Middle-deep layer geothermal buried pipe cascade coupling heat supply system

Abstract

The utility model provides a mid-deep layer geothermal buried pipe cascade coupling heat supply system which comprises a mid-deep layer geothermal buried pipe, a plate heat exchanger, a mid-deep layer geothermal heat pump heat supply unit, a high-grade energy generator, a heat source side circulating water pump, a user side circulating water pump and a user side. A middle-deep layer geothermal heat pump heat supply unit and a plate heat exchanger which are parallel are connected between the input end of the heat source side circulating water pump and the output end of the middle-deep layer geothermal buried pipe, the output end of the user side circulating water pump is connected with a user side in series, and the user side is further connected with a high-grade energy generator used for supplying heat to the user side when the load is high in series. Based on the principles of energy gradient utilization and coupling supplement, the problems that a single mid-deep geothermal energy system is low in efficiency and poor in economical efficiency are solved through efficient energy gradient utilization and multi-source energy complementation.

Description

Technical Field

[0001] The utility model belongs to the technical field of geothermal energy utilization, and in particular relates to a medium-deep geothermal buried pipe cascade coupling heating system. Background Art

[0002] As a renewable energy, deep-seated geothermal energy has the characteristics of large reserves, wide distribution, and environmental friendliness. However, due to its low outlet water temperature, it cannot be directly used for high-quality energy needs such as heating, so it needs to be improved through equipment such as heat pumps. However, the efficiency of the heat pump system will gradually decrease as the outlet water temperature on the evaporator side decreases, which requires coupling with other high-quality energy sources for supplementation.

[0003] At present, the development and utilization of medium-deep geothermal energy mainly adopts coaxial heat exchange technology, but due to the high construction cost of the underground part, the overall economic efficiency is average. Therefore, how to effectively couple medium-deep geothermal energy with other high-grade energy sources such as electricity, natural gas, solar energy, hydrogen energy, etc. to improve the economic efficiency and market promotion effect of the project has become an urgent problem to be solved.

[0004] In the existing technology, although there are some attempts to couple deep geothermal energy with other energy sources, most solutions have problems such as low efficiency, poor economy, and complex systems. Therefore, there is an urgent need for a new coupling energy supply system that can fully utilize the geothermal potential and ensure the economic reliability of the system. Utility Model Content

[0005] In view of the above problems, the purpose of the utility model is to provide a medium-deep geothermal buried pipe cascade coupling heating system, which is based on the principles of energy cascade utilization and coupled supplementation, and solves the problems of low efficiency and poor economy of a single medium-deep geothermal energy system through efficient energy cascade utilization and multi-source energy complementation.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A medium-deep geothermal buried pipe cascade coupling heating system, comprising medium-deep geothermal buried pipes, a plate heat exchanger, a medium-deep geothermal heat pump heating unit, a high-grade energy generator, a heat source side circulating water pump, a user side circulating water pump and a user end, wherein a parallel medium-deep geothermal heat pump heating unit and a plate heat exchanger are connected between the input end of the heat source side circulating water pump and the output end of the medium-deep geothermal buried pipe, the output end of the user side circulating water pump is connected in series to the user end, and a high-grade energy generator for supplying heat to the user end when the load is high is also connected in series to the user end.

[0008] Furthermore, a step-lift circulating water pump is connected in series between the user end and the high-grade energy generator.

[0009] Furthermore, the medium-deep geothermal buried pipe and the heat source side circulating water pump are connected through a first hot side circulating pipeline, and the medium-deep geothermal heat pump heating unit and the plate heat exchanger are connected to the heat source side circulating water pump through a second hot side circulating pipeline.

[0010] Furthermore, the high-grade energy generator includes one or more combinations of electric energy equipment, natural gas equipment, solar energy equipment or hydrogen energy equipment.

[0011] Furthermore, a heat pump heating valve is connected in series between the medium-deep geothermal heat pump heating unit and the circulating water pump on the heat source side, and a geothermal heating valve is connected in series between the plate heat exchanger and the circulating water pump on the heat source side.

[0012] Furthermore, the user end is provided with a user-side water supply pipeline and a user-side return pipeline, and the step-lift circulation pipeline is provided on the step-lift circulation pump. The user end is connected to the user-side circulation water pump through the user-side return pipeline, and is connected to the medium-deep geothermal heat pump heating unit and the plate heat exchanger through the user-side water supply pipeline; the step-lift circulation water pump is connected to the user-side water supply pipeline through the step-lift circulation pipeline, and the step-lift circulation pipeline is connected to the user-side water supply pipeline at the same time.

[0013] Furthermore, the cascade lifting circulation pipeline includes a cascade water inlet pipe, a cascade return pipe and a cascade circulation pipe. The high-grade energy generator is connected to the user-side water supply pipeline through the cascade water inlet pipe, the cascade lifting circulation water pump is connected to the user-side water supply pipeline through the cascade return pipe, and the cascade lifting circulation water pump is connected to the user-side return pipe through the cascade circulation pipe.

[0014] Furthermore, a first valve is provided on the user-side water supply pipeline between the step water inlet pipe and the step water return pipe, a second valve is provided on the step water return pipe between the step lifting circulation water pump and the user-side water supply pipeline, and a third valve is provided on the step circulation pipe.

[0015] Furthermore, a third temperature sensor group is connected in series between the user end and the step-lift circulating water pump, a second temperature sensor group is connected in series between the step-lift circulating water pump and the high-grade energy generator, and a first temperature sensor is connected in series between the user end and the user-side circulating water pump.

[0016] Furthermore, the second temperature sensor group includes a second temperature sensor and a third temperature sensor, the second temperature sensor is connected in series to the step return pipe between the high-grade energy generator and the step lifting circulation water pump, and the third temperature sensor is connected in series to the step water supply pipe between the high-grade energy generator and the user-side water supply pipe; the second temperature sensor group includes a fourth temperature sensor and a fifth temperature sensor, the fourth temperature sensor is connected in series to the user-side water supply pipe between the user end and the step water supply pipe, and the fifth temperature sensor is connected in series to the user-side return pipe between the user end and the step circulation pipe.

[0017] The utility model adopts the above technical solution, which has the following advantages and effects:

[0018] The utility model provides a medium-deep geothermal buried pipe cascade coupling heating system, which is based on the principles of energy cascade utilization and coupled supplementation. In the initial and final stages of heating, when the terminal load is small, the geothermal energy of the medium-deep geothermal buried pipe is directly utilized through a plate heat exchanger for heating. In the early and middle stages of heating, when the terminal load is large, the geothermal energy is boosted by a medium-deep geothermal heat pump heating unit for heating. In the middle stage of heating, when the terminal load is large and the geothermal energy temperature is low, the geothermal energy is further boosted by coupling high-grade energy for heating. After the low-grade geothermal energy and high-grade energy are coupled and utilized, the efficiency of the heating system will decrease by about 3% for every 1 degree increase in the outlet water temperature on the heat pump condenser side of the medium-deep geothermal heat pump heating unit. The geothermal energy can be used to the maximum extent and most efficiently, and the working mode can be flexibly adjusted according to the heating demand and geothermal energy conditions to meet the heating needs of end users with the best economy and energy efficiency ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the utility model.

[0020] The accompanying drawings are marked as follows: 1-medium and deep geothermal buried pipes, 2-first hot side circulation pipeline, 21-second hot side circulation pipeline, 3-heat source side circulation water pump group, 4-geothermal heating valve, 5-heat pump heating valve, 6-medium and deep geothermal heat pump heating unit, 7-plate heat exchanger, 8-user side circulation water pump, 9-cascade lifting circulation water pump, 10-high-grade energy generator, 11-first temperature sensor, 12-second temperature sensor, 13-third temperature sensor, 14-fourth temperature sensor, 15-fifth temperature sensor, 16-first valve, 17-second valve, 18-third valve, 19-user end, 20-cascade lifting circulation pipeline. DETAILED DESCRIPTION

[0021] The following will be combined with the accompanying drawings to describe the embodiments of the present invention in detail, so as to more clearly understand the purpose, characteristics and advantages of the present invention. It should be understood that the embodiments shown in the accompanying drawings are not intended to limit the scope of the present invention, but are only intended to illustrate the essential spirit of the technical solution of the present invention.

[0022] like Figure 1 The utility model provides a medium-deep geothermal buried pipe cascade coupling heating system, comprising a medium-deep geothermal buried pipe 1, a plate heat exchanger 7, a medium-deep geothermal heat pump heating unit 6, a high-grade energy generator 10, a heat source side circulating water pump 3, a user side circulating water pump 8 and a user end 19, wherein a parallel medium-deep geothermal heat pump heating unit 6 and a plate heat exchanger 7 are connected between the input end of the heat source side circulating water pump 3 and the output end of the medium-deep geothermal buried pipe 1, and the output end of the user side circulating water pump 8 is connected in series to the user end 19, and a high-grade energy generator 10 for supplying heat to the user end 19 when the load is high is also connected in series to the user end 19.

[0023] Specifically, the medium-deep geothermal buried pipe 1 and the medium-deep geothermal heat pump heating unit 6 are connected through the heat source side circulating water pump 3 to establish a heat source circulation between the medium-deep geothermal buried pipe 1 and the medium-deep geothermal heat pump heating unit 6, and the medium-deep geothermal buried pipe 1 is used to extract geothermal energy from the medium-deep underground layer. The plate heat exchanger 7 is used to increase the temperature of geothermal energy. After the plate heat exchanger 7 and the medium-deep geothermal buried pipe 1 are connected through the heat source side circulating water pump 3, the geothermal energy is delivered to the user end 19 through the plate heat exchanger 7. The plate heat exchanger 7 and the user end 19 are connected through the user side circulating water pump 8 to supply heat to the user end 19. The medium-deep geothermal heat pump heating unit 6 and the user end 19 also establish a circulation between the medium-deep geothermal heat pump heating unit 6 and the user end 19 through the user side circulating water pump 8, and the medium-deep geothermal heat pump heating unit 6 can supply heating to the user end 19. A high-quality energy generator 10 is connected in series before the circulating water pump 8 on the user side. The high-quality energy generator 10 can supply heat to the user end 19 in a series-parallel manner when the load is high.

[0024] Furthermore, a step-lift circulating water pump 9 is connected in series between the user end 19 and the high-grade energy generator 10. The high-grade energy generator 10 is connected to the user end 19 through the step-lift circulating water pump 9. The heat source circulation between the user end 19 and the high-grade energy generator 10 is established through the step-lift circulating water pump 9.

[0025] Furthermore, the medium-deep geothermal buried pipe 1 and the heat source side circulating water pump 3 are connected through the first hot side circulating pipeline 2, and the medium-deep geothermal heat pump heating unit 6 and the plate heat exchanger 7 are both connected to the heat source side circulating water pump 3 through the second hot side circulating pipeline 21.

[0026] Specifically, the first hot side circulation pipeline 2 includes a first hot side circulation return pipe and a first hot side circulation water supply pipe, the second hot side circulation pipeline 21 includes a second hot side circulation return pipe and a second hot side circulation water supply pipe, the first hot side circulation water supply pipe and the second hot side circulation water supply pipe are connected, the input end of the medium-deep geothermal buried pipe 1 is connected to the first hot side circulation water supply pipe, and the output ends of the medium-deep geothermal heat pump heating unit 6 and the plate heat exchanger 7 are respectively connected through the second hot side circulation water supply pipe. The output end of the medium-deep geothermal buried pipe 1 is connected to the first hot side circulation return pipe, the first hot side circulation return pipe is connected to the input end of the heat source side circulation water pump 3, and the output end of the heat source side circulation water pump 3 is respectively connected to the input end of the medium-deep geothermal heat pump heating unit 6 and the plate heat exchanger 7.

[0027] Furthermore, the high-quality energy generator 10 includes one or more combinations of electric energy equipment, natural gas equipment, solar energy equipment or hydrogen energy equipment. Since other energy sources such as electric energy, natural gas, solar energy, hydrogen energy, etc. are high-quality energy sources that can be directly utilized, the high-quality energy generator 10 can directly and effectively utilize the high-quality energy.

[0028] The utility model can couple high-grade energy such as electricity, natural gas, solar energy, hydrogen energy, etc. according to actual needs, and jointly utilize electricity, natural gas, solar energy, hydrogen energy and geothermal energy through boilers or other equipment to meet heating needs.

[0029] Furthermore, a heat pump heating valve is connected in series between the medium-deep geothermal heat pump heating unit 6 and the heat source side circulating water pump 3, and a geothermal heating valve is connected in series between the plate heat exchanger 7 and the heat source side circulating water pump 3. Heat pump heating valves are provided on the second hot side circulating return water pipe and the second hot side circulating water supply pipe between the medium-deep geothermal heat pump heating unit 6 and the heat source side circulating water pump 3, and geothermal heating valves are provided on the second hot side circulating return water pipe and the second hot side circulating water supply pipe between the plate heat exchanger 7 and the heat source side circulating water pump 3. The heat pump heating valve is used to control the on-off of the second hot side circulating pipeline 21 between the medium-deep geothermal heat pump heating unit 6 and the heat source side circulating water pump 3, and the geothermal heating valve is used to control the on-off of the second hot side circulating pipeline 21 between the plate heat exchanger 7 and the heat source side circulating water pump 3.

[0030] Furthermore, a user-side water supply pipeline and a user-side return pipeline are provided on the user end 19, and a step-lifting circulation pipeline 20 is provided on the step-lifting circulation water pump 9. The user end 19 is connected to the user-side circulation water pump 8 through the user-side return pipeline, and is connected to the medium-deep geothermal heat pump heating unit 6 and the plate heat exchanger 7 through the user-side water supply pipeline; the step-lifting circulation water pump 9 is connected to the user-side water supply pipeline through the step-lifting circulation pipeline 20, and the step-lifting circulation pipeline 20 is connected to the user-side water supply pipeline at the same time.

[0031] Specifically, when the high-quality energy generator 10 and the step-lift circulating water pump 9 are used to provide joint heating to the user end 19, the step-lift circulating pipeline 20 includes a step water inlet pipe, a step water return pipe and a step circulation pipe. The high-quality energy generator 10 is connected to the user-side water supply pipeline through the step water inlet pipe, the step-lift circulating water pump 9 is connected to the user-side water supply pipeline through the step water return pipe, and the step-lift circulating water pump 9 is simultaneously connected to the user-side water return pipeline through the step circulation pipe. The step-lift circulating water pump 9 is connected in series to the step water return pipe for the circulation of the heat source medium between the high-quality energy generator 10 and the user-side water supply pipeline.

[0032] The user-side water supply pipeline is connected to the inlet and output ends of the medium-deep geothermal heat pump heating unit 6 and the plate heat exchanger 7 at the same time, and the user-side return water pipeline is connected to the loop input end of the medium-deep geothermal heat pump heating unit 6 and the plate heat exchanger 7 after connecting to the user-side circulating water pump 8.

[0033] Furthermore, a first valve 16 is provided on the user-side water supply pipeline between the step water inlet pipe and the step water return pipe, a second valve 17 is provided on the step water return pipe between the step lifting circulation water pump 9 and the user-side water supply pipeline, and a third valve 18 is provided on the step circulation pipe.

[0034] Specifically, the first valve 16 and the second valve 17 are used to jointly control the hydraulic balance of the entire system, solve the problem of heat source medium flow distribution between the medium and deep geothermal heat pump heating unit 6 and the high-grade energy generator 10, and realize energy cascade utilization during series operation. The third valve 18 can be opened when the load proportion borne by the high-grade energy generator 10 is relatively large. At this time, the first valve 16 and the second valve 17 are closed to realize parallel operation and achieve coupled utilization of different energy sources.

[0035] Furthermore, a third temperature sensor group is connected in series between the user end 19 and the step-lift circulating water pump 9, a second temperature sensor group is connected in series between the step-lift circulating water pump 9 and the high-grade energy generator 10, and a first temperature sensor 11 is connected in series between the user end 19 and the user-side circulating water pump 8.

[0036] Specifically, the first temperature sensor 11 is connected in series to the user-side water supply pipeline between the step return pipe and the medium-deep geothermal heat pump heating unit 6. The first temperature sensor 11 is used to monitor the outlet water temperature of the medium-deep geothermal heat pump heating unit 6. The second temperature sensor group includes a second temperature sensor 12 and a third temperature sensor 13, wherein the second temperature sensor 12 is connected in series to the step return pipe between the high-grade energy generator 10 and the step lifting circulating water pump 9, and the third temperature sensor 13 is connected in series to the step supply pipe between the high-grade energy generator 10 and the user-side water supply pipeline. The second temperature sensor 12 is used to monitor the inlet water temperature on the high-grade energy generator 10 side, and the third temperature sensor 13 is used to monitor the outlet water temperature on the high-grade energy generator 10 side. The second temperature sensor group includes a fourth temperature sensor 14 and a fifth temperature sensor 15. The fourth temperature sensor 14 is connected in series to the user-side water supply pipeline between the user end 19 and the cascade water supply pipe, and the fifth temperature sensor 15 is connected in series to the user-side return water pipeline between the user end 19 and the cascade circulation pipe. The fourth temperature sensor 14 is used to monitor the water supply temperature of the user end 19, and the fifth temperature sensor 15 is used to monitor the outlet water temperature of the user end 19. The first valve 16, the second valve 17, the third valve 18 and the frequency of the cascade lifting circulation water pump 9 are controlled and adjusted according to the temperature monitored by the first temperature sensor 11.

[0037] When the utility model is used in practice, at the beginning and end of heating, since the load of the user end 19 is 30%-50%, and the outlet water temperature of the medium-deep geothermal buried pipe 1 is 35-45°C, it is necessary to simultaneously start the user-side circulating water pump 8 to establish the pipeline circulation from the user end 19 to the plate heat exchanger 7, and start the heat source side circulating water pump 3 to establish the pipeline circulation between the medium-deep geothermal buried pipe 1 and the plate heat exchanger 7. At this time, the water circulation between the medium-deep geothermal buried pipe 1, the heat source side circulating water pump 3, the plate heat exchanger 7, the user-side circulating water pump 8 and the user end 19 is realized by opening the geothermal heating valve and closing the heat pump heating valve. The heat source medium in the medium-deep geothermal buried pipe 1 circulates in the medium-deep geothermal buried pipe 1 under the drive of the heat source side circulating water pump 3 to extract geothermal energy and transfer the heat to the user end 19 through the plate heat exchanger 7, and heat is supplied to the user end 19 through the heat source medium circulation of the user end 19.

[0038] In the early stage of heating, since the load of the user end 19 is 50%-70% and the outlet water temperature of the medium-deep geothermal buried pipe 1 is 20-35°C, the user-side circulating water pump 8 is started to establish the pipeline circulation between the user and the medium-deep geothermal heat pump heating unit 6, and the heat source side circulating water pump 3 is started to establish the pipeline circulation between the medium-deep geothermal buried pipe 1 and the medium-deep geothermal heat pump heating unit 6. At this time, the water circulation between the medium-deep geothermal buried pipe 1, the heat source side circulating water pump 3, the medium-deep geothermal heat pump heating unit 6, the user-side circulating water pump 8 and the user end 19 is realized by closing the geothermal heating valve and opening the heat pump heating valve. The heat source medium in the medium-deep geothermal buried pipe 1 is driven by the circulating water pump 3 on the heat source side. It circulates in the medium-deep geothermal buried pipe 1 to extract geothermal energy and raises the temperature to 45°C through the medium-deep geothermal heat pump heating unit 6. The heat is then transferred to the user end 19 and heat is supplied to the user end 19 through the circulation of the heat source medium at the user end 19.

[0039] In the middle stage of heating, since the load at the user end 19 is 70%-100% and the outlet water temperature of the medium-deep geothermal buried pipe 1 is below 20°C, the user-side circulating water pump 8 is started to establish a pipeline circulation between the user end 19 and the medium-deep geothermal heat pump heating unit 6, and the heat source side circulating water pump 3 is started to establish a pipeline circulation between the medium-deep geothermal buried pipe 1 and the medium-deep geothermal heat pump heating unit 6. By closing the geothermal heating valve and opening the heat pump heating valve, the heat source medium in the medium-deep geothermal buried pipe 1 is driven by the heat source side circulating water pump 3 to circulate in the medium-deep geothermal buried pipe 1 to extract geothermal energy and raise the temperature to 40°C through the medium-deep geothermal heat pump heating unit 6. Then, the high-grade energy generator 10 and the step-lifting circulating water pump 9 are started to raise the water supply temperature of the user end 19 to 45°C, and then the heat is transferred to the user end 19 and the heat source medium of the user end 19 is circulated to supply heat to the user end 19.

Claims

1. A medium-deep geothermal buried pipe cascade coupling heating system, characterized by: It includes medium-deep geothermal buried pipes, plate heat exchangers, medium-deep geothermal heat pump heating units, high-grade energy generators, heat source side circulating water pumps, user side circulating water pumps and user ends. A parallel medium-deep geothermal heat pump heating unit and a plate heat exchanger are connected between the input end of the heat source side circulating water pump and the output end of the medium-deep geothermal buried pipes. The output end of the user side circulating water pump is connected in series to the user end. The user end is also connected in series to a high-grade energy generator for supplying heat to the user end when the load is high.

2. According to claim 1, a mid-deep geothermal buried pipe cascade coupling heating system is characterized by: A step-lift circulating water pump is connected in series between the user end and the high-grade energy generator.

3. The medium-deep geothermal buried pipe cascade coupling heating system according to claim 2 is characterized by: The medium-deep geothermal buried pipe and the heat source side circulating water pump are connected through a first hot side circulating pipeline, and the medium-deep geothermal heat pump heating unit and the plate heat exchanger are connected to the heat source side circulating water pump through a second hot side circulating pipeline.

4. The medium-deep geothermal buried pipe cascade coupling heating system according to claim 3 is characterized by: The high-grade energy generator includes one or more combinations of electric energy equipment, natural gas equipment, solar energy equipment or hydrogen energy equipment.

5. The medium-deep geothermal buried pipe cascade coupling heating system according to claim 4 is characterized by: A heat pump heating valve is connected in series between the medium-deep geothermal heat pump heating unit and the heat source side circulating water pump, and a geothermal heating valve is connected in series between the plate heat exchanger and the heat source side circulating water pump.

6. The medium-deep geothermal buried pipe cascade coupling heating system according to claim 5 is characterized by: The user end is provided with a user-side water supply pipeline and a user-side return pipeline, and the step-lift circulation pipeline is provided on the step-lift circulation pump. The user end is connected to the user-side circulation water pump through the user-side return pipeline, and is connected to the medium-deep geothermal heat pump heating unit and the plate heat exchanger through the user-side water supply pipeline; the step-lift circulation water pump is connected to the user-side water supply pipeline through the step-lift circulation pipeline, and the step-lift circulation pipeline is connected to the user-side water supply pipeline at the same time.

7. The medium-deep geothermal buried pipe cascade coupling heating system according to claim 6 is characterized by: The cascade lifting circulation pipeline includes a cascade water inlet pipe, a cascade return pipe and a cascade circulation pipe. The high-grade energy generator is connected to the user-side water supply pipeline through the cascade water inlet pipe, the cascade lifting circulation water pump is connected to the user-side water supply pipeline through the cascade return pipe, and the cascade lifting circulation water pump is connected to the user-side return pipe through the cascade circulation pipe.

8. The medium-deep geothermal buried pipe cascade coupling heating system according to claim 7 is characterized by: A first valve is arranged on the user-side water supply pipeline between the step water inlet pipe and the step water return pipe, a second valve is arranged on the step water return pipe between the step lifting circulation water pump and the user-side water supply pipeline, and a third valve is arranged on the step circulation pipe.

9. The medium-deep geothermal buried pipe cascade coupling heating system according to claim 8, characterized in that: A third temperature sensor group is connected in series between the user end and the step-lift circulating water pump, a second temperature sensor group is connected in series between the step-lift circulating water pump and the high-grade energy generator, and a first temperature sensor is connected in series between the user end and the user-side circulating water pump.

10. The medium-deep geothermal buried pipe cascade coupling heating system according to claim 9, characterized in that: The second temperature sensor group includes a second temperature sensor and a third temperature sensor, the second temperature sensor is connected in series to the step return pipe between the high-grade energy generator and the step lifting circulation water pump, and the third temperature sensor is connected in series to the step water supply pipe between the high-grade energy generator and the user-side water supply pipe; the second temperature sensor group includes a fourth temperature sensor and a fifth temperature sensor, the fourth temperature sensor is connected in series to the user-side water supply pipe between the user end and the step water supply pipe, and the fifth temperature sensor is connected in series to the user-side return pipe between the user end and the step circulation pipe.

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