A geothermal long-time energy storage coupled deep peak shaving system

Abstract

The present application relates to the technical field of flexibility reconstruction of combined heat and power (CHP) units, and particularly relates to a geothermal long-time energy storage coupled deep peak shaving system. Based on the aquifer thermal energy storage unit (ATES) and the geothermal long-time energy storage of hot and cold wells (HW / CW), combined with the electric heat pump unit (EHP), the waste heat recovery of the CHP is realized, the capacity of the wind and solar power absorbed by the power grid and the response speed of the CHP peak shaving are improved; combined with the collaborative heat storage and supply operation of the electric heat pump unit (EHP) and the two-stage plate heat exchanger (HX1 / HX2), the three-stage deep peak shaving of the CHP is realized, and the depth of the CHP power generation peak shaving and the heat supply range are improved. Overall, the wind and solar power curtailment rate and the system operation cost are reduced, and the system is suitable for large-scale wind and solar high-permeability absorption and deep peak shaving operation scene of combined heat and power units.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of peak shaving flexibility reconstruction of combined heat and power units, in particular to a geothermal long-time energy storage coupled deep peak shaving system. BACKGROUND

[0002] In the "heat-to-power" operation mode, the peak shaving flexibility of a combined heat and power unit (CHP) is restricted by the heat and power decoupling capability, and there are many challenges in renewable energy consumption, deep peak shaving, response speed, and multi-energy system collaborative optimization.

[0003] In terms of renewable energy consumption, the heating load directly determines the power output in this mode. Especially during the winter heating period in the north, the minimum output of the heat and power unit is significantly bottlenecked due to the "heat-to-power" principle, resulting in insufficient peak shaving capacity and difficulty in effectively responding to the volatility of new energy generation. When the wind and solar power generation is large, the unit cannot quickly reduce power output due to the limitation of heating demand, resulting in wind and solar curtailment.

[0004] Deep peak shaving also faces difficulties. The current deep peak shaving requires the unit load rate to be reduced to below 30%, but low-load operation brings a series of problems: first, the energy efficiency decreases significantly and equipment wear and tear intensifies; second, unstable combustion easily leads to boiler coking, fire extinguishing, and other difficulties in stable combustion; third, when the load changes rapidly, the temperature difference between the cylinder and the rotor increases, which may shorten the equipment life; finally, when the load is reduced to the critical value, the steam extraction amount decreases, which may not meet the demand of the heat network, and needs to rely on heat storage or backup heat sources.

[0005] In terms of response speed, the load regulation rate of traditional heat and power units is slow, which is difficult to match the rapid fluctuations of new energy. It usually takes tens of minutes for a CHP unit to rise from the minimum load to the full load (about 30-60 minutes for traditional coal-fired units), while the power fluctuation period of wind and solar power may be as short as minutes (such as photovoltaic "climbing" events). In addition, the thermal inertia of the hot water pipe network causes the heating adjustment speed to be slower than the power adjustment, and the electricity-heat-gas system needs to respond collaboratively, while the traditional decentralized control mode cannot meet the demand of rapid adjustment. Therefore, it is necessary to optimize the control system and improve the response capacity through flexibility reconstruction.

[0006] Multi-energy system collaborative optimization also faces challenges. Although various technical routes such as heat storage tanks, electric boilers, and main steam auxiliary heating can be integrated, the system coupling is complex. At the same time, it is necessary to comprehensively optimize power peak shaving, heat supply and demand, economy, and environmental protection, and face the trade-off between renewable energy consumption and unit life loss (frequent load change will shorten the equipment life).

[0007] Therefore, the core of the peak regulation flexibility reconstruction of the combined heat and power unit is to break the bottleneck of "heat and power decoupling", realize the transformation from "heat determines power" to "power and heat interaction" mode through the heat storage and electricity storage technology, unit equipment reconstruction and multi-energy collaborative optimization. SUMMARY

[0008] The purpose of the present application is to provide a geothermal long-time energy storage coupled deep peak regulation system which realizes the deep peak regulation of the combined heat and power unit (CHP) system by combining the aquifer energy storage unit (ATES) with the electric heat pump unit (EHP) and the first / second plate heat exchanger (HX1 / HX2). The system not only effectively reduces the curtailment rate of wind and solar power generation, but also significantly improves the deep peak regulation capability of the CHP system.

[0009] To achieve the above purpose, the present application provides the following technical solutions:

[0010] A geothermal long-time energy storage coupled deep peak regulation system, comprising a combined heat and power unit, an electric heat pump unit, an aquifer energy storage unit, a first plate heat exchanger, a second plate heat exchanger, a power grid and a heat grid, wherein,

[0011] The condenser of the combined heat and power unit is connected with the evaporator of the electric heat pump unit; the combined heat and power unit is connected with the power grid and the heat grid respectively; the first condenser of the electric heat pump unit is connected with the heat grid, and the second condenser of the electric heat pump unit is connected with the first plate heat exchanger; the hot well group of the aquifer energy storage unit is connected with the second plate heat exchanger, and the cold well group of the aquifer energy storage unit is connected with the first plate heat exchanger; the first plate heat exchanger is connected with the second condenser of the electric heat pump unit and the cold well group of the aquifer energy storage unit respectively; the second plate heat exchanger is connected with the combined heat and power unit, the first plate heat exchanger and the hot well group of the aquifer energy storage unit; the power grid is connected with the combined heat and power unit, the wind and solar power field and the electric heat pump unit simultaneously; the heat grid is connected with the combined heat and power unit, the first condenser of the electric heat pump unit, the first plate heat exchanger and the second plate heat exchanger simultaneously.

[0012] The geothermal long-time energy storage coupled deep peak regulation system as described above, further comprises:

[0013] The condenser of the combined heat and power unit is connected with the evaporator of the electric heat pump unit to provide low-temperature waste heat resources for the electric heat pump unit; the combined heat and power unit is connected with the power grid and the heat grid respectively to simultaneously provide electric power and heat.

[0014] The geothermal long-time energy storage coupled deep peak regulation system as described above, further comprises:

[0015] The electric heat pump unit comprises a set of evaporators and two sets of condensers; the evaporators are connected with the combined heat and power unit condenser for recovering the combined heat and power unit condensing heat; the first-stage condenser is connected with the heat network to provide a first-stage peak regulation heat source; the second-stage condenser is connected with the first-stage heat exchanger to provide a second-stage peak regulation heat source and a heat storage heat source for the aquifer energy storage unit; the electric heat pump unit is connected with the power grid to consume the excess wind-solar power of the power grid and convert it into heat to realize the heat storage of the aquifer energy storage unit, the consumption of the wind-solar power and the peak regulation of the combined heat and power unit.

[0016] The geothermal long-time energy storage coupled deep peak regulation system as described above is further provided with:

[0017] The aquifer energy storage unit comprises a set of hot well groups and a set of cold well groups; the hot well groups are connected with the second-stage plate heat exchanger to provide a third-stage peak regulation heat source and a heat storage channel; the cold well groups are connected with the first-stage plate heat exchanger to provide a heat storage water source.

[0018] The geothermal long-time energy storage coupled deep peak regulation system as described above is further provided with:

[0019] The first-stage plate heat exchanger is connected with the second-stage condenser of the electric heat pump unit and the cold well groups respectively; heat exchange with the electric heat pump unit provides a heat source for the cold well group geothermal water energy storage and the heat network peak regulation.

[0020] The geothermal long-time energy storage coupled deep peak regulation system as described above is further provided with:

[0021] The second-stage plate heat exchanger is connected with the combined heat and power unit, the first-stage plate heat exchanger and the hot well groups respectively; during the heat storage period, heat exchange with the combined heat and power unit provides a heat storage heat source for the aquifer energy storage unit; during the heating period, heat exchange with the hot well groups provides a peak regulation heat source for the heat network.

[0022] The geothermal long-time energy storage coupled deep peak regulation system as described above is further provided with:

[0023] The power grid is connected with the combined heat and power unit, the wind-solar power plant and the electric heat pump unit respectively to provide power for the combined heat and power unit and the wind-solar power plant and provide power supply for the electric heat pump unit.

[0024] The geothermal long-time energy storage coupled deep peak regulation system as described above is further provided with:

[0025] The heat network is connected with the combined heat and power unit, the first-stage condenser of the electric heat pump unit, the first-stage plate heat exchanger and the second-stage plate heat exchanger to provide a basic heat source and a third-stage peak regulation heat source for user load.

[0026] The geothermal long-time energy storage coupled deep peak regulation system as described above is further provided with:

[0027] The control valve is connected with the combined heat and power unit, the electric heat pump unit, the inlet and outlet pipelines of the first plate heat exchanger and the second plate heat exchanger, and different operation modes of the system are realized by switching the on-off state of the control valve.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] 1) The heat storage and peak regulation capacity is significantly enhanced: the ATES of the underground aquifer is used for efficient heat storage, and the CHP and EHP and the two-stage plate heat exchanger are closely coupled. This innovative scheme not only successfully realizes various operation models and three-stage deep peak regulation, but also significantly improves the heat storage capacity of the ATES and further improves the peak regulation range of the CHP.

[0030] 2) The wind and light consumption capacity is greatly improved: through the ingenious coupling of the EHP and the CHP, the system can effectively consume wind and light power and recover the low-temperature condensing heat generated by the CHP. This measure not only significantly improves the operation energy efficiency of the CHP, but also effectively improves the overall consumption capacity of the system to wind and light power, thereby greatly reducing the wind and light curtailment rate.

[0031] 3) The peak regulation response speed is improved: the cooperation of the EHP and the two-stage plate heat exchanger enables the EHP to quickly consume wind and light power. This not only improves the electric-thermal conversion efficiency, but also significantly shortens the peak regulation response time and effectively reduces the thermal inertia effect in the CHP peak regulation process. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0033] Figure 1 The figure is a schematic diagram of the geothermal long-time energy storage coupled deep peak regulation system in the embodiment of the present application.

[0034] Figure 2 The figure is a simulation result diagram of the geothermal long-time energy storage coupled deep peak regulation system in the embodiment of the present application.

[0035] In the figure: 1, combined heat and power unit; 2, electric heat pump unit; 3, aquifer energy storage unit; 4, first plate heat exchanger; 5, second plate heat exchanger; 6, power grid; 7, heat grid; v1-v13, control valve. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0037] Embodiment:

[0038] It should be noted that the terms "first", "second" and the like in the description, claims, and drawings of the present application and the foregoing drawings are used to distinguish like objects, and are not necessarily used to describe a particular sequential or chronological order. It should be understood that the data thus used can be interchanged, where appropriate, to permit the embodiments of the present application described herein to be carried out in sequences other than those illustrated or described herein. Furthermore, the terms "comprise" and "have", and any variations thereof, as used in the embodiments of the present application, are intended to cover not exclusively inclusive, for example, a process, method, system, product, or apparatus that includes a series of steps or units does not have to be limited to those steps or units clearly listed, but can include additional steps or units not clearly listed

[0039] In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified. In addition, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0040] Figure 1 The principle diagram of the geothermal long-time energy storage coupled deep peak regulation system in the embodiments of the present application is shown in the figure. Figure 2 The simulation result diagram of the geothermal long-time energy storage coupled deep peak regulation system in the embodiments of the present application is shown in the figure. Figure 1 2

[0041] The geothermal long-time energy storage coupled deep peak regulation system provided by the present application is shown in the figure. Figure 1 The system mainly comprises a water-containing combined heat and power unit (CHP) 1, an electric heat pump unit (EHP) 2, an aquifer thermal energy storage unit (ATES) 3, a first plate heat exchanger (HX1) 4, a second plate heat exchanger (HX2) 5, a power grid (PG) 6, a heat grid (HG) 7, and control valves (v1-v13).

[0042] ​​The condenser 11 of the cogeneration unit 1 is connected with the evaporator 21 of the EHP to provide low-temperature waste heat resource for the EHP; and is connected with the power grid 6 and the heat grid 7 to simultaneously provide electric power and heat.

[0043] The electric heat pump unit 2 comprises a group of evaporators 21 and two groups of condensers (22 / 23); the evaporators 21 are connected with the CHP condenser 11 to recover the condensing heat of the CHP; the primary condenser 22 is connected with the heat grid 6 to provide a 1st-stage peak-shaving heat source; the secondary condenser 23 is connected with the primary heat exchanger 4 to provide a 2nd-stage peak-shaving heat source and an ATES heat storage heat source; the EHP is connected with the power grid 6 to consume the wind-solar over-generation electric power of the power grid 6 and convert it into heat to realize ATES heat storage, wind-solar electric power consumption and CHP peak shaving.

[0044] The aquifer energy storage unit 3 comprises a group of hot well groups 31 and a group of cold well groups 32; the hot well groups 31 are connected with the secondary plate heat exchanger 5 to provide a 3rd-stage peak-shaving heat source and a heat storage channel; the cold well groups 32 are connected with the primary plate heat exchanger 4 to provide a heat storage water source.

[0045] The primary plate heat exchanger 4 is connected with the EHP secondary condenser 23, the heat grid 7, the secondary plate heat exchanger 5 and the cold well groups 32; through heat exchange with the EHP secondary condenser 23, a heat source is provided for the cold well groups 32 geothermal water energy storage and the heat grid 7 peak shaving.

[0046] The secondary plate heat exchanger 5 is connected with the cogeneration unit 1, the primary plate heat exchanger 4 and the hot well groups 31; in the heat storage period, through heat exchange with the CHP, a heat storage heat source is provided for the ATES; in the heating period, through heat exchange with the hot well groups 31, a 3rd-stage peak-shaving heat source is provided for the heat grid 7.

[0047] The power grid 6 is connected with the cogeneration unit 1, the wind-solar power plant and the electric heat pump unit 2 to respectively export electric power for the CHP and the wind-solar power plant and provide power for the EHP.

[0048] The heat grid 7 is connected with the cogeneration unit 1, the EHP primary condenser 22, the primary plate heat exchanger 4 and the secondary plate heat exchanger 5 to provide a basic heat source and a 3rd-stage peak-shaving heat source for user load.

[0049] The control valves (v1-v13) are connected with the inlet and outlet pipelines of the cogeneration unit 1, the electric heat pump unit 2, the primary plate heat exchanger 4, the secondary plate heat exchanger 5 and other devices to realize five modes of operation, i.e. ATES heat storage, electric power consumption, 1st-stage peak shaving, 2nd-stage peak shaving and 3rd-stage peak shaving, by switching the states of the valves.

[0050] 1) ATES heat storage operation mode

[0051] CHP according to the maximum power output, the surplus co-production of heat through the heat exchanger with the second plate heat exchanger 5, heating from the ATES cold well group 32 of geothermal water, the realization of ATES heat storage, to provide heat reserve for peak shaving; valve switch state as shown in the following table:

[0052]

[0053] 2) the mode of operation of power consumption

[0054] The grid 6 from the wind and light power plant over power, EHP through the grid 6 of wind and light power; EHP using grid power recovery CHP condenser 11 of waste heat, through the second group of condensers 23 and the first plate heat exchanger 4 of EHP heat transfer from the ATES cold well group 32 of geothermal water, ultimately through the injection of hot well group 31 to realize ATES heat storage, to provide heat reserve for peak shaving; valve switch state as shown in the following table:

[0055]

[0056] 3) 1st peak shaving mode

[0057] CHP reduces the amount of power generation while the heat supply decreases, the grid 6 for the wind and light power plant over power to provide a channel, EHP using grid wind and light power recovery CHP condenser 11 of waste heat, through the first group of condensers 22 for the heat network 7 to provide 1st peak shaving heat, reduce CHP heat output and power output, fast response to consumption and peak shaving operation; valve switch state as shown in the following table:

[0058]

[0059] 4) 2nd peak shaving mode

[0060] CHP continues to reduce the amount of power generation while the heat supply decreases, the grid 6 for the wind and light power plant over power to increase channel capacity, EHP using grid wind and light power recovery CHP condenser 11 of waste heat, through the first group of condensers 22 and the second group of condensers 23 for the heat network 7 to provide 2nd peak shaving heat, further reduce CHP heat output and power output, improve the scope of operation of consumption and peak shaving; valve switch state as shown in the following table:

[0061]

[0062] 5) 3rd peak shaving mode

[0063] The CHP minimizes the power generation and the heat supply, the grid 6 maximizes the power transmission of the over-generation of the wind and solar power field, the EHP recovers the waste heat of the CHP condenser 11 by using the grid wind and solar power, and the four of the first group of condensers 22, the second group of condensers 23, the ATES heat storage and the one / two-stage plate heat exchanger 4 / 5 supply heat at the same time to provide three-stage peak shaving heat for the heat network 7, thereby minimizing the CHP heat supply and power generation, and improving the maximum depth of consumption and peak shaving operation; the valve opening and closing states are shown in the following table:

[0064]

[0065] It should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like 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 and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0066] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature can be directly above or obliquely above the second feature, or it can only mean that the first feature is higher in horizontal height than the second feature. The first feature can be directly below or obliquely below the second feature, or it can only mean that the first feature is lower in horizontal height than the second feature.

[0067] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, different embodiments or examples described in the present specification and the features of different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0068] The above examples are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the essence of the present application should be covered within the protection scope of the present application.

Claims

1. A geothermal long-term energy storage coupled with deep peak shaving system, characterized in that: This includes combined heat and power (CHP) units, electric heat pump units, aquifer energy storage units, primary plate heat exchangers, secondary plate heat exchangers, power grids, and heating networks. The condenser of the combined heat and power (CHP) unit is connected to the evaporator of the electric heat pump unit; the CHP unit is connected to both the power grid and the heating network; the primary condenser of the electric heat pump unit is connected to the heating network, and the secondary condenser of the electric heat pump unit is connected to the primary plate heat exchanger; the hot well group of the aquifer energy storage unit is connected to the secondary plate heat exchanger, and the cold well group of the aquifer energy storage unit is connected to the primary plate heat exchanger; the primary plate heat exchanger is connected to both the secondary condenser of the electric heat pump unit and the cold well group of the aquifer energy storage unit; the secondary plate heat exchanger is connected to both the CHP unit and the primary plate heat exchanger. The heat grid is connected to the heat well group of the aquifer energy storage unit and the plate heat exchanger. It is also connected to the combined heat and power (CHP) unit, the wind and solar power plant, and the electric heat pump unit. The heat grid is simultaneously connected to the first-stage condenser, the first-stage plate heat exchanger, and the second-stage plate heat exchanger of the CHP unit and the electric heat pump unit. The first-stage condenser is connected to the heat grid, providing a first-stage peak-shaving heat source. The second-stage condenser is connected to the first-stage heat exchanger, providing a second-stage peak-shaving heat source and a heat source for the aquifer energy storage unit. The aquifer energy storage unit includes a group of heat wells. The heat well group is connected to the second-stage plate heat exchanger, providing a third-stage peak-shaving heat source and a heat storage channel.

2. The geothermal long-term energy storage coupled with deep peak shaving system according to claim 1, characterized in that: The condenser of the cogeneration unit is connected to the evaporator of the electric heat pump unit, providing low-temperature waste heat resources for the electric heat pump unit; the cogeneration unit is connected to the power grid and the heating network respectively, providing both electricity and heat.

3. The geothermal long-term energy storage coupled with deep peak shaving system according to claim 1, characterized in that: The electric heat pump unit includes one set of evaporators and two sets of condensers; the evaporators are connected to the condensers of the cogeneration unit to recover the condensing heat of the cogeneration unit; the electric heat pump unit is connected to the power grid to absorb the excess wind and solar power generated by the grid and convert it into heat, so as to realize the heat storage of the aquifer energy storage unit, the absorption of wind and solar power and the peak regulation of the cogeneration unit.

4. The geothermal long-term energy storage coupled with deep peak shaving system according to claim 1, characterized in that: The aquifer energy storage unit also includes a group of cold wells, which are connected to a primary plate heat exchanger to provide a source of hot water for storage.

5. The geothermal long-term energy storage coupled with deep peak shaving system according to claim 1, characterized in that: The primary plate heat exchanger is connected to the secondary condenser of the electric heat pump unit and the cold well group respectively; through heat exchange with the electric heat pump unit, it provides a heat source for geothermal energy storage of the cold well group and peak shaving of the heating network.

6. The geothermal long-term energy storage coupled with deep peak shaving system according to claim 1, characterized in that: The secondary plate heat exchanger is connected to the cogeneration unit, the primary plate heat exchanger, and the hot well group, respectively. During the heat storage period, it provides a heat source for the aquifer energy storage unit through heat exchange with the cogeneration unit. During the heating period, it provides a peak-shaving heat source for the heating network through heat exchange with the hot well group.

7. The geothermal long-term energy storage coupled with deep peak shaving system according to claim 1, characterized in that: The power grid is connected to the combined heat and power (CHP) unit, the wind and solar power plant, and the electric heat pump unit, respectively, to supply power to the CHP unit and the wind and solar power plant, and to provide power to the electric heat pump unit.

8. The geothermal long-term energy storage coupled with deep peak shaving system according to claim 1, characterized in that: The heating network is simultaneously connected to the primary condenser, primary plate heat exchanger, and secondary plate heat exchanger of the combined heat and power unit and the electric heat pump unit, providing a basic heat source and a tertiary peak-shaving heat source for user loads.

9. The geothermal long-term energy storage coupled with deep peak shaving system according to claim 1, characterized in that: It also includes control valves, which are connected to the inlet and outlet pipelines of the cogeneration unit, the electric heat pump unit, the primary plate heat exchanger, and the secondary plate heat exchanger. The control valves achieve different operating modes of the system by switching on / off states.

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