cooling heat exchanger and transports it to the water storage tank. The water pump draws circulating water from the water storage tank and distributes it in two directions to the first water distributor and the second water distributor.

[0006] The primary cooling unit includes a plate heat exchanger, a second wet film, a third water distributor, a second water collection tray, a second water storage tank, and a second water pump. The second wet film is located directly behind the evaporative cooling heat exchanger. The third water distributor is located above the second wet film and distributes water onto it. The second water collection tray is located below the second wet film, and the second water storage tank is located below the second water collection tray. The second water collection tray collects the circulating water flowing from the second wet film and transports it to the second water storage tank. The second water pump draws circulating water from the second water storage tank and transports it to the cold aisle of the plate heat exchanger. The hot aisle input end of the heat exchanger is connected to an external cooling water network, and the hot aisle output end of the heat exchanger is connected to the input end of the evaporative cooling heat exchanger. The circulating water is transported to the third water distributor after heat exchange in the cold aisle of the plate heat exchanger.

[0007] Preferably, the crossflow closed cooling tower further includes a precooling surface cooler, which is located at the air inlet of the shell and directly in front of the wet film. The water pump draws circulating water from the water storage tank and delivers it to the precooling surface cooler. After the circulating water is output from the precooling surface cooler, it is divided into two paths and delivered to the first water distributor and the second water distributor.

[0008] Preferably, the crossflow closed cooling tower further includes a first filtration and sewage discharge device, the two ends of which are respectively connected to the water collection tray and the water storage tank.

[0009] Preferably, the crossflow closed cooling tower further includes a third water collection tray, which is located directly below the wet film and collects the circulating water flowing from the wet film. The water collection tray is located directly below the evaporative cooling heat exchanger and collects the circulating water flowing from the evaporative cooling heat exchanger. The water collection tray is connected to the water storage tank through a water pipe. The first filter and sewage discharge device is connected to the third water collection tray and the water storage tank at both ends.

[0010] Preferably, the evaporative cooling heat exchanger includes multiple heat pipe groups, a liquid inlet pipe, multiple manifolds, a liquid outlet pipe, and fin groups. One end of the heat pipe group located at the top of the multiple heat pipe groups is connected to the liquid inlet pipe, and the other end is connected to the manifold. One end of the heat pipe group located in the middle of the multiple heat pipe groups is connected to one manifold, and the other end is connected to another manifold. One end of the heat pipe group located at the bottom of the multiple heat pipe groups is connected to the manifold, and the other end is connected to the liquid outlet pipe. The fin groups are intersected and embedded perpendicularly with the multiple heat pipe groups.

[0011] The heat pipe assembly includes N flow-guiding heat exchange tubes. One end of the liquid inlet pipe is provided with a main water inlet, and the other end is provided with N water outlets. The confluence flow-guiding pipe is provided with N water inlets and N water outlets on the same end. One end of the liquid outlet pipe is provided with N water inlets, and the other end is provided with a main water outlet. One end of the flow-guiding heat exchange tube is connected to the water outlet, and the other end of the flow-guiding heat exchange tube is connected to the water inlet.

[0012] The beneficial effects of this invention are as follows: The closed-loop cooling tower fully utilizes natural cold sources, forming two cold water sources at high and low temperatures. The high-temperature cold water source serves as the primary cooling source for the external coolant. In this invention, the high-temperature cold water source performs primary cooling of the external coolant in the plate heat exchanger. The external coolant after primary cooling is then sent to the evaporative cooling heat exchanger, where the low-temperature cold water source pre-cools the external ambient air and sprays it onto the evaporative cooling heat exchanger via a water distributor, thus evaporating and exchanging heat with the cooling liquid in the evaporative cooling heat exchanger. Furthermore, this closed-loop cooling tower uses the aforementioned evaporative cooling heat exchanger with radial finned tubes, further improving the heat exchange efficiency.

[0013] In an evaporative cooling heat exchanger, coolant is input from the main inlet of the inlet pipe and output from N outlets to N guide heat exchange tubes. Equal amounts of coolant flow in the same direction and at the same speed in the N guide heat exchange tubes converge into a manifold. After heat exchange and cooling, the coolant flows from the N outlets of the manifold into another N guide heat exchange tubes for further heat exchange and cooling. After multiple flows and heat exchange, the cooled liquid is delivered to an external pipe from the main outlet of the outlet pipe. The N guide heat exchange tubes form a heat pipe group, achieving the same flow rate and a larger heat exchange area, thereby improving the heat exchange efficiency of the heat exchange tube group. Multiple heat pipe groups are connected through multiple manifolds, allowing the coolant to undergo multiple heat exchange and cooling processes before being output to the N guide tubes after converging in the manifold. This also ensures that the temperature difference of the coolant in the N guide heat exchange tubes is very small. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of an evaporative cooling heat exchanger according to the present invention. Figure 1 ;

[0015] Figure 2 This is a schematic diagram of the structure of an evaporative cooling heat exchanger according to the present invention. Figure 2 ;

[0016] Figure 3 This is a schematic diagram of the structure of an evaporative cooling heat exchanger according to the present invention. Figure 3 ;

[0017] Figure 4 This is a schematic diagram of the liquid inlet pipe in an evaporative cooling heat exchanger according to the present invention;

[0018] Figure 5 This is a schematic diagram of the liquid outlet pipe in an evaporative cooling heat exchanger according to the present invention;

[0019] Figure 6 This is a schematic diagram of the structure of a manifold in an evaporative cooling heat exchanger according to the present invention;

[0020] Figure 7 This is a schematic diagram of the structure of a crossflow closed-loop cooling tower according to the present invention. Figure 1 ;

[0021] Figure 8 This is a schematic diagram of the structure of a crossflow closed-loop cooling tower according to the present invention. Figure 2 ;

[0022] 10. Heat pipe assembly; 11. Flow guide heat exchanger tube; 20. Liquid inlet pipe; 21. Main water inlet; 22. Water outlet; 23. Water inlet; 24. Main water outlet; 25. Combination flow guide pipe; 26. Liquid outlet pipe; 40. Shell; 41. Fan; 421. Plate heat exchanger; 422. Second water pump; 423. Second water storage tank; 425. Second water collection tray; 426. Third water distributor; 427. Second wet film; 428. Water collection tray; 431. Water pump; 432. Water storage tank; 433. First filter and sewage discharge device; 434. Third water collection tray; 435. Wet film; 436. First water distributor; 437. Second water distributor; 438. Evaporative cooling heat exchanger; 439. Pre-cooling surface cooler. Detailed Implementation

[0023] 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.

[0024] 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.

[0025] 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.

[0026] To further cool the coolant, the crossflow closed cooling tower preferably includes a primary cooling unit. The input end of the primary cooling unit is connected to the external cooling water network, and the output end of the primary cooling unit is connected to the input end of the evaporative cooling heat exchanger. The output end of the evaporative cooling heat exchanger is connected to the external cooling water network.

[0027] like Figure 7 As shown, Figure 7 This is a schematic diagram of the structure of a crossflow closed-loop cooling tower according to the present invention. Figure 1It includes a housing 40 and, within the housing, a fan 41, a wet film 435, a first water distributor 436, a second water distributor 437, an evaporative cooling heat exchanger 438, a water collection tray 428, a water storage tank 432, a water pump 431, and a primary cooling unit. The fan is located at the top of the housing, the wet film is located directly behind the air inlet of the housing, the evaporative cooling heat exchanger is located directly behind the wet film, the first water distributor is located above the wet film and distributes circulating water to the wet film, and the second water distributor is located above the evaporative cooling heat exchanger. Above the heat exchanger, circulating water is distributed to the evaporative cooling heat exchanger. A water collection tray is located below the wet film and the evaporative cooling heat exchanger, and a water storage tank is located below the water collection tray. The water collection tray collects the circulating water flowing from the wet film and the evaporative cooling heat exchanger and transports it to the water storage tank. A water pump draws circulating water from the water storage tank and distributes it in two directions to the first water distributor and the second water distributor. The first water distributor distributes circulating water to the wet film, and the second water distributor distributes circulating water to the evaporative cooling heat exchanger. This cycle continues. The input end of the primary cooling unit is connected to the external cooling water network, and the output end of the primary cooling unit is connected to the input end of the evaporative cooling heat exchanger. The output end of the evaporative cooling heat exchanger is also connected to the external cooling water network. Specifically, the primary cooling unit includes a plate heat exchanger 421, a second wet film 427, a third water distributor 426, a second water collection tray 425, a second water storage tank 423, and a second water pump 422. The second wet film is located directly behind the evaporative cooling heat exchanger 438. The third water distributor is located above the second wet film to distribute water onto it. The second water collection tray is located below the second wet film, and the second water storage tank is located below the second water collection tray. The second water collection tray collects the circulating water flowing from the second wet film and transports it to the second water storage tank. The second water pump draws circulating water from the second water storage tank and transports it to the cold aisle of the plate heat exchanger. The hot aisle input end of the heat exchanger is connected to the external cooling water network, and the hot aisle output end of the heat exchanger is connected to the input end of the evaporative cooling heat exchanger. After the circulating water exchanges heat in the cold aisle of the plate heat exchanger, it is transported to the third water distributor, which distributes the circulating water onto the second wet film. This cycle continues.

[0028] In this invention, in order to maintain the purity of the circulating water in the water tank and prevent external impurities from clogging the water pump, preferably, a first filtration and sewage discharge device is provided between the water collection tray and the water tank. Air carrying external impurities dissolves and settles into the first filtration and sewage discharge device after being purified by the circulating water in the wet membrane, and is then transported to the water tank.

[0029] To obtain spray water at a lower temperature, such as Figure 8 As shown, Figure 8 This is a schematic diagram of the structure of a crossflow closed-loop cooling tower according to the present invention. Figure 2In this invention, the crossflow closed cooling tower also includes a precooling surface cooler 439, which is located at the air inlet of the shell and directly in front of the wet film. A water pump draws circulating water from the water storage tank and delivers it to the precooling surface cooler. After the circulating water is output from the precooling surface cooler, it is divided into two paths and delivered to the first water distributor and the second water distributor. The first water distributor distributes the circulating water to the wet film, and the second water distributor distributes the circulating water to the evaporative cooling heat exchanger. The cycle continues in this manner.

[0030] In this invention, the evaporative cooling heat exchanger, as the core component of the closed-loop cooling tower, plays a decisive role in the cooling effect of the closed-loop cooling tower. The specific structure of the evaporative cooling heat exchanger is as follows: Figure 1 , Figure 2 , Figure 3 As shown, Figure 1 , Figure 2 , Figure 3 This is a schematic diagram of the structure of an evaporative cooling heat exchanger according to the present invention. Figure 1 , two The third type includes multiple heat pipe groups 10, liquid inlet pipes 20, multiple manifold guide pipes 25, liquid outlet pipes 26, and fin groups. The multiple heat pipe groups are arranged evenly from top to bottom. The number of heat pipe groups depends on the cooling temperature requirement of the coolant and the overall size of the evaporative cooling heat exchanger. For example, the lower the required temperature of the coolant, the more heat pipe groups are needed; conversely, the smaller the structural requirements of the evaporative cooling heat exchanger, the fewer heat pipe groups are needed. In this invention, the heat pipe group located at the top... One end of the heat pipe assembly is connected to the liquid inlet pipe and the other end is connected to the manifold. One end of the heat pipe assembly located at the bottom rear of the multiple heat pipe assemblies is connected to the manifold and the other end is connected to the liquid outlet pipe. One end of the heat pipe assembly located in the middle of the multiple heat pipe assemblies is connected to one manifold and the other end is connected to another manifold. Through this connection arrangement, the multiple heat pipe assemblies are connected through the manifold, which meets the length requirements of the heat pipe assembly. In this invention, the fin assembly is perpendicularly intersecting and embedded with the multiple heat pipe assemblies to achieve heat conduction and heat dissipation of the heat pipe assemblies.

[0031] To achieve higher heat exchange efficiency while maintaining the same flow rate, this invention improves heat exchange efficiency by increasing the heat exchange area, such as... Figure 2 As shown, specifically, the heat pipe assembly 10 includes N flow-guiding heat exchange pipes 11. The coolant flows within the heat pipe assembly, and the coolant is divided into N channels of equal flow rate, in the same direction, and with equal velocity, flowing and transporting within the N flow-guiding heat exchange pipes. The connection relationships between the N flow-guiding heat exchange pipes and the inlet pipe, the manifold pipe, and the outlet pipe are as follows: Figure 4 , Figure 5 , Figure 6 As shown, Figure 4 , Figure 5 , Figure 6 This is a schematic diagram of the structure of the inlet pipe, outlet pipe, and manifold of an evaporative cooling heat exchanger according to the present invention. The inlet pipe 20 has a main water inlet 21 on one end face and N water outlets 22 on the other end face. The manifold has N water inlets 23 and N water outlets 24 on the same end face. The outlet pipe has N water inlets on one end face and a main water outlet on the other end face. One end of the manifold heat exchanger is connected to the water outlet and the other end is connected to the water inlet. In this way, the inlets of the N heat exchange tubes in the top heat pipe group are connected to the N water outlets of the liquid inlet pipe, and the outlets of the N heat exchange tubes in the top heat pipe group are connected to the N water inlets of the manifold. The inlets of the N heat exchange tubes in the heat pipe group arranged in sequence are connected to the N water outlets of the manifold. They are connected in sequence according to this rule. The outlets of the N heat exchange tubes in the bottom heat pipe group are connected to the N water inlets of the liquid outlet pipe. Finally, the water is collected in the liquid outlet pipe and discharged through the main outlet of the liquid outlet pipe.

[0032] Coolant is input from the main inlet of the inlet pipe and output from N outlets into N heat exchange tubes. Equal amounts of coolant flow in the same direction and at the same speed in each of the N heat exchange tubes converge into a manifold. After heat exchange and cooling, the coolant flows from the N outlets of the manifold into another N heat exchange tubes for further heat exchange and cooling. After multiple flows and heat exchange, the cooled coolant is delivered to an external pipeline from the main outlet of the outlet pipe. The N heat exchange tubes form a heat pipe group, achieving the same flow rate and a larger heat exchange area, thereby improving the heat exchange efficiency of the heat exchange tube group. Multiple heat pipe groups are connected through multiple manifolds, allowing the coolant to undergo multiple heat exchange and cooling processes before being output to the N heat exchange tubes after converging in the manifold. This also ensures that the temperature difference of the coolant in the N heat exchange tubes is very small.

[0033] The closed-loop cooling tower of this invention utilizes an isenthalpic humidification process where external air and a second wet film successively undergo isenthalpic humidification. This creates two relatively low-temperature cold water sources in the first and second water tanks. The high-temperature cold water source provides primary cooling for the external coolant, while the low-temperature cold water source provides secondary cooling. In this invention, the high-temperature cold water source performs primary cooling of the external coolant in a plate heat exchanger. The cooled external coolant is then sent to an evaporative cooling heat exchanger where the low-temperature cold water source pre-cools the external ambient air and sprays it onto the evaporative cooling heat exchanger via a water distributor, thus evaporating and exchanging heat with the coolant in the evaporative cooling heat exchanger. Furthermore, this closed-loop cooling system uses the aforementioned evaporative cooling heat exchanger with longitudinal finned tubes, further improving heat exchange efficiency.

[0034] To further filter and purify the circulating water, the front-end wet membrane spray water and the rear-end evaporative cooling heat exchanger spray water can be collected and filtered separately. Preferably, such as... Figure 8As shown, the crossflow closed cooling tower also includes a third water collection tray 434, which is located directly below the wet film and collects the circulating water flowing from the wet film. The water collection tray is located directly below the evaporative cooling heat exchanger and collects the circulating water flowing from the evaporative cooling heat exchanger. The water collection tray is connected to the water storage tank through a water pipe. The first filter and sewage discharge device 433 is connected to the third water collection tray and the water storage tank at both ends.

[0035] Cooling water is first delivered to the primary cooling unit for primary plate heat exchange cooling, and then to the evaporative cooling heat exchanger for secondary indirect evaporative heat exchange cooling. A second water pump draws water from the second water tank and delivers it to the plate heat exchanger. After heat exchange with the cooling water, the water is output to the third water distributor. The third water distributor sprays the heat-exchanged water onto the second wet film. The sprayed water undergoes an isenthalpic humidification process in the second wet film, and after cooling, it collects in the second water collection tray and flows into the second water tank. The water pump then draws water from the water tank and delivers it to… In the first and second water distributors, the second water distributor sprays the heat-exchanged water onto the wet film. The sprayed water undergoes an isenthalpic humidification process in the wet film, and after cooling, it is collected in the water collection tray and then flows into the water storage tank. The third water distributor sprays the heat-exchanged water onto the evaporative cooling heat exchanger. The cooling water passes through the plate heat exchanger and the evaporative cooling heat exchanger for primary and secondary cooling respectively before being output. The fan draws in external air and passes through the first wet film, the evaporative cooling heat exchanger, and the second wet film in sequence, and then discharges it from the outlet of the closed cooling tower.

[0036] The following describes the operating conditions of a closed-circuit cooling tower with an external dry-bulb temperature of 35 degrees Celsius, a relative humidity of 56.7%, and an air intake volume of 50,000 m³ / h. External air (0) with a dry-bulb temperature of 35 degrees Celsius and a relative humidity of 56.7% is pre-cooled by a pre-cooling surface cooler with internally flowing cold water at 26.5 degrees Celsius. The external air (0) becomes external air (1) with a dry-bulb temperature of 30.2 degrees Celsius and a relative humidity of 74.4%. The heat exchange is 77.8 KW in one hour. The outlet water temperature of the pre-cooling surface cooler rises to 29.8 degrees Celsius. The external air (1) then undergoes an isenthalpic humidification process with the water at 28.35 degrees Celsius in the first wet film. The water at 28.35 degrees Celsius in the first wet film drops to 26.5 degrees Celsius and flows into the water storage tank. The portion of external air (1) output from above the first wet film becomes external air (21) with a dry-bulb temperature of 26.7 degrees Celsius and a relative humidity of 90%. The portion of external air (1) output from below the first wet film becomes external air (22) with a dry-bulb temperature of 27.8 degrees Celsius and a relative humidity of 90%. The external air (21) and evaporative cooling The 29°C cooling liquid in the heat exchanger undergoes evaporative heat exchange to become external air (31) with a dry bulb temperature of 29.3°C and a relative humidity of 90%. The external air (22) undergoes evaporative heat exchange with the evaporative cooling heat exchanger containing the high-temperature cooling liquid to become external air (32) with a dry bulb temperature of 28.5°C and a relative humidity of 90%. After heat exchange, the external air (31) and external air (32) are output to the second wet film. After heat exchange through the second wet film, they become external air (4) with a dry bulb temperature of 34.84°C and a relative humidity of 65%. The 29°C spray water in the second wet film is cooled to 27°C and flows into the second water tank. It is then pumped by the second water pump to the plate heat exchanger to exchange heat with the 31°C cooling water. After heat exchange, the cooling water is cooled from 31°C to 29°C and input into the evaporative cooling heat exchanger. The spray water is heated to 29°C and then sent to the third water distributor to spray the second wet film. The external air (4) is drawn out to the outside of the shell by the fan.

[0037] The following describes the operation of a closed-circuit cooling tower with an external air dry-bulb temperature of 16.5 degrees Celsius, a relative humidity of 65%, and an air intake of 50,000 m³ / h. External air (0) with a dry-bulb temperature of 16.5 degrees Celsius and a relative humidity of 65% is pre-cooled by a pre-cooling surface cooler containing internally flowing cold water at 13.25 degrees Celsius. External air (0) then becomes external air (1) with a dry-bulb temperature of 14.6 degrees Celsius and a relative humidity of 73.4%. The heat exchange in one hour is 16.25 kW. The outlet water temperature of the pre-cooling surface cooler rises to 14.4 degrees Celsius. External air (1) then undergoes an isenthalpic humidification process with the 14-degree Celsius water in the first wet film. The 14-degree Celsius water in the first wet film drops to 13.25 degrees Celsius and flows into the water storage tank. External air (1) exits from the first wet film and becomes external air (2) with a dry-bulb temperature of 13.25 degrees Celsius and a relative humidity of 90%. External air (2) then undergoes an evaporative cooling process... The 21-degree cooling liquid in the heat exchanger is evaporated and heat exchanged to become external air (3) with a dry bulb temperature of 17.6 degrees and a relative humidity of 69.6%. After heat exchange, the external air (3) is output to the second wet film. After heat exchange through the second wet film, it becomes external air (4) with a dry bulb temperature of 24.14 degrees and a relative humidity of 90%. The 25-degree spray water in the second wet film is cooled to 15 degrees and flows into the second water tank. It is then pumped by the second water pump to the plate heat exchanger to exchange heat with the 31-degree cooling water. After heat exchange, the cooling water is cooled from 31 degrees to 21 degrees and input into the evaporative cooling heat exchanger. After the spray water is heated to 25 degrees, it is sent to the third water distributor to spray the second wet film. The external air (4) is drawn out to the outside of the shell by the fan.

[0038] This invention utilizes an inlet distributor to divert a large flow of external coolant into multiple small flow heat exchanger tube groups. An outlet manifold then collects the cooled coolant from these small flow heat exchanger tube groups back to the outside, achieving high input / output and low-flow evaporative cooling, thus increasing both flow rate and heat exchange efficiency. Furthermore, within a single heat exchanger tube group, the appropriate number of longitudinal finned tubes can be selected based on actual flow requirements, with the flow converged and diverged in a first and second pipe. The use of longitudinal finned tubes further enhances heat exchange efficiency. In this invention, a flow interceptor is installed in the first and second pipes, serving to converge and diverge the fluid from a single group of longitudinal finned tubes. To change the flow rate of a single group of longitudinal finned tubes, the position of the flow interceptor in the first and second pipes can be adjusted. To further improve evaporative heat exchange efficiency, a sandwich wet film is also installed between the multiple heat exchanger tube groups. External air passes through this wet film to achieve a lower airflow level for heat exchange with the longitudinal finned tubes.

[0039] The closed-loop cooling tower of this invention fully utilizes natural cold sources, forming two cold water sources at high and low temperatures. The high-temperature cold water source serves as the primary cooling source for the external coolant. In this invention, the high-temperature cold water source performs primary cooling of the external coolant in a plate heat exchanger. The external coolant, after primary cooling, is then sent to an evaporative cooling heat exchanger where the low-temperature cold water source pre-cools the external ambient air. The coolant is then sprayed onto the evaporative cooling heat exchanger via a water distributor, evaporating and exchanging heat with the cooling liquid within the evaporative cooling heat exchanger. Furthermore, this closed-loop cooling system utilizes the aforementioned evaporative cooling heat exchanger with longitudinal finned tubes, further improving heat exchange efficiency.

[0040] 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.

[0041] 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 crossflow closed-loop cooling tower employing a radial finned tube heat exchanger, characterized in that: The crossflow closed-circuit cooling tower includes a shell and a fan, a wet film, a first water distributor, a second water distributor, an evaporative cooling heat exchanger, a water collection tray, a water storage tank, a water pump, and a primary cooling unit disposed within the shell. The fan is located at the top of the shell, the wet film is located directly behind the air inlet of the shell, and the evaporative cooling heat exchanger is located directly behind the wet film. The first water distributor is located above the wet film and distributes circulating water to the wet film. The second water distributor is located above the evaporative cooling heat exchanger and distributes circulating water to the evaporative cooling heat exchanger. The water collection tray is located below the wet film and the evaporative cooling heat exchanger, and the water storage tank is located below the water collection tray. The water collection tray collects the circulating water flowing from the wet film and the evaporative cooling heat exchanger and transports it to the water storage tank. The water pump draws circulating water from the water storage tank and distributes it in two directions to the first water distributor and the second water distributor. The primary cooling unit includes a plate heat exchanger, a second wet film, a third water distributor, a second water collection tray, a second water storage tank, and a second water pump. The second wet film is located directly behind the evaporative cooling heat exchanger. The third water distributor is located above the second wet film and distributes water onto it. The second water collection tray is located below the second wet film, and the second water storage tank is located below the second water collection tray. The second water collection tray collects the circulating water flowing from the second wet film and transports it to the second water storage tank. The second water pump draws circulating water from the second water storage tank and transports it to the cold aisle of the plate heat exchanger. The hot aisle input end of the heat exchanger is connected to an external cooling water network, and the hot aisle output end of the heat exchanger is connected to the input end of the evaporative cooling heat exchanger. The circulating water is transported to the third water distributor after heat exchange in the cold aisle of the plate heat exchanger.

2. The crossflow closed-circuit cooling tower according to claim 1, characterized in that: The crossflow closed cooling tower also includes a precooling surface cooler, which is located at the air inlet of the shell and directly in front of the wet film. The water pump draws circulating water from the water storage tank and delivers it to the precooling surface cooler. After the circulating water is output from the precooling surface cooler, it is divided into two paths and delivered to the first water distributor and the second water distributor.

3. The crossflow closed-circuit cooling tower according to claim 1 or 2, characterized in that: The crossflow closed cooling tower also includes a first filtration and sewage discharge device, the two ends of which are respectively connected to the water collection tray and the water storage tank.

4. The crossflow closed-loop cooling tower according to claim 3, characterized in that: The crossflow closed cooling tower also includes a third water collection tray, which is located directly below the wet film and collects the circulating water flowing from the wet film. The water collection tray is located directly below the evaporative cooling heat exchanger and collects the circulating water flowing from the evaporative cooling heat exchanger. The water collection tray is connected to the water storage tank through a water pipe. The first filter and sewage discharge device is connected to the third water collection tray and the water storage tank at both ends.

5. The crossflow closed-circuit cooling tower according to claim 1 or 2, characterized in that: The evaporative cooling heat exchanger includes multiple heat pipe groups, a liquid inlet pipe, multiple manifolds, a liquid outlet pipe, and fin groups. One end of the heat pipe group located at the top of the multiple heat pipe groups is connected to the liquid inlet pipe, and the other end is connected to the manifold. One end of the heat pipe group located in the middle of the multiple heat pipe groups is connected to one manifold, and the other end is connected to another manifold. One end of the heat pipe group located at the bottom of the multiple heat pipe groups is connected to the manifold, and the other end is connected to the liquid outlet pipe. The fin groups are intersected and embedded perpendicularly with the multiple heat pipe groups. The heat pipe assembly includes N flow-guiding heat exchange tubes. One end of the liquid inlet pipe is provided with a main water inlet, and the other end is provided with N water outlets. The confluence flow-guiding pipe is provided with N water inlets and N water outlets on the same end. One end of the liquid outlet pipe is provided with N water inlets, and the other end is provided with a main water outlet. One end of the flow-guiding heat exchange tube is connected to the water outlet, and the other end of the flow-guiding heat exchange tube is connected to the water inlet.

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