Photovoltaic complementary multi-stage heating flash compression and air source heat pump heating system

Abstract

The photovoltaic complementary multi-stage heating flash evaporation compression type and air source heat pump heating system disclosed in the present invention comprises a heat network circulating water pipe, a heat network circulating water pump is arranged on the heat network circulating water pipe, and the heating section of the heat network circulating water pipe is connected with a solar thermal collection system, an air source heat pump system, a negative pressure flash evaporation sewage source heat pump system and a heat storage tank in sequence according to the return water flow direction. The solar thermal collection system comprises a shell and tube heat exchanger, a hot oil circulation pump and a trough type solar thermal collector; the present invention utilizes the low-grade thermal energy in the air and domestic sewage in combination with the solar thermal collector, the compression heat pump, the flash tank and the heat storage tank, realizes the deep recovery of the waste heat that can be utilized on the user side, heats the heat network circulating water return water in a stepped heating manner, reduces the working temperature difference of each stage of the heat pump, improves the COP of the heat pump, reduces the power consumption of the heat pump, and simultaneously configures the solar thermal collector to replace the heat pumps of different heating sections under different light intensities, and configures the heat storage tank to further reduce the heating cost by utilizing the peak and valley electricity prices.

Description

Technical Field

[0001] The present invention belongs to the technical field of heating equipment, and in particular relates to a photoelectric complementary multi-stage heating flash evaporation compression type and air source heat pump heating system. Background Art

[0002] Heating in the severe cold season in northern my country mainly relies on fossil energy such as coal and natural gas. These resources will produce a large amount of pollutants and greenhouse gases during the mining and use process, leading to environmental degradation. In the context of the interaction of energy shortage, environmental degradation and climate issues, establishing an energy-saving, efficient, low-carbon and environmentally friendly heating technology route as a substitute or supplement for the traditional centralized heating system is an important issue that needs to be solved urgently.

[0003] As the original waste heat of the city, domestic sewage has a series of advantages such as easy collection, high low-grade thermal energy, relatively stable water volume and temperature, and easy utilization. As a low-grade heat source for clean urban heating, it has huge energy-saving potential. Compression heat pumps are mainly based on the reverse Carnot cycle principle and are divided into several categories such as air source, sewage source, and water source heat pumps. They use electric energy to extract low-grade thermal energy to generate high-grade thermal energy. They have the advantages of stable energy transmission, high heat exchange efficiency, energy saving and environmental protection, and can turn air energy and sewage energy into a usable resource. However, air source heat pumps are affected by the low outdoor ambient temperature in cold areas, which is prone to problems such as evaporator frosting. At the same time, the excessive temperature difference between high and low temperature heat sources will reduce the heating performance coefficient of the heat pump; and the waste heat of sewage is limited by the flow of domestic sewage in the living area, and the waste heat that can be extracted is limited. Summary of the invention

[0004] The purpose of the present invention is to provide a photovoltaic complementary multi-stage heating flash compression type and air source heat pump heating system, which utilizes solar energy, air energy and sewage energy to perform step-by-step heating on heating return water.

[0005] The technical solution adopted by the present invention is a photovoltaic complementary multi-stage heating flash evaporation compression type and air source heat pump heating system, including a heat network circulating water pipe, a heat network circulating water pump is arranged on the heat network circulating water pipe, and the heat network circulating water pipe is sequentially connected with a solar energy collection system, an air source heat pump system, a negative pressure flash evaporation sewage source heat pump system and a heat storage tank according to the return water flow direction;

[0006] The solar thermal collection system includes a shell and tube heat exchanger, which is connected to a hot oil circulation pump through a pipeline, and the hot oil circulation pump is connected to a trough type solar collector through a pipeline. The connection position between the water inlet of the shell and tube heat exchanger and the circulating water pipe of the heating network is located in front of the connection position between the air source heat pump system and the circulating water pipe of the heating network, and the connection position between the water outlet of the shell and tube heat exchanger and the circulating water pipe of the heating network is located between the connection positions between the air source heat pump system and the negative pressure flash type sewage source heat pump system and the circulating water pipe of the heating network, and at the rear end of the connection position between the negative pressure flash type sewage source heat pump system and the circulating water pipe of the heating network.

[0007] The present invention is also characterized in that

[0008] The heating network circulating water pipe is connected to the water inlet and outlet of the heat storage tank through pipes respectively. A stop valve and an electric regulating valve d are arranged in sequence on the connecting pipe between the heating network circulating water pipe and the water inlet of the heat storage tank, and a stop valve is arranged on the connecting pipe between the heating network circulating water pipe and the water outlet of the heat storage tank; a stop valve is arranged between the two nodes connecting the heat storage tank and the heating network circulating water pipe.

[0009] The air source heat pump system includes a condenser a, which includes a compressor a and an evaporator a which are sequentially connected through a pipeline to form a closed loop, and an expansion valve a is provided on the pipeline connecting the evaporator a and the condenser a;

[0010] The water inlet and outlet of condenser a are connected in parallel to the circulating water pipe of the heating network through pipes. A stop valve and an electric regulating valve a are arranged in sequence on the pipe connecting the water inlet of condenser a and the circulating water pipe of the heating network. A stop valve is arranged on the pipe connecting the water outlet of condenser a and the circulating water pipe of the heating network. A stop valve is arranged between the two nodes connecting condenser a and the circulating water pipe of the heating network.

[0011] The pressure flash evaporation sewage source heat pump system includes a condenser b, which includes a compressor b and an evaporator b which are sequentially connected through a pipeline to form a closed loop, and an expansion valve b is provided on the pipeline connecting the evaporator b and the condenser b;

[0012] The water inlet and outlet of condenser b are connected in parallel to the circulating water pipe of the heating network through pipes. A stop valve and an electric regulating valve b are arranged in sequence on the pipe connecting the water inlet of condenser b and the circulating water pipe of the heating network. A stop valve is arranged on the pipe connecting the water outlet of condenser b and the circulating water pipe of the heating network. A stop valve is arranged between the two nodes connecting condenser b and the circulating water pipe of the heating network.

[0013] The inlet of evaporator b is connected to a flash tank through a pipeline. A vacuum pump is arranged on one side wall of the flash tank. A spray nozzle is arranged inside the flash tank near the top wall. The spray nozzle is connected to the user sewage source through a pipeline. A sewage spray pump is arranged on the pipeline connecting the spray nozzle and the user sewage source. A water storage tank is arranged below the spray nozzle. The water storage tank is connected to a sewage return pump through a pipeline.

[0014] The outlet of evaporator b is connected to a condensate pump through a pipeline, the condensate pump is connected to a condensate tank and a flash tank through a pipeline, a stop valve is provided on the pipeline connecting the condensate pump and the condensate tank, and a stop valve is provided on the pipeline connecting the condensate pump and the flash tank.

[0015] The beneficial effects of the present invention are:

[0016] (1) The present invention utilizes a solar collector, a compression heat pump, a flash tank, and a heat storage tank to utilize low-grade thermal energy in the air and domestic sewage, thereby achieving deep recovery of waste heat that can be utilized on the user side.

[0017] (2) Negative pressure flash type sewage source heat pump system establishes a negative pressure flash tank to generate flash steam as the low-temperature heat source of the sewage source heat pump, solving the problem of blockage of the low-temperature heat exchanger of the sewage source heat pump. The whole process is similar to the distillation of domestic sewage. The condensed water produced can be used as circulating water replenishment for the heating network or as domestic water for some non-drinking water, reducing the water consumption of the system.

[0018] (3) The present invention heats the return water of the heat network circulation water by a stepped heating method, thereby reducing the working temperature difference of each stage of the heat pump, improving the COP of the heat pump, and reducing the power consumption of the heat pump. At the same time, a solar collector is configured to replace the heat pumps of different heating sections under different light intensities, and a heat storage tank is configured to utilize peak and valley electricity prices to further reduce the heating cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the photovoltaic complementary multi-stage heating flash compression type and air source heat pump heating system of the present invention.

[0020] In the figure, 1. trough solar collector, 2. collector oil circulation pump, 3. shell and tube heat exchanger, 4. condenser a, 5. compressor a, 6. evaporator a, 7. expansion valve a, 8. sewage spray pump, 9. sewage return pump, 10. flash tank, 11. spray nozzle, 12. vacuum pump, 13. condensate tank, 14. condensate pump, 15. heat storage tank, 16. electric regulating valve c, 17. electric regulating valve a, 18. heat network circulation water pump, 19. condenser b, 20. compressor b, 21. evaporator b, 22. expansion valve b, 23. electric regulating valve b, 24. electric regulating valve d, 25. heat network circulation water pipe. DETAILED DESCRIPTION

[0021] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] The structure of the photovoltaic complementary multi-stage heating flash compression type and air source heat pump heating system of the present invention is as follows: Figure 1 As shown, it includes a heat network circulating water pipe 25, on which a heat network circulating water pump 18 is arranged, and on which a solar energy collection system, an air source heat pump system, a negative pressure flash type sewage source heat pump system and a heat storage tank 15 are arranged in sequence according to the return direction.

[0023] The solar thermal collection system includes a trough solar collector 1, which is connected to a shell and tube heat exchanger 3 through a pipeline. A heat collecting oil circulation pump 2 is arranged on the pipeline connecting the solar collector 1 and the shell and tube heat exchanger 3. The water inlet of the shell and tube heat exchanger 3 is connected to the heat network circulating water pipe 25 at the front end of the air source heat pump system through a pipeline. A stop valve and an electric regulating valve c16 are arranged in sequence on the connecting pipeline of the heat network circulating water pipe 25 and the water inlet of the shell and tube heat exchanger 3. The water outlet pipeline of the shell and tube heat exchanger 3 is divided into two routes, one route is connected to the heat network circulating water pipe 25 between the air source heat pump system and the negative pressure flash type sewage source heat pump system, and the other route is connected to the heat network circulating water pipe 25 at the rear end of the negative pressure flash type sewage source heat pump system. Stop valves are arranged on the two connecting pipelines.

[0024] The air source heat pump system includes a condenser a4, a compressor a5 and an evaporator a6 which are connected in sequence to form a closed loop. An expansion valve a7 is arranged on the connecting pipe between the evaporator a6 and the condenser a4. The condenser a4 is connected in parallel to the heat network circulating water pipe 25. A stop valve is arranged between the two nodes where the condenser a4 is connected in parallel with the heat network circulating water pipe 25. A stop valve and an electric regulating valve a17 are arranged in sequence on the connecting pipe between the heat network circulating water pipe 25 and the water inlet of the condenser a4. A stop valve is arranged on the connecting pipe between the water outlet of the condenser a4 and the heat network circulating water pipe 25.

[0025] The flash evaporation sewage source heat pump system is connected in sequence to the condenser b19, the compressor b20 and the evaporator b21 constituting a closed loop. An expansion valve b22 is arranged on the connecting pipe between the evaporator b21 and the condenser b19. The condenser b19 is connected in parallel to the heat network circulating water pipe 25. A stop valve is arranged between the two nodes where the condenser b19 and the heat network circulating water pipe 25 are connected in parallel. A stop valve and an electric regulating valve b23 are arranged in sequence on the connecting pipe between the heat network circulating water pipe 25 and the water inlet of the condenser b19. The water outlet of the condenser b19 is connected to the heat network circulating water pipe 25. A stop valve is arranged on the connecting pipeline; the water inlet of the evaporator b21 is connected with the flash tank 10 through a pipeline, and the flash tank 10 generates flash steam as a low-temperature heat source for the evaporator b21 to solve the problem of blockage of the sewage source evaporator b21. A spray nozzle 11 is arranged inside the flash tank 10, and the spray nozzle 11 is connected with the user sewage source through a pipeline. A sewage spray pump 8 is arranged on the connecting pipeline, and a water storage space is arranged at the bottom of the flash tank 10. The water storage space is connected with the sewage return pump 9 through a pipeline. A vacuum pump 12 is arranged on one side wall of the flash tank 10 to maintain the negative pressure state inside the flash tank 10; the outlet of the evaporator 10 is connected with the condensate pump 14 through a pipeline, and the condensate pump 14 is connected with the flash tank 10 and the condensate tank 13 through pipelines respectively. The condensate in the condensate tank 13 can be used for non-drinking water such as heat pipe circulating water replenishment to reduce the water consumption of the system. A stop valve is arranged on the connecting pipeline between the condensate pump 14 and the flash tank 10 and the condensate tank 13.

[0026] The heat storage tank 15 is connected in parallel to the heat network circulating water pipe 25, and a stop valve is arranged between the two nodes where the heat storage tank 15 and the heat network circulating water pipe 25 are connected in parallel. A stop valve and an electric regulating valve d24 are arranged in sequence on the connecting pipe between the heat network circulating water pipe 25 and the inlet of the heat storage tank 15, and a stop valve is arranged on the connecting pipe between the outlet of the heat storage tank 15 and the heat network circulating water pipe 25.

[0027] The working mode of the present invention is two-stage heating of an air source heat pump system and a pressure flash evaporation sewage source heat pump system. The solar thermal collection system can replace the air source heat pump system or the air source heat pump system and the pressure flash evaporation sewage source heat pump system to heat the return water of the heating network according to the light intensity.

[0028] When there is sufficient sunlight during the day, the air source heat pump system and the flash-type sewage source heat pump system are turned off, and the return water of the heating network is heated only by the solar thermal collection system. The trough solar collector 1 concentrates and heats the internal heat transfer oil, and the heat collection oil circulation pump 2 drives the heat transfer oil circulation. The heat transfer oil goes to the shell and tube heat exchanger 3 to exchange heat with the return water of the heating network, and heats the return water of the heating network to the water supply temperature. The excess heat is stored in the heat storage tank 15.

[0029] When the sunlight is insufficient during the day, the solar thermal collection system alone is not enough to heat the return water of the heating network to the water supply temperature. At this time, the solar thermal collection system and the heat storage tank 15 jointly heat the return water of the heating network. When the thermal power of the solar thermal collection system and the heat storage tank 15 is not enough to heat the return water of the heating network to the required water supply temperature, the flash evaporation sewage source heat pump system is started as the high-temperature heating section, and the solar thermal collection system is used as the low-temperature heating section. The trough solar collector 1 concentrates and heats the internal heat transfer oil, and the heat collection oil circulation pump 2 drives the heat transfer oil circulation. The heat transfer oil goes to the shell and tube heat exchanger 3 and exchanges heat with the return water of the heating network to complete the low-temperature section heating. The return water of the heating network heated at a low temperature by the solar thermal collection system enters the compressed flash evaporation sewage source heat pump system, and the domestic sewage is heated in the sewage Under the action of the spray pump 8, the sewage is sprayed into the flash tank 10 by the sewage spray nozzle 11. The vacuum pump 12 on one side of the flash tank 10 maintains a negative pressure state in the tank. By utilizing the characteristic that the saturated temperature of water vapor decreases with the decrease of ambient pressure, the sewage is evaporated in the tank and absorbs its own low-temperature waste heat. The generated negative pressure steam flows out of the flash tank 10 to the evaporator b21 as a low-temperature heat source. After absorbing heat, the circulating working fluid in the evaporator b21 is sent to the condenser b19 through the compressor b to release heat and exchange heat with the return water of the heat network, thereby completing the heating of the high-temperature section of the return water of the heat network. After releasing heat, the circulating working fluid is reduced in pressure by the expansion valve b22 and then sent to the evaporator b21; if this is the off-peak period, the heating power of the flash type sewage source heat pump system is increased, and the excess heat is stored in the heat storage tank 15 to supplement heat during the peak period.

[0030] When there is no light at night, the solar thermal collection system is turned off, and the air source heat pump system and the flash-pressure sewage source heat pump system are started. The air source heat pump system serves as the low-temperature heating section of the circulating water in the heat network, and the flash-pressure sewage source heat pump system serves as the high-temperature heating section. The circulating working fluid in the air source heat pump system evaporates and absorbs heat on the evaporator a6 side, and releases heat to the condenser a4 through the compressor a5, and heats the return water of the heat network at the low temperature section; after releasing heat, the circulating working fluid is decompressed by the expansion valve a7 and then sent to the evaporator a6;

[0031] After low-temperature heating by the air source heat pump system, the circulating water of the heat network flows into the high-pressure flash type sewage source heat pump system. Under the action of the sewage spray pump 8, the domestic sewage is sprayed into the flash tank 10 by the sewage spray nozzle 11. The vacuum pump 12 on one side of the flash tank 10 maintains a negative pressure state in the tank. By utilizing the characteristic that the saturated temperature of water vapor decreases with the decrease of ambient pressure, the sewage evaporates in the tank and absorbs its own low-temperature waste heat. The generated negative-pressure steam flows out of the flash tank 10 to the evaporator b21 as a low-temperature heat source. After absorbing heat, the circulating working fluid in the evaporator b21 is sent to the condenser b19 through the compressor b to release heat and exchange heat with the return water of the heat network, thereby completing the high-temperature heating of the return water of the heat network. After releasing heat, the circulating working fluid is reduced in pressure by the expansion valve b22 and then sent to the evaporator b21. If it happens to be a valley power period at this time, the heating power of the air source heat pump system and the flash type sewage source heat pump system will be increased, and the excess heat will be stored in the heat storage tank 15 to supplement heat during the peak power period.

[0032] The present invention utilizes the trough solar collector 1, the air source heat pump system, the flash tank 10, and the heat storage tank 15 for combined heating, which is used for staged heating of the circulating water return of the heat network. While recycling the low-temperature waste heat of the air and domestic sewage, the heat pump heating performance coefficient can be improved, and the power consumption of the heat pump can be reduced. At the same time, the peak and valley electricity prices can be reasonably utilized in conjunction with the heat storage tank 15 to further reduce the operating cost, reduce the emission of pollutants, improve the energy utilization rate, improve the heating quality, and achieve the purpose of energy saving and emission reduction.

Claims

1. Photovoltaic complementary multi-stage heating flash compression type and air source heat pump heating system, characterized in that: It comprises a heat network circulating water pipe (25), on which a heat network circulating water pump (18) is arranged, and the heat network circulating water pipe (25) is connected in sequence to a solar heat collection system, an air source heat pump system, a negative pressure flash type sewage source heat pump system and a heat storage tank (15) according to the return water flow direction; The solar thermal collection system comprises a shell and tube heat exchanger (3), the shell and tube heat exchanger (3) being connected to a hot oil circulation pump (2) via a pipeline, the hot oil circulation pump (2) being connected to a trough type solar thermal collector (1) via a pipeline, the water inlet of the shell and tube heat exchanger (3) being connected to the heat network circulation water pipe (25) being located at the front end of the connection position between the air source heat pump system and the heat network circulation water pipe (25), the water outlet of the shell and tube heat exchanger (3) being connected to the heat network circulation water pipe (25) being located respectively between the connection position between the air source heat pump system and the negative pressure flash type sewage source heat pump system and the heat network circulation water pipe (25) and at the rear end of the connection position between the negative pressure flash type sewage source heat pump system and the heat network circulation water pipe (25); The air source heat pump system comprises a condenser a (4), wherein the condenser a (4) comprises a compressor a (5) and an evaporator a (6) which are connected in sequence through a pipeline to form a closed loop, and an expansion valve a (7) is provided on the pipeline connecting the evaporator a (6) and the condenser a (4); The water inlet and the water outlet of the condenser a (4) are connected in parallel to the heat network circulating water pipe (25) through pipes; a stop valve and an electric regulating valve a (17) are arranged in sequence on the pipe connecting the water inlet of the condenser a (4) and the heat network circulating water pipe (25); a stop valve is arranged on the pipe connecting the water outlet of the condenser a (4) and the heat network circulating water pipe (25); and a stop valve is arranged between the two nodes connecting the condenser a (4) and the heat network circulating water pipe (25); The pressure flash evaporation sewage source heat pump system comprises a condenser b (19), wherein the condenser b (19) comprises a compressor b (20) and an evaporator b (21) which are sequentially connected through a pipeline to form a closed loop, and an expansion valve b (22) is provided on the pipeline connecting the evaporator b (21) and the condenser b (19); The water inlet and the water outlet of the condenser b (19) are connected in parallel to the heat network circulating water pipe (25) through pipes; a stop valve and an electric regulating valve b (23) are sequentially arranged on the pipe connecting the water inlet of the condenser b (19) and the heat network circulating water pipe (25); a stop valve is arranged on the pipe connecting the water outlet of the condenser b (19) and the heat network circulating water pipe (25); and a stop valve is arranged between the two nodes connecting the condenser b (19) and the heat network circulating water pipe (25); The inlet of the evaporator b (21) is connected to a flash tank (10) via a pipeline. A vacuum pump (12) is provided on one side wall of the flash tank. A spray nozzle (11) is provided inside the flash tank (10) near the top wall. The spray nozzle (11) is connected to a user sewage source via a pipeline. A sewage spray pump (8) is provided on the pipeline connecting the spray nozzle (11) and the user sewage source. A water storage tank is provided below the spray nozzle (11). The water storage tank is connected to a sewage return pump (9) via a pipeline. The outlet of the evaporator b (21) is connected to a condensate pump (14) via a pipeline, and the condensate pump (14) is connected to a condensate tank (13) and the flash tank (10) via a pipeline. A stop valve is provided on the pipeline connecting the condensate pump (14) and the condensate tank (13), and a stop valve is provided on the pipeline connecting the condensate pump (14) and the flash tank (10).

2. The photovoltaic complementary multi-stage heating flash compression type and air source heat pump heating system according to claim 1 is characterized in that: The heat network circulating water pipe (25) is connected to the water inlet and the water outlet of the heat storage tank (15) respectively through pipes; a stop valve and an electric regulating valve d (24) are arranged in sequence on the pipe connecting the heat network circulating water pipe (25) and the water inlet of the heat storage tank (15); a stop valve is arranged on the pipe connecting the heat network circulating water pipe (25) and the water outlet of the heat storage tank (15); and a stop valve is arranged between two nodes connecting the heat storage tank (15) and the heat network circulating water pipe (25).

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