Heat storage system and method based on heat supply pipe network

Abstract

The invention relates to the technical field of central heating, and provides a heat storage system and method based on a heat supply pipe network, and the heat storage system comprises a closed circulation heat storage loop formed by communicating part of main pipes in the urban heat supply pipe network; the countercurrent pump station is connected to the main pipe heat storage loop and used for driving the working medium to flow in the set direction; the heat exchange station is connected between the main pipe heat storage loop and the thermal power plant; the main control platform is in communication connection with the heat supply initial station, the countercurrent pump station and the heat exchange station and is used for controlling the flow direction, the flow rate and the temperature of a working medium, so that heat energy of the thermal power plant is stored to the main pipe heat storage loop in a stepped manner through the heat supply initial station and the countercurrent pump station; or the heat energy stored in the main pipe heat storage loop is supplied to a heat regeneration system of the thermal power plant through cascade heat release of the countercurrent pump station and the heat exchange station, so that cascade heat storage, heat release or heat energy conveying of the urban heat supply pipe network are achieved. The scheme solves the core contradiction that the investment is large, site selection is difficult, or the operation efficiency of the thermal power plant is damaged due to the increase of the return water temperature in the prior art.

Description

Technical Field

[0001] This invention relates to the field of centralized heating technology, and in particular to a heat storage system and method based on a heating pipeline network. Background Technology

[0002] Against the backdrop of green transformation and development, thermal power plants face prominent issues of power generation capacity loss and energy waste during both the off-season and the heating season. Meanwhile, as key infrastructure for grid security, national energy security, and winter heating for urban residents, reducing energy loss during operation through energy storage technology has become an important development direction for thermal power plants.

[0003] However, existing energy storage technologies all have obvious limitations: pumped hydro storage, molten salt storage and battery storage projects have high total costs, limited and unstable profit channels in the electricity market, and high uncertainty in investment returns; although cryogenic thermal storage tank clusters require less investment, they occupy a large area, are difficult to site, and are very difficult to construct within thermal power plants.

[0004] It is worth noting that urban heating networks themselves possess significant heat storage capacity. Existing technologies, such as patents CN202110294128.3 and CN114440288B, employ a bypass method in the primary network during the heating season to regulate the heat entering the heating station while simultaneously increasing the temperature of the water returning to the power plant. These methods have inherent drawbacks: as the water temperature returning to the power plant increases, the cooling effect of the power plant's condenser decreases, leading to reduced power generation efficiency and a consequent decrease in waste heat utilization, directly impacting the economic operation of the power plant; existing technologies cannot achieve bidirectional controllable flow and cascade utilization of heat energy during the non-heating season, making it difficult to simultaneously meet the dual demands of peak shaving and energy efficiency improvement for power plants; these methods fail to effectively decouple the thermoelectric coupling contradiction, still restricting the operational flexibility of power plants during both the heating and non-heating seasons. Summary of the Invention

[0005] To address the issue that existing methods of using heating pipelines for heat storage during the heating season lead to a decrease in power generation efficiency, creating a conflict between heat storage and the energy efficiency of thermal power plant operations, and that the existing structure and operation methods of urban heating pipeline networks are not suitable for heat storage during the non-heating season, this invention proposes a heat storage system and method based on heating pipeline networks.

[0006] To achieve the above objectives, one aspect of the present invention provides a thermal storage system based on a heating network, comprising: A closed-loop main pipe heat storage circuit, consisting of a portion of the pipes in the urban heating network, is filled with working fluid. A reversible flow pump station includes a reversible flow water pump system in the primary heating station of a thermal power plant, which is connected to the main pipeline heat storage circuit and used to drive the working fluid to flow in a set direction and flow rate; A heat exchange station is connected between the main pipeline heat storage circuit and the thermal power plant; The main control platform is communicatively connected to the heating station, reversible pump station, heat exchange station, and main pipeline heat storage circuit. It is used to regulate the flow direction, flow rate, and temperature of the working fluid, so that the heat energy of the thermal power plant is stored in stages through the heating station and reversible pump station to the main pipeline heat storage circuit, or the heat energy stored in the main pipeline heat storage circuit is released in stages through the reversible pump station and heat exchange station to the regenerative system of the thermal power plant, so as to realize the cascade heat storage, heat release, or heat transmission of the urban heating network.

[0007] In some embodiments, the main control platform is configured to achieve cascaded heat storage and release of the urban heating network by linearly and continuously and smoothly adjusting the temperature and flow rate of the working fluid.

[0008] In some embodiments, the main heat storage circuit is formed by connecting the supply and return water pipes of the urban heating network with equal diameters at the end furthest from the thermal power plant, according to the heat storage volume requirements; wherein, when the urban heating system has multiple sets of heating pipes, and the insulation performance of the supply and return water pipes is different, the main heat storage circuit is formed by connecting the supply water pipes and the return water pipes with equal diameters at the end furthest from the thermal power plant.

[0009] In some embodiments, during the non-heating season, the main control platform controls the start-up, shutdown, and operation of the heating first station and heat exchange station, as well as the flow direction adjustment and linear, continuous, and smooth adjustment of the flow rate of the reversible pump station, to realize the switching between the cascade heat storage and cascade heat release or the heat storage and heat release modes of the system. When the working fluid flows along the first direction, the heating station operates as a heat source system that releases the heat energy of the thermal power plant, and stores its heat energy in stages through the reversible pump station to the main pipeline heat storage circuit. The temperature of the working fluid at the corresponding section of the main pipeline heat storage circuit increases linearly, continuously and smoothly or remains constant. When the working fluid flows in the second direction, the heat energy stored in the main pipe heat storage circuit is released to the regenerative system of the thermal power plant through the reversible pump station and heat exchange station. The temperature of the working fluid at the corresponding section of the main pipe heat storage circuit decreases linearly and smoothly or remains constant.

[0010] In some embodiments, the thermal storage system further includes a condensate bypass system, which is connected to the pipeline between the condensate pump and the low-pressure heater of the thermal power plant, and the condensate bypass system is connected to the heat exchange station. When the working fluid flows along the second direction, the heat energy stored in the main pipe heat storage circuit is released to the regenerative system of the thermal power plant through the reversible pump station and heat exchange station, heating the condensate flowing through the condensate bypass system.

[0011] In some embodiments, during the heating season, the connecting pipe of the main heat storage circuit is disconnected, restoring the heating system to its original design performance, and the reversible pump station is adjusted to unidirectional operation.

[0012] In some embodiments, during the heating season, the thermal storage system further includes a cluster of low-temperature thermal storage tanks located along the main heating pipeline. The main control platform works in conjunction with the urban heating control platform to enable the cluster of low-temperature thermal storage tanks to remotely and synchronously store the thermal energy of the thermal power plant.

[0013] In some embodiments, during the heating season, the main control platform and the urban heating control platform are configured to operate in a high-precision "quantity regulation" mode. By maintaining a stable working fluid temperature and precisely regulating the flow rate, the low-temperature thermal storage tank cluster remotely and synchronously stores the thermal energy output from the heat source system of the thermal power plant.

[0014] In some embodiments, when the main pipeline thermal storage circuit passes through a pressure relief station, the upstream pipeline of the main pipeline thermal storage circuit crosses the pressure relief station and connects with the downstream pipeline, and is physically isolated from the downstream pipeline at the connection point by a valve and a pressure relief device.

[0015] In some embodiments, the reversible pump station includes a variable frequency speed-regulating pump and a valve group, which can switch the flow direction of the working medium by changing the pump rotation direction or switching the valve and pipeline system, and adjust the flow rate of the working medium by changing the pump speed and the valve opening.

[0016] In some embodiments, the main control platform is integrated with the thermal power plant control system and the urban heating control system, and the thermal power plant control system is configured to have dominant control under preset operating conditions.

[0017] In some embodiments, temperature, pressure and flow rate sensors are provided in the main pipe thermal storage circuit, and the sensors are communicatively connected to the main control platform for real-time monitoring.

[0018] In some embodiments, the working fluid is water, and the heat exchange station is a water-to-water heat exchange station.

[0019] In another aspect of the present invention, a heat storage method based on a heating network is also provided, employing the heat storage system based on a heating network as described above, including: The main control platform controls the flow of the working fluid and adjusts the temperature and flow rate of the main pipe heat storage circuit in a linear, continuous and smooth manner. When the working fluid flows along the first direction, the thermal energy of the thermal power plant is stored in stages through the heating station and the reversible pump station to the main pipeline heat storage circuit. The temperature of the working fluid at the corresponding section of the main pipeline heat storage circuit increases linearly, continuously and smoothly or remains constant. When the working fluid flows in the second direction, the heat energy stored in the main pipe heat storage circuit is supplied to the regenerative system of the thermal power plant through the cascade heat release of the reversible pump station and heat exchange station. The temperature of the working fluid at the corresponding section of the main pipe heat storage circuit decreases linearly and smoothly or remains constant.

[0020] This invention has at least the following beneficial effects: It proposes a thermal storage system and method based on a heating network. During the non-heating season, by transforming a portion of the urban heating network into a closed-loop thermal storage circuit, and innovatively modifying and integrating the primary heating station and reversible pump station, and by continuously and smoothly adjusting the temperature of the main pipeline thermal storage circuit, it achieves large-scale, safe, and efficient thermal storage, release, and transmission of heat energy in the heating network during the non-heating season. This fundamentally solves the core contradictions of existing technologies, such as high investment and difficult site selection, enabling large-scale, low-cost, and efficient thermal storage. During the heating season, by technically transforming the power plant and heating system and improving their collaborative capabilities, it implements remote synchronous storage of large quantities of heat energy from the power plant using a cluster of low-temperature thermal storage tanks. This effectively avoids the negative impact on the power plant's power generation efficiency caused by increasing the return water temperature, achieving low-cost and high-efficiency thermal storage. The cascaded heat storage and release method significantly improves the efficiency of thermal energy utilization and avoids the devaluation of high-quality thermal energy. In particular, the cascaded heat storage and release method with linear and smooth temperature regulation is the key to ensuring that the heat storage pipeline loop can store and release heat on a large scale, safely and efficiently.

[0021] Specifically, the closed-loop main pipeline thermal storage circuit, formed by the urban heating network, fully utilizes the inherent thermal storage technology attributes and huge thermal storage capacity of existing urban infrastructure. It overcomes the high investment costs and uncertain returns of existing technologies such as pumped storage and battery storage, as well as the large land area and difficult site selection issues associated with building dedicated thermal storage tanks within power plants. This achieves large-scale thermal storage with the lowest incremental cost, effectively activating the inherent thermal storage capacity of the urban heating system. The reversible pump station, in conjunction with the main control platform, heat exchange station, and primary heating station, achieves "cascaded" thermal storage and release between the thermal storage circuit and the power plant through precise coordinated control of the working fluid's flow direction, flow rate, and temperature. This innovative operating mode allows the system to directly and accurately supply heat energy to a suitable regenerative system (heating condensate) within the power plant during heat release, ensuring the power plant's operational efficiency as a ballast for grid security. During the non-heating season, heat energy is effectively utilized by supplying it to the power plant's regenerative system. During the heating season, the heat energy generated by the primary heating station of the thermal power plant is remotely and synchronously stored in a large quantity in a cluster of heat storage tanks within the heating system. The main control platform provides centralized and unified control of the primary heating station, reversible pump stations, and heat exchange stations, forming an intelligent response unit. It not only meets the needs of thermal power plants for continuous and stable heat flow regulation during peak shaving and frequency regulation, but also achieves efficient, flexible, and precise operation under both non-heating and heating seasons through a "precise control of flow and temperature" strategy. This overcomes the limitations of existing technologies in terms of investment, safety, and geography, ultimately forming a technically feasible and highly efficient complete solution that powerfully promotes the green transformation and upgrading of thermal power plants.

[0022] Meanwhile, the heat storage method based on the heating pipeline network proposed in this invention can also achieve the above objectives, and will not be elaborated further here. Attached Figure Description

[0023] 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.

[0024] Figure 1 The diagram shown illustrates the structure, control, and heat transfer of a heat storage system based on a heating network, according to an embodiment of the present invention. Figure 2 The diagram shown is a schematic diagram of a heat storage system based on a heating network provided in another embodiment of the present invention during the non-heating season. Figure 3The diagram shown is a schematic diagram of a heat storage system based on a heating network provided in another embodiment of the present invention during the heating season. Figure 4 The diagram shown is a structural schematic of a heat storage method based on a heating network, which is another embodiment of the present invention. Detailed Implementation

[0025] 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.

[0026] 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.

[0027] One or more embodiments of this application will now be described with reference to the accompanying drawings.

[0028] Based on the above objectives, the first aspect of the present invention proposes an embodiment of a heat storage system based on a heating network. Figure 1 The diagram shown illustrates the structure, control, and heat transfer of a heat storage system based on a heating network, as provided in one embodiment of the present invention. Figure 1 As shown, a heat storage system based on a heating network includes: a closed-loop main pipe heat storage loop formed by connecting a portion of the pipelines in the urban heating network, filled with a working fluid; a reversible pump station, including a reversible pump system in the heating station of a thermal power plant, connected to the main pipe heat storage loop and used to drive the working fluid to flow in a set direction and velocity; a heat exchange station, connected between the main pipe heat storage loop and the thermal power plant; and a main control platform, communicatively connected to the heating station, the reversible pump station, the main pipe heat storage loop, and the heat exchange station, used to control the flow direction, flow rate, and temperature of the working fluid, so that the thermal energy of the thermal power plant is stored in stages through the heating station and the reversible pump station to the main pipe heat storage loop, or the thermal energy stored in the main pipe heat storage loop is released in stages through the reversible pump station and the heat exchange station and supplied to the regenerative system of the thermal power plant, thereby realizing the cascaded heat storage, release, or transmission of thermal energy in the urban heating network. Among them, the main pipeline heat storage circuit is a closed loop formed by connecting the water supply pipe and return pipe in the urban heating network at their far ends with equal diameters according to specific conditions, and its interior is filled with water as the working medium.

[0029] In some embodiments, cascaded thermal storage and release are achieved by constructing a dual-temperature loop system. Specifically, the main pipe thermal storage loop consists of a high-temperature thermal storage loop and a low-temperature thermal storage loop. The high-temperature loop operates at a temperature range of approximately 100-130°C and is mainly used for storing and releasing high-grade thermal energy; the low-temperature loop operates at a temperature range of approximately 65-100°C and is mainly used for storing and releasing medium- and low-grade thermal energy.

[0030] As a specific implementation method, the cascade thermal energy storage process is as follows: When a thermal power plant needs to store its excess heat energy, the main control platform first controls the reversible water pump system and other reversible pump stations at the primary heating station to drive the working fluid to flow in the first direction. The working fluid in the high-temperature thermal energy storage loop preferentially exchanges heat with the high-temperature steam in the gas-water heat exchange system of the primary heating station. Subsequently, the working fluid in the low-temperature thermal energy storage loop exchanges heat with the aforementioned steam, thus completing the storage of high-grade thermal energy and the cascade storage of medium- and low-grade thermal energy, respectively. Throughout the thermal energy storage process, the main control platform adjusts the output heat of the primary heating station and the flow rate of the reversible pump stations to maintain the rate of temperature difference change at the high-temperature port, low-temperature port, and the entire loop within a linear and smooth range of less than 5°C / hour, achieving stable cascade thermal energy storage.

[0031] As a feasible implementation, the cascade heat release process is as follows: When the thermal power plant needs to replenish heat energy, the main control platform controls the reversible pump station to switch the working fluid flow direction. In the heat exchange system of the heat exchange station, the working fluid in the low-temperature thermal storage loop first heats the condensate in the thermal power plant's regenerative system from about 60°C to about 90°C, completing the release of low-grade heat energy; subsequently, the working fluid in the high-temperature thermal storage loop further heats the condensate from about 90°C to about 120°C. Throughout the heat release process, based on parameters such as the temperature of the low-temperature and high-temperature thermal storage loops, the main control platform adjusts the flow rate of the reversible pump station system, the operating conditions of the heat exchange station, and controls the output heat to heat the condensate, ensuring that the rate of temperature difference change at the high-temperature port, low-temperature port, and the entire loop of both loops remains linearly and smoothly within 5°C / hour, achieving stable cascade heat release.

[0032] According to several embodiments of the present invention, the main control platform is configured to linearly and smoothly adjust the temperature and flow rate of the working fluid in the main pipeline heat storage circuit to achieve cascade heat storage and release in the urban heating network. The cascade heat storage and release method significantly improves thermal energy utilization efficiency and avoids the devaluation of high-quality thermal energy. In particular, the cascade heat storage and release method with linear and smooth temperature adjustment is key to ensuring that the heat storage pipeline circuit can store and release heat on a large scale, safely, and efficiently.

[0033] In one feasible embodiment, the specific operating data are as follows: Heat storage stage: High-temperature loop heat storage 3378.94 MWh, low-temperature loop heat storage 3365.36 MWh, total heat storage 6744.3 MWh. Heat release stage: High-temperature loop heat release power increases from 303.26 MW to 290.20 MW, low-temperature loop heat release power increases from 303.26 MW to 232.53 MW; Temperature control: High-temperature loop temperature decreases from approximately 130°C to approximately 100°C, low-temperature loop temperature decreases from approximately 100°C to approximately 65°C, achieving significant cascade utilization of thermal energy.

[0034] Understandably, this thermal storage system both stores and releases heat during the non-heating season (usually from April to October each year), and its behavior is determined by the electricity market (electricity price) and the peak-shaving demand of the power grid, with the core function of providing peak-shaving services for the power grid. During the heating season (usually from November to March of the following year), it stores heat while supplying heat, and its behavior is jointly determined by the peak-shaving demand of the thermal power plant itself and the urban heating forecast. This thermal storage system shares the peak-shaving pressure of the thermal power plant by storing heat, improves its power generation peak-shaving capacity, and at the same time meets the urban heating needs of the people more safely and stably.

[0035] In some embodiments, a complete implementation of the thermal storage system for cascaded thermal storage and release during the non-heating season is also provided, such as... Figure 2 As shown, a 3120MW thermal power plant is equipped with two 300MW subcritical units, two 600MW supercritical units, and two 660MW ultra-supercritical generator units. The 37.8km long two sets of 1.4m diameter heating trunk lines are modified to form a thermal storage system.

[0036] Since the insulation performance of the return water pipes of the two sets of heating pipelines is lower than that of the supply water pipes, at a distance of 37.8 kilometers from the thermal power plant, the two supply water pipes and the two return water pipes of the two sets of heating pipelines are connected by equal diameters to form two thermal storage systems with a pipe diameter of 1.4 meters and a length of 75.6 kilometers. Among them, based on the insulation performance, the high-temperature system operates at a temperature of 100-130℃ and is specifically used for storing and releasing high-grade heat energy; the low-temperature system operates at a temperature of 65-100℃ and is specifically used for storing and releasing medium- and low-grade heat energy.

[0037] During periods of low grid load, the system initiates a cascaded thermal storage procedure. The main control platform controls the reversible pump station to drive the working fluid to flow in the first direction (the thermal storage direction). Specifically, the working fluid temperatures in both the high-temperature and low-temperature loops are at low temperatures. The working fluids in the high-temperature and low-temperature loops exchange heat with the high-temperature working fluid from the thermal power unit at the primary heating station, gradually increasing in temperature at a rate not exceeding 5°C per hour. Ultimately, the high-temperature loop reaches its upper limit of 130°C, and the low-temperature loop reaches its upper limit of 100°C, after which stable operation is achieved, realizing cascaded thermal storage. During this process, the system precisely adjusts the power based on the formula P=c×Q×ΔT. Here, the specific heat capacity c is related to the water temperature, P is the thermal power, Q is the working fluid flow rate, and ΔT is the temperature difference between the two ends of the thermal storage loop in the main pipe. By real-time monitoring using temperature, pressure, and flow rate sensors installed in the pipeline system, and based on the changes in flow rate during the operation of the pipeline thermal storage and transportation system, and the rigid requirements for the pipe material to withstand temperature differences per unit time, and referring to the specifications for urban heating systems, the maximum design flow rate of the system shall not exceed 3.5 m / s, and the upper limit of the temperature difference per unit length of the pipeline system shall be <0.3968℃, approximately 0.4℃.

[0038] During peak grid load periods, the system executes a cascaded heat release procedure. The main control platform controls the reversible pump station to switch the working fluid flow direction, directing it along the second direction (heat release direction). The specific implementation process is as follows: First, heat energy is extracted from the working fluid in the low-temperature loop through the water-to-water heat exchange station, heating the condensate from approximately 60°C to approximately 90°C; then, heat energy is extracted from the high-temperature loop to further heat the condensate; through this sequential heat release method, heat energy is utilized according to its quality. Typical operating data shows that in one complete heat storage-heat release cycle, the heat storage capacity of the high-temperature loop reaches 3378.94 MWh, the heat storage capacity of the low-temperature loop reaches 3365.36 MWh, and the total system heat storage capacity is 6744.3 MWh. During the heat release process, the heat release power of the high-temperature circuit gradually decreased to 290.20MW after operating at 303.26MW for a period of time, and the heat release power of the low-temperature circuit gradually decreased to 232.53MW after operating at 303.26MW for a period of time, perfectly demonstrating the characteristics of cascaded heat release and stable operation.

[0039] The above-described implementation of cascaded thermal storage and release, through the coordinated operation of the dual-loop system and the precise control of the main control platform, achieves graded management and efficient utilization of thermal energy according to quality, as well as stable and smooth control, effectively improving the overall energy utilization efficiency of the system and providing reliable technical support for peak-shaving operation of thermal power plants.

[0040] In other embodiments, specific implementation methods for the operation of the thermal storage system during the heating season are also provided, such as... Figure 3As shown, a 3120MW thermal power plant, through system switching, restored the closed thermal storage loop during the non-heating season to the performance state required by the original design of the heating system, and adjusted the reversible pump station to a unidirectional operation mode to undertake the urban heating transmission task in the form of "quantity regulation".

[0041] A cluster of low-temperature thermal storage tanks, with a total volume of 238,000 cubic meters, is deployed in stages along a 50-kilometer stretch of the main heating pipeline. This cluster, through deep collaboration with the main control platform and the heating control platform, enables remote and synchronous storage of the thermal energy output from the primary heating station.

[0042] During the heating season, as a feasible implementation, the system adopts flow regulation as the basic operating mode to maintain the supply water temperature stable within the qualified range. The power plant and urban heating system increase the supply water flow rate Q1 and the return water flow rate Q2 to simultaneously store excess heat energy output from the power plant into a cluster of low-temperature thermal storage tanks along the pipeline. Specifically, by maintaining a stable supply water temperature and precise flow rate regulation, the increased thermal storage flow rate Q1 in the supply pipe of the heating network flows into the upper water distributor of the low-temperature thermal storage tank (cluster), while the return water pipe in the heating network receives the low-temperature water flow Q2 flowing out from the lower water distributor of the low-temperature thermal storage tank (cluster), with Q1 = Q2. This achieves the following: the power plant simultaneously stores the required heat energy in thermal storage tanks at different cross-sections along the pipeline through the main pipeline system, while an equal amount of low-temperature water Q2 flowing out of the thermal storage tanks returns to the power plant, maintaining a water balance of Q2 = Q1.

[0043] In practice, the system's configuration is optimized according to seasonal characteristics throughout the year. For example, during the non-heating season, the system primarily operates by completing more than two heat storage and release cycles per day, with continuous operation time reaching approximately 9 hours and a daily heat throughput of about 7000 MWh, fully utilizing its long-term energy storage function. Once the heating season begins, the system switches to a combined heating and synchronous heat storage mode. By regulating heating supply and remotely synchronizing the storage of thermal power plant energy, it improves the peak-shaving capacity of the thermal power plant and the overall urban heating level. Based on the fact that system heat loss can be controlled to around 5%, strict logical consistency is maintained among all operating parameters, and all technical indicators meet the requirements of urban heating system specifications, the engineering feasibility of the technical solution is ensured.

[0044] The aforementioned thermal energy storage system based on a heating network, during the non-heating season, transforms a portion of the urban heating network into a closed-loop thermal energy storage circuit. It innovatively integrates the primary heating station with a reversible pump station, and through continuous and smooth adjustment of temperature and flow, achieves safe, large-scale, tiered thermal energy storage, release, and transmission within the heating network. This fundamentally solves the core contradictions of existing thermal power plant energy storage technologies, such as high investment and difficult site selection, achieving large-scale, low-cost, and efficient thermal energy storage. During the heating season, through technological upgrades to the thermal power plant and heating system and improved synergy, it implements remote synchronous large-scale storage of thermal energy from the thermal power plant using a cluster of low-temperature thermal energy storage tanks. This effectively avoids the negative impact on the power plant's power generation efficiency caused by increasing the return water temperature, achieving low-cost, high-efficiency thermal energy storage. The tiered thermal energy storage and release method significantly improves thermal energy utilization efficiency and avoids the devaluation of high-quality thermal energy. In particular, the linear and smooth temperature adjustment of the tiered thermal energy storage and release method is key to ensuring large-scale, safe, and efficient thermal energy storage and release within the thermal energy storage pipeline circuit.

[0045] In addition, this application focuses on the regulation of the thermal storage system. By improving the regulation accuracy and power of gas-water and water-water heat exchange stations, it ensures the minimum technical output of the thermal power plant during ultra-low load operation and meets the requirements for continuous heat flow regulation and smooth, stable control during peak shaving and frequency regulation. Furthermore, by improving systems such as steam extraction, cylinder disconnection, and turbine bypass from the thermal power unit boiler to the thermal power plant's primary heating station, the thermal power plant can leverage the powerful capabilities of the thermal storage system to flexibly select the thermal storage mode based on stable combustion load, balancing operational safety and stability, minimum technical output control, and enhanced power generation capacity. Finally, by upgrading the thermal power plant's automated control system and integrating it with the heating system control system into a unified main control platform, it enables systematic and precise control of the thermal power plant and heating system under various operating conditions.

[0046] Understandably, to adapt to the closed-loop operation mode of the thermal storage and transmission system, the functions of pipelines in the traditional heating network need to be redefined. In this application, the thermal storage system during the non-heating season utilizes the existing "supply pipe" and "return pipe" to form a bidirectional closed-loop circuit, which no longer has a single function of supplying or returning water. Therefore, when describing this system, it can be collectively referred to as the "main trunk thermal storage circuit." Correspondingly, the two ends of this circuit are defined as port A and port B. Port A and port B are located at the power plant end and are the sections connecting the main trunk thermal storage circuit to the primary heating station and heat exchange station through pipelines and valve systems. Port A is defined as follows: When the power plant stores heat through the primary heating station, the high-temperature working fluid, after being heated, enters the inlet of the main pipeline heat storage loop. Simultaneously, when the main pipeline heat storage loop releases heat to the power plant, the high-temperature working fluid flows from the heat storage loop to the outlet of the heat exchange station. Port B is defined as follows: When the power plant stores heat through the primary heating station, the low-temperature working fluid in the main pipeline heat storage loop, before being heated, flows to the outlet of the primary heating station. Simultaneously, when the main pipeline heat storage loop releases heat to the power plant, the low-temperature working fluid, after heat exchange, flows from the heat exchange station to the inlet of the heat storage loop. This definition is independent of the working fluid flow direction. Regardless of whether the system is in heat storage or heat release mode, the physical positions of ports A and B remain fixed. During heat storage and heat release modes, the connection between the main pipeline heat storage loop and the primary heating station and heat exchange station is controlled through a valve system. During heat storage, open the valve connecting to the primary heating station and close the valve connecting to the heat exchange station. During heat release, open the valve connecting to the heat exchange station and close the valve connecting to the primary heating station.

[0047] In some specific embodiments, the standard operating procedure of the thermal storage system of this application is also provided: Under the thermal storage condition of the main pipe thermal storage loop, a "forward" flow direction is set. When the power plant stores heat into the thermal storage system, the low-temperature working fluid at port B is heated to the temperature level of port A via a "gas-water" heat exchange station before entering port A. Under the heat release condition of the main pipe thermal storage loop, a "reverse" flow direction is set. When the thermal storage system releases heat into the power plant, the high-temperature working fluid at port A is cooled to the temperature level of port B via a "water-water" heat exchanger before entering port B. During thermal storage and release, the requirement that the temperature difference between each cross-section of the pipeline does not exceed 5°C per hour should be followed. The temperature should be gradually increased to the upper limit of the thermal storage system temperature or decreased to the lower limit of the thermal storage system temperature, and maintained until the thermal storage and release requirements are met. The port temperature difference corresponding to the thermal storage and release power is set. The thermal storage and transmission system needs to undergo one or more thermal storage and release cycles daily. After each heat storage and release, the relationship between the temperature difference (ΔT) at both ends of the system and the subsequent heat release and storage power (P) can be simplified to: P = c × Q × ΔT, where the specific heat capacity c needs to be adjusted according to the water temperature during actual operation. The temperature difference ΔT is an absolute value (unit: °C), and the water flow rate Q is a mass flow rate (unit: 10,000 tons / hour). This relationship shows that when the water flow rate Q increases, the heat storage and release power increases; if the temperature difference ΔT is too low, the heat storage and release power cannot meet the demand. Therefore, at the end of heat storage and release, the temperature difference between port A and port B must not be lower than the minimum initial temperature difference required for the subsequent heat storage and release process. A total heat storage volume should be set, and the total heat storage volume within each operating cycle (one to several days) should be balanced with the total heat release volume; at the end of each heat storage operation, the temperature difference between port A and port B must meet the basic requirements for subsequent heat release power. Temperature changes during the heat release process must be controlled. During heat release, the operating technical requirements of the thermal power plant and the regulation that the temperature drop in the pipeline should not exceed 5°C per hour must be followed. The system temperature should be gradually reduced to the lower limit allowed by the thermal storage system and maintained at this temperature level for continuous heat release until the set heat release requirements are met. The port temperature difference at the end of heat release is set. Similar to the thermal storage condition, the heat released by the system after each heat release is related to the ability to store heat again. The relationship between the temperature difference between the two ends of the system and the thermal storage power is consistent with the aforementioned heat release power formula. If excessive heat release leads to an excessively low temperature difference, it will affect subsequent thermal storage power and energy storage. Therefore, at the end of heat release, the temperature difference between port A and port B must not be lower than the minimum starting temperature difference required for the next round of thermal storage. The total heat release amount is set. Within each operating cycle, the total heat release amount should be balanced with the total thermal storage amount; at the end of each heat release, the temperature difference between the inlet and outlet of the pipeline system should meet the requirements of the thermal storage power for the next stage. The downtime required for the thermal storage and transmission system to switch from "forward" operation to "reverse" operation (or vice versa) should be clearly defined. It is usually about 30 minutes, but the specific time depends on the functional configuration of the reversible pump station and the actual condition of the pipeline system. It should be determined on the spot during actual operation.The timing of shutdown switching should be carefully considered, taking into account factors such as grid load regulation commands and the matching of total heat storage and release. Based on the comprehensive evaluation results of the system, the switching time point or the frequency of switching can be flexibly adjusted.

[0048] At the start of the heating season, measures such as short-circuiting, bypassing, overtaking, and physical isolation of various water pipes in the system from the non-heating season should be restored to the performance state required by the original heating system design. Simultaneously, the main control platform's functions should be expanded to enable collaborative control of the heating system platform and joint management of the main heating pipeline and the cluster of storage tanks along the pipeline, which involve thermal storage functions. Based on the thermal storage requirements, the control precision of the gas-water heat exchange station and water pump system should be improved to ensure stable water supply temperature and precise flow control. According to the thermal storage operation requirements, the control precision of water pumps and valves in the main pipeline system should be optimized to achieve precise water volume regulation. Taking full advantage of the low investment cost and no negative impact on the power generation efficiency of thermal power plants, multiple low-temperature thermal storage tanks should be rationally arranged at suitable locations along the main heating pipeline to form a cluster. Their total volume and thermal storage capacity should meet the thermal power plant's thermal storage and urban heating needs, and the operating pressure should match the heating network. Related pressure regulation and energy recovery technologies can be implemented with reference to existing patents. To meet the operational needs of the heating season, the main control platform was upgraded to effectively coordinate the operation of the power plant and the heating system, and to achieve unified management of the thermal energy storage process of the low-temperature thermal storage tank cluster. To achieve the water temperature stability and precise flow control required for remote synchronous thermal energy storage, the system operates primarily through "quantity regulation." Relying on the synergy between the power plant and the urban heating system during the heating season, and the stable temperature and controllable flow at each section of the main pipeline, the power plant can synchronously store surplus thermal energy in thermal storage tanks at different sections along the main pipeline to meet the peak-shaving needs of power generation and heating.

[0049] During remote synchronous thermal storage, the thermal power plant's supply water flow (Q1) exceeding the city's immediate demand, delivered through the heating system's water supply pipes, synchronously flows into the thermal storage tank cluster. Simultaneously, the cluster releases an equal amount of low-temperature water (Q2) back to the heating system's return water pipe and flows back to the power plant, achieving water balance: Q1 = Q2. Since the temperature loss during water delivery to different sections is essentially the same under both thermal storage and non-storage conditions, and the return water temperature is relatively constant, the total amount of remote synchronous thermal storage is equivalent to local thermal storage at the power plant, both meeting the needs of power generation and peak heating demand. Based on this remote thermal storage capability, the urban heating system and the power plant collaboratively manage the thermal storage facilities. The thermal storage process is primarily controlled by the power plant, while the heat release process is primarily controlled by the heating system, achieving coordinated optimization of power generation peak shaving and heating security. During the early and late cold periods, the heating coverage of the system will be expanded to include areas previously heated by high-cost heat sources such as natural gas. These areas will then be uniformly supplied by thermal power plants, while also meeting the needs of power plants operating at extremely low loads. In the construction of urban heating systems, the focus will be on improving large-scale centralized heating ring networks and their sub-ring networks, gradually forming a multi-ring interconnected pipeline structure, laying the foundation for enhancing the system's heat storage and distribution capabilities.

[0050] According to several embodiments of the present invention, the thermal storage circuit of the main heating pipeline is formed by connecting the supply and return water pipes of the urban heating network with equal diameters at the end furthest from the thermal power plant, based on the thermal storage volume requirements. Specifically, when the urban heating system has multiple sets (more than one set) of heating pipelines, and the insulation performance of the supply and return water pipes differs, the thermal storage circuit of the main pipeline is formed by connecting the supply water pipes and the return water pipes with equal diameters at the end furthest from the thermal power plant. In this embodiment, the "farthest end" specifically refers to the pipeline location relative to the thermal storage space requirements.

[0051] As a feasible implementation, the main pipeline thermal storage loop is constructed in the following specific way: When there are two sets of heating pipelines and the insulation performance of the heating main supply pipe and return pipe is the same, the loop is formed by connecting them at the far end of the network with pipes of the same diameter and valves; when there are two sets of heating mains and the insulation performance of the return pipe is lower than that of the supply pipe, the two sets of supply pipes and the two sets of return pipes are connected at the far end respectively to form an independently operating high-temperature thermal storage loop and a low-temperature thermal storage loop. In the specific implementation process, if the thermal storage loop passes through a pressure relief station, under the condition of meeting the pressure and other requirements, its upstream pipeline needs to cross the pressure relief station and connect with the downstream pipeline, and valves and pressure relief devices are installed at the connection point to achieve physical isolation from the downstream pipeline network.

[0052] As another feasible embodiment, the main pipeline heat storage loop is constructed in the following way: Taking a thermal power plant as an example, the insulation performance of the return water pipes of its two sets of four DN1400 heating main lines totaling 37.8 kilometers is lower than that of the supply water pipes. At the far end of the thermal power plant (i.e., at 37.8 kilometers), the supply water pipes and return water pipes of the two sets of heating pipelines are connected to each other and to each other with equal diameters through DN1400 connecting pipes, forming two main pipeline heat storage loops. The connecting pipes are insulated with the same specifications as the main pipelines, and a valve system is installed to switch between heating season and non-heating season operating conditions.

[0053] According to several embodiments of the present invention, during the non-heating season, the main pipeline heat storage loop acts as a closed-loop heat storage system. The main control platform controls the start-up, shutdown, and operating conditions of the primary heating station and heat exchange station, as well as the flow direction of the reversible pump station and linearly and continuously adjusts its flow rate to achieve the switching between cascade heat storage and cascade heat release, or between heat storage and heat release operating conditions. When the working fluid flows along the first direction, the primary heating station operates as a heat source system for outputting heat energy from the thermal power plant, and the heat energy is carried by the high-temperature working fluid through the reversible pump station to the main pipeline heat storage loop in a cascade heat storage manner. The temperature of the working fluid at the corresponding section of the main pipeline heat storage loop increases linearly and continuously or remains constant. When the working fluid flows along the second direction, the heat energy stored in the main pipeline heat storage loop is carried by the high-temperature working fluid through the reversible pump station and heat exchange station in a cascade heat release manner to the regenerative system of the thermal power plant. The temperature of the working fluid at the corresponding section of the main pipeline heat storage loop decreases linearly and continuously or remains constant. It is understood that the first direction is opposite to the second direction. For example, in one embodiment, a thermal power plant controls a reversible pump station to flow the working fluid along the first direction (heat storage direction) for 4-6 hours during periods of low grid load (such as nighttime), storing approximately 3500 MWh of heat; and during periods of high grid load (such as daytime), the working fluid flows along the second direction (heat release direction) for 5-6 hours, releasing approximately 3000 MWh of heat, effectively meeting the power plant's peak shaving needs.

[0054] According to several embodiments of the present invention, the thermal storage system further includes a condensate bypass system, which is connected to the pipeline between the condensate pump and the low-pressure heater of the thermal power plant, and is also connected to the heat exchange station. When the working fluid flows in the second direction, the thermal energy stored in the main pipeline thermal storage loop is released in stages through a reversible pump station and heat exchange station to the regenerative system of the thermal power plant, heating the condensate flowing through the condensate bypass system. Specifically, a bypass pipeline directly connecting the condensate pump outlet to the low-pressure heater is established on the pipeline between the condensate pump outlet and the low-pressure heater, allowing the condensate pump outlet to first enter the heat exchange station for heating before returning to the low-pressure heater. This embodiment effectively solves the specific technical problem of heating condensate with thermal energy in a pipeline energy storage system.

[0055] In some embodiments, the condensate bypass system is implemented as follows: a bypass pipe is installed in parallel on the main pipeline between the condensate pump outlet and the low-pressure heater inlet of the thermal power plant. Shut-off valves are installed on this bypass pipe and the main pipeline, and the bypass pipe is connected to the condensate side interface of the water-to-water heat exchange station via a connecting pipe. When the system detects the need for heat release, the main control platform controls the reversible pump station to drive the working fluid to flow in the second direction (heat release direction), opens the shut-off valve on the bypass pipe from the condensate pump outlet to the heat exchange station, and closes the shut-off valve on the main pipeline between the condensate pump outlet and the low-pressure heater inlet. This allows condensate at a temperature of 40-60°C to enter the heat exchange station from the condensate pump outlet, be heated to approximately 100-120°C, and then return to the low-pressure heater inlet pipeline. During this process, the high-temperature working fluid in the heat storage loop flows through the heat source side of the heat exchange station, transferring heat to the condensate and cooling it to the temperature required by the main pipeline energy storage system, thus completing the supply of heat energy to the thermal power plant's regenerative system. When the thermal energy storage system requires heat storage, the main control platform controls the working fluid to flow along the first direction (the heat storage direction). It extracts heat energy from the power plant's heat source system, which specifically includes the steam extraction pipeline system and a gas-water heat exchanger, storing the heat output from the power plant's heat source system in the main pipeline heat storage loop. For example, saturated steam at 0.8-1.2 MPa is extracted from the turbine and heated from 65°C to the required temperature of the main pipeline energy storage system via a gas-water heat exchanger. This heat is then injected into the main pipeline heat storage loop to store the power plant's heat energy. The temperature of the main pipeline energy storage system must meet the specifications for temperature difference changes in the heating pipeline, and the cascade heat storage must be dynamically and precisely controlled according to the design temperature of the main pipeline energy storage system.

[0056] According to several embodiments of the present invention, during the heating season, the connecting pipes of the main heat storage circuit are disconnected, restoring the original performance state required by the original design of the heating system, and the reversible pump station is adjusted to unidirectional operation. During the heating season, the heat storage system also includes a cluster of low-temperature heat storage tanks set along the main heating pipeline. The main control platform works in conjunction with the urban heating control platform to enable the low-temperature heat storage tank cluster to remotely and synchronously store the thermal energy of the thermal power plant.

[0057] According to several embodiments of the present invention, during the heating season, the main control platform and the urban heating control platform are configured in a quantity regulation operation mode. By maintaining a stable working fluid temperature and precisely regulating the flow rate, the low-temperature thermal storage tank cluster remotely and synchronously stores the heat energy output from the thermal power plant's heat source system. During the heating season, the specific implementation of the thermal storage system switching includes: fully adjusting the isolation valves and other components on the remote connecting pipelines to the performance state required by the original design of the heating system, restoring the supply and return water pipes to their original operating states. The reversible pump station is adjusted to unidirectional operation, controlling the flow rate of the supply water pipe within the design range. As a feasible embodiment, the main control platform establishes a data connection with the urban heating SCADA system to collaboratively control the low-temperature thermal storage tank cluster arranged along the line. For example, the main pipeline has a maximum transmission capacity of 4200MW. Within a range of 20-50 kilometers from the thermal power plant, a cluster of thermal storage tanks with a total volume of 238,000 cubic meters is arranged along the pipeline. By maintaining a stable water supply temperature and regulating the flow rate, 14440MWh of thermal energy can be remotely and synchronously stored daily on the basis of the original transmission capacity of 2300MW.

[0058] As a specific implementation method, the quantity regulation operation is achieved in the following way: the main control platform formulates a thermal storage operation plan every 24-72 hours based on weather forecasts and load predictions, and controls the temperature and flow rate within the design range through the variable frequency speed-regulating water pumps and valve systems of the heating first station and the reversible flow pump station, so as to ensure that the inlet temperature and flow rate of the thermal storage tank always meet the design requirements.

[0059] According to several embodiments of the present invention, when the main pipeline thermal storage circuit passes through a pressure relief station, the upstream pipeline of the main pipeline thermal storage circuit crosses the pressure relief station and connects with the downstream pipeline, and is physically isolated from the downstream pipeline at the connection point through valves and pressure relief devices. When the main pipeline thermal storage circuit needs to cross a pressure relief station, the specific implementation is as follows: a crossing pipeline is led out upstream of the pressure relief station. This pipeline uses the same pipe diameter, material, and insulation specifications as the main pipeline, and crosses to the downstream of the pressure relief station to connect with the downstream pipeline. A double-shut-off relief valve assembly is installed at the connection point, and a pressure sensor is set up for real-time monitoring to ensure effective isolation from the downstream pipeline network.

[0060] According to several embodiments of the present invention, a reversible pumping station includes a variable frequency speed-regulating pump and a valve assembly. The working fluid flow direction is switched by changing the pump's rotation direction or by switching the valves and piping system, and the working fluid flow rate is adjusted by changing the pump speed and valve opening. The reversible flow modification of the pumping station involved in the "main pipeline heat storage loop" is carried out using conventional centrifugal pumps in conjunction with valve assemblies to switch the flow direction, or by selecting dedicated reversible pumps. Under the premise of meeting the technical requirements of "continuous heat flow regulation and smooth and stable control," pumps with variable frequency speed regulation functions and a fast, high-precision valve system are configured, and operation and maintenance are strengthened to support the peak-shaving and frequency regulation needs of the thermal power plant. Specifically, the working fluid flow direction is changed by controlling the pump's rotation direction or switching the valve opening and closing state. The reversible pumping station adopts one of the following two configurations: one is to configure a reversible centrifugal pump set, and the flow direction is switched by the forward and reverse rotation of the motor; the other is to configure a conventional centrifugal pump set in conjunction with a four-way reversing valve assembly. For example, a pumping station uses three 550cW variable frequency speed-regulating water pumps, coupled with hydraulically driven DN1200 four-way valves, to complete flow direction switching within 30 minutes. Alternatively, conventional centrifugal pumps can be used with four-way valve assemblies, or reversible water pumps can be used directly with a fast-acting and precisely positioned valve system to achieve bidirectional transport of the working fluid.

[0061] According to several embodiments of the present invention, the main control platform integrates the thermal power plant control system and the urban heating control system, and the thermal power plant control system is configured to have dominant control under preset operating conditions. To achieve this coordinated control, temperature, pressure, and flow rate sensors are deployed in the thermal storage system according to the needs of peak shaving and frequency regulation. These sensors synchronously upload real-time monitoring data to the main control platform, providing a data foundation for continuous, smooth, and precise regulation of thermal energy, thereby meeting the requirements of the thermal power plant for accurate prediction and efficient utilization of thermal energy in the thermal storage system. As a feasible embodiment, the integration of the main control platform is achieved by adding a heating and energy storage control module to the thermal power plant's DCS system and establishing redundant fiber optic communication with the existing heating SCADA system. The control authority setting adopts a hierarchical strategy. During normal operation, the thermal power plant control is dominant, and when the heating system malfunctions, it can automatically switch to the heating control priority mode.

[0062] According to several embodiments of the present invention, the heat exchange station adopts a water-to-water heat exchange station. Different performance levels of water-to-water heat exchange stations are configured to meet the different temperature increase requirements of the heat-using end of the heat exchange station. For example, at the power plant end, to meet the requirement of accurately releasing high-temperature heat energy to the regenerating system, a water-to-water heat exchange station with a heat exchange end temperature difference of 5°C is constructed to maximize the requirement of increasing the condensate temperature, heating the condensate to approximately 100-130°C; at other user ends with lower temperature increase requirements, to reduce investment costs, a water-to-water heat exchange station with a larger heat exchange end temperature difference can be used.

[0063] According to several embodiments of the present invention, temperature, pressure, and flow rate sensors are installed in the main pipeline thermal storage loop. These sensors are communicatively connected to the main control platform for real-time monitoring. Specifically, a monitoring section is installed every 2-3 kilometers along the main pipeline thermal storage loop. Each section is equipped with: a platinum resistance temperature sensor (accuracy ±0.2℃), a pressure transmitter (accuracy ±0.1%), and an ultrasonic flow meter (accuracy ±1%). These sensors are connected to the main control platform via an industrial Ethernet network, with a data sampling frequency of 1 time / second, to monitor the pipeline's operating status in real time.

[0064] To further understand the thermal storage system based on a heating network according to the present invention, the following detailed description is provided in specific embodiments.

[0065] Example 1: During the non-heating season, please refer to... Figure 2 1. System Construction The following is a detailed explanation using a large-scale thermal power plant with an installed capacity of 3120MW. This power plant is equipped with two 300MW subcritical units, two 600MW supercritical units, and two 660MW ultra-supercritical units. The plant's existing two sets of four parallel heating main lines (two supply pipes and two return pipes) with a pipe diameter of 1.4 meters were converted into a thermal storage system.

[0066] As one specific implementation method, the main pipe thermal storage loop is constructed as follows: Because the insulation performance of the return water pipe is lower than that of the supply water pipe, at the far end of the pipeline network, 37.8 kilometers from the power plant, two supply water pipes of equal diameter are connected to form a high-temperature thermal storage loop using pipes of the same diameter and valves, and two return water pipes of equal diameter are connected to form a low-temperature thermal storage loop. This creates two independent circulation loops, each with a diameter of 1.4 meters and a length of 75.6 kilometers, with a total system storage capacity of 233,000 tons. Based on insulation performance, the high-temperature loop is designed to store thermal energy in the range of 100-130℃, while the low-temperature loop is designed to store energy in the range of 65-100℃.

[0067] As a feasible implementation, the modification and construction of key equipment includes: The first station for heating in a thermal power plant: the heat source system that outputs heat energy from the thermal power plant.

[0068] Reversible flow pump station: The original unidirectional distributed variable frequency pump system in the heating system and the primary heating station of the thermal power plant is transformed into a reversible flow pump system. The direction of the working fluid is switched by changing the direction of the pump, and the flow rate is regulated by adjusting the pump speed and valve opening.

[0069] Water-to-water heat exchange station: Construct a water-to-water heat exchange station with a heat exchange end temperature difference of 5℃ and a power of 650MW at the thermal power plant end.

[0070] Condensate bypass system: A bypass pipeline system is established in the pipeline between the condensate pump outlet and the low-pressure heater, directly connected to the above-mentioned water-to-water heat exchange station.

[0071] Main control platform: Integrates the control systems (such as DCS) related to thermal power plants with the heating control systems (such as SCADA) to form a unified main control platform, which is mainly used for thermal power plant control and is used for coordinated management and control of pumping stations, water-to-water heat exchange stations, etc.

[0072] 2. Operation process (1) Energy storage operating conditions (first direction - "forward" water flow) Startup: Before the initial system startup, the working fluid water temperature is the same in both the low-temperature and high-temperature systems. During off-peak hours of the power grid, the main control platform controls the primary heating station and the reversible flow pump station to drive the working fluid to flow in the first direction (heat storage direction). During initial startup, the water temperature in both the low-temperature and high-temperature systems is the same. The working fluid is heated through a gas-water heat exchange station, gradually increasing in temperature to their respective set operating conditions at a rate of 5°C per hour.

[0073] Heating process: At the beginning, the low-temperature working fluid at port B enters the gas-water heat exchanger of the first heating station and is heated until it reaches the same water temperature as at port A before entering the water supply pipe.

[0074] Temperature rise control: Based on the pipeline's ability to withstand temperature differences, the entire system is controlled to gradually increase in temperature at a rate not exceeding 5°C per hour. With a maximum flow velocity not exceeding 3.5 m / s, the corresponding temperature rise control value along the pipeline is no more than 0.3968°C (approximately 0.4°C) per kilometer.

[0075] Power Calculation: The thermal storage power is adjusted according to the formula P (MW) = c × Q (tons / hour) × ΔT (°C). For example, during initial startup, when the system flow rate is 3.0 m / s and the initial temperature difference between port A and port B is ΔT = 0°C, the thermal storage power P = 0; after 1 hour, ΔT = 5°C, and the thermal storage power P = 194.02 MW. The thermal power required by the power plant to heat condensate to 120°C under relevant loads is shown in Table 1 below.

[0076] Table 1

[0077] Thermal storage target: Continuous operation until the set total thermal storage is reached, while the temperature difference between port A and port B meets the set heat release power requirements.

[0078] Typical operating conditions after thermal storage: Cryogenic system: The temperature at port A is 100℃. After traveling 31.18 kilometers, the temperature remains at 100℃. After traveling another 44.42 kilometers, the temperature at port B is 82.23℃, with a heat storage capacity of 3365.36 MWh. High-temperature system: The temperature at port A is 130℃. After traveling 31.61 kilometers, the temperature remains at 130℃. After another 43.99 kilometers, the temperature at port B is 112.40℃, with a heat storage of 3378.94 MWh. The total heat storage of the system is 6744.3 MWh. Details are shown in Table 2 below.

[0079] Table 2

[0080] (2) Energy release condition (second direction - "reverse" water flow) Switching: After the thermal storage is completed, the system needs about 0.5 hours to complete operations such as stopping the pump, slowing down the water flow, and switching the valves to switch the water flow direction from "forward" to "reverse".

[0081] Heat release process: During peak grid load periods, the main control platform switches the flow direction of the reversible pump station, driving the working fluid to flow in a second direction (heat release direction) opposite to the first direction. The high-temperature working fluid at port A enters the water-to-water heat exchange station, releasing heat to the condensate flowing through the condensate bypass system, raising its temperature to approximately 120°C before returning to the low-pressure heater. The working fluid temperature then drops to the set temperature and enters port B.

[0082] Operational Example: First, during 5.85 hours of continuous "equal power" heat release operation, the outlet water temperature of the thermal power plant was kept stable at 120℃, the system flow rate was <1.9m / s, and the total heat release was 3287.2MWh. Details are shown in Table 3 below.

[0083] Table 3

[0084] After continuing variable-power heat release operation for another 2.58 hours, the heat release power of the low-temperature system ranged from 303.26MW to 232.53MW with a flow rate of 1.88-1.99m / s, while the heat release power of the high-temperature system ranged from 303.26MW to 290.20MW with a flow rate of 1.88-2.73m / s. The corresponding outlet water temperature of the thermal power plant ranged from 120℃ to 111.27℃. The total heat release was 1456.73MWh. Details are shown in Table 4 below.

[0085] Table 4

[0086] 3. Operation cycle and results This thermal storage system can operate on a daily or multi-day cycle. It can complete more than two thermal storage and release cycles per day, with continuous thermal storage and release operation time of approximately 9 hours and a daily heat throughput of about 7000 MWh. System switching time is controlled within 30 minutes, including operations such as pump shutdown, water flow deceleration, and valve switching, fully demonstrating its "long-term energy storage" capability. Considering that the daily heat loss of the thermal storage and transmission system is approximately 5%, the power plant determines the amount of thermal storage and release based on operating conditions, ensuring a balance between the total thermal storage and release within each cycle.

[0087] Example 2: During the heating season, please refer to... Figure 3 1. System Switching and Configuration When the heating season begins, the system described in Example 1 will be switched and adjusted: Circuit restoration: All short-circuit and connection modifications implemented in the main pipeline heat storage area during the non-heating season will be adjusted to the performance state required by the original heating system design.

[0088] Pump station adjustment: The operation mode of the reversible flow pump station will be adjusted to a unidirectional operation mode to ensure the "quantity regulation" heating method.

[0089] Main control platform collaboration: Retain and extend the functions of the main control platform, and deeply collaborate with the urban heating network control platform.

[0090] As a feasible implementation, the thermal storage facilities are configured as follows: Several low-temperature thermal storage tanks are installed along the main heating pipeline, forming a cluster of low-temperature thermal storage tanks. For example, along the primary power grid within a 50-kilometer radius of the power plant, a cluster with a total volume of 238,000 m³ is arranged. 3 The thermal storage tank cluster has a total heat storage capacity of 144,410 MWh. The operating parameters of the thermal storage tank cluster are as follows: the water temperature in the supply pipe meets the inlet temperature requirements of the upper water distributor of the thermal storage tank; the outlet water temperature of the lower water distributor of the thermal storage tank is the same as the return water temperature; the inlet water flow rate of the upper water distributor of the thermal storage tank is the same as the outlet water flow rate of the lower water distributor and meets the design requirements; and through coupling with the pressure reducing and boosting system, its pressure-bearing capacity is <0.6 MPa.

[0091] 2. Operation process System switchover: All measures implemented during the non-heating season, such as short circuits, connections, bypasses, and physical isolation, will be restored to the original heating system state. A collaborative control mechanism will be established between the main control platform and the city's heating control platform.

[0092] Quantity regulation operation: Quantity regulation is adopted as the basic operating mode to maintain the water supply temperature stable within the qualified range. Remote synchronous storage of thermal energy from the power plant is achieved through precise control of the water supply temperature and flow rate. Specific operating parameters: Maximum transmission capacity of the main heating pipeline is 4200MW, original heating power is 2300MW, and maximum daily heating supply is 55200MWh. After the upgrade, through quantity regulation, the average daily heating supply will increase by 14440MWh during the coldest period.

[0093] Thermal energy storage process: The power plant outputs water flow exceeding the city's heating demand, which flows synchronously into the thermal energy storage tank cluster. At the same time, an equal amount of low-temperature water from the thermal energy storage tank cluster flows back to the return water pipe and flows into the power plant. The thermal energy supply water flow Q1 = the thermal energy return water flow Q2, maintaining water balance. Based on the stable and qualified temperature and accurate flow of each section of the main pipe, remote synchronous storage of thermal energy is achieved.

[0094] 3. Performance Before the upgrade, the power plant had a maximum heating capacity of 2300MW and a maximum daily heating capacity of 55200MWh. By implementing quantity regulation through this system and remotely storing heat synchronously during the heating season, the average daily heating capacity can be increased by 14440MWh during the coldest period, effectively solving both the power plant's peak power generation and urban heating peak shaving issues during the heating season.

[0095] Benefits of the thermal power plant: solved the construction of 240,000 m³ 3 The site selection for thermal storage tanks is simplified, eliminating the need for additional investment in thermal storage facilities. During the heating season, 14,440 MWh of thermal energy is stored daily for peak power generation, generating corresponding peak power generation revenue.

[0096] Benefits of the heating system: Although the investment of hundreds of millions of yuan in building a cluster of low-temperature thermal storage tanks increased operating costs, it significantly boosted the heating capacity of the thermal power plant. Based on a thermal power plant heat energy cost of 15 yuan / GJ, compared to natural gas heating at 82.8 yuan / GJ, this resulted in substantial savings in heat source costs, demonstrating significant benefits.

[0097] System flexibility: During the early and late cold periods, by expanding the system's scope, areas that previously relied on high-cost heating methods such as natural gas can be switched to this system, with the heating provided by the thermal power plant, while simultaneously meeting the ultra-low load operation requirements of the thermal power plant.

[0098] A second aspect of the present invention provides a heat storage method based on a heating network, employing the heat storage system based on a heating network as described above. Figure 4 A flowchart of a heat storage method based on a heating network provided by an embodiment of the present invention is shown, as follows: Figure 4 As shown, it includes: S1. Adjust the flow direction of the working fluid through the main control platform, and adjust the temperature and flow rate of the main pipe heat storage circuit according to linear, continuous and smooth changes; S2. When the working fluid flows in the first direction, the thermal energy of the thermal power plant is stored in stages through the heating station and the reversible pump station to the main pipeline thermal storage circuit. The temperature of the working fluid in the corresponding section of the main pipeline thermal storage circuit increases linearly, continuously and smoothly or remains constant. S3. When the working fluid flows in the second direction, the heat energy stored in the main pipe heat storage circuit is supplied to the regenerative system of the thermal power plant through the cascade heat release of the reversible pump station and heat exchange station. The temperature of the working fluid at the corresponding section of the main pipe heat storage circuit decreases linearly and smoothly or remains constant.

[0099] Finally, it should be noted that those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program for setting system parameters can be stored in a computer-readable storage medium. When executed, the program can include the processes of the embodiments of the above methods. The storage medium for the program can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc. The above computer program embodiments can achieve the same or similar effects as any of the corresponding foregoing method embodiments.

[0100] Furthermore, the method disclosed in the embodiments of the present invention can also be implemented as a computer program executed by a processor, which may be stored in a computer-readable storage medium. When the computer program is executed by the processor, it performs the functions defined in the method disclosed in the embodiments of the present invention.

[0101] Furthermore, the above-described method steps and system units can also be implemented using a controller and a computer-readable storage medium for storing a computer program that enables the controller to perform the functions of the above-described steps or units.

[0102] Those skilled in the art will also understand that the various exemplary logic blocks, modules, circuits, and algorithm steps described in conjunction with the disclosure herein can be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this interchangeability between hardware and software, the functionality of various illustrative components, blocks, modules, circuits, and steps has been generally described. Whether this functionality is implemented as software or as hardware depends on the specific application and the design constraints imposed on the system as a whole. Those skilled in the art can implement the functionality in various ways for each specific application, but such implementation decisions should not be construed as departing from the scope of the embodiments disclosed herein.

[0103] In one or more exemplary designs, functionality may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, functionality may be stored as one or more instructions or code on or transmitted via a computer-readable medium. Computer-readable media include computer storage media and communication media, including any medium that facilitates the transfer of a computer program from one location to another. Storage media may be any available medium accessible to a general-purpose or special-purpose computer. By way of example, and not limitation, computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disc storage devices, disk storage devices or other magnetic storage devices, or any other medium that may be used to carry or store the required program code in the form of instructions or data structures and is accessible to a general-purpose or special-purpose computer or a general-purpose or special-purpose processor. Furthermore, any connection may be appropriately referred to as computer-readable media. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the aforementioned coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are all included in the definition of media. As used herein, disks and optical discs include compact discs (CDs), laser discs, optical discs, digital multifunction discs (DVDs), floppy disks, and Blu-ray discs, where disks typically reproduce data magnetically, while optical discs reproduce data optically using lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0104] 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.

[0105] 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.

[0106] The embodiment numbers disclosed in the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0107] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0108] 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 invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of different aspects of the 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 invention should be included within the protection scope of the invention.

Claims

1. A heat-supply-pipe-network-based thermal storage system, characterized by, include: A closed-loop main pipe heat storage circuit, consisting of a portion of the pipes in the urban heating network, is filled with working fluid. A reversible flow pump station includes a reversible flow water pump system in the primary heating station of a thermal power plant, which is connected to the main pipeline heat storage circuit and used to drive the working fluid to flow in a set direction and flow rate; A heat exchange station is connected between the main pipeline heat storage circuit and the thermal power plant; The main control platform is communicatively connected to the heating station, the reversible pump station, the heat exchange station, and the main pipeline heat storage circuit. It is used to regulate the flow direction, flow rate, and temperature of the working fluid, so that the heat energy of the thermal power plant is stored in stages through the heating station and the reversible pump station to the main pipeline heat storage circuit, or the heat energy stored in the main pipeline heat storage circuit is released in stages through the reversible pump station and the heat exchange station to the regenerative system of the thermal power plant, so as to realize the cascade heat storage, heat release, or heat transmission of the urban heating network.

2. The heat-supply-pipeline-based thermal storage system according to claim 1, characterized by, The main control platform is configured to linearly, continuously, and smoothly adjust the temperature and flow rate of the working fluid in the main pipeline heat storage circuit to achieve cascade heat storage and release in the urban heating network.

3. The heat-supply-pipeline-based thermal storage system according to claim 1, characterized by, The main pipeline heat storage circuit is formed by connecting the water supply pipe and return pipe of the urban heating network with equal diameters at the end furthest from the thermal power plant, according to the heat storage volume requirements. In the case where the urban heating system has multiple sets of heating pipes and the insulation performance of the water supply pipes and the return water pipes is different, the main pipe heat storage circuit is formed by connecting the water supply pipes and the return water pipes of each set with equal diameters at the end away from the thermal power plant.

4. The heat distribution grid based thermal storage system of claim 3, wherein, During the non-heating season, the main control platform controls the start-up, shutdown, and operation of the primary heating station and heat exchange station, as well as the flow direction adjustment and linear, continuous, and smooth flow adjustment of the reversible pump station, to achieve the switching between cascade heat storage and cascade heat release, or between heat storage and heat release modes, of the system. When the working fluid flows along the first direction, the heating station operates as a heat source system that outputs the heat energy of the thermal power plant, and stores its heat energy in stages through the reversible pump station to the main pipe heat storage circuit. The temperature of the working fluid at the corresponding section of the main pipe heat storage circuit increases linearly, continuously and smoothly or remains constant. When the working fluid flows in the second direction, the heat energy stored in the main pipe heat storage circuit is released to the regenerative system of the thermal power plant through the reversible pump station and heat exchange station. The temperature of the working fluid at the corresponding section of the main pipe heat storage circuit decreases linearly and smoothly or remains constant.

5. The heat-supply-pipeline-based thermal storage system according to claim 4, characterized by The thermal storage system also includes a condensate bypass system, which is connected to the pipeline between the condensate pump and the low-pressure heater of the thermal power plant, and is connected to the heat exchange station. When the working fluid flows along the second direction, the heat energy stored in the main pipe heat storage circuit is released to the regenerative system of the thermal power plant through the reversible pump station and heat exchange station, heating the condensate flowing through the condensate bypass system.

6. The heat-supply-pipeline-based thermal storage system according to claim 3, characterized by During the heating season, the connecting pipes of the main heat storage circuit are disconnected, restoring the heating system to its original design performance, and the reversible pump station is adjusted to unidirectional operation.

7. The heat-supply-pipeline-based thermal storage system according to claim 6, characterized by In the heating season state, the heat storage system further comprises a cluster of low-temperature heat storage tanks arranged along the heating main pipe, and the master control platform cooperates with the city heating control platform to enable the cluster of low-temperature heat storage tanks to remotely and synchronously store the heat energy from the thermal power plant.

8. The heat distribution grid based thermal storage system of claim 7, wherein, In the heating season state, the master control platform and the city heating control platform are configured to operate in a quantity-regulating mode, so as to enable the cluster of low-temperature heat storage tanks to remotely and synchronously store the heat energy output by the heat source system of the thermal power plant by keeping the working medium temperature stable and regulating the flow.

9. The heat-supply-pipeline-based thermal storage system according to claim 1, characterized by, When the main pipe heat storage circuit passes through a pressure isolation station, the upstream pipeline of the main pipe heat storage circuit is in communication with the downstream pipeline across the pressure isolation station, and is physically separated from the downstream pipeline at the connection point by a valve and a pressure relief device.

10. The heat-supply-pipeline-based thermal storage system according to claim 1, characterized by, The reversible flow pump station comprises a variable frequency water pump and a valve group, and the working medium flow direction is switched by changing the water pump rotation direction or switching the valve and the pipeline system, and the working medium flow is regulated by changing the water pump rotation speed and the valve opening degree.

11. The heat-supply-pipe-network-based thermal storage system according to claim 1, characterized by, The master control platform is integrated with a thermal power plant control system and a city heating control system, and the thermal power plant control system is configured to have dominant control in a preset working condition.

12. The heat-supply-pipeline-based thermal storage system according to claim 1, characterized by, Temperature, pressure and flow rate sensors are arranged in the main pipe heat storage circuit, and the sensors are in communication connection with the master control platform for real-time monitoring.

13. The heat-supply-pipe-network-based thermal storage system according to claim 1, characterized by, The working medium is water, and the heat exchange station is a water-water heat exchange station.

14. A heat storage method based on a heat supply pipe network, characterized by The heat storage system based on the heating pipe network according to claim 1 comprises: The master control platform adjusts the working medium flow direction according to the heat storage and heat release working conditions, and adjusts the temperature and flow of the main pipe heat storage circuit according to linear continuous smooth changes; When the working medium flows in the first direction, the heat energy from the thermal power plant is stored in the main pipe heat storage circuit via the heating first station and the reversible flow pump station, and the temperature of the working medium at the corresponding section of the main pipe heat storage circuit is linearly and continuously smoothly increased or kept constant; When the working medium flows in the second direction, the heat energy stored in the main pipe heat storage circuit is supplied to the heat recovery system of the thermal power plant via the reversible flow pump station and the heat exchange station, and the temperature of the working medium at the corresponding section of the main pipe heat storage circuit is linearly and continuously smoothly decreased or kept constant.

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