Combined heat and power generation system and method coupled with buried pipe energy storage

Abstract

The invention discloses a combined heat and power generation system and method coupled with buried pipe energy storage, and belongs to the field of geothermal power generation and geothermal heating, the combined heat and power generation system coupled with buried pipe energy storage comprises an axial flow type ORC generator set, high-temperature geothermal water is used for generating power and supplying heat to a user terminal; the cooling tower is connected with the axial-flow type ORC generator set and used for dissipating heat of the axial-flow type ORC generator set; the ground heat exchanger is connected with the axial-flow ORC generator set through a plate heat exchanger; and the ground source heat pump system is connected with the buried pipe heat exchanger, extracts underground stored cold energy through the buried pipe heat exchanger, supplies the underground stored cold energy to a user terminal or outputs low-temperature geothermal water through a plate heat exchanger. The ORC power generation technology is combined with the medium-deep layer and shallow layer geothermal energy utilization technology, the shallow layer buried pipe energy storage technology is coupled, and energy is utilized to the maximum extent.

Description

Technical Field

[0001] The present invention relates to the technical fields of geothermal power generation and geothermal heating, and in particular to a cogeneration system and method coupled with ground buried pipe energy storage. Background Art

[0002] Under the background of the gradual depletion of fossil energy and the increasing global attention to environmental protection, geothermal energy, as a widely distributed, rich in reserves, clean and pollution-free renewable energy, has gradually come into people's view. The economic cost is high and the construction period is long during the exploitation of geothermal energy. The geothermal energy resources in China are mainly medium-grade resources, and the quality of geothermal resources is not particularly high. Therefore, it is particularly important to utilize the extracted geothermal energy in a cascade manner to improve the utilization efficiency as much as possible.

[0003] Existing geothermal energy utilization technologies mostly appear separately, such as power generation, heating (including medium-depth and shallow geothermal energy), etc., with problems of incomplete energy utilization and low efficiency, and energy waste occurs during the non-heating season due to the time issue of energy utilization. Summary of the Invention

[0004] The purpose of the present invention is to provide a cogeneration system and method coupled with ground buried pipe energy storage, which combines the ORC power generation technology with medium-depth and shallow geothermal energy utilization technologies, and couples the shallow ground buried pipe energy storage technology to maximize the utilization of energy; during the non-heating season, the waste heat of the generator set is stored in the underground space through the ground buried pipe system, and the heat is extracted through the ground buried pipe system during the winter heating season, improving the energy utilization efficiency and the heating effect of the system during the heating period.

[0005] To achieve the above purpose, the present invention provides a cogeneration system coupled with ground buried pipe energy storage, including

[0006] An axial flow ORC generator set, which uses high-temperature geothermal water for power generation and supplies heat to the user terminal.

[0007] A cooling tower connected to the axial flow ORC generator set, which is used for heat dissipation of the axial flow ORC generator set.

[0008] A ground buried pipe heat exchanger, and the ground buried pipe heat exchanger is connected to the axial flow ORC generator set through a plate heat exchanger.

[0009] A ground source heat pump system connected to the ground buried pipe heat exchanger, which extracts the cold stored in the ground through the ground buried pipe heat exchanger and supplies it to the user terminal or outputs low-temperature geothermal water through a plate heat exchanger.

[0010] Preferably, the axial flow ORC power generation unit includes an evaporator, a reheater, a working fluid pump, a condenser, and a turbine connected in series in sequence. The turbine is connected to the evaporator, and the evaporator, reheater, working fluid pump, condenser, and turbine are connected end to end in sequence to form a loop. The reheater is connected to a plate heat exchanger, and the condenser is connected to a cooling tower and a user terminal respectively.

[0011] Preferably, a valve V1 is provided in the output circuit from the condenser to the cooling tower, and a valve V2 and a circulation pump 1 are sequentially provided in the input circuit from the cooling tower to the condenser.

[0012] Preferably, a valve V4 is provided in the output circuit from the condenser to the user terminal, and a circulation pump 2 and a valve V3 are sequentially provided in the input circuit from the user terminal to the condenser.

[0013] Preferably, a circulation pump 3 and a valve V6 are sequentially provided in the output circuit from the plate heat exchanger to the user terminal, and a valve V5 is provided in the input circuit from the user terminal to the plate heat exchanger. The valve V5 is provided between the circulation pump 2 and the valve V3.

[0014] Preferably, one end of the buried pipe heat exchanger is connected to the ground source heat pump system for input and output through a valve V9 and a valve V10. A valve V8 is provided at the input end of the other end of the buried pipe heat exchanger, and a valve V7 is provided at the output end. A valve V11 is provided between the valve V7 and the valve V8.

[0015] The present invention also provides an operation method for a cogeneration system coupled with buried pipe energy storage, including a spring operation method, a summer operation method, an autumn operation method, and a winter operation method. The spring operation method includes the following steps:

[0016] The valves V1, V2, and V11 are opened, and the system generates electricity. The extracted high-temperature geothermal water enters the axial flow ORC power generation unit for power generation, and the used geothermal tail water is recharged into the recharge well. The heat of the axial flow ORC power generation unit is dissipated into the air through the cooling tower.

[0017] Preferably, the summer operation method includes the following steps:

[0018] The valves V1, V2, V9, V10, and V11 are opened, and the system generates electricity and provides cooling. The extracted high-temperature geothermal water enters the axial flow ORC power generation unit for power generation, and the used geothermal tail water is recharged into the recharge well. The heat of the axial flow ORC power generation unit is dissipated into the air through the cooling tower; the ground source heat pump system extracts the cold quantity underground through the buried pipe heat exchanger and improves the quality, and supplies the cold quantity to the user terminal.

[0019] Preferably, the autumn operation method includes the following steps:

[0020] Valves V1, V2, V7, and V8 are opened, and the system generates electricity and stores heat. The extracted high-temperature geothermal water enters the axial-flow ORC power generation unit for power generation. The used geothermal tail water is then recharged after passing through a plate heat exchanger and a buried pipe heat exchanger, storing the heat of the geothermal tail water in the underground soil. The heat of the axial-flow ORC power generation unit is dissipated into the air through a cooling tower.

[0021] Preferably, the winter operation method includes the following steps:

[0022] Valves V3, V4, V5, V6, V9, V10, and V11 are opened, and the system generates electricity and provides heating. The extracted high-temperature geothermal water enters the axial-flow ORC power generation unit for power generation. The used geothermal tail water supplies heat to the user terminal through a plate heat exchanger, and finally the tail water is recharged; the heat on the condenser side of the axial-flow ORC power generation unit is transported to the user terminal for heating; the ground source heat pump system extracts the heat from the underground through a buried pipe heat exchanger, improves the grade, and supplies the heat to the user terminal.

[0023] Therefore, the present invention adopts the above-mentioned cogeneration system and method with coupled buried pipe energy storage, and has the following beneficial effects:

[0024] (1) The present invention combines the ORC power generation technology with the medium-depth and shallow geothermal energy utilization technologies, and couples the shallow buried pipe energy storage technology, which can maximize the utilization of energy;

[0025] (2) The system of the present invention stores the waste heat of the power generation unit in the underground space through the buried pipe system during the non-heating season, and extracts the heat through the buried pipe system during the winter heating season, which can improve the heating effect of the system during the heating period while improving the energy utilization rate.

[0026] Next, through the drawings and embodiments, the technical solutions of the present invention will be further described in detail. Description of the Drawings

[0027] Figure 1 It is a schematic structural diagram of an embodiment of a cogeneration system with coupled buried pipe energy storage according to the present invention. Detailed Embodiments

[0028] In order to make the objectives, technical solutions, and advantages of the embodiments disclosed in the present invention clearer and more understandable, the following further elaborates on the embodiments of the present invention in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention and are not used to limit the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts fall within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end.

[0029] It should be noted that the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or server that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0030] Similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0031] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings or the orientation or positional relationship in which the product of this invention is customarily placed during use. It is only for the convenience of describing the present invention and 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 should not be construed as a limitation to the present invention.

[0032] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "install", and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] Embodiment

[0034] As Figure 1As shown in the figure, a cogeneration system coupled with a ground-coupled energy storage includes an axial-flow ORC generator set, a cooling tower, a ground heat exchanger, and a ground source heat pump system. The axial-flow ORC generator set uses high-temperature geothermal water for power generation and supplies heat to the user terminal; the cooling tower is connected to the axial-flow ORC generator set and is used for heat dissipation of the axial-flow ORC generator set; the ground heat exchanger is connected to the axial-flow ORC generator set through a plate heat exchanger; the ground source heat pump system is connected to the ground heat exchanger, and the ground source heat pump system extracts the cold energy stored underground through the ground heat exchanger and supplies it to the user terminal or outputs low-temperature geothermal water through the plate heat exchanger.

[0035] The axial-flow ORC generator set includes an evaporator, a reheater, a working fluid pump, a condenser, and a turbine connected in series in sequence. The turbine is connected to the evaporator, and the evaporator, reheater, working fluid pump, condenser, and turbine are connected end to end in sequence to form a loop. The reheater is connected to the plate heat exchanger, and the condenser is connected to the cooling tower and the user terminal respectively. A valve V1 is provided in the output circuit from the condenser to the cooling tower, and a valve V2 and a circulation pump one are provided in sequence in the input circuit from the cooling tower to the condenser. A valve V4 is provided in the output circuit from the condenser to the user terminal, and a circulation pump two and a valve V3 are provided in sequence in the input circuit from the user terminal to the condenser. A circulation pump three and a valve V6 are provided in sequence in the output circuit from the plate heat exchanger to the user terminal, and a valve V5 is provided in the input circuit from the user terminal to the plate heat exchanger. The valve V5 is provided between the circulation pump two and the valve V3. One end of the ground heat exchanger is connected to the ground source heat pump system for input and output through valves V9 and V10. The input end of the other end of the ground heat exchanger is provided with a valve V8, and the output end is provided with a valve V7. A valve V11 is provided between the valve V7 and the valve V8.

[0036] Through power generation and heat supply, the above system maximally utilizes the extracted geothermal water. According to the change of seasons, the system operation mode will also be adjusted accordingly to improve the system efficiency and ensure the energy supply quality. Therefore, the present invention also provides an operation method for a cogeneration system coupled with a ground-coupled energy storage, including a spring operation method, a summer operation method, an autumn operation method, and a winter operation method.

[0037] The spring operation method includes the following steps:

[0038] Valves V1, V2, and V11 are opened, and the system only generates electricity. The extracted high-temperature geothermal water enters the axial-flow ORC generator set for power generation, and the used geothermal tail water is recharged into the recharge well. The heat of the axial-flow ORC generator set is dissipated into the air through the cooling tower.

[0039] The summer operation method includes the following steps:

[0040] Valves V1, V2, V9, V10, and V11 are opened, and the system generates electricity and provides cooling. The extracted high-temperature geothermal water enters the axial-flow ORC power generation unit for power generation, and the used geothermal tail water is recharged into the recharge well. The heat of the axial-flow ORC power generation unit is dissipated into the air through the cooling tower. The ground-source heat pump system extracts the cold energy from the ground through the buried pipe heat exchanger and improves its quality, and supplies the cold energy to the user terminal.

[0041] The operation method in autumn includes the following steps:

[0042] Valves V1, V2, V7, and V8 are opened, and the system generates electricity and stores heat. The extracted high-temperature geothermal water enters the axial-flow ORC power generation unit for power generation, and the used geothermal tail water is recharged after passing through the plate heat exchanger and the buried pipe heat exchanger, and part of the heat of the geothermal tail water can be stored in the underground soil to improve the heating quality of the ground-source heat pump in winter. The heat of the axial-flow ORC power generation unit is dissipated into the air through the cooling tower.

[0043] The operation method in winter includes the following steps:

[0044] Valves V3, V4, V5, V6, V9, V10, and V11 are opened, and the system generates electricity and provides heating. The extracted high-temperature geothermal water enters the axial-flow ORC power generation unit for power generation, and the heat of the used geothermal tail water is supplied to the user terminal through the plate heat exchanger, and finally the tail water is recharged. The heat on the condenser side of the axial-flow ORC power generation unit is transported to the user terminal for heating. The ground-source heat pump system extracts the heat from the ground through the buried pipe heat exchanger and improves its quality, and supplies the heat to the user terminal.

[0045] Therefore, the present invention adopts the above-mentioned cogeneration system and method with coupled buried pipe energy storage, combines the ORC power generation technology with the medium-depth and shallow geothermal energy utilization technologies, and couples the shallow buried pipe energy storage technology to maximize the utilization of energy; in the non-heating season, the waste heat of the power generation unit is stored in the underground space through the buried pipe system, and the heat is extracted through the buried pipe system during the winter heating season, improving the energy utilization rate and the heating effect of the system during the heating period.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A heat and power cogeneration system coupled with underground pipe energy storage, characterized in that: It includes an axial-flow ORC generator set, which uses high-temperature geothermal water to generate electricity and provide heat to the end users; A cooling tower connected to the axial flow ORC generator set is used to dissipate heat from the axial flow ORC generator set; A ground pipe heat exchanger, which is connected to an axial flow ORC generator set through a plate heat exchanger; The ground source heat pump system connected to the buried pipe heat exchanger uses the buried pipe heat exchanger to extract the cold stored underground and supply it to the user end or output low-temperature geothermal water through a plate heat exchanger.

2. The heat and power cogeneration system coupled with buried pipe energy storage according to claim 1 is characterized in that: The axial flow ORC generator set includes an evaporator, a reheater, a working fluid pump, a condenser, and a turbine connected in series in sequence. The turbine is connected to the evaporator, and the evaporator, reheater, working fluid pump, condenser, and turbine are connected end to end in sequence to form a loop. The reheater is connected to a plate heat exchanger, and the condenser is connected to a cooling tower and a user terminal respectively.

3. The heat and power cogeneration system coupled with buried pipe energy storage according to claim 2 is characterized in that: A valve V1 is provided in the output loop from the condenser to the cooling tower, and a valve V2 and a circulating pump 1 are provided in sequence in the input loop from the cooling tower to the condenser.

4. The heat and power cogeneration system coupled with buried pipe energy storage according to claim 3 is characterized in that: A valve V4 is provided in the output loop from the condenser to the user end, and a circulation pump 2 and a valve V3 are provided in sequence in the input loop from the user end to the condenser.

5. The heat and power cogeneration system coupled with buried pipe energy storage according to claim 4 is characterized in that: A circulation pump 3 and a valve V6 are sequentially arranged in the output loop from the plate heat exchanger to the user end, and a valve V5 is arranged in the input loop from the user end to the plate heat exchanger. The valve V5 is arranged between the circulation pump 2 and the valve V3.

6. The heat and power cogeneration system coupled with buried pipe energy storage according to claim 5 is characterized in that: One end of the buried pipe heat exchanger is connected to the ground source heat pump system for input and output through valves V9 and V10. The input end of the other end of the buried pipe heat exchanger is provided with valve V8, the output end is provided with valve V7, and a valve V11 is provided between valves V7 and V8.

7. The method for operating a heat and power cogeneration system coupled with underground pipe energy storage according to any one of claims 1 to 6, characterized in that: It includes a spring operation method, a summer operation method, an autumn operation method and a winter operation method. The spring operation method includes the following steps: When valves V1, V2 and V11 are opened, the system generates electricity, the extracted high-temperature geothermal water enters the axial flow ORC generator set to generate electricity, and the utilized geothermal tail water is reinjected into the reinjection well. The heat of the axial flow ORC generator set is dissipated into the air through the cooling tower.

8. The method for operating a heat and power cogeneration system coupled with underground pipe energy storage according to claim 7, characterized in that: The summer operation method includes the following steps: When valves V1, V2, V9, V10 and V11 are opened, the system generates electricity and supplies cooling. The extracted high-temperature geothermal water enters the axial-flow ORC generator set to generate electricity. The geothermal tail water after utilization is reinjected into the reinjection well. The heat of the axial-flow ORC generator set is dissipated into the air through the cooling tower. The ground-source heat pump system extracts the cold from the ground through the buried pipe heat exchanger, improves the quality, and supplies the cold to the end users.

9. The method for operating a heat and power cogeneration system coupled with underground pipe energy storage according to claim 8, characterized in that: The fall run method includes the following steps: When valves V1, V2, V7 and V8 are opened, the system generates electricity and stores heat. The extracted high-temperature geothermal water enters the axial flow ORC generator set to generate electricity. The utilized geothermal tail water is re-injected through the plate heat exchanger and the buried pipe heat exchanger to store the heat of the geothermal tail water in the underground soil. The heat of the axial flow ORC generator set is dissipated into the air through the cooling tower.

10. The method for operating a heat and power cogeneration system coupled with underground pipe energy storage according to claim 9, characterized in that: The winter operation method includes the following steps: When valves V3, V4, V5, V6, V9, V10 and V11 are opened, the system generates electricity and provides heating. The extracted high-temperature geothermal water enters the axial flow ORC generator set to generate electricity. The utilized geothermal tail water passes through the plate heat exchanger to supply heat to the user end, and finally the tail water is re-injected; the heat on the condenser side of the axial flow ORC generator set is transported to the user end for heating; the ground source heat pump system extracts the underground heat through the buried pipe heat exchanger, improves the quality, and supplies the heat to the user end.

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