Air-cooled heat exchange system

Abstract

The application discloses a wind-cooled heat exchange system, comprising a compressor, an exhaust cooler, a wind-cooled condenser, a main throttling device and an evaporator, which are sequentially connected to form a main circulation loop; the exhaust cooler is configured to make gaseous refrigerant discharged from the compressor first flow through the exhaust cooler to be pre-cooled and then enter the wind-cooled condenser to be condensed. The application adds a compact exhaust cooler in the heat exchange system, so that the refrigerant is pre-cooled to be saturated gas refrigerant by the exhaust cooler before entering the wind-cooled condenser to be condensed to liquid refrigerant, thereby improving the overall heat transfer coefficient of the wind-cooled condenser, reducing the size requirement of the wind-cooled condenser, and further reducing the size of the unit.

Description

TECHNICAL FIELD

[0001] The present application relates to a heat exchange system, in particular to an air-cooled heat exchange system. BACKGROUND

[0002] In recent years, more environmentally friendly requirements have been put forward for the refrigerant types of heat exchange systems. New refrigerants (for example: R134a type refrigerant) can meet higher environmental protection requirements, but the heat exchange capacity per unit volume is lower. Compared with the air-cooled heat exchange system using old refrigerants (for example: R22 type refrigerant), the air-cooled condenser of the air-cooled heat exchange system using new refrigerants needs longer fan coils and more fans, so that the size of the air-cooled condenser and the heat exchange system is larger. For some old buildings, the space for placing the heat exchange system is designed in advance, and the space has a fixed accommodation size. In the case of matching the accommodation size, the heat exchange capacity of the heat exchange system using new refrigerants cannot meet the requirements due to its lower refrigeration efficiency. SUMMARY

[0003] The present application provides an air-cooled heat exchange system in a first aspect, comprising: a compressor, an exhaust cooler, an air-cooled condenser, a main throttling device and an evaporator, the compressor, the exhaust cooler, the air-cooled condenser, the main throttling device and the evaporator are connected in sequence to form a main circulation loop; the exhaust cooler is configured so that the gaseous refrigerant discharged from the compressor first flows through the exhaust cooler to be pre-cooled before entering the air-cooled condenser to be condensed.

[0004] According to the above-mentioned first aspect, the compressor has a first suction port, a second suction port and an exhaust port; the air-cooled condenser has an inlet and an outlet; the exhaust cooler includes a first refrigerant passage and a second refrigerant passage, the first refrigerant passage is connected between the exhaust port of the compressor and the inlet of the air-cooled condenser in the main circulation loop; the air-cooled heat exchange system further comprises an additional passage connected between the outlet of the air-cooled condenser and the second suction port of the compressor; the air-cooled heat exchange system further comprises an additional throttling device, the additional throttling device and the second refrigerant passage are connected in sequence in the additional passage, so that a part of the refrigerant discharged from the outlet of the air-cooled condenser first flows through the additional throttling device, and then flows through the second refrigerant passage to exchange heat with the refrigerant in the first refrigerant passage, thereby providing cold energy for the refrigerant in the first refrigerant passage.

[0005] According to the first aspect, the exhaust cooler further comprises a cooling medium passage in communication with a cooling medium, such that the cooling medium in the cooling medium passage exchanges heat with the refrigerant in the first refrigerant passage, thereby providing the refrigerant in the first refrigerant passage with cold energy.

[0006] According to the first aspect, the exhaust cooler is a plate heat exchanger.

[0007] According to the first aspect, the plate heat exchanger is configured such that the flow directions of the refrigerant in the second refrigerant passage and the cooling medium passage are opposite to the flow direction of the refrigerant in the first refrigerant passage.

[0008] According to the first aspect, the second refrigerant passage comprises a plurality of second refrigerant sub-paths, the first refrigerant passage comprises a plurality of first refrigerant sub-paths, and the cooling medium passage comprises a plurality of cooling medium sub-paths; wherein the plurality of first refrigerant sub-paths are alternately arranged between the plurality of second refrigerant sub-paths and the plurality of cooling medium sub-paths.

[0009] According to the first aspect, the second suction port of the compressor is arranged close to the exhaust port of the compressor.

[0010] According to the first aspect, the exhaust cooler is configured such that the gaseous refrigerant discharged from the compressor is first cooled to saturated gaseous refrigerant by flowing through the exhaust cooler, and then enters the air-cooled condenser to be condensed.

[0011] According to the first aspect, the air-cooled heat exchange system further comprises a control device and a sensing device, the first refrigerant passage has an outlet, and the second refrigerant passage has an outlet; the sensing device is configured to detect the superheat at the outlet of the first refrigerant passage and / or the outlet of the second refrigerant passage; and the control device is configured to adjust the opening degree of the additional throttling device according to the superheat detected by the sensing device.

[0012] According to the first aspect above, the sensing device includes a pressure sensor and a temperature sensor, the sensing device being configured to obtain the superheat by detecting the pressure and temperature at the outlet of the first refrigerant channel and / or at the outlet of the second refrigerant channel; the outlet of the first refrigerant channel having a first preset superheat and / or the outlet of the second refrigerant channel having a second preset superheat; wherein the control device is configured to: increase the opening of the additional throttling device when the superheat at the outlet of the first refrigerant channel is greater than the first preset superheat; decrease the opening of the additional throttling device when the superheat at the outlet of the first refrigerant channel is less than the first preset superheat; and / or the control device is configured to: increase the opening of the additional throttling device when the superheat at the outlet of the second refrigerant channel is greater than the second preset superheat; decrease the opening of the additional throttling device when the superheat at the outlet of the second refrigerant channel is less than the second preset superheat.

[0013] This application provides an air-cooled heat exchange system that incorporates a compact exhaust cooler. This allows the refrigerant to be pre-cooled into a saturated gaseous refrigerant before entering the air-cooled condenser and condensing into a liquid refrigerant. Compared to a system using only an air-cooled condenser, the heat exchange system using the combination of an exhaust cooler and an air-cooled condenser improves the overall heat transfer coefficient of the air-cooled condenser. Therefore, it achieves the same maximum heat exchange capacity as air-cooled heat exchange systems using older refrigerants without requiring an increase in the number of fans or the length of the fan coil units. Attached Figure Description

[0014] Figure 1A This is a block diagram of an air-cooled heat exchange system 100 according to an embodiment of this application;

[0015] Figure 1B for Figure 1A The diagram shows the refrigerant flow path of the air-cooled heat exchange system 100.

[0016] Figure 2 for Figure 1A Flow diagram of the exhaust cooler 150;

[0017] Figure 3 for Figure 1A A block diagram of the control device 180 of the air-cooled heat exchange system 100 shown;

[0018] Figure 4 This is a block diagram of an air-cooled heat exchange system 400 according to another embodiment of this application;

[0019] Figure 5 This is a block diagram of an air-cooled heat exchange system 500 according to another embodiment of this application. Detailed Implementation

[0020] Various specific embodiments of the present invention will now be described with reference to the accompanying drawings, which form part of this specification. It should be understood that although terms indicating direction, such as "front," "rear," "upper," "lower," "left," "right," "top," and "bottom," are used herein to describe various exemplary structural parts and elements, their use is merely for ease of description and is based on the exemplary orientations shown in the accompanying drawings. Since the embodiments disclosed herein can be arranged in different orientations, these terms indicating direction are illustrative only and should not be considered limiting.

[0021] Figure 1A This is a structural block diagram of an air-cooled heat exchange system 100 according to an embodiment of this application. Figure 1B for Figure 1A The diagram shows the refrigerant flow path in the air-cooled heat exchange system 100. Figure 1A As shown, the air-cooled heat exchange system 100 includes a compressor 110, an exhaust cooler 150, an air-cooled condenser 120, a main throttling device 130, and an evaporator 140, which are connected in sequence to form a main circulation loop 115. The air-cooled heat exchange system 100 also includes an additional throttling device 160 and an additional passage 116, with the additional throttling device 160 connected in the additional passage 116.

[0022] Specifically, compressor 110 has a first suction port 111, a second suction port 113, and a discharge port 112; air-cooled condenser 120 has an inlet 121 and an outlet 122; main throttling device 130 has an inlet 131 and an outlet 132; and evaporator 140 has an inlet 141 and an outlet 142. Discharge cooler 150 has a first refrigerant passage 151, a second refrigerant passage 152, and a cooling medium passage 153. The first refrigerant passage 151 has an inlet 151a and an outlet 151b, and the second refrigerant passage 152 has an inlet 152a and an outlet 152b. Additional throttling device 160 has an inlet 161 and an outlet 162. Additional passage 116 connects the outlet 122 of air-cooled condenser 120 and the second suction port 113 of compressor 110.

[0023] In the main circulation loop 115, the discharge port 112 of the compressor 110 is connected to the inlet 151a of the first refrigerant passage 151, the outlet 151b of the first refrigerant passage 151 is connected to the inlet 121 of the air-cooled condenser 120, the outlet 122 of the air-cooled condenser 120 is connected to the inlet 131 of the main throttling device 130, the outlet 132 of the main throttling device 130 is connected to the inlet 141 of the evaporator 140, and the outlet 142 of the evaporator 140 is connected to the first suction port 111 of the compressor 110.

[0024] In the additional passage 116, the inlet 161 of the additional throttling device 160 is connected to the outlet 122 of the air-cooled condenser 120, the outlet 162 of the additional throttling device 160 is connected to the inlet 152a of the second refrigerant passage 152, and the outlet 152b of the second refrigerant passage 152 is connected to the second suction port 113 of the compressor 110.

[0025] like Figure 1B As shown, when the air-cooled heat exchange system 100 is charged with refrigerant and is running, in the main circulation loop 115, the high-pressure gaseous refrigerant discharged from the compressor 110 first flows through the first refrigerant passage 151 of the exhaust cooler 150. In the first refrigerant passage 151, a portion of heat (e.g., sensible heat) is released before the refrigerant is cooled to a saturated gaseous state and then enters the air-cooled condenser 120. In the air-cooled condenser 120, heat (e.g., latent heat) is further released, and the refrigerant is condensed into a high-pressure liquid refrigerant. Then, a portion of the high-pressure liquid refrigerant flows into the main throttling device 130, where it is throttled into a low-pressure two-phase refrigerant and flows into the evaporator 140. In the evaporator 140, the refrigerant absorbs heat and evaporates into a low-pressure gaseous refrigerant. Finally, the refrigerant flows out of the evaporator 140 and returns to the compressor 110, completing the refrigerant cycle. The evaporator 140 is used to connect to the supply and return water pipes 183 to provide the required cooling capacity to the user side. In the additional passage 116, another portion of the high-pressure liquid refrigerant flowing out of the air-cooled condenser 120 flows into the additional throttling device 160. After being throttled by the additional throttling device 160 into a low-pressure two-phase refrigerant, it is then sent into the second refrigerant passage 152 in the exhaust cooler 150. In the second refrigerant passage 152, it absorbs the heat released by the high-pressure gaseous refrigerant in the first refrigerant passage 151 and is evaporated into a low-pressure gaseous refrigerant. Finally, it returns to the compressor 110 through the second suction port 113.

[0026] In the embodiments of this application, the exhaust cooler 150 is located upstream of the air-cooled condenser 120 in the main circulation loop 115. The gaseous refrigerant discharged from the compressor 110 can first flow through the first refrigerant channel 151 in the exhaust cooler 150, exchange heat with the refrigerant in the second refrigerant channel 152 in the exhaust cooler 150 to be pre-cooled into saturated gaseous refrigerant, and then enter the air-cooled condenser 120 to be condensed.

[0027] In the existing air-cooled heat exchange system, the high-pressure gaseous refrigerant discharged from the compressor outlet needs to go through three stages in the air-cooled condenser to condense into liquid refrigerant. In the first stage, the high-pressure gaseous refrigerant needs to release sensible heat first to become saturated gaseous refrigerant, so that the gas temperature is reduced to the saturated condensation temperature. In the second stage, the saturated gaseous refrigerant at the saturated condensation temperature releases latent heat further to condense the gas into liquid. In the third stage, the liquid refrigerant releases sensible heat to further cool into supercooled refrigerant liquid. In the above three stages, the heat transfer coefficient of the air-cooled condenser in the second stage is greater than that in the first stage and the third stage.

[0028] Therefore, the air-cooled heat exchange system 100 of the present application can pre-cool the gaseous refrigerant to remove the superheat by the exhaust cooler 150 under the condition of the maximum total heat exchange capacity, absorb the sensible heat of the gaseous refrigerant, and make the air-cooled condenser 120 better absorb the latent heat of the gaseous refrigerant to condense the gaseous refrigerant into liquid refrigerant, thereby improving the overall heat transfer coefficient of the air-cooled condenser 120, reducing the size requirement of the air-cooled condenser 120, and further reducing the size of the unit. Under the condition of the same heat exchange capacity, the fan coil of the air-cooled condenser 120 can be made smaller, thereby saving the volume of the air-cooled condenser 120. Under the condition of the same size of the fan coil of the air-cooled condenser 120, the heat exchange capacity can be larger. Although part of the refrigerant flows through the additional passage 116, which may have some impact on the performance of the unit, by setting the flow rate of the refrigerant flowing through the additional passage 116 at a small proportion, both the size requirement of the air-cooled condenser 120 and the performance of the unit can be kept within an acceptable range.

[0029] The exhaust cooler 150 further includes a cooling medium passage 153 for connecting with a cooling medium to provide the required heat to the user side. The cooling medium passage 153 can circulate a cooling medium such as cold water, which can also exchange heat with the high-pressure gaseous refrigerant in the first refrigerant passage 151 to provide cold energy to the high-pressure gaseous refrigerant in the first refrigerant passage 151. In the present embodiment, the cooling medium is water, and the cooling medium passage 153 is connected with a supply and return water pipe 181. The air-cooled heat exchange system 100 can provide hot water to the user side through the supply and return water pipe 181. In some embodiments, when the user side has a hot water demand, the cooling medium passage 153 can be connected to provide hot water to the user side, and the second refrigerant passage 152 can be disconnected to reduce the impact of the additional passage 116 on the performance of the unit. In some embodiments, when the user side has no hot water demand, the cooling medium passage 153 can be disconnected, and the second refrigerant passage 152 can be connected. In other embodiments, the second refrigerant passage 152 and the cooling medium passage 153 can be connected at the same time according to actual needs.

[0030] Returning to Figure 1A In the embodiment, the air-cooled heat exchange system 100 further comprises a sensing device 185 and a control device 180. The sensing device 185 is communicatively connected to the outlet 151b of the first refrigerant passage 151 and the outlet 152b of the second refrigerant passage 152, and is configured to detect the superheat at the outlet 151b of the first refrigerant passage 151 and the outlet 152b of the second refrigerant passage 152. The control device 180 is communicatively connected to the sensing device 185 through a connection 198, and is communicatively connected to the additional throttling device 160 through a connection 192. Based on the superheat detected by the sensing device 185, the control device 180 is configured to adjust the opening degree of the additional throttling device 160, so as to adjust the refrigerant flow rate through the second refrigerant passage 152 in the exhaust cooler 150. In the embodiment, the sensing device 185 comprises a sensor 185a and a sensor 185b. The sensor 185a is communicatively connected to the outlet 151b of the first refrigerant passage 151, and is configured to detect the superheat at the outlet 151b of the first refrigerant passage 151. The sensor 185b is communicatively connected to the outlet 152b of the second refrigerant passage 152, and is configured to detect the superheat at the outlet 152b of the second refrigerant passage 152. Each of the sensors 185a and 185b comprises a temperature sensor and a pressure sensor, and the superheat of the refrigerant at the outlet 151b of the first refrigerant passage 151 and the outlet 152b of the second refrigerant passage 152 is obtained by detecting the temperature and pressure of the refrigerant in the corresponding passage.

[0031] Specifically, the outlet 151b of the first refrigerant passage 151 has a first preset superheat. When the sensing device 185 detects that the superheat of the refrigerant at the outlet 151b is greater than the first preset superheat, the control device 180 controls to increase the opening degree of the additional throttling device 160, so as to increase the refrigerant flow rate through the second refrigerant passage 152, thereby further reducing the temperature of the refrigerant discharged from the compressor 110. When the sensing device 185 detects that the superheat of the refrigerant at the outlet 151b is less than the first preset superheat, the control device 180 controls to decrease the opening degree of the additional throttling device 160, so as to decrease the refrigerant flow rate through the second refrigerant passage 152, thereby increasing the temperature of the refrigerant discharged from the compressor 110.

[0032] The outlet 152b of the second refrigerant passage 152 has a second preset superheat. When the sensing device 185 detects that the superheat of the refrigerant at the outlet 152b is greater than the second preset superheat, the control device 180 controls to increase the opening degree of the additional throttling device 160. When the sensing device 185 detects that the superheat of the refrigerant at the outlet 152b is less than the second preset superheat, the control device 180 controls to decrease the opening degree of the additional throttling device 160.

[0033] The first preset superheat degree and the second preset superheat degree can be preset according to the specific working condition of the air-cooled heat exchange system 100. For example, the first preset superheat degree can be preset according to the specific size of the air-cooled condenser 120 and the maximum heat exchange requirement of the air-cooled heat exchange system, to ensure that the air-cooled condenser 120 of a certain size can meet the heat exchange requirement of the air-cooled heat exchange system 100 after the pre-cooling by the exhaust cooler 150. The second preset superheat degree can be set according to the saturation temperature of the refrigerant vapor under a certain pressure, to ensure that the refrigerant sucked into the compressor 110 from the second suction port 113 of the compressor 110 does not contain liquid refrigerant.

[0034] In some other embodiments, by setting a suitable first preset superheat degree or a second preset superheat degree, the sensing device 185 can also be communicatively connected to only one of the outlet 151b and the outlet 152b, and detect the superheat degree of the refrigerant at one of the outlets, and adjust the opening degree of the additional throttling device 160 based on the detected superheat degree.

[0035] In the air-cooled heat exchange system 100 of the present embodiment, the control device 180 controls most of the refrigerant to flow through the main circulation loop 115, and only a small amount of refrigerant flows through the additional passage 116, to provide cold energy for the refrigerant in the first refrigerant passage 151. Therefore, in order to improve the working efficiency of the compressor, the second suction port 113 is used to connect to the compression cavity (not shown in the figure) between the first suction port 111 and the exhaust port 112 of the compressor 110, for example, closer to the exhaust port 112 than the first suction port 111.

[0036] Figure 2 For Figure 1A A channel flow direction diagram of one embodiment of the exhaust cooler 150 in the air-cooled heat exchange system 100, for illustrating the flow direction of the refrigerant in the channels in the exhaust cooler 150. In the embodiment as shown in the figure, the solid hollow arrow represents the first refrigerant sub-channel 271, the dashed hollow arrow represents the second refrigerant sub-channel 272, and the solid solid arrow represents the cooling medium sub-channel 273.

[0037] As Figure 2As shown, the first refrigerant passage 151 in the exhaust heat exchanger 150 includes a plurality of first refrigerant sub-passages 271 which are in fluid communication with each other, for example, each sub-passage is connected to a common main passage to form the first refrigerant passage 151. Similarly, the second refrigerant passage 152 includes a plurality of second refrigerant sub-passages 272 which are in fluid communication with each other, and the cooling medium passage 153 includes a plurality of cooling medium sub-passages 273 which are in fluid communication with each other. The plurality of first refrigerant sub-passages 271 are alternately arranged between the plurality of second refrigerant sub-passages 272 and the plurality of cooling medium sub-passages 273, such that each first refrigerant sub-passage 271 has at least one of the second refrigerant sub-passage 272 and the cooling medium sub-passage 273 arranged on its adjacent sides. In this way, the positions of the sub-passages are arranged such that even if only one of the second refrigerant passage 152 and the cooling medium passage 153 has fluid passing therethrough, the refrigerant in the first refrigerant sub-passage 271 has at least one adjacent side with refrigerant or cooling medium which can exchange heat therewith.

[0038] When the first refrigerant passage 151 and the second refrigerant passage 152 in the exhaust heat exchanger 150 have refrigerant passing therethrough, and the cooling medium passage 153 has cooling medium passing therethrough at the same time, the flow direction of the refrigerant in the first refrigerant sub-passage 271 is arranged to be opposite to the flow direction of the fluid in the second refrigerant sub-passage 272 and the cooling medium sub-passage 273. In this way, the flow direction of the fluid in each sub-passage is arranged such that the refrigerant in the first refrigerant sub-passage 271 can exchange heat more fully with the refrigerant and the cooling medium in the adjacent sub-passages. In some other embodiments, the fluid in each sub-passage can also be arranged to have other flow directions.

[0039] It should be noted that in the embodiments shown, the exhaust heat exchanger 150 is a plate heat exchanger, and in other embodiments, the exhaust heat exchanger can also be other multi-medium passage heat exchangers. Figure 2 In the embodiments shown, the exhaust heat exchanger 150 is a plate heat exchanger, and in other embodiments, the exhaust heat exchanger can also be other multi-medium passage heat exchangers.

[0040] Figure 3 is a schematic structural block diagram of the control device 180 of the air-cooled heat exchange system 100. As shown, the control device 180 includes a control unit 181, a temperature sensor 182, a pressure sensor 183, a flow sensor 184, a communication unit 185, and a storage unit 186. Figure 3As shown, the control device 180 includes a bus 382, ​​a processor 394, an input interface 386, an output interface 388, and a memory 384 containing a control program 396. The various components of the control device 180, including the processor 394, input interface 386, output interface 388, and memory 384, are communicatively connected to the bus 382, ​​enabling the processor 394 to control the operation of the input interface 386, output interface 388, and memory 384. Specifically, the memory 384 stores programs, instructions, and data, while the processor 394 reads programs, instructions, and data from the memory 384 and can write data to the memory 384. By executing the programs and instructions read from the memory 384, the processor 394 controls the operation of the input interface 386 and output interface 388.

[0041] Combination Figure 3 and Figure 1A As shown, input interface 386 is communicatively connected to sensor 185 via connection 198, and output interface 388 is communicatively connected to additional throttling devices 160 via connection 192. Processor 394 controls the operation of air-cooled heat exchange system 100 by executing programs and instructions in memory 384. More specifically, control device 180 can receive superheat data detected by sensor 185 via input interface 386 and send control signals to each controlled additional throttling device 160 via output interface 388, thereby enabling air-cooled heat exchange system 100 to meet operating requirements.

[0042] Figure 4 The block diagram of the air-cooled heat exchange system 400 illustrates another embodiment of the air-cooled heat exchange system. (See diagram below.) Figure 4 As shown, the difference between the air-cooled heat exchange system 400 and the air-cooled heat exchange system 100 is that the air-cooled heat exchange system 400 also includes an economizer 426. The economizer 426 further cools the liquid refrigerant flowing from the air-cooled condenser 120 to obtain a greater subcooling, and further evaporates the refrigerant flowing from the second refrigerant channel 152 into gaseous refrigerant, thereby improving the cooling capacity of the air-cooled heat exchange system and having a certain effect on improving the system's energy efficiency ratio. Specifically, the economizer 426 has a first port 433, a second port 434, a third port 435, and a fourth port 436, wherein the first port 433 and the second port 434 are fluidly connected within the economizer 426, and the third port 435 and the fourth port 436 are also fluidly connected within the economizer 426. The first port 433 of the economizer 426 is fluidly connected to the outlet 122 of the air-cooled condenser 120. The second port 434 of the economizer 426 is in fluid communication with the inlet 131 of the main throttling device 130 and the inlet 161 of the auxiliary throttling device 160. The third port 435 of the economizer 426 is in fluid communication with the outlet 152b of the second refrigerant passage 152. The fourth port 436 of the economizer 426 is in fluid communication with the second suction port 113 of the compressor 110.

[0043] Thus, when the air-cooled heat exchange system 400 is charged with refrigerant and in operation, in the main cycle loop 115, the high-pressure gaseous refrigerant discharged from the compressor 110 still flows through the first refrigerant passage 151 of the gas cooler 150 first, is cooled to the saturated condensing temperature by releasing a portion of heat in the first refrigerant passage 151, and then enters the air-cooled condenser 120 to be further condensed into high-pressure liquid refrigerant by releasing more heat. The high-pressure liquid refrigerant then flows into the economizer 426 from the first port 433 of the economizer 426, and is further cooled by releasing more heat in the economizer 426. The high-pressure liquid refrigerant then flows out from the second port 434. A portion of the high-pressure liquid refrigerant flowing out from the second port 434 flows into the main throttling device 130, is throttled into low-pressure liquid refrigerant, and then flows into the evaporator 140 to be evaporated into low-pressure gaseous refrigerant by absorbing heat. The low-pressure gaseous refrigerant then flows out from the evaporator 140 and re-enters the compressor 110 to complete the cycle of the refrigerant. In the additional loop 116, another portion of the high-pressure liquid refrigerant flowing out from the second port 434 flows into the additional throttling device 160, is throttled into low-pressure liquid refrigerant, and then flows into the second refrigerant passage 152 of the gas cooler 150 to be evaporated into low-pressure gaseous refrigerant by absorbing the portion of heat released by the high-pressure gaseous refrigerant in the first refrigerant passage 151. The low-pressure gaseous refrigerant then flows into the economizer 426 from the third port 435 of the economizer 426, is further evaporated by absorbing more heat in the economizer 426, and then flows out from the fourth port 436. The low-pressure gaseous refrigerant then re-enters the compressor 110 from the second suction port 113.

[0044] In the present embodiment, the refrigerant flowing into the air-cooled condenser 120 is first cooled by flowing through the gas cooler 150, and thus the size requirement of the air-cooled condenser 120 can be reduced, and the size of the air-cooled heat exchange system 400 can be reduced as well, when the air-cooled heat exchange system 400 has the same maximum heat exchange capacity.

[0045] Figure 5 FIG. 5 is a block diagram of an air-cooled heat exchange system 500, showing still another embodiment of the air-cooled heat exchange system. As shown in FIG. 5, the air-cooled heat exchange system 500 is similar to the air-cooled heat exchange system 400 shown in FIG. 4, and the same components are denoted by the same reference numerals. The difference between the air-cooled heat exchange system 400 and the air-cooled heat exchange system 500 is that the air-cooled heat exchange system 500 has an additional throttling device 160 in the additional loop 116. Figure 5As shown, the difference between the air-cooled heat exchange system 500 and the air-cooled heat exchange system 100 is that the air-cooled heat exchange system 500 further comprises a flash tank 545 and a third throttling device 543. The flash tank 545 and the third throttling device 543 are connected between the outlet 132 of the main throttling device 130 and the inlet 141 of the evaporator 140. The flash tank 545 has a similar function as the economizer, which can improve the refrigeration capacity of the air-cooled heat exchange system and improve the system energy efficiency ratio. Specifically, the flash tank 545 has a total inlet 554, a gas inlet 556, a gas outlet 557, and a liquid outlet 555, and the third throttling device 543 has an inlet 547 and an outlet 548. The total inlet 554 of the flash tank 545 is connected with the outlet 132 of the main throttling device 130, the gas inlet 556 of the flash tank 545 is connected with the outlet 152b of the second refrigerant passage 152, the gas outlet 557 of the flash tank 545 is connected with the second suction port 113 of the compressor 110, the liquid outlet 555 of the flash tank 545 is connected with the inlet 547 of the third throttling device 543, and the outlet 548 of the third throttling device 543 is connected with the inlet 141 of the evaporator 140.

[0046] Thus, when the air-cooled heat exchange system 500 is filled with refrigerant and operates, in the main circulation loop 115, the high-pressure gaseous refrigerant discharged by the compressor 110 still flows through the first refrigerant passage 151 of the gas cooler 150 first, is cooled to the saturated condensation temperature by releasing a part of heat in the first refrigerant passage 151, and then enters the air-cooled condenser 120, where the high-pressure gaseous refrigerant is further condensed into high-pressure liquid refrigerant by releasing heat. Then, a part of the high-pressure liquid refrigerant flows into the main throttling device 130, is throttled into low-pressure two-phase refrigerant, and then flows into the flash tank 545 through the total inlet 554 of the flash tank 545, where the liquid-phase refrigerant is separated from the gaseous-phase refrigerant. The separated liquid-phase refrigerant flows into the third throttling device 543, is further throttled, and then flows into the evaporator 140, where the liquid-phase refrigerant is evaporated into low-pressure gaseous refrigerant by absorbing heat, and finally flows out of the evaporator 140 and returns to the compressor 110, completing the circulation of the refrigerant. In the additional passage 116, another part of the high-pressure liquid refrigerant flowing out of the outlet 122 of the air-cooled condenser 120 flows into the additional throttling device 160, is throttled into low-pressure two-phase refrigerant by the additional throttling device 160, and then enters the second refrigerant passage 152 in the gas cooler 150, where the low-pressure two-phase refrigerant is evaporated into low-pressure gaseous refrigerant by absorbing the part of heat released by the high-pressure gaseous refrigerant in the first refrigerant passage 151, and then flows into the flash tank 545 through the gas inlet 556 of the flash tank 545, mixes with the gaseous-phase refrigerant in the flash tank 545, and then flows out of the gas outlet 557. Finally, the refrigerant returns to the compressor 110 through the second suction port 113.

[0047] In the present embodiment, the refrigerant flowing into the air-cooled condenser 120 is also pre-cooled by flowing through the exhaust gas cooler 150 first, so that the size requirement of the air-cooled condenser 120 can be reduced, and the size of the unit can be reduced as well, under the condition that the air-cooled heat exchange system 500 has the same maximum heat exchange capacity.

[0048] Compared with the air-cooled heat exchange system 100, the air-cooled heat exchange systems 400 and 500 can improve the refrigeration capacity of the system and reduce the cost per refrigeration capacity ($ / RT) to some extent due to the use of the economizer and the flash tank.

[0049] The present application adds an exhaust gas cooler in the air-cooled heat exchange system, so that the gaseous refrigerant discharged from the compressor is pre-cooled by the exhaust gas cooler 150 to remove the superheat and absorb the sensible heat of the gaseous refrigerant, so that the air-cooled condenser 120 can better absorb the latent heat of the gaseous refrigerant to condense the gaseous refrigerant into liquid refrigerant, thereby improving the overall heat transfer coefficient of the air-cooled condenser 120. Thus, under the condition of the same maximum heat exchange capacity, the required fan coil length and the number of fans of the air-cooled condenser are reduced, and the required floor area of the air-cooled condenser and the unit is reduced.

[0050] Although the present application will be described with reference to the specific embodiments shown in the drawings, it should be understood that the air-cooled heat exchange system of the present application can have many variations without departing from the spirit and scope of the present application. Those skilled in the art will also realize that there are different ways to change the structural details of the embodiments disclosed in the present application, all of which fall within the spirit and scope of the present application and the claims.

Claims

1. An air-cooled heat exchange system, characterized by Comprises: a compressor (110), an exhaust gas cooler (150), an air-cooled condenser (120), a main throttling device (130), and an evaporator (140), which are connected in sequence to form a main circulation loop (115), wherein the exhaust gas cooler (150) comprises a first refrigerant passage (151), a second refrigerant passage (152), and a cooling medium passage (153); wherein the first refrigerant passage (151), the second refrigerant passage (152), and the cooling medium passage (153) are fluidly isolated from each other within the exhaust gas cooler (150); wherein the exhaust gas cooler (150) is configured to direct gaseous refrigerant discharged from the compressor (110) through the first refrigerant passage (151) to pre-cool the gaseous refrigerant before being condensed in the air-cooled condenser (120); wherein the second refrigerant passage (152) is configured to direct refrigerant discharged from the air-cooled condenser (120) through the exhaust gas cooler (150) to exchange heat with the gaseous refrigerant directed through the first refrigerant passage (151) and pre-cool the gaseous refrigerant; and wherein the cooling medium passage (153) is configured to direct cooling medium through the exhaust gas cooler (150) to exchange heat with the gaseous refrigerant directed through the first refrigerant passage (151) and pre-cool the gaseous refrigerant.

2. The air-cooled heat exchange system of claim 1, wherein: the compressor (110) has a first suction port (111), a second suction port (113), and a discharge port (112); the air-cooled condenser (120) has an inlet (121) and an outlet (122); the first refrigerant passage (151) is connected to the main circulation loop (115) and between the discharge port (112) of the compressor (110) and the inlet (121) of the air-cooled condenser (120), and the evaporator (140) is connected between the outlet (122) of the air-cooled condenser (120) and the first suction port (111) of the compressor (110); the air-cooled heat exchange system (100) further comprises an additional passage (116) connected between the outlet (122) of the air-cooled condenser (120) and the second suction port (113) of the compressor (110); The air-cooled heat exchange system (100) further comprises an additional throttling device (160), and the additional throttling device (160) and the second refrigerant passage (152) are sequentially connected in the additional passage (116), wherein the additional passage (116) is configured to guide a part of the refrigerant discharged from the outlet (122) of the air-cooled condenser (120) to pass through the additional throttling device (160) and then pass through the second refrigerant passage (152) to exchange heat with the gaseous refrigerant in the first refrigerant passage (151).

3. The air-cooled heat exchange system according to claim 1, wherein: The exhaust gas cooler (150) is a plate heat exchanger.

4. The air-cooled heat exchange system according to claim 3, wherein: The plate heat exchanger is configured such that the flow direction of the refrigerant guided to pass through the second refrigerant passage (152) and the flow direction of the cooling medium guided to pass through the cooling medium passage (153) are opposite to the flow direction of the gaseous refrigerant guided to pass through the first refrigerant passage (151).

5. The air-cooled heat exchange system according to claim 4, wherein: The second refrigerant passage (152) comprises a plurality of second refrigerant sub-passages (272), the first refrigerant passage (151) comprises a plurality of first refrigerant sub-passages (271), and the cooling medium passage (153) comprises a plurality of cooling medium sub-passages (273); wherein the plurality of first refrigerant sub-passages (271) are alternately arranged between the plurality of second refrigerant sub-passages (272) and the plurality of cooling medium sub-passages (273).

6. The air-cooled heat exchange system according to claim 2, wherein: The second suction port (113) of the compressor (110) is arranged close to the exhaust port (112) of the compressor (110).

7. The air-cooled heat exchange system according to claim 1, wherein: The exhaust gas cooler (150) is configured such that the gaseous refrigerant discharged from the compressor (110) is pre-cooled to saturated gaseous refrigerant by flowing through the exhaust gas cooler (150) first, and then enters the air-cooled condenser (120) to be condensed.

8. The air-cooled heat exchange system according to claim 2, wherein: The air-cooled heat exchange system (100) further comprises a control device (180) and a sensing device (185), the first refrigerant passage (151) has an outlet (151b), and the second refrigerant passage (152) has an outlet (152b); The sensing device (185) is configured to detect the superheat degree at the outlet (151b) of the first refrigerant passage (151) and / or the outlet (152b) of the second refrigerant passage (152). The control device (180) is configured to adjust the opening degree of the additional throttling device (160) based on the superheat detected by the sensing device (185) at the outlet (151b) of the first refrigerant passage (151) and / or the outlet (152b) of the second refrigerant passage (152).

9. The air-cooled heat exchange system of claim 8, wherein: The sensing device (185) comprises a pressure sensor and a temperature sensor, and is configured to obtain the superheat by detecting the pressure and temperature at the outlet (151b) of the first refrigerant passage (151) and / or the outlet (152b) of the second refrigerant passage (152); The outlet (151b) of the first refrigerant passage (151) has a first preset superheat and / or the outlet (152b) of the second refrigerant passage (152) has a second preset superheat; The control device (180) is configured to increase the opening degree of the additional throttling device (160) in response to the superheat at the outlet (151b) of the first refrigerant passage (151) being greater than the first preset superheat, and decrease the opening degree of the additional throttling device (160) in response to the superheat at the outlet (151b) of the first refrigerant passage (151) being less than the first preset superheat; and / or The control device (180) is configured to increase the opening degree of the additional throttling device (160) in response to the superheat at the outlet (152b) of the second refrigerant passage (152) being greater than the second preset superheat, and decrease the opening degree of the additional throttling device (160) in response to the superheat at the outlet (152b) of the second refrigerant passage (152) being less than the second preset superheat.

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