Dual-mode coupling type return air flow heat removal method and device

Abstract

The invention relates to a dual-mode coupling type return air flow heat removal method and device. Return air flow exchanges heat with spraying water, the return air flow is cooled for the first time, heat in the spraying water exchanges with a first working medium of a plate heat exchanger, and the temperature of the first working medium is increased; after being cooled by the heat pump unit, the first working medium enters the fin type heat exchanger unit or the heat pump unit and exchanges heat with the return air flow cooled once or the spray water, so that the temperature of the return air flow is reduced again, the temperature of the spray water is reduced, the temperature of the first working medium is increased by the two routes, and the first working medium returns to the heat pump unit; the second working medium in the heat pump unit absorbs heat of the first working medium and transmits the heat to the use end to be used by people, the temperature of the used second working medium is reduced, the second working medium returns to the heat pump unit again, and therefore recycling of heat of return air flow is achieved, the temperature of return air can be greatly reduced, and hot air energy is recycled to a large extent. And additional heat energy consumption is reduced in the operation process of the device.

Description

Technical Field

[0001] This application relates to the field of waste heat recovery and utilization, and particularly to a dual-mode coupled return air flow heat extraction method and its device. Background Art

[0002] The return air volume of coal mines is huge and remains stable at about 18°C to 20°C all year round, which is a very high-quality low-temperature heat source. The utilization of coal mine return air is important and meaningful. The heat exchange temperature ranges of the existing spray-type return air heat exchange system and finned plate heat exchanger are both small. For the spray-type return air heat exchange system, the return air temperature can generally only be reduced to 5°C or higher, and there is still a large amount of heat energy in the return air that cannot be recovered. For the finned plate heat exchanger, the return air temperature can be reduced below 0°C, but the temperature drop of the return air is limited, and it is difficult to achieve a temperature drop of more than 15°C, resulting in insufficient utilization of the low-temperature heat source of coal mine return air. Summary of the Invention

[0003] In view of this, this application proposes a dual-mode coupled return air flow heat extraction method and its device, which can greatly reduce the temperature of the return air, achieve a large range of recovery of hot air energy, and reduce additional heat energy consumption during the operation of the device.

[0004] According to one aspect of this application, a dual-mode coupled return air flow heat extraction method is provided, including the following process: The return air flow enters the return air diffusion tower, and the spray water in the return air diffusion tower exchanges heat with the heat in the return air flow, the temperature of the return air flow drops for the first time, the temperature of the spray water rises, the spray water flows out of the return air diffusion tower, the temperature of the spray water drops after flowing through the plate heat exchanger, and then flows back into the return air diffusion tower to exchange heat with the heat in the return air flow; The first working medium exchanges heat through the plate heat exchanger, the temperature of the first working medium rises, the temperature of the first working medium drops after passing through the heat pump unit, part of the first working medium flows back into the plate heat exchanger and the temperature rises again, and another part of the first working medium flows into the fin heat exchanger group to exchange heat with the return air flow after the first drop, the temperature of the first working medium rises, the temperature of the return air flow drops for the second time, and the first working medium flows back into the heat pump unit; The second working medium exchanges heat through the heat pump unit, the temperature of the second working medium rises, the temperature of the second working medium drops after passing through the use end, and the second working medium then flows back into the heat pump unit; The return air flow can exchange heat with the spray water and the fin heat exchanger group respectively.

[0005] In a possible implementation, the return air flow enters from one side of the return air diffusion tower. Small droplets of the sprayed water ejected from a position near the top mix with the return air flow and exchange heat. The sprayed water after heat exchange collects in the bottom sump of the return air diffusion tower. The sprayed water in the sump enters the collection pool, is pressurized by a spray water pump, filtered to remove impurities through a water processor, and then enters the plate heat exchanger to extract heat. The sprayed water after extracting heat is sprayed again through a nozzle to extract heat.

[0006] In a possible implementation, the first working fluid is pressurized by a heat source circulation pump and then enters the heat pump unit to extract heat. After extracting heat, the first working fluid passes through a three-way valve, and the first working fluid is divided into two paths, both of which can increase the temperature of the first working fluid. The first working fluid after the temperature increase is mixed and then enters the heat source side circulation pump again. One path of the first working fluid enters the plate heat exchanger to absorb heat; the other path of the first working fluid enters the fin heat exchanger group to absorb the heat of the return air flow after the first temperature drop. The three-way valve can adjust the flow rates of the first working fluid in the two paths according to the temperatures of the first working fluid discharged from the plate heat exchanger and the fin heat exchanger group.

[0007] In a possible implementation, when the fin heat exchanger group exchanges heat with the first working fluid: In the first step, close the fourth-zone defrost control valve at the inlet of the return air diffusion tower, and ensure that the first-zone defrost control valve, the second-zone defrost control valve, and the third-zone defrost control valve provided in the return air diffusion tower are all in the open state. At this time, the fourth-zone fin heat exchanger is in the defrost state, and the first-zone fin heat exchanger, the second-zone fin heat exchanger, and the third-zone fin heat exchanger are in the heat extraction state. In the second step, open the fourth-zone defrost control valve and close the first-zone defrost control valve. At this time, the second-zone fin heat exchanger, the third-zone fin heat exchanger, and the fourth-zone fin heat exchanger are in the heat extraction state, and the first-zone fin heat exchanger is in the defrost state. In the third step, open the first-zone defrost control valve and close the second-zone defrost control valve. At this time, the first-zone fin heat exchanger, the third-zone fin heat exchanger, and the fourth-zone fin heat exchanger are in the heat extraction state, and the second-zone fin heat exchanger is in the defrost state. In the fourth step, open all the second-zone defrost control valves and close the third-zone defrost control valve. At this time, the first-zone fin heat exchanger, the second-zone fin heat exchanger, and the fourth-zone fin heat exchanger are in the heat extraction state, and the third-zone fin heat exchanger is in the defrost state. The fifth step is the same as the first step, cycling the heat extraction and defrost functions of the fin heat exchanger.

[0008] In a possible implementation manner, the second working medium passes through the wellhead heater and the heating terminal radiator respectively. After passing through the usage end, the temperature of the second working medium drops, and it is pressurized by the terminal circulation pump, enters the heat pump unit to absorb heat and then the temperature rises, and is pressurized by the terminal circulation pump again for heating.

[0009] According to another aspect of the present application, a dual-mode coupled return air flow heat extraction device is provided, which uses the dual-mode coupled return air flow heat extraction method described in any one of the above. It includes: the return air diffusion tower, the spray head, the plate heat exchanger, the fin heat exchanger group, the heat pump unit and the usage end; one side of the return air diffusion tower is open and suitable for introducing the return air flow. The fin heat exchanger group is arranged on the top of the return air diffusion tower, the spray head is arranged at the bottom of the fin heat exchanger group, and there is a pipeline connection between the bottom water outlet of the return air diffusion tower and the spray head, and the plate heat exchanger is arranged between the bottom water outlet of the return air diffusion tower and the spray head; the heat pump unit is respectively connected in a loop with the fin heat exchanger group and the plate heat exchanger group, and the heat pump unit is connected in a loop with the usage end.

[0010] In a possible implementation manner, a sump is sunken and arranged at the bottom of the return air diffusion tower. There is a water outlet at the bottom of the return air diffusion tower, and a collecting pool, a spray water pump and a water processor are sequentially arranged between the water outlet and the plate heat exchanger; the number of the spray heads is multiple, and the multiple spray heads are arranged side by side in the return air diffusion tower.

[0011] In a possible implementation manner, a three-way valve is arranged at the first outlet of the heat pump unit. The two outlet ends of the three-way valve are respectively connected to the plate heat exchanger and the fin heat exchanger group. The first working medium discharged from the plate heat exchanger and the fin heat exchanger group merges into the heat pump unit through a pipeline, and a heat source circulation pump is arranged on the merging pipeline; a thermal resistor is arranged on the pipeline of the first working medium outlet end of the fin heat exchanger, and a thermal resistor is arranged on the pipeline of the first working medium outlet end of the plate heat exchanger. Both thermal resistors are electrically connected to the three-way valve; the first working medium is antifreeze, and the freezing point temperature of the antifreeze is -10°C to -30°C.

[0012] In a possible implementation manner, a water baffle is arranged between the spray head and the fin heat exchanger group, and the density of the water baffle is smaller than the size of the small liquid droplets in the return air flow; the fin heat exchanger group is provided with a plurality of fin heat exchanger partitions, the number of the fin heat exchanger partitions is greater than or equal to four, each partition is provided with a defrost control valve and a fin heat exchanger, the defrost control valve is arranged on the pipeline corresponding to the bottom of the fin heat exchanger, and both ends of the defrost control valve are respectively arranged at the liquid inlet end and the liquid outlet end of the first working medium; each fin heat exchanger is inclined, and the included angle between the fin heat exchanger and the flow direction of the return air flow is a first preset angle θ, and the value range of the first preset angle θ is: 30° ≤ θ ≤ 60°.

[0013] In a possible implementation manner, the number of the heat pump units is multiple; the second working medium outlet ends of the heat pump units are respectively connected to the wellhead heater and the heating terminal radiator through pipelines, the outlet ends of the wellhead heater and the heating terminal radiator are provided with a terminal circulation pump, and the outlet end of the terminal circulation pump is connected to the second medium inlet end of the heat pump unit through a pipeline.

[0014] The beneficial effects of the present application: Heat exchange is carried out between the return air flow and the sprayed water to realize the first cooling of the return air flow, and the heat in the sprayed water is exchanged with the first working medium in the plate heat exchanger, so that the temperature of the first working medium rises, and after being cooled by the heat pump unit, it enters the fin heat exchanger group to carry out heat exchange with the return air flow that has been cooled once, so that the temperature of the return air flow drops again, or the first working medium after being cooled by the heat pump unit flows back into the plate heat exchanger to carry out heat exchange with the sprayed water, so that the temperature of the sprayed water drops. Both routes will increase the temperature of the first working medium and return it to the heat pump unit. The second working medium in the heat pump unit absorbs the heat of the first working medium and transfers it to the use end for people to use. The temperature of the second working medium drops after use and then returns to the heat pump unit again, thereby realizing the recycling of the heat of the return air flow. According to a dual-mode coupling type return air flow heat extraction method and device of the present application, the temperature of the return air can be greatly reduced, a large range of hot air energy can be recovered, and additional heat energy consumption is reduced during the operation of the device.

[0015] According to the following detailed description of the exemplary embodiments with reference to the accompanying drawings, other features and aspects of the present application will become clear. Description of the Drawings

[0016] The drawings included in the specification and constituting a part of the specification show the exemplary embodiments, features and aspects of the present application together with the specification, and are used to explain the principles of the present application.

[0017] Figure 1Shows the connection and process schematic diagram of a dual-mode coupled return air flow heat extraction method and its device according to an embodiment of the present application;

[0018] Figure 2 Shows the partial structure diagram of a dual-mode coupled return air flow heat extraction method and its device according to an embodiment of the present application.

[0019] Various exemplary embodiments, features, and aspects of the present application will be described in detail below with reference to the accompanying drawings. The same reference numerals in the drawings denote elements having the same or similar functions. Although various aspects of the embodiments are shown in the drawings, the drawings do not have to be drawn to scale unless otherwise specified.

[0020] Among them, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application or simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application.

[0021] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality" means two or more unless otherwise specifically defined.

[0022] The special term "exemplary" here means "serving as an example, embodiment, or illustration". Any embodiment described as "exemplary" here does not have to be construed as superior to or better than other embodiments.

[0023] In addition, for a better description of the present application, numerous specific details are given in the following detailed implementation manners. Those skilled in the art should understand that the present application can also be implemented without some specific details. In some instances, methods, means, elements, and circuits well known to those skilled in the art are not described in detail so as to highlight the gist of the present application.

[0024] Figure 1Among them, 1 is the return air diffusion tower, 2 is the sprinkler head, 3 is the collecting pool, 4 is the sump, 5 is the spray water pump, 6 is the water processor, 7 is the plate heat exchanger, 8 is the baffle, 9 is the heat pump unit, 10 is the three-way valve, 11 is the fin heat exchanger group, 12 is the defrost control valve, 13 is the heat source circulation pump, 14 is the terminal circulation pump, 15 is the wellhead heater, and 16 is the heating terminal radiator.

[0025] Figure 2 Among them, 11-1 is the fin heat exchanger in the first partition, 11-2 is the fin heat exchanger in the second partition, 11-3 is the fin heat exchanger in the third partition, 11-4 is the fin heat exchanger in the fourth partition, 12-1 is the defrost control valve in the first partition, 12-2 is the defrost control valve in the second partition, 12-3 is the defrost control valve in the third partition, and 12-4 is the defrost control valve in the fourth partition.

[0026] A dual-mode coupled return air flow heat extraction method and its device, which can recycle and utilize the low-temperature preheating of coal mine return air, and meet the return air heat extraction device and operation method for the heat of coal mine production and life.

[0027] A dual-mode coupled return air flow heat extraction method includes the following process: The return air flow enters the return air diffusion tower 1. The spray water in the return air diffusion tower 1 exchanges heat with the heat in the return air flow, the temperature of the return air flow drops for the first time, and the temperature of the spray water rises. The spray water flows out of the return air diffusion tower 1, the temperature of the spray water drops after flowing through the plate heat exchanger 7, and then it flows back into the return air diffusion tower 1 to exchange heat with the heat of the return air flow; The first working medium exchanges heat through the plate heat exchanger 7, the temperature of the first working medium rises, the temperature of the first working medium drops after passing through the heat pump unit 9, part of the first working medium flows back into the plate heat exchanger 7 and the temperature rises again, and the other part of the first working medium flows into the fin heat exchanger group 11 to exchange heat with the return air flow after the first drop, the temperature of the first working medium rises, the temperature of the return air flow drops for the second time, and the first working medium flows back to the heat pump unit 9; The second working medium exchanges heat through the heat pump unit 9, the temperature of the second working medium rises, the temperature of the second working medium drops after passing through the using end, and the second working medium then flows back to the heat pump unit 9; The return air flow can exchange heat with the spray water and the fin heat exchanger group 11 respectively. Specific embodiments:

[0029] A sprinkler head 2 is arranged in the middle of the return air diffusion tower 1, and a collecting pool 3 is arranged at the lowest part of the lower part. The small droplets of the spray water sprayed by the sprinkler head 2 are evenly mixed with the return air flow in the return air diffusion tower 1 and fully exchange heat. The return air temperature can be reduced to 5°C - 10°C, and the temperature of the spray water rises from 2°C - 7°C to 10°C - 15°C, and is collected in the collecting pool 3.

[0030] The spray water in the sump 3 enters the collecting sump 4, is pressurized by the spray water pump 5, the impurities are filtered out by the on-line water treatment device 6, and then enters the plate heat exchanger 7 to extract heat. After extracting heat, the temperature of the spray water drops to 2°C - 7°C and then enters the nozzle 2 again for heat extraction.

[0031] The working medium on the heat source side is circulated and pressurized by the heat source circulation pump 13, enters the heat pump unit 9 to extract heat, and the temperature of the working medium drops from 0°C - 5°C to -15°C - -10°C. The low-temperature working medium coming out of the heat pump unit 9 is divided into two paths at the three-way valve 10 (three-way temperature control valve). One path enters the plate heat exchanger 7 to absorb heat and the temperature rises to 0°C - 5°C; the other path enters the fin heat exchanger bank 11 to absorb heat and the temperature rises to 0°C - 5°C. The high-temperature working media coming out of the plate heat exchanger 7 and the fin heat exchanger bank 11 are mixed and then enter the heat source circulation pump 13 again for pressurization and then enter the heat pump unit 9 to extract heat.

[0032] The working medium used in the heat source side circulation system is antifreeze, and ethylene glycol aqueous solution or calcium chloride aqueous solution can be used. According to different requirements for the freezing point temperature of the working medium of -10°C - -30°C, the volume ratio of ethylene glycol to water is 26% - 46%, and the mass concentration of the calcium chloride solution is 14% - 27%.

[0033] Thermistors are set to detect the temperatures of the working media at the outlets of the plate heat exchanger 7 and the fin heat exchanger bank 11 respectively. The three-way valve 10 is set to adjust and control the flow rate ratio of the working media leading to the plate heat exchanger 7 and the fin heat exchanger bank 11 respectively, so as to adjust the heat extracted by the plate heat exchanger 7 and the fin heat exchanger bank 11 within an appropriate range.

[0034] The working medium on the terminal side enters the wellhead heater 15 and the heating terminal radiator 16 respectively to dissipate heat for heating, and the temperature of the working medium drops from 30°C - 40°C to 20°C - 30°C. The low-temperature working medium returned from the wellhead heater 15 and the heating terminal radiator 16 is pressurized by the terminal circulation pump 14 and enters the heat pump unit 9 to absorb heat, and the temperature rises to 30°C - 40°C, and then is pressurized by the terminal circulation pump 14 again for heating.

[0035] The return air of the coal mine first exchanges heat with the spray water in the return air diffusion tower 1, and the temperature of the return air drops from 18°C - 20°C to 5°C - 10°C; the return air passes through the water baffle 8, and the remaining small droplets of the spray water in the return air are separated from the return air flow on the water baffle 8; the return air flow exchanges heat through the fin heat exchanger bank 11, and the temperature drops from 5°C - 10°C to -10°C - -5°C, and then is discharged from the return air diffusion tower 1.

[0036] The finned heat exchanger group 11 is divided into several parallel zones, and each zone is respectively equipped with a defrost control valve 12 to control the working state of the corresponding finned heat exchanger zone. When the defrost control valve 12 is opened, the corresponding finned heat exchanger zone is in the heat extraction state; when the defrost control valve 12 is closed, the corresponding finned heat exchanger zone is in the defrost state. The finned heat exchanger is usually divided into 4 - 6 zones. The finned heat exchanger zone can defrost automatically relying on the heat of the return air flow in the defrost state, without additional energy consumption.

[0037] The included angle between each finned heat exchanger and the flow direction of the return air flow is the first preset angle θ; the value range of the first preset angle θ is 30° - 60°. Each finned heat exchanger is inclined at a certain angle with respect to the flow direction of the return air flow, increasing the heat exchange area of the finned heat exchanger and the cross-sectional area of the return air flow, and reducing the resistance of the return air heat extraction device.

[0038] By adjusting the three-way valve 10, the flow rate ratio of the working medium respectively leading to the plate heat exchanger 7 and the finned heat exchanger group 11 is controlled to ensure that the heat extracted by the plate heat exchanger 7 and the finned heat exchanger group 11 is within an appropriate range. When the temperature of the working medium at the outlet of the plate heat exchanger 7 is too high, the three-way valve 10 is adjusted to increase the flow rate ratio of the working medium leading to the plate heat exchanger 7 and decrease the flow rate ratio of the working medium leading to the finned heat exchanger group 11; when the temperature of the working medium at the outlet of the finned heat exchanger group 11 is too high, the three-way valve 10 is adjusted to increase the flow rate ratio of the working medium leading to the finned heat exchanger group 11 and decrease the flow rate ratio of the working medium leading to the plate heat exchanger 7. When the temperatures of the working medium at the outlets of both the plate heat exchanger 7 and the finned heat exchanger group 11 are too high, the heat source circulation pump 13 is adjusted to increase the total flow rate of the working medium leading to the plate heat exchanger 7 and the finned heat exchanger group 11; conversely, the heat source circulation pump 13 is adjusted to decrease the total flow rate of the working medium leading to the plate heat exchanger 7 and the finned heat exchanger group 11.

[0039] In a possible implementation manner, the return air flow enters from one side of the return air diffusion tower 1, and the small droplets of the sprayed water sprayed from a position near the top are mixed with the return air flow to exchange heat. The sprayed water after heat exchange is collected in the bottom sump 3 of the return air diffusion tower 1; the sprayed water in the sump 3 enters the collection pool 4, is pressurized by the spray water pump 5, filtered by the water treatment device 6 to remove impurities, and then enters the plate heat exchanger 7 to extract heat. The sprayed water after extracting heat is sprayed again through the nozzle 2 for heat extraction.

[0040] In a possible implementation manner, the first working medium is pressurized by the heat source circulation pump 13 and then enters the heat pump unit 9 to extract heat. After extracting heat, the first working medium passes through the three-way valve 10 and is divided into two paths, both of which can increase the temperature of the first working medium. After the temperature of the first working medium increases, the two paths of the first working medium are mixed and then enter the heat source side circulation pump again; one path of the first working medium enters the plate heat exchanger 7 to absorb heat; the other path of the first working medium enters the fin heat exchanger group 11 to absorb the heat of the return air flow after the first temperature reduction; the three-way valve 10 can adjust the flow rates of the two paths of the first working medium according to the temperatures of the first working medium discharged from the plate heat exchanger 7 and the fin heat exchanger group 11.

[0041] In a possible implementation manner, when the fin heat exchanger group 11 exchanges heat with the first working medium; in the first step, close the fourth-zone defrost control valve 12-4 at the inlet of the return air diffusion tower 1, and ensure that the first-zone defrost control valve 12-1, the second-zone defrost control valve 12-2, and the third-zone defrost control valve 12-3 arranged in the return air diffusion tower 1 are all in the open state. At this time, the fourth-zone fin heat exchanger 11-4 is in the defrost state, and the first-zone fin heat exchanger 11-1, the second-zone fin heat exchanger 11-2, and the third-zone fin heat exchanger 11-3 are in the heat extraction state; in the second step, open the fourth-zone defrost control valve 12-4 and close the first-zone defrost control valve 12-1. At this time, the second-zone fin heat exchanger 11-2, the third-zone fin heat exchanger 11-3, and the fourth-zone fin heat exchanger 11-4 are in the heat extraction state, and the first-zone fin heat exchanger 11-1 is in the defrost state; in the third step, open the first-zone defrost control valve 12-1 and close the second-zone defrost control valve 12-2. At this time, the first-zone fin heat exchanger 11-1, the third-zone fin heat exchanger 11-3, and the fourth-zone fin heat exchanger 11-4 are in the heat extraction state, and the second-zone fin heat exchanger 11-2 is in the defrost state; in the fourth step, open all the second-zone defrost control valves 12-2 and close the third-zone defrost control valve 12-3. At this time, the first-zone fin heat exchanger 11-1, the second-zone fin heat exchanger 11-2, and the fourth-zone fin heat exchanger 11-4 are in the heat extraction state, and the third-zone fin heat exchanger 11-3 is in the defrost state; the fifth step is the same as the first step, and the heat extraction and defrost functions of the fin heat exchanger are cycled.

[0042] In the illustrated embodiment, the fin heat exchanger is divided into 4 parallel zones. During operation, the defrost control valve 12-1 of the first zone, the defrost control valve 12-2 of the second zone, and the defrost control valve 12-3 of the third zone are opened, while the defrost control valve 12-4 of the fourth zone is closed; at this stage (the first stage), the fin heat exchangers 11-1 of the first zone, 11-2 of the second zone, and 11-3 of the third zone are in the heat extraction state, and the fin heat exchanger 11-4 of the fourth zone is in the defrost state. After operating for 5 minutes, the defrost control valve 12-4 of the fourth zone is opened, and the defrost control valve 12-1 of the first zone is closed; at this stage (the second stage), the fin heat exchangers 11-2 of the second zone, 11-3 of the third zone, and 11-4 of the fourth zone are in the heat extraction state, and the fin heat exchanger 11-1 of the first zone is in the defrost state. After operating for another 5 minutes, the defrost control valve 12-1 of the first zone is opened, and the defrost control valve 12-2 of the second zone is closed; at this stage (the third stage), the fin heat exchangers 11-1 of the first zone, 11-3 of the third zone, and 11-4 of the fourth zone are in the heat extraction state, and the fin heat exchanger 11-2 of the second zone is in the defrost state. After operating for another 5 minutes, the defrost control valve 12-2 of the second zone is opened, and the defrost control valve 12-3 of the third zone is closed; at this stage (the fourth stage), the fin heat exchangers 11-1 of the first zone, 11-2 of the second zone, and 11-4 of the fourth zone are in the heat extraction state, and the fin heat exchanger 11-3 of the third zone is in the defrost state. After operating for another 5 minutes, the defrost control valve 12-3 of the third zone is opened, and the defrost control valve 12-4 of the fourth zone is closed; at this stage, it returns to the same heat extraction and defrost working state as the first stage. By repeatedly switching the on / off state of the defrost control valve 12 in this way, the heat extraction and defrost functions of the fin heat exchanger are realized.

[0043] In a possible implementation, the second working fluid passes through the wellhead heater 15 and the heating terminal radiator 16 respectively. After passing through the using end, the temperature of the second working fluid drops, and it is pressurized by the terminal circulation pump 14 and enters the heat pump unit 9 to absorb heat and then the temperature rises. It is pressurized by the terminal circulation pump 14 again for heating.

[0044] A dual-mode coupled return air flow heat extraction device using the dual-mode coupled return air flow heat extraction method of any one of the above, comprising: a return air diffusion tower 1, a spray head 2, a plate heat exchanger 7, a fin heat exchanger group 11, a heat pump unit 9 and a user end; one side of the return air diffusion tower 1 is open and suitable for introducing a return air flow, the fin heat exchanger group 11 is arranged at the top of the return air diffusion tower, the spray head 2 is arranged at the bottom of the fin heat exchanger group 11, a pipeline is connected between the bottom water outlet of the return air diffusion tower and the spray head 2, and the plate heat exchanger 7 is arranged between the bottom water outlet of the return air diffusion tower and the spray head 2; the heat pump unit 9 is respectively connected to the fin heat exchanger group 11 and the plate heat exchanger 7 in a loop, and the heat pump unit 9 is connected to the user end in a loop.

[0045] In a possible implementation manner, a sump 3 is provided by sinking the bottom of the return air diffusion tower 1, a water outlet is provided at the bottom of the return air diffusion tower, a collecting pool 4, a spray water pump 5 and a water treatment device 6 are sequentially arranged between the water outlet and the plate heat exchanger 7; the number of the spray heads 2 is multiple, and the multiple spray heads 2 are arranged side by side in the return air diffusion tower 1.

[0046] In a possible implementation manner, a three-way valve 10 is provided at the first outlet of the heat pump unit 9, two outlet ends of the three-way valve 10 are respectively connected to the plate heat exchanger 7 and the fin heat exchanger group 11, the first working medium discharged from the plate heat exchanger 7 and the fin heat exchanger group 11 is combined into the heat pump unit 9 through a pipeline, and a heat source circulation pump 13 is arranged on the combined pipeline; a thermal resistor is arranged on the pipeline of the first working medium outlet end of the fin heat exchanger, a thermal resistor is arranged on the pipeline of the first working medium outlet end of the plate heat exchanger 7, and both thermal resistors are electrically connected to the three-way valve 10; the first working medium is antifreeze, and the freezing point temperature of the antifreeze is -10°C - -30°C.

[0047] In a possible implementation manner, a water baffle 8 is arranged between the spray head 2 and the fin heat exchanger group 11, and the density of the water baffle 8 is smaller than the size of the small liquid droplets in the return air flow; the fin heat exchanger group 11 is provided with a plurality of fin heat exchanger partitions, the number of the fin heat exchanger partitions is greater than or equal to four, each partition is provided with a defrost control valve 12 and a fin heat exchanger, the defrost control valve 12 is arranged on the corresponding pipeline at the bottom of the fin heat exchanger, and both ends of the defrost control valve 12 are arranged at the inlet end and the outlet end of the first working medium; each fin heat exchanger is inclined, and the included angle between the fin heat exchanger and the flow direction of the return air flow is a first preset angle θ, and the value range of the first preset angle θ is: 30° ≤ θ ≤ 60°.

[0048] In a possible implementation, the number of heat pump units 9 is multiple; the second working medium outlet ends of the heat pump units 9 are respectively connected to the wellhead heater 15 and the heating end radiator 16 through pipelines, and an end circulation pump 14 is provided at the outlet ends of the wellhead heater 15 and the heating end radiator 16. The outlet end of the end circulation pump 14 is connected to the second medium inlet end of the heat pump unit 9 through a pipeline.

[0049] The dual-mode coupled return air flow heat extraction device and operation method of the present invention have the following advantages:

[0050] (1) Through the dual-mode coupled return air flow heat extraction device, the return air temperature can be reduced by more than 30°C at one time, a large amount of heat energy can be obtained, and at the same time, the ventilation resistance increases very little.

[0051] (2) The return air temperature can be reduced to below -10°C, realizing the ultimate recovery of return air energy.

[0052] (3) Solve the frosting problem of heat extraction by the finned heat exchanger, and there is no additional heat energy consumption during defrosting.

[0053] It should be noted that although a dual-mode coupled return air flow heat extraction method and its device are introduced by taking this application as an example as above, those skilled in the art can understand that this application should not be limited to this. In fact, users can flexibly set each parameter according to personal preferences and / or actual application scenarios as long as the design is reasonable.

[0054] In this way, through the heat exchange between the return air flow and the sprayed water, the first cooling of the return air flow is realized, and the heat in the sprayed water is exchanged with the first working medium in the plate heat exchanger, so that the temperature of the first working medium rises, and after being cooled by the heat pump unit, it enters the finned heat exchanger group to exchange heat with the return air flow that has been cooled once, so that the temperature of the return air flow drops again, or the first working medium after being cooled by the heat pump unit flows back into the plate heat exchanger to exchange heat with the sprayed water, so that the temperature of the sprayed water drops. Both routes will increase the temperature of the first working medium and return it to the heat pump unit. The second working medium in the heat pump unit absorbs the heat of the first working medium and transmits it to the user end for people to use. The temperature of the used second working medium drops and then returns to the heat pump unit again, thereby realizing the recycling of the heat of the return air flow. According to a dual-mode coupled return air flow heat extraction method and its device of the present application, the temperature of the return air can be greatly reduced, the ultimate recovery of hot air energy is realized, and the additional heat energy consumption is reduced during the operation of the device.

[0055] The embodiments of the present application have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to technologies in the market, or to enable other ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A dual-mode coupled return air flow heat extraction method, characterized in that, it includes the following processes: The return air flow enters the return air diffusion tower, and the spray water in the return air diffusion tower exchanges heat with the heat in the return air flow. The temperature of the return air flow drops for the first time, the temperature of the spray water rises, the spray water flows out of the return air diffusion tower, the temperature of the spray water drops after flowing through the plate heat exchanger, and then it flows back into the return air diffusion tower to exchange heat with the heat of the return air flow; The first working medium exchanges heat through the plate heat exchanger, the temperature of the first working medium rises, the temperature of the first working medium drops after passing through the heat pump unit, part of the first working medium flows back into the plate heat exchanger and the temperature rises again, and another part of the first working medium flows into the fin heat exchanger group to exchange heat with the return air flow after the first drop. The temperature of the first working medium rises, the temperature of the return air flow drops for the second time, and the first working medium flows back to the heat pump unit; The second working medium exchanges heat through the heat pump unit, the temperature of the second working medium rises, the temperature of the second working medium drops after passing through the using end, and the second working medium flows back to the heat pump unit again; The return air flow can exchange heat with the spray water and the fin heat exchanger group respectively.

2. The dual-mode coupled return air flow heat extraction method according to claim 1, characterized in that, The return air flow enters from one side of the return air diffusion tower, and the small droplets of the spray water sprayed from a position near the top mix with the return air flow and exchange heat. The spray water after heat exchange is collected in the bottom sump of the return air diffusion tower; The spray water in the sump enters the collection pool, is pressurized by a spray water pump, filtered to remove impurities through a water processor, and then enters the plate heat exchanger to extract heat. The spray water after extracting heat is sprayed again through a nozzle to extract heat.

3. The dual-mode coupled return air flow heat extraction method according to claim 1, characterized in that, The first working medium is pressurized by a heat source circulation pump and then enters the heat pump unit to extract heat. After the first working medium extracts heat, it passes through a three-way valve, and the first working medium is divided into two paths, both of which can raise the temperature of the first working medium. After the temperature of the first working medium rises, they are mixed and then enter the heat source side circulation pump again; One path of the first working medium enters the plate heat exchanger to absorb heat; Another path of the first working medium enters the fin heat exchanger group to absorb the heat of the return air flow after the first temperature drop; The three-way valve can adjust the flow rates of the two paths of the first working medium according to the temperatures of the first working medium discharged from the plate heat exchanger and the fin heat exchanger group.

4. The dual-mode coupled return air flow heat extraction method according to claim 3, characterized in that, when the fin heat exchanger group exchanges heat with the first working medium; First step, close the defrost control valve of the fourth zone at the inlet of the return air diffusion tower, and ensure that the defrost control valves of the first zone, the second zone, and the third zone arranged in the return air diffusion tower are all in the open state. At this time, the fin heat exchanger of the fourth zone is in the defrost state, and the fin heat exchangers of the first zone, the second zone, and the third zone are in the heat extraction state; Second step, open the defrost control valve of the fourth zone and close the defrost control valve of the first zone. At this time, the fin heat exchangers of the second zone, the third zone, and the fourth zone are in the heat extraction state, and the fin heat exchanger of the first zone is in the defrost state; Third step, open the defrost control valve of the first zone and close the defrost control valve of the second zone. At this time, the fin heat exchangers of the first zone, the third zone, and the fourth zone are in the heat extraction state, and the fin heat exchanger of the second zone is in the defrost state; Fourth step, open the defrost control valve of the second zone and close the defrost control valve of the third zone. At this time, the fin heat exchangers of the first zone, the second zone, and the fourth zone are in the heat extraction state, and the fin heat exchanger of the third zone is in the defrost state; Fifth step is the same as the first step, cycling the heat extraction and defrost functions of the fin heat exchanger.

5. The dual-mode coupled return air flow heat extraction method according to claim 1, characterized in that, the second working medium passes through the wellhead heater and the heating terminal radiator respectively. After passing through the using end, the temperature of the second working medium drops, and it is pressurized by the terminal circulation pump, enters the heat pump unit to absorb heat and then the temperature rises, and is pressurized by the terminal circulation pump again for heating.

6. A dual-mode coupled return air flow heat extraction device, characterized in that, using the dual-mode coupled return air flow heat extraction method according to any one of claims 1-5, including: the return air diffusion tower, the spray head, the plate heat exchanger, the fin heat exchanger group, the heat pump unit, and the using end; One side of the return air diffusion tower is open, suitable for introducing the return air flow. The fin heat exchanger group is arranged at the top of the return air diffusion tower, the spray head is arranged at the bottom of the fin heat exchanger group, and there is a pipeline connection between the bottom water outlet of the return air diffusion tower and the spray head, and the plate heat exchanger is arranged between the bottom water outlet of the return air diffusion tower and the spray head; The heat pump unit is respectively connected in a loop with the fin heat exchanger group and the plate heat exchanger group, and the heat pump unit is connected in a loop with the using end.

7. The dual-mode coupled return air flow heat extraction device according to claim 6, characterized in that, a sump is sunken at the bottom of the return air diffusion tower, a water outlet is arranged at the bottom of the return air diffusion tower, and a sump, a spray water pump, and a water processor are sequentially arranged between the water outlet and the plate heat exchanger; The number of the spray heads is multiple, and the multiple spray heads are arranged side by side in the return air diffusion tower.

8. The dual-mode coupled return air flow heat extraction device according to claim 6, characterized in that, a three-way valve is provided at the first outlet of the heat pump unit, and the two outlet ends of the three-way valve are respectively connected to the plate heat exchanger and the fin heat exchanger group. The first working medium discharged from the plate heat exchanger and the fin heat exchanger group merges into the heat pump unit through a pipeline, and a heat source circulation pump is provided on the merging pipeline; a thermal resistor is provided on the pipeline at the first working medium outlet end of the fin heat exchanger, and a thermal resistor is provided on the pipeline at the first working medium outlet end of the plate heat exchanger. Both thermal resistors are electrically connected to the three-way valve; the first working medium is antifreeze, and the freezing point temperature of the antifreeze is -10°C to -30°C.

9. The dual-mode coupled return air flow heat extraction device according to claim 8, characterized in that, a water baffle is provided between the spray head and the fin heat exchanger group, and the density of the water baffle is smaller than the size of the small liquid droplets in the return air flow; the fin heat exchanger group is provided with a plurality of fin heat exchanger partitions, the number of the fin heat exchanger partitions is greater than or equal to four, and each partition is provided with a defrost control valve and a fin heat exchanger. The defrost control valve is provided on the pipeline corresponding to the bottom of the fin heat exchanger, and both ends of the defrost control valve are provided at the inlet end and the outlet end of the first working medium; each fin heat exchanger is inclined, and the included angle between the fin heat exchanger and the flow direction of the return air flow is a first preset angle θ, and the value range of the first preset angle θ is: 30° ≤ θ ≤ 60°.

10. The dual-mode coupled return air flow heat extraction device according to claim 6, characterized in that, the number of the heat pump units is multiple; the second working medium outlet ends of the heat pump units are respectively connected to the wellhead heater and the heating terminal radiator through pipelines. An end circulation pump is provided at the outlet ends of the wellhead heater and the heating terminal radiator, and the outlet end of the end circulation pump is connected to the second medium inlet end of the heat pump unit through a pipeline.

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