Coupling system and method for heat storage tank and urban heat supply pipe network

Abstract

The invention relates to the technical field of heat supply and energy storage, and provides a coupling system and method of a heat storage tank and an urban heat supply pipe network. A surge tank; the first reversible pump turbine is arranged between a water supply pipe of the urban heat supply pipe network and a water distributor at the upper part of the low-temperature heat storage tank; the second reversible pump turbine is arranged between a water return pipe of the urban heat supply pipe network and a water distributor at the lower part of the low-temperature heat storage tank; the hybrid energy storage management system is connected with the first reversible pump turbine and the second reversible pump turbine; one of the first reversible pump turbine and the second reversible pump turbine can selectively serve as a water turbine to operate, pressure potential energy of water from the water supply pipe or the water return pipe is converted into mechanical energy and electric energy, and the mechanical energy and the electric energy are utilized or stored through the hybrid energy storage management system. And water of the lower water distributor or the upper water distributor of the low-temperature heat storage tank is pressurized and injected into the corresponding water return pipe or water supply pipe. According to the scheme, the technical bottleneck of efficient coupling of the low-temperature heat storage tank and the urban heat supply pipe network is broken through.

Description

Technical Field

[0001] This invention relates to the field of centralized heating and energy storage technology, and in particular to a coupling system and method for a thermal storage tank and an urban heating network. Background Technology

[0002] Against the backdrop of green transformation, thermal power plants face immense pressure to balance heating and power generation peak shaving during the heating season, necessitating large-scale energy storage facilities. However, existing technologies such as pumped hydro storage, molten salt storage, and battery storage generally suffer from high total investment costs and limited and unstable profit channels in the electricity market, leading to uncertain returns and high risks. In contrast, low-temperature thermal storage tanks for storing hot water at around 90℃ to 140℃ offer low investment costs and are suitable for thermal peak shaving, making them a promising solution. However, their widespread application faces a core challenge: if built within a thermal power plant, they are limited by land area and site selection; if built along urban heating networks outside the plant, the significant pressure difference caused by the urban heating network's operating pressure (approximately 1.6 MPa) being much higher than the thermal storage tank's operating pressure (not exceeding 0.38 MPa) must be addressed. Simply coupling pressure reduction and increase using valves and pumps will result in wasted pressure potential energy and low system efficiency. Meanwhile, the efficient operation of cryogenic thermal storage tanks relies on a stable "climate layer," which places extremely high demands on the control precision of inlet and outlet water temperature and flow rate, including speed control under frequent switching of operating conditions, interlock protection and vaporization, and safety management.

[0003] In existing technologies, patent CN208205157U uses a pump set to couple the pressurized system with the atmospheric pressure storage tank, resulting in huge energy consumption under high pressure differentials. Patent CN104832977A uses a unidirectional water turbine to recover potential energy, which cannot meet the requirements of bidirectional reversible operation for heat storage and release, nor the requirements of cryogenic heat storage tanks for hydraulic conditions and system control functions. Furthermore, the construction and operation of existing battery energy storage systems face mandatory constraints related to site selection, safety, and fire-fighting water supply, which urgently need to be overcome.

[0004] Therefore, there is an urgent need for a technical solution that can systematically address the coupling between low-temperature thermal storage tanks and relatively high-pressure urban heating networks, as well as their synergistic development with battery energy storage. Summary of the Invention

[0005] To address the challenges of coupling existing low-temperature thermal storage tanks with relatively high-pressure urban heating networks, which makes it difficult to achieve efficient recovery and storage of high-pressure differential potential energy, meet bidirectional reversibility and precise control requirements, and realize the coupling of low-temperature thermal storage tanks with relatively high-pressure urban heating networks and their synergistic development with battery energy storage, thus hindering reliable safety and economic support for energy storage systems, this invention proposes a coupling system and method for thermal storage tanks and urban heating networks.

[0006] To achieve the above objectives, one aspect of the present invention provides a coupling system between a thermal storage tank and an urban heating network, comprising: Low-temperature thermal storage tanks; Pressure stabilizing tank; A first reversible water pump turbine is connected between the water supply pipe of the urban heating network and the upper water distributor of the low-temperature heat storage tank, and a second reversible water pump turbine is connected between the return water pipe of the urban heating network and the lower water distributor of the low-temperature heat storage tank. A hybrid energy storage management system connected to the first and second reversible pump-turbines includes a battery energy storage unit; Among them, one of the first and second reversible pump-turbines can be selectively operated as a water turbine to convert the pressure potential energy of water from the supply pipe or return pipe relative to the low-temperature thermal storage tank into mechanical energy and / or electrical energy, which is utilized or stored by the hybrid energy storage management system to drive the other as a water pump to inject water from the lower water distributor into the return pipe or water from the upper water distributor into the supply pipe. The driving energy for operating as a water pump is selected from one or more of the converted energy, the electrical energy stored in the battery energy storage unit, and the electrical energy of the urban power grid.

[0007] In some embodiments, the coupling system may also be configured with a hybrid power pump system, which is mechanically connected between the first and second reversible pump-turbines. The hybrid power pump system is used to directly transfer all or part of the mechanical energy generated by one of the pumps when it is running as a turbine to the other reversible pump-turbine when it is running as a pump, and to drive the pump-turbine in coordination with its own motor torque.

[0008] In some embodiments, under thermal storage conditions, the first reversible pump-turbine operates as a turbine to convert the pressure potential energy of the high-pressure, high-temperature water in the supply pipe relative to the low-temperature thermal storage tank into mechanical energy and electrical energy, or all of it into electrical energy. The second reversible pump-turbine operates as a pump to pressurize the low-pressure, low-temperature water from the lower water distributor of the low-temperature thermal storage tank and inject it into the return water pipe. The driving energy of the second reversible pump-turbine can be provided by the mechanical energy or the electrical energy converted from it, based on the principle of real-time electricity price and optimal system efficiency, and the surplus energy can be stored in the battery energy storage unit in the form of electrical energy. Alternatively, it can be provided independently by the electricity from the urban power grid and all the converted electrical energy can be stored in the battery energy storage unit. In the heat release condition, the second reversible water pump turbine operates as a turbine to convert the pressure potential energy of the water in the return water pipe relative to the low-temperature thermal storage tank into mechanical energy or all of it into electrical energy. The first reversible water pump turbine operates as a pump to pressurize the water in the upper water distributor of the low-temperature thermal storage tank and inject it into the water supply pipe. The driving energy of the first reversible water pump turbine can be provided by the mechanical energy or all the electrical energy converted by it, the electrical energy of the battery energy storage unit, and / or the electrical energy of the urban power grid, depending on the real-time electricity price and the principle of optimal system efficiency. Alternatively, it can be provided by the electrical energy of the urban power grid independently and all the converted electrical energy can be stored in the battery energy storage unit.

[0009] In some embodiments, the coupling system further includes a first steam-water separator disposed between the first reversible water pump turbine and the upper water distributor of the cryogenic thermal storage tank, and a second steam-water separator disposed between the second reversible water pump turbine and the lower water distributor of the cryogenic thermal storage tank, for separating the gas generated when water flows through the corresponding reversible water pump turbine.

[0010] In some embodiments, the coupling system further includes a first regulating valve disposed between the first reversible water pump turbine and the first steam-water separator, and a second regulating valve disposed between the second reversible water pump turbine and the second steam-water separator, for regulating the flow rate.

[0011] In some embodiments, the pressure stabilizing tank is disposed between the lower water distributor of the cryogenic heat storage tank and the second regulating valve, for buffering the flow difference between the first regulating valve and the second regulating valve, so that the pressure inside the tank is always kept within the safe range of the design pressure.

[0012] In some embodiments, the coupling system further includes a first valve disposed on the pipeline between the first reversible water pump turbine and the water supply pipe of the urban heating network, and a second valve disposed on the pipeline between the second reversible water pump turbine and the return pipe of the urban heating network.

[0013] In some embodiments, the coupling system further includes an emergency fire-fighting system connected to the return water pipe of the urban heating network and / or the lower outlet of the low-temperature thermal storage tank to obtain an emergency fire-fighting water source.

[0014] In some embodiments, the number of the cryogenic thermal storage tanks is one or more, and corresponds to one or more pairs of the first and second reversible water pump turbines and one or more of the pressure stabilizing tanks.

[0015] In some embodiments, the cryogenic thermal storage tank has an operating pressure not exceeding 0.38 MPa and a maximum operating temperature range of 90~150℃.

[0016] In some embodiments, the hybrid energy storage management system is connected to the urban power grid via a main transformer. The hybrid energy storage management system includes a hybrid energy storage management platform, a cryogenic thermal storage tank control system, a plant bus, a battery energy storage converter, a battery management system, a battery array, and a back-to-back frequency converter.

[0017] In another aspect of the present invention, a coupling method between a thermal storage tank and an urban heating network is provided, applied to the coupling system of the thermal storage tank and urban heating network described in any of the preceding claims, comprising: In response to the low-temperature thermal storage tank being in thermal storage mode, the first reversible water pump turbine is controlled to operate as a water turbine, converting the pressure potential energy of the high-pressure, high-temperature water from the water supply pipe relative to the low-temperature thermal storage tank into mechanical energy and electrical energy, or converting all of it into electrical energy. Based on the principle of optimal real-time electricity price and system efficiency, the second reversible water pump turbine can be driven by the energy provided by the mechanical energy or the electrical energy converted therefrom, and the surplus energy can be stored in the battery energy storage unit in the form of electrical energy. Alternatively, the second reversible water pump turbine can be driven by the energy provided independently by the electricity from the urban power grid, and all the converted electrical energy can be stored in the battery energy storage unit. The low-pressure, low-temperature water from the lower water distributor of the low-temperature thermal storage tank is pressurized and injected into the return water pipe by the second reversible water pump turbine, according to the principle of balancing the inlet and outlet water flow of the low-temperature thermal storage tank.

[0018] In some embodiments, a method for coupling a thermal storage tank with an urban heating network further includes: In response to the low-temperature thermal storage tank being in heat release mode, the second reversible water pump turbine is controlled to operate as a water turbine, converting the pressure potential energy of the high-pressure low-temperature water from the return water pipe relative to the low-temperature thermal storage tank into mechanical energy or entirely into electrical energy. Based on the principle of optimal real-time electricity price and system efficiency, the first reversible water pump turbine can be driven by energy independently provided by the urban power grid as a water pump, and all the converted electrical energy can be stored in the battery energy storage unit. Alternatively, the first reversible water pump turbine can be driven by energy jointly provided by the mechanical energy or all the electrical energy converted therefrom, the electrical energy of the battery energy storage unit, and / or the electrical energy of the urban power grid. Through the first reversible water pump turbine, and based on the principle of balanced inlet and outlet water flow of the low-temperature thermal storage tank, the low-pressure, high-temperature outlet water from the upper water distributor of the low-temperature thermal storage tank is pressurized and injected into the water supply pipe.

[0019] The present invention has at least the following beneficial effects: The coupling system between the thermal storage tank and the urban heating network proposed in this invention can fully recover and efficiently utilize the huge pressure potential energy between the urban heating network and the low-temperature thermal storage tank, while solving a series of problems such as operation regulation, economy and safety, and has significant comprehensive benefits.

[0020] Specifically, through the coordinated operation of the first and second reversible pump-turbine units and the hybrid energy storage management system, the potential energy contained in the pressure difference between the urban heating network and the cryogenic thermal storage tank is recovered and efficiently utilized within the system as electrical energy or a combination of electrical and mechanical energy. Alternatively, it can be stored in the battery energy storage unit for providing high-value ancillary services to the urban power grid, such as frequency regulation and backup. Its reversible operation allows the cryogenic thermal storage tank to convert the excess pressure potential energy of the supply or return water pipe relative to the storage tank into electrical energy during both heat storage and heat release operations, simultaneously completing the pressurization task required on the other side. This avoids energy waste and meets the requirements of bidirectional operation. The battery energy storage unit included in the hybrid energy storage management system and its connection to the urban power grid jointly solve the dilemmas of limited project economics and battery safety constraints. Battery energy storage units enable the recovery and storage of off-peak electricity, allowing for participation in grid peak-valley arbitrage or the provision of high-value ancillary services, thus broadening profit channels. At the same time, the deep integration of this coupled system with the heating network provides a reliable emergency water source from the urban heating network or cryogenic thermal storage tanks for emergency fire fighting, significantly improving safety.

[0021] Meanwhile, the coupling method between thermal storage tanks and urban heating networks proposed in this invention solves key issues regarding site selection and safety in the application of low-temperature thermal storage tanks for power plant peak power generation and heating peak shaving. This allows power plants to remotely and synchronously store hot water at approximately 90-150°C during off-peak hours in the non-heating season by strategically arranging clusters of atmospheric or pressurized low-temperature thermal storage tanks along the heating network. This hot water can then be used to heat condensate during peak hours to save energy and increase power generation. Alternatively, during the heating season, the storage of thermal energy remotely and synchronously for urban heating peak shaving and power plant peak power generation peak shaving becomes a highly economical and socially beneficial feasible method. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0023] Figure 1 The diagram shown is a structural schematic of a coupling system between a thermal storage tank and an urban heating network, according to an embodiment of the present invention. Figure 2 The diagram shown is a schematic diagram of the coupling system between the thermal storage tank and the urban heating network in a hybrid energy storage management system configured with a hybrid water pump (sub) system, according to another embodiment of the present invention. Figure 3 The diagram shown illustrates the energy and working fluid transfer between the thermal storage tank and the urban heating network in a hybrid energy storage management system without a hybrid power pump (sub) system, according to another embodiment of the present invention. Figure 4 The diagram shown illustrates the energy and working fluid transfer between the thermal storage tank and the urban heating network in a hybrid energy storage management system configured with a hybrid water pump (sub) system, according to another embodiment of the present invention. Figure 5 The diagram shown is a structural schematic of a hybrid energy storage management system with a hybrid water pump system provided according to another embodiment of the present invention. Detailed Implementation

[0024] The following describes embodiments of the present invention. However, it should be understood that the disclosed embodiments are merely examples, and other embodiments may take various alternative forms.

[0025] Furthermore, it should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or apparatus that comprises a list of elements may include not only those elements but also elements not expressly listed or inherent to such process, method, article, or apparatus.

[0026] One or more embodiments of this application will now be described with reference to the accompanying drawings.

[0027] Based on the above objectives, the first aspect of the present invention provides an embodiment of a coupling system between a thermal storage tank and an urban heating network. Figure 1 The diagram shown illustrates the construction of a coupling system between a thermal storage tank and an urban heating network, as provided in one embodiment of the present invention. Figure 1As shown, a coupling system between a thermal storage tank and an urban heating network includes: a low-temperature thermal storage tank; a first reversible water pump turbine installed between the supply pipe of the urban heating network and the upper water distributor of the low-temperature thermal storage tank; and a second reversible water pump turbine installed between the return pipe of the urban heating network and the lower water distributor of the low-temperature thermal storage tank; and a hybrid energy storage management system connected to the first and second reversible water pump turbines and the low-temperature thermal storage tank system elements, the hybrid energy storage management system including a battery energy storage unit; wherein, one of the first and second reversible water pump turbines can be selectively operated as a water turbine, converting the pressure potential energy of water from the supply or return pipe relative to the low-temperature thermal storage tank into mechanical energy and electrical energy, which is utilized or stored by the hybrid energy storage management system, driving the other to operate as a water pump, injecting water from the lower water distributor into the return pipe or injecting water from the upper water distributor into the supply pipe, wherein the driving energy for operating as a water pump is selected from one or more of the converted energy, the electrical energy stored in the battery energy storage unit, and the electrical energy of the urban power grid.

[0028] The aforementioned coupling system between a thermal storage tank and a city heating network, through the coordinated operation of a first reversible pump-turbine, a second reversible pump-turbine, and a hybrid energy storage management system, recovers the potential energy contained in the pressure difference between the city heating network and the low-temperature thermal storage tank. This potential energy is then efficiently utilized within the system as electrical energy, or simultaneously / stored in a battery energy storage unit to provide high-value ancillary services to the city power grid, such as frequency regulation and backup. Its reversible operation allows the low-temperature thermal storage tank to convert the excess pressure potential energy of the supply or return water pipe relative to the storage tank into electrical energy during both heat storage and heat release operations, simultaneously completing the pressurization task required on the other side. This avoids energy waste and meets the requirements of bidirectional operation. Furthermore, the battery energy storage unit included in the hybrid energy storage management system and its connection to the city power grid jointly solve the dilemmas of limited project economics and battery safety constraints. The battery energy storage unit enables the storage of electrical energy recovered from pressure potential energy and off-peak electricity from the urban power grid, and allows it to participate in grid peak-valley arbitrage or provide high-value ancillary services, thus broadening profit channels. At the same time, the deep integration of this coupling system with the heating network provides a reliable emergency water source from the urban heating network or low-temperature thermal storage tanks for emergency fire fighting, significantly improving safety.

[0029] In some embodiments, Figure 1 On this basis, Figure 2A schematic diagram of the coupling system between the thermal storage tank and the urban heating network in a hybrid energy storage management system configured with a hybrid water pump (sub) system, according to another embodiment of the present invention, is shown. The hybrid energy storage management system is equipped with a hybrid water pump system, which is mechanically connected between a first reversible water pump turbine and a second reversible water pump turbine. This system directly transfers the mechanical energy generated by one of the turbines operating as a water turbine to the other reversible water pump turbine operating as a water pump, combining the mechanical energy with the torque of its own electric motor to drive its operation in a "mechanical energy + electrical energy" manner. This hybrid water pump system acts as an efficiency-enhancing device, establishing an efficient mechanical energy transfer path between the two units, directly transferring all or part of the mechanical energy generated by the turbine unit to the pump shaft of the pump unit. Specifically, the input shaft of the hybrid water pump system is connected to the rotor shaft of the first reversible water pump turbine via a coupling, and the output shaft is connected to the rotor shaft of the second reversible water pump turbine in the same manner. The hybrid power pump system is equipped with sensors to monitor torque and speed. Its core control actions involve engaging and disengaging the mechanical transmission path, and adjusting the torque transmission ratio between the turbine and the electric motor when engaged. Understandably, both the hybrid energy storage management system and the hybrid power pump system can be expanded accordingly with the flexible configuration of the cryogenic thermal storage tank. The system's operation is intelligently scheduled by the hybrid energy storage management system, which can control the start-up, shutdown, and operation modes of the equipment, and make real-time decisions on the optimal energy transfer and drive strategies based on multi-source information.

[0030] In some embodiments, Figure 3 This diagram illustrates energy and working fluid transfer in a hybrid energy storage management system without a hybrid power pump (sub-system) according to another embodiment of the present invention. Figure 4 This diagram illustrates the energy and working fluid transfer within a hybrid energy storage management system configured with a hybrid power pump (sub-system) according to another embodiment of the present invention. It is understood that in this coupled system, mechanical energy transfer is achieved through the hybrid power pump (sub-system) configured within the hybrid energy storage management system. In the specific operation of this coupled system, the heat storage and heat release conditions of the cryogenic thermal storage tank are achieved by switching the operating modes of the first and second reversible pump-turbines.

[0031] In thermal storage operation, the first reversible pump-turbine operates as a turbine to convert the pressure potential energy of the high-pressure, high-temperature water from the supply pipe relative to the thermal storage tank into mechanical and electrical energy, or entirely into electrical energy. Specifically, before the water from the supply pipe enters the upper distributor of the thermal storage tank, the first reversible pump-turbine converts the excess pressure potential energy relative to the thermal storage tank into mechanical and electrical energy, or entirely into electrical energy. The second reversible pump-turbine operates as a pump to pressurize the low-pressure, low-temperature water from the lower distributor of the thermal storage tank and inject it into the return water pipe. Specifically, to maintain a balance between the low-pressure, low-temperature outlet water from the lower distributor and the high-pressure, high-temperature inlet water from the upper distributor, the second reversible pump-turbine pressurizes the low-pressure, low-temperature outlet water and injects it into the return water pipe of the urban heating network. The driving energy of the second reversible pump-turbine can be provided by mechanical energy or the electrical energy converted from it, based on the real-time electricity price and the principle of optimal system efficiency (i.e., according to the electricity price of the urban power grid and the demand for battery energy storage by ancillary services). Excess energy can be stored in the battery energy storage unit as electrical energy. Alternatively, it can be provided independently by the urban power grid, with all converted electrical energy stored in the battery energy storage unit. Specifically, all mechanical energy can be converted into electrical energy and stored in the battery energy storage unit, with the urban power grid providing the electricity to drive the second reversible pump-turbine. Alternatively, some mechanical energy can be directly transferred to the second reversible pump-turbine to drive its operation, and the remaining mechanical energy can be converted into electrical energy by the first reversible pump-turbine and stored in the battery energy storage unit. Alternatively, all mechanical energy can be converted into electrical energy to drive the second reversible pump-turbine, with the remaining energy stored in the battery energy storage unit.

[0032] In the heat release operation, the second reversible pump-turbine operates as a turbine, converting the pressure potential energy of the water in the return pipe relative to the low-temperature thermal storage tank into mechanical energy or entirely into electrical energy. Specifically, the second reversible pump-turbine converts the pressure potential energy of the water from the return pipe into mechanical energy or entirely into electrical energy before sending the high-pressure low-temperature water from the return pipe into the lower water distributor of the low-temperature thermal storage tank. The first reversible pump-turbine operates as a pump, pressurizing the water from the upper water distributor of the low-temperature thermal storage tank and injecting it into the supply pipe. Specifically, to maintain a balance between the low-pressure low-temperature inlet water of the lower water distributor and the low-pressure high-temperature outlet water of the upper water distributor, the first reversible pump-turbine pressurizes the low-pressure high-temperature outlet water and injects it into the supply pipe. The driving energy of the first reversible pump-turbine can be provided by mechanical energy or all the electrical energy converted from it, the electrical energy of the battery energy storage unit, and / or the electrical energy of the urban power grid, based on the real-time electricity price and the principle of optimal system efficiency (i.e., according to the electricity price of the urban power grid and the demand for battery energy storage by ancillary services). Alternatively, it can be provided independently by the electrical energy of the urban power grid and all the converted electrical energy can be stored in the battery energy storage unit. Specifically, the first reversible pump-turbine can be driven by the electrical energy provided by the urban power grid and all the mechanical energy can be converted into electrical energy and stored in the battery energy storage unit; or all the mechanical energy can be directly transferred to the first reversible pump-turbine and driven by the electrical energy stored in the battery management unit and / or the electrical energy of the urban power grid; or all the mechanical energy can be converted into electrical energy and driven by the electrical energy stored in the battery management unit and / or the electrical energy of the urban power grid.

[0033] More specifically, the aforementioned coupling system between a thermal storage tank and an urban heating network not only provides high-value ancillary services to the urban power grid when the thermal storage tank is in a heat preservation / static storage state, but also, when the thermal storage tank is in heat storage and heat release conditions, it can still provide corresponding ancillary services to the urban power grid based on different energy dispatch methods during off-peak, peak, and off-peak periods, ensuring the normal operation of the thermal storage tank while providing corresponding ancillary services to the urban power grid. For example: (I) Energy dispatch of the low-temperature thermal storage tank under heat storage conditions. The first reversible pump-turbine operates as a turbine, and the second reversible pump-turbine operates as a pump. The first reversible pump-turbine converts the excess pressure potential energy of the high-pressure, high-temperature water (flow rate Q1) from the urban heating network supply pipe relative to the low-temperature thermal storage tank into mechanical energy and electrical energy. The hybrid energy storage management system and battery energy storage unit operate in tandem under the condition that the state of charge (SOC) meets the relevant requirements such as the lower and upper limits of operation.

[0034] Mode 1: Urban power grid is in a low-voltage period Coupled systems of urban heating networks without hybrid power pump systems (please refer to...) Figure 1), or a coupled system of a city heating network equipped with a hybrid water pump system (please refer to) Figure 2 The hybrid water pump system is set to the off state, and all the mechanical energy generated by the first reversible water pump turbine is converted into electrical energy by its coaxial generator. Its hybrid energy storage management system can store all the converted electrical energy in the battery energy storage unit, while simultaneously driving the water pump with low-cost electricity purchased from the city grid. Temporary shortages are supported by the battery energy storage unit (please refer to...). Figure 3 ); Also, based on the characteristics of battery energy storage—which can reduce or increase charging power and can instantly switch from charging to discharging—it can provide "up-frequency regulation" and "down-frequency regulation" services to the urban power grid and provide power support to water pumps (please refer to...). Figure 3 ).

[0035] Mode 2: Urban power grid is in peak period Coupled systems of urban heating networks without hybrid power pump systems (please refer to...) Figure 1 In the first reversible pump-turbine, all mechanical energy generated is converted into electrical energy by its coaxial generator. Its hybrid energy storage management system uses a portion of the electrical energy to drive the pump, while the remaining energy, combined with that from the battery storage unit, is released into the city power grid. It can also provide "up-frequency regulation" and "down-frequency regulation" services to the city power grid through bidirectional, real-time electrical exchange (please refer to...). Figure 3 ); Coupled systems of urban heating networks equipped with hybrid water pump systems (please refer to...) Figure 2 The hybrid water pump system is configured in a partially engaged state. Part of the mechanical energy generated by the first reversible pump turbine drives the pump, while the remainder is converted into electrical energy. Its hybrid energy storage management system combines the remaining electrical energy with that from the battery storage unit and releases it to the city grid. It can also release electrical energy to the city grid via bidirectional, real-time AC communication, and can provide "up-frequency regulation" and "down-frequency regulation" services to the city grid (please refer to...). Figure 4 ); Urban heating network coupling system with hybrid water pump system (please refer to) Figure 2 The system controls a hybrid power pump system to achieve partial engagement (e.g., transferring 60% of the mechanical energy). A portion of the mechanical energy generated by the first reversible pump-turbine is directly used to drive the second reversible pump-turbine via a drive shaft, while the remaining mechanical energy is converted into electrical energy and stored or used directly. This mechanical-to-electrical energy transfer mode maximizes system energy efficiency by reducing losses in the "mechanical-electrical-mechanical" conversion process.

[0036] Mode 3: Urban power grid is in a period of low activity. Urban heating network coupling systems, with or without hybrid power pump systems, can select the aforementioned corresponding operating modes, perform charge / discharge adjustments, and provide "up-frequency regulation" and "down-frequency regulation" services according to the operating strategy (please refer to...). Figure 1-4 ).

[0037] (II) Energy Dispatch of Low-Temperature Thermal Storage Tanks under Heat Release Conditions The second reversible pump-turbine operates as a turbine, while the first reversible pump-turbine operates as a pump. The second reversible pump-turbine converts the excess pressure potential energy of the high-pressure low-temperature water (flow rate Q2) from the return pipe of the urban heating network relative to the low-temperature thermal storage tank into mechanical energy and electrical energy. The hybrid energy storage management system and the battery energy storage unit operate in tandem under the condition that the state of charge (SOC) meets the relevant requirements such as the lower and upper limits of operation.

[0038] Mode 1: Urban power grid is in a low-voltage period Coupled systems of urban heating networks without hybrid power pump systems (please refer to...) Figure 1 ), or a coupled system of a city heating network equipped with a hybrid water pump system (please refer to) Figure 2 The hybrid water pump system is set to the off state, and all the mechanical energy generated by the second reversible water pump turbine is converted into electrical energy by its coaxial generator. Its hybrid energy storage management system can store all the converted electrical energy in the battery energy storage unit, while simultaneously driving the water pump with low-cost electricity purchased from the city grid. Temporary shortages are supported by the battery energy storage unit (please refer to...). Figure 3 ); Also, based on the characteristics of battery energy storage—which can reduce or increase charging power and can instantly switch from charging to discharging—it can provide "up-frequency regulation" and "down-frequency regulation" services to the urban power grid and provide power support to water pumps (please refer to...). Figure 3 ).

[0039] Mode 2: Urban power grid is in peak period Coupled systems of urban heating networks without hybrid power pump systems (please refer to...) Figure 1 The second reversible pump-turbine converts all mechanical energy generated by its coaxial generator into electrical energy. Its hybrid energy storage management system uses the converted electrical energy to drive the pump, supplementing any shortfall with energy from battery storage units and / or the city power grid. Simultaneously, it releases energy from the battery storage units to the city power grid and can also provide "up-frequency regulation" and "down-frequency regulation" services to the city power grid through bidirectional, real-time AC power exchange (please refer to...). Figure 3 ); Urban heating network coupling system with hybrid water pump system (please refer to) Figure 2The hybrid water pump system is set to a fully engaged state. Its hybrid energy storage management system combines the mechanical energy generated by the second reversible water pump turbine with the electrical energy from the battery energy storage unit and / or the urban power grid to drive the water pump. Simultaneously, it releases electrical energy from the battery energy storage unit to the urban power grid. It can also release electrical energy to the urban power grid via bidirectional, real-time AC communication, and can provide "up-frequency regulation" and "down-frequency regulation" services to the urban power grid (please refer to...). Figure 4 ).

[0040] Mode 3: Urban power grid is in a period of low activity. Urban heating network coupling systems, with or without hybrid power pump systems, can select the aforementioned corresponding operating modes, perform charge / discharge adjustments, and provide "up-frequency regulation" and "down-frequency regulation" services according to the operating strategy (please refer to...). Figure 1-4 ).

[0041] In some embodiments, the hybrid energy storage management system ensures that the flow rate entering the cryogenic storage tank (Q1) and the flow rate leaving the cryogenic storage tank (Q2) are dynamically balanced at all times by precisely adjusting the power of the first and second reversible pump-turbines and the opening of the regulating valves, i.e., Q1=Q2. This strict flow balance regulation effectively prevents the safety risks of overpressure and vaporization of the cryogenic storage tank caused by overpressure and underpressure, maintains the stability of the thermocline structure, and ensures the hydraulic balance of the main circulation flow in the urban heating network. The hybrid energy storage management system achieves high-precision control of the cryogenic storage tank's thermocline, meeting various technical requirements such as speed control, equipment interlock protection, and vaporization safety management under frequent start-stop conditions.

[0042] The hybrid water pump system, as part of the hybrid energy storage management system, has its operating status (disconnected, partially connected, fully connected) intelligently scheduled by the hybrid energy storage management system. For example... Figure 5 As shown, Figure 5A schematic diagram of a hybrid energy storage management system configured with a hybrid power pump system is shown. The hybrid energy storage management system includes a hybrid energy storage management platform, a cryogenic thermal storage tank control system, a hybrid power pump system, a plant bus, a battery energy storage converter (PCS), a battery management system (BMS), battery arrays (i.e., battery energy storage units), and back-to-back frequency converters (SFCs). It is used to realize functions such as sequential logic, speed control, interlocking protection, control strategies, power collection, energy distribution, and energy storage of the cryogenic thermal storage tank system, and is electrically connected to the urban power grid. The PCS is responsible for bidirectional energy conversion between the battery and the AC bus, and the SFC can be used for smooth starting of high-power reversible pump turbines. The hybrid energy storage management system is connected to the urban power grid through a main transformer, used to receive electrical energy from the grid and store it in the battery energy storage units, or to feed the electrical energy stored in the battery energy storage units into the urban power grid according to grid dispatch needs, or to provide ancillary services to the urban power grid. As an intelligent decision-making center, the hybrid energy storage management system dynamically calculates and selects the energy transfer mode with the best global economics or highest energy efficiency based on real-time monitoring of pipeline pressure differential, equipment efficiency characteristics, state of charge (SOC) of battery energy storage units, and electricity price signals or ancillary service demands of the urban power grid. This enables the coupled system to achieve dynamic and seamless switching between efficient mechanical direct connection and flexible power dispatch, thereby improving the comprehensive utilization rate of pressure potential energy and enhancing the adaptability and economy of system operation.

[0043] In some embodiments, based on the operating conditions of the energy-saving coupling system of the low-temperature thermal storage tank and the urban heating network, and drawing on the design concept of high-temperature resistant water pumps for heating, the materials, sealing, cooling and pressure control of the traditional water turbine unit are systematically transformed into a reversible water pump turbine. Both the first reversible water pump turbine and the second reversible water pump turbine are high-temperature resistant reversible water pump turbines to adapt to the operating environment of water with a temperature of 130°C or higher.

[0044] In some embodiments, the cryogenic thermal storage tank is designed to meet specific requirements for safe and efficient coupling with high-pressure urban heating networks. The cryogenic thermal storage tank operates at a pressure not exceeding 0.38 MPa and has a maximum operating temperature range of 90–150°C, while the urban heating network operates at approximately 1.6 MPa. In one specific embodiment, the cryogenic thermal storage tank is a vertical cylindrical pressure vessel with a design pressure not exceeding 0.6 MPa, for example, a typical design pressure of 0.15–0.6 MPa, and a maximum operating temperature range of 90–150°C. The typical operating pressure of the urban heating network's supply pipe is approximately 1.8 MPa, and the typical operating pressure of the return pipe is approximately 1.2 MPa. The upper and lower water distributors inside the low-temperature thermal storage tank act as diffusion devices, enabling water to flow into or out of the tank at a low speed and uniform cross-sectional distribution. This minimizes disturbance to the existing water temperature stratification inside the tank. This "hot at the top and cold at the bottom" water distribution strategy is conducive to achieving efficient heat storage and release and maintaining a stable sloping temperature layer inside the low-temperature thermal storage tank, ensuring the thermal energy storage efficiency and output quality of the thermal storage tank.

[0045] In some embodiments, the size of the cryogenic thermal storage tank can be flexibly configured according to actual peak-shaving needs. The number of cryogenic thermal storage tanks can be one or more, corresponding to one or more pairs of the first and second reversible pump-turbine systems. Specifically, if there is one cryogenic thermal storage tank, the first and second reversible pump-turbine systems are one or more pairs; if there are multiple cryogenic thermal storage tanks (e.g., two), the first and second reversible pump-turbine systems are one or more pairs (e.g., two pairs) forming a one-to-one or many-to-many connection. It is understood that the hybrid energy storage management system can also be expanded accordingly. For small-scale thermal storage needs, a single cryogenic thermal storage tank is paired with a pair of reversible pump-turbine systems to form a standard coupling unit. For larger-scale thermal storage needs, multiple cryogenic thermal storage tanks are connected in parallel to form a cryogenic thermal storage tank group, which is connected to multiple pairs of first and second reversible pump-turbine systems through a main pipeline system, forming a "many-to-many" clustered system, achieving modular expansion and redundant operation.

[0046] The aforementioned coordinated operation of the first reversible pump-turbine, the second reversible pump-turbine, and the hybrid energy storage management system allows for the recovery of the potential energy contained in the pressure difference between the cryogenic thermal storage tank and the urban heating network. This potential energy can be efficiently utilized within the system as electrical energy or a combination of electrical and mechanical energy, or stored in a battery energy storage unit for providing high-value ancillary services to the urban power grid, such as frequency regulation and backup power. Furthermore, the cryogenic thermal storage tank can be insulated with a thermal insulation layer to reduce heat loss. Based on the high mechanical energy conversion rate of 93-95% and the power generation efficiency of 91.5-94% achieved by the reversible pump-turbine of this invention, the comprehensive utilization rate of pressure potential energy in this coupled system can reach approximately 90%.

[0047] In some embodiments, the hybrid energy storage management system can receive and store electrical energy converted from reversible pump-turbines operating as water turbines, and can absorb electrical energy from the urban power grid during off-peak hours. Simultaneously, according to grid dispatch instructions, the stored electrical energy can be fed back to the urban power grid, or used to provide ancillary services such as frequency regulation and backup, generating economic benefits. It can also be connected to the urban power grid, all reversible pump-turbines, and related valves via electrical and communication networks to control the start-up, shutdown, operating mode switching, and power of the first and second reversible pump-turbines, in order to collaboratively achieve the heat storage or heat release conditions of the cryogenic thermal storage tank, and maintain the balance of water temperature stratification and inlet / outlet water flow within the cryogenic thermal storage tank, as detailed below: Operating condition coordination and flow balance: Regardless of whether the low-temperature thermal storage tank is in thermal storage or thermal release mode, real-time monitoring and power regulation ensure that the dynamic fluctuation range of the water flow entering and leaving the low-temperature thermal storage tank is less than the regulation capacity of the pressure stabilizing tank, and that the water flow entering and leaving the low-temperature thermal storage tank is basically equal, that is, to maintain dynamic balance. This is the basis for maintaining the safe operation of the low-temperature thermal storage tank, the stability of the heating network flow, and the stability of the water temperature stratification structure inside the thermal storage tank.

[0048] Operating modes and safety interlocks: The hybrid energy storage management system has built-in strict sequential logic. For example, when starting the thermal storage mode of the cryogenic thermal storage tank, the first reversible water pump turbine is started to turbine mode, the second reversible water pump turbine is started to pump mode, and then subsequent operations are performed to ensure a smooth process without overpressure or impact.

[0049] Power dispatch and economic operation: Strategy 1 (Real-time Compensation): The electrical energy generated by the reversible pump-turbine operating as a water turbine is prioritized and used in real-time to drive the reversible pump-turbine operating as a pump. Excess power generation is stored in battery energy storage units, while insufficient power generation is supplemented by batteries or the power grid.

[0050] Strategy Two (Planned Arbitrage): During periods of low grid electricity prices (such as at night), all the electrical energy converted by the water turbine is stored, while low-priced electric pumps are purchased from the grid. During peak electricity prices or when the grid requires it, the stored electrical energy is sold or used to provide ancillary services, thereby generating significant economic benefits through price differences and service compensation. This model fundamentally overcomes the obstacles of traditional schemes, such as excessively high operating energy consumption and poor economic efficiency due to pressure differentials.

[0051] Based on the aforementioned functions, the battery capacity and related equipment performance configuration of the battery energy storage unit require comprehensive design. Its battery capacity should be sufficient to buffer and manage the potential recoverable energy corresponding to the "available pressure difference" and design flow rate between the urban heating network and the storage tank, and to cover system losses. Simultaneously, this configuration should be scalable, allowing for flexible adjustments based on the depth of grid service participation and market fluctuations to maximize the overall economic benefits of the system.

[0052] Please refer to several embodiments of the present invention. Figure 1-2 This coupling system includes a series of safety and efficiency-enhancing components that work in conjunction with the core energy conversion equipment to ensure the safe, stable, and efficient operation of the system. The system includes a first steam-water separator located between the upper water distributor of the first reversible water pump turbine and the cryogenic thermal storage tank, and a second steam-water separator located between the lower water distributor of the second reversible water pump turbine and the cryogenic thermal storage tank. These separators separate the gas generated when water flows through the corresponding reversible water pump turbine, ensuring normal system operation. Both the first and second steam-water separators are electrically connected to the hybrid energy storage management system. Furthermore, a pressure stabilizing tank is located between the lower water distributor of the cryogenic thermal storage tank and the second regulating valve. This tank buffers the flow difference between the first and second regulating valves, stabilizing pressure fluctuations caused by factors such as the difference in inlet and outlet water flow in the cryogenic thermal storage tank, ensuring that the tank pressure remains within a safe range above the saturated vapor pressure and below the design pressure. Furthermore, the coupling system also includes a first regulating valve located between the first reversible water pump turbine and the first steam-water separator, and a second regulating valve located between the second reversible water pump turbine and the second steam-water separator, for regulating the flow rate. Furthermore, the coupling system also includes a first valve located on the pipeline between the first reversible water pump turbine and the supply pipe of the urban heating network, and a second valve located on the pipeline between the second reversible water pump turbine and the return pipe of the urban heating network. Furthermore, the coupling system also includes an emergency fire-fighting system, which is connected to the return pipe of the urban heating network and / or the lower outlet of the low-temperature thermal storage tank, enabling direct use of the system's own circulating or stored low-temperature water as an emergency fire-fighting water source.

[0053] More specifically, in the high-temperature water path (water supply pipe – low-temperature thermal storage tank), a first valve is installed on the pipeline between the water supply pipe of the urban heating network and the first reversible water pump turbine to control the flow of high-temperature water into the system. On the connecting pipe between the first reversible water pump turbine and the upper water distributor of the low-temperature thermal storage tank, along the water flow direction, are sequentially installed the following: a first regulating valve for finely adjusting flow and pressure; a first steam-water separator for separating gases that may be released when the water flows through the turbine for pressure reduction, preventing cavitation or vibration; the separated gas is discharged through an automatic exhaust valve; and a safety valve, located near the inlet of the thermal storage tank, providing overpressure protection.

[0054] In the low-temperature water path (return pipe – low-temperature thermal storage tank), a second valve is installed on the pipeline between the return pipe of the urban heating network and the second reversible pump turbine to control the flow of low-temperature water into the system. On the connecting pipe between the second reversible pump turbine and the lower water distributor of the low-temperature thermal storage tank, the following are installed sequentially: a second regulating valve for fine-tuning flow and pressure; a pressure stabilizing tank for efficient pressure stabilization and protection of the low-temperature thermal storage tank system under low-temperature conditions; and a second steam-water separator, functioning the same as the first steam-water separator, to ensure the purity of the water entering the storage tank.

[0055] All the aforementioned pressure tanks, valves, regulating valves, steam-water separators, and safety valves are electrically connected to the hybrid energy storage management system, accepting its unified monitoring and regulation to achieve automated and intelligent system operation. It is understandable that in actual implementation, the number of pressure tanks, valves, steam-water separators, and safety valves can be flexibly increased according to system scale and reliability requirements. The establishment of this safety and efficiency enhancement system effectively improves the stability and safety of the entire coupled system.

[0056] In another specific embodiment, the inlet of the emergency fire-fighting system is connected to the return water connection pipe between the urban heating network and the second reversible pump turbine. This emergency fire-fighting system is electrically connected to the hybrid energy storage management system, receiving unified monitoring and activation control. When a fire occurs in the battery energy storage unit or other equipment area within the system, the hybrid energy storage management system can automatically or manually activate the emergency fire-fighting mode. At this time, priority can be given to using the continuously circulating low-temperature water in the urban heating network's return water pipe, or the low-temperature water stored at the bottom of the low-temperature thermal storage tank after heat release, as an immediate and effective fire-fighting water source to achieve rapid fire control and cooling, thereby significantly improving the safety protection level of the entire coupled system. Specifically, when using the low-temperature water at the bottom of the thermal storage tank as the emergency fire-fighting water source, the coupled system will interlock and stop all upper water intake and extraction operations of the low-temperature thermal storage tank, ensuring that the emergency fire-fighting water source strictly originates from the low-temperature zone at the bottom of the tank, and strictly controlling the outlet water temperature to meet fire-fighting requirements. After a fire is extinguished, the cryogenic thermal storage tank must be started according to relevant standards before resuming thermal storage operation to ensure that indicators such as oxygen content in the water inside the tank meet the standards. When using cryogenic water from the return water pipe of the urban heating network as an emergency fire water source, this coupling system will promptly activate the supplementary water system of the heating system according to the preset plan. While ensuring fire water supply, it will maintain the stability of water volume, water pressure, and water temperature in the return water pipe, ensuring that the normal operation of the urban heating main system is not affected.

[0057] Based on the above design, this coupled system achieves multi-functional deep linkage and resource sharing of "energy storage-heating-firefighting". The low-temperature circulating water continuously running in the return water pipe of the urban heating network constitutes a natural and massive "reservoir" for fire-fighting water; while the low-temperature thermal storage tank itself, after heat release, also stores a large amount of usable low-temperature fire-fighting water. This not only greatly improves the safety of battery energy storage facilities and lowers the threshold for their construction site selection and investment in independent fire-fighting systems, but also comprehensively improves the infrastructure resilience, safety assurance level, and investment utilization efficiency of the entire integrated energy station.

[0058] In summary, the coupling system between the thermal storage tank and the urban heating network provided by this invention can fully recover and efficiently utilize the enormous pressure potential energy between the urban heating network and the low-temperature thermal storage tank, while solving a series of problems such as operation regulation, economy and safety, and has significant comprehensive benefits.

[0059] A second aspect of the present invention also provides a coupling method between a thermal storage tank and an urban heating network, using the coupling system for the thermal storage tank and urban heating network as described above, comprising: In response to the low-temperature thermal storage tank being in thermal storage mode, the first reversible water pump turbine is controlled to operate as a water turbine, converting the pressure potential energy of the high-pressure, high-temperature water from the water supply pipe relative to the low-temperature thermal storage tank into mechanical energy and electrical energy, or converting all of it into electrical energy. Based on the principle of real-time electricity price and optimal system efficiency, the second reversible pump turbine can be driven by energy provided by mechanical energy or the electrical energy converted from it, and the surplus energy can be stored in the battery energy storage unit in the form of electrical energy. Alternatively, the second reversible pump turbine can be driven by energy provided independently by the urban power grid, and all the converted electrical energy can be stored in the battery energy storage unit. The low-pressure, low-temperature water from the lower distributor of the low-temperature thermal storage tank is pressurized and injected into the return water pipe by the second reversible water pump turbine, based on the principle of balancing the inlet and outlet water flow of the low-temperature thermal storage tank.

[0060] According to several embodiments of the present invention, the coupling method between the thermal storage tank and the urban heating network further includes: In response to the low-temperature thermal storage tank being in heat release mode, the second reversible water pump turbine is controlled to operate as a water turbine, converting the pressure potential energy of the high-pressure low-temperature water relative to the low-temperature thermal storage tank from the return water pipe into mechanical energy or entirely into electrical energy. Based on the principle of optimal real-time electricity price and system efficiency, the first reversible pump turbine can be driven by energy independently provided by the urban power grid as a pump, and all the converted electrical energy can be stored in the battery energy storage unit. Alternatively, the first reversible pump turbine can be driven by energy jointly provided by mechanical energy or all the electrical energy converted from it, the electrical energy of the battery energy storage unit and / or the electricity of the urban power grid. The first reversible water pump turbine pressurizes the low-pressure, high-temperature water from the upper water distributor of the low-temperature thermal storage tank and injects it into the water supply pipe according to the principle of balancing the inlet and outlet water flow of the low-temperature thermal storage tank.

[0061] For a further understanding of the coupling method of the aforementioned thermal storage tank and urban heating network coupling system, please refer to [link / reference needed]. Figure 1-5 The following provides more specific operating methods.

[0062] I. Coupled System Design and Configuration Phase 1. Parameter Determination: Based on the total heat storage volume, working fluid temperature, urban heating network design / operating pressure, peak and off-peak electricity prices, and ancillary service requirements, determine the design pressure, operating pressure range, volume, and quantity of the low-temperature thermal storage tanks; determine the corresponding effective regulating water volume, pre-charge pressure, diaphragm / airbag performance parameters, and total tank volume of the pressure stabilizing tank; and determine the capacity and quantity of the battery array and the parameters of the main transformer.

[0063] 2. Equipment selection and configuration: Determine the quantity and correspondence of the low-temperature thermal storage tank, the first reversible water pump turbine, and the second reversible water pump turbine, such as one-to-one or many-to-many; determine whether to configure a hybrid power pump system.

[0064] Configure a hybrid energy storage management system, refer to Figure 2 As shown, it consists of a hybrid energy storage management platform, a cryogenic thermal storage tank control system, a hybrid power water pump system (or not equipped), a plant bus, a battery energy storage converter PCS, a battery management system BMS, a battery array, and a back-to-back frequency converter SFC, etc., and is used to uniformly dispatch electrical energy and mechanical energy.

[0065] Configure the corresponding piping system, pressure tank, valves, regulating valves, steam-water separator, safety valves and emergency fire protection system.

[0066] 3. System Integration and Debugging: After completing the equipment installation and pipeline connection, conduct system debugging and trial operation, optimize the control program, and ensure that all subsystems work together.

[0067] II. Operational Phase of the Coupled System The coupled system operates under the unified intelligent scheduling of the hybrid energy storage management system. It can intelligently select different energy transfer paths based on whether the coupled system is equipped with a hybrid water pump system, and dynamically select the optimal energy transfer mode based on real-time operating conditions, equipment efficiency, battery status, and grid signals. While achieving thermal energy storage or release, it efficiently recovers and utilizes pressure potential energy, ensuring the safe, stable, and economical operation of the coupled system. The core operating process is as follows: (a) Thermal storage conditions (thermal energy stored in a low-temperature thermal storage tank) High-pressure and high-temperature water depressurization and energy recovery: control the high-pressure and high-temperature water (flow rate Q1) from the urban heating network water supply pipe to flow through the first reversible water pump turbine, drive it to operate as a water turbine, and convert the excess pressure potential energy of the high-pressure and high-temperature water in the water supply pipe relative to the low-temperature heat storage tank into mechanical energy.

[0068] Low-temperature water pressurization and flow balance control: The second reversible water pump turbine is synchronously controlled to operate as a water pump, pressurizing and precisely injecting the low-pressure low-temperature water (flow rate Q2) from the lower water distributor of the low-temperature heat storage tank into the return water pipe of the urban heating network, and maintaining the flow stability of the main heating loop and the inclined temperature layer structure inside the heat storage tank according to the flow balance standard of Q2=Q1.

[0069] For the energy required to drive the second reversible pump-turbine, the system offers the following typical selectable modes: Pure electric drive mode: In this mode, no hybrid power pump system is configured. All the mechanical energy generated by the first reversible pump turbine is converted into electrical energy by its coaxial generator and delivered to the hybrid energy storage management system. The hybrid energy storage management system then dispatches this electrical energy, or uses low-cost electricity from the city power grid, to drive the second reversible pump turbine.

[0070] Mechanical Energy Driven: In this mode, a hybrid power pump system is configured, with the hybrid energy storage management system controlling the partial engagement of the hybrid power pump system. Through the hybrid power pump system, a portion of the mechanical energy generated by the first reversible pump turbine is directly transmitted to the second reversible pump turbine via a mechanical drive shaft, driving its operation. The remaining mechanical energy is converted into electrical energy by the first reversible pump turbine and stored in the battery energy storage unit (battery array) or used for other purposes by the hybrid energy storage management system.

[0071] (ii) Heat release condition (heat energy output from low temperature storage tank) High-pressure low-temperature water depressurization and energy recovery: control the high-pressure low-temperature water (flow rate Q2) from the return water pipe of the urban heating network to flow through the second reversible water pump turbine, drive it to operate as a water turbine, thereby converting the excess pressure potential energy of the high-pressure low-temperature water in the return water pipe relative to the low-temperature heat storage tank into mechanical energy.

[0072] High-temperature low-pressure water pressurization and flow balance control: The first reversible water pump turbine is synchronously controlled to operate as a water pump, pressurizing the high-temperature low-pressure water (flow rate Q1) from the upper water distributor of the low-temperature heat storage tank and accurately injecting it into the water supply pipe of the urban heating network, and strictly maintaining that its outflow rate Q1 is equal to its inflow rate Q2, i.e., Q1=Q2.

[0073] For the energy required to drive the first reversible pump-turbine, the system provides the following typical selectable modes: Pure electric drive mode: In this mode, no hybrid power pump system is configured. All electrical energy generated by the second reversible pump-turbine is stored in the battery energy storage unit, and the first reversible pump-turbine is driven by the electricity provided by the urban power grid; or the first reversible pump-turbine is driven by the electrical energy converted from the second reversible pump-turbine, combined with the electrical energy stored in the battery energy storage unit, or combined with the electrical energy from the urban power grid; or the first reversible pump-turbine is driven by the electrical energy converted from the second reversible pump-turbine, combined with the electrical energy stored in the battery energy storage unit, and combined with the electrical energy from the urban power grid.

[0074] Mechanical Energy Dominant Drive Mode: In this mode, a hybrid power pump system is configured, with a hybrid energy storage management system controlling its full engagement. Through this system, all mechanical energy generated by the second reversible pump-turbine is directly transferred to the first reversible pump-turbine, combining with electricity from the city grid or stored in the battery storage unit to drive the first reversible pump-turbine as a pump; or, alternatively, a combination of electricity from the city grid and stored in the battery storage unit to drive the first reversible pump-turbine as a pump. The system can, as needed, coordinate with the electric motor or supplemental power from the battery / city grid to provide precise torque regulation for operation.

[0075] During the execution of any of the above operating conditions, the hybrid energy storage management system serves as the core decision-making unit. Based on real-time monitoring of pipeline pressure, equipment efficiency, battery energy storage unit state of charge (SOC), and urban power grid electricity price signals or ancillary service requests, it dynamically selects the energy drive mode (pure electric mode or mechanical mode) with the highest energy efficiency or optimal economics, and the specific energy source (recycled electricity, stored electricity, or grid electricity). Furthermore, through intelligent charging and discharging management of the battery energy storage units, the system can store surplus energy and provide ancillary services such as frequency regulation and backup when the grid needs it, or return energy stored during off-peak hours to the grid during peak hours, thereby maximizing the system's operational benefits.

[0076] The above are exemplary embodiments disclosed in this invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments of this invention as defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.

[0077] It should be understood that, as used herein, the singular form “a” is intended to include the plural form as well, unless the context clearly supports an exception. It should also be understood that, as used herein, “and / or” refers to any and all possible combinations of one or more of the associated listed items.

[0078] The embodiment numbers disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the disclosed embodiments (including the claims) is limited to these examples. Within the framework of the embodiments of the present invention, technical features from the above embodiments or different embodiments can also be combined, and many other variations of different aspects of the embodiments of the present invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of the present invention should be included within the protection scope of the embodiments of the present invention.

Claims

1. A coupling system between a thermal storage tank and an urban heating network, characterized in that, include: Low-temperature thermal storage tanks; Pressure stabilizing tank; A first reversible water pump turbine is connected between the water supply pipe of the urban heating network and the upper water distributor of the low-temperature heat storage tank, and a second reversible water pump turbine is connected between the return water pipe of the urban heating network and the lower water distributor of the low-temperature heat storage tank. A hybrid energy storage management system connected to the first and second reversible pump-turbines includes a battery energy storage unit; Among them, one of the first and second reversible pump-turbines can be selectively operated as a water turbine to convert the pressure potential energy of water from the supply pipe or return pipe relative to the low-temperature thermal storage tank into mechanical energy and / or electrical energy, which is utilized or stored by the hybrid energy storage management system to drive the other as a water pump to inject water from the lower water distributor into the return pipe or water from the upper water distributor into the supply pipe. The driving energy for operating as a water pump is selected from one or more of the converted energy, the electrical energy stored in the battery energy storage unit, and the electrical energy of the urban power grid.

2. The coupling system between the thermal storage tank and the urban heating network according to claim 1, characterized in that, The hybrid energy storage management system can also be configured with a hybrid power pump system, which is mechanically connected between the first and second reversible pump-turbines. This system is used to directly transfer all or part of the mechanical energy generated by one of the pumps as a turbine to the other reversible pump-turbine as a pump, and to drive its operation in coordination with the torque of its own electric motor.

3. The coupling system between the thermal storage tank and the urban heating network according to claim 1, characterized in that, In the thermal storage condition, the first reversible water pump turbine operates as a water turbine to convert the pressure potential energy of the high-pressure, high-temperature water in the supply pipe relative to the low-temperature thermal storage tank into mechanical energy and electrical energy, or all of it into electrical energy. The second reversible water pump turbine operates as a water pump to pressurize the low-pressure, low-temperature water from the lower water distributor of the low-temperature thermal storage tank and inject it into the return water pipe. The driving energy of the second reversible water pump turbine can be provided by the mechanical energy or the electrical energy converted from it, based on the real-time electricity price and the principle of optimal system efficiency, and the surplus energy can be stored in the battery energy storage unit in the form of electrical energy. Alternatively, it can be provided independently by the electricity from the urban power grid and all the converted electrical energy can be stored in the battery energy storage unit. In the heat release condition, the second reversible water pump turbine operates as a turbine to convert the pressure potential energy of the water in the return water pipe relative to the low-temperature thermal storage tank into mechanical energy or all of it into electrical energy. The first reversible water pump turbine operates as a pump to pressurize the water in the upper water distributor of the low-temperature thermal storage tank and inject it into the water supply pipe. The driving energy of the first reversible water pump turbine can be provided by the mechanical energy or all the electrical energy converted by it, the electrical energy of the battery energy storage unit, and / or the electrical energy of the urban power grid, depending on the real-time electricity price and the principle of optimal system efficiency. Alternatively, it can be provided by the electrical energy of the urban power grid independently and all the converted electrical energy can be stored in the battery energy storage unit.

4. The coupling system between the thermal storage tank and the urban heating network according to claim 1, characterized in that, The coupling system further includes a first steam-water separator disposed between the first reversible water pump turbine and the upper water distributor of the cryogenic thermal storage tank, and a second steam-water separator disposed between the second reversible water pump turbine and the lower water distributor of the cryogenic thermal storage tank, for separating the gas generated when water flows through the corresponding reversible water pump turbine.

5. The coupling system between the thermal storage tank and the urban heating network according to claim 4, characterized in that, The coupling system further includes a first regulating valve disposed between the first reversible water pump turbine and the first steam-water separator, and a second regulating valve disposed between the second reversible water pump turbine and the second steam-water separator, for regulating the flow rate.

6. The coupling system between the thermal storage tank and the urban heating network according to claim 5, characterized in that, The pressure stabilizing tank is located between the lower water distributor of the low-temperature thermal storage tank and the second regulating valve, and is used to buffer the flow difference between the first regulating valve and the second regulating valve, so that the pressure inside the tank is always kept within the safe range of the design pressure.

7. The coupling system between the thermal storage tank and the urban heating network according to claim 1, characterized in that, The coupling system further includes a first valve disposed on the pipeline between the first reversible water pump turbine and the water supply pipe of the urban heating network, and a second valve disposed on the pipeline between the second reversible water pump turbine and the return pipe of the urban heating network.

8. The coupling system between the thermal storage tank and the urban heating network according to claim 1, characterized in that, The coupling system also includes an emergency fire-fighting system, which is connected to the return water pipe of the urban heating network and / or the lower outlet of the low-temperature thermal storage tank to obtain an emergency fire-fighting water source.

9. The coupling system between the thermal storage tank and the urban heating network according to claim 1, characterized in that, The number of the cryogenic thermal storage tanks is one or more, and they correspond to one or more pairs of the first and second reversible water pump turbines and one or more of the pressure stabilizing tanks.

10. The coupling system between the thermal storage tank and the urban heating network according to claim 1, characterized in that, The working pressure of the cryogenic thermal storage tank is no higher than 0.38 MPa, and the maximum working temperature range is 90~150℃.

11. The coupling system of the thermal storage tank and the urban heating network according to claim 1, characterized in that, The hybrid energy storage management system is connected to the urban power grid through the main transformer, and includes a hybrid energy storage management platform, a cryogenic thermal storage tank control system, a plant bus, a battery energy storage converter, a battery management system, a battery array, and a back-to-back frequency converter.

12. A method for coupling a thermal storage tank with an urban heating network, characterized in that, A coupling system for a thermal storage tank and a city heating network as described in any one of claims 2-11, comprising: In response to the low-temperature thermal storage tank being in thermal storage mode, the first reversible water pump turbine is controlled to operate as a water turbine, converting the pressure potential energy of the high-pressure, high-temperature water from the water supply pipe relative to the low-temperature thermal storage tank into mechanical energy and electrical energy, or converting all of it into electrical energy. Based on the principle of optimal real-time electricity price and system efficiency, the second reversible water pump turbine can be driven by the energy provided by the mechanical energy or the electrical energy converted therefrom, and the surplus energy can be stored in the battery energy storage unit in the form of electrical energy. Alternatively, the second reversible water pump turbine can be driven by the energy provided independently by the electricity from the urban power grid, and all the converted electrical energy can be stored in the battery energy storage unit. The low-pressure, low-temperature water from the lower water distributor of the low-temperature thermal storage tank is pressurized and injected into the return water pipe by the second reversible water pump turbine, according to the principle of balancing the inlet and outlet water flow of the low-temperature thermal storage tank.

13. The coupling method between the thermal storage tank and the urban heating network according to claim 12, characterized in that, Also includes: In response to the low-temperature thermal storage tank being in heat release mode, the second reversible water pump turbine is controlled to operate as a water turbine, converting the pressure potential energy of the high-pressure low-temperature water from the return water pipe relative to the low-temperature thermal storage tank into mechanical energy or entirely into electrical energy. Based on the principle of optimal real-time electricity price and system efficiency, the first reversible water pump turbine can be driven by energy independently provided by the urban power grid as a water pump, and all the converted electrical energy can be stored in the battery energy storage unit. Alternatively, the first reversible water pump turbine can be driven by energy jointly provided by the mechanical energy or all the electrical energy converted therefrom, the electrical energy of the battery energy storage unit, and / or the electrical energy of the urban power grid. Through the first reversible water pump turbine, and based on the principle of balanced inlet and outlet water flow of the low-temperature thermal storage tank, the low-pressure, high-temperature outlet water from the upper water distributor of the low-temperature thermal storage tank is pressurized and injected into the water supply pipe.

Images