Flue gas waste heat absorption type refrigeration water body cold storage system and control method thereof

Abstract

This invention discloses a flue gas waste heat absorption refrigeration water storage system and its control method. The system includes a flue gas heat extraction unit, an absorption refrigeration unit, a cooling capacity distribution unit, and a water storage unit. The flue gas heat extraction unit extracts waste heat from the flue gas. The absorption refrigeration unit uses the waste heat to drive a refrigeration cycle to generate cooling capacity. The cooling capacity distribution unit is configured to selectively distribute the cooling capacity generated by the absorption refrigeration unit to the water storage unit and / or directly to cooling users. The water storage unit stores the cooling capacity generated by the absorption refrigeration unit and supplies the stored cooling capacity to cooling users. This invention transforms stable flue gas waste heat resources into adjustable and storable cooling energy products to meet summer cooling demands and balance power plant operating loads.

Description

Technical Field

[0001] This invention relates to the field of waste heat utilization technology, and in particular to a flue gas waste heat absorption refrigeration water storage system and its control method. Background Technology

[0002] In the thermal power and high-energy-consuming industries, flue gas waste heat recovery is a key link in improving energy efficiency and achieving energy conservation and emission reduction. Currently, the industry's utilization methods for medium- and low-temperature flue gas waste heat are relatively concentrated and singular, mainly focusing on directly converting it into heat energy through heat exchangers for heating boiler feedwater, providing centralized heating, or driving organic Rankine cycle power generation. However, these conventional methods share a common limitation: their output form (heat or electricity) is inflexible in matching seasonal and time-specific user demands, especially in dealing with the surge in cooling demand during the summer. For the numerous cogeneration power plants, a sharp drop in summer heat load leads to a heat-power imbalance, reducing the economic efficiency of unit operation. The aforementioned waste heat utilization schemes, primarily focused on heat generation, not only fail to alleviate this imbalance but may also lose their application scenarios due to the shutdown of the heating network. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, embodiments of the present invention propose a flue gas waste heat absorption cooling water storage system and its control method, which converts stable flue gas waste heat resources into adjustable and storable cold energy products to meet summer cooling demand and balance the power plant operating load.

[0005] The flue gas waste heat absorption refrigeration water storage system of this invention includes: A flue gas heat extraction unit, wherein the flue gas heat extraction unit is used to extract waste heat from flue gas; An absorption refrigeration unit is connected to the flue gas heat extraction unit, and the absorption refrigeration unit uses the waste heat of the flue gas to drive a refrigeration cycle to generate cooling capacity. The absorption refrigeration unit is connected to the absorption refrigeration unit, the water storage unit, and the cold users through the cold capacity distribution unit. The cold capacity distribution unit is configured to selectively distribute the cold capacity generated by the absorption refrigeration unit to the water storage unit and / or directly to the cold users. The water storage unit is used to store the cold capacity generated by the absorption refrigeration unit and is connected to the cold users to supply the stored cold capacity to them.

[0006] In some embodiments, the system is integrated with the thermal system of a thermal power plant. The flue gas heat exchange unit is constructed as a heat exchanger and is located in the tail flue of the power plant boiler. Flue gas flows through the primary side of the flue gas heat exchange unit, and a heat transfer medium flows through the secondary side of the flue gas heat exchange unit. The cooling capacity generated by the absorption refrigeration unit is supplied to equipment cooling points and / or plant building cooling points in the thermal system.

[0007] In some embodiments, the absorption refrigeration unit is configured as a lithium bromide absorption chiller or an ammonia absorption chiller, and the generator of the absorption refrigeration unit is connected to the flue gas heat extraction unit to form a heat medium circulation loop.

[0008] In some embodiments, the water-based cold storage unit includes a cold storage water body, a first heat exchange circuit, and a second heat exchange circuit. The first heat exchange circuit is located between the absorption refrigeration unit and the cold storage water body and is used to store cold energy in the cold storage water body. The second heat exchange circuit is located between the cold storage water body and the cold user and is used to provide the cold energy stored in the cold storage water body to the cold user.

[0009] The control method of the flue gas waste heat absorption refrigeration water storage system according to the present invention includes: The system obtains real-time operating parameters, which include at least the available amount of waste heat from flue gas, the demand load of cold users, and the cold storage status of the water-based cold storage unit. Based on the real-time operating parameters, the system's preset operating mode is determined; The cold energy distribution unit is controlled to execute the preset operating mode, including at least one of the following: direct cooling mode, cold storage mode, and cold release mode.

[0010] In some embodiments, the step of determining the preset operating mode of the system includes: In response to the cold user demand load being greater than the maximum instantaneous cooling capacity of the absorption refrigeration unit under the current available flue gas waste heat, the cold release mode is activated, and the direct cooling mode and / or cold storage mode are executed simultaneously. In the aforementioned cooling release mode, by controlling the cooling capacity distribution unit and the water-based cooling storage unit, the stored cooling capacity is extracted from the water-based cooling storage unit to supplement the supply to the cooling users.

[0011] In some embodiments, the step of determining the preset operating mode of the system includes: In response to receiving a signal or forecast that electricity prices are at their peak, the cooling mode is activated first to meet the current cooling demand load of users. At the same time, the absorption refrigeration unit is controlled to reduce its load or shut down.

[0012] In some embodiments, the step of determining the preset operating mode of the system includes: Acquire operating condition data of the thermal system; In response to the determination that the thermal system is in a low heat load operating state in summer, the operating load of the flue gas heat extraction unit and the absorption refrigeration unit is increased to actively increase the extraction and consumption of flue gas heat.

[0013] In some embodiments, if the cooling capacity generated by the absorption refrigeration unit exceeds the sum of the current cooling user demand load and the maximum cooling capacity of the water-based cold storage unit, the control method further includes: Send information about surplus cooling capacity that can be dispatched to external energy networks.

[0014] In some embodiments, the control method further includes a prediction and optimization step: Based on historical operational data and weather forecast data, predict the trend of available flue gas waste heat and the demand load trend of cooling users within the future preset time period; Based on the prediction results, a cold storage and release plan for the water body cold storage unit is formulated in advance, and the working mode switching of the cold energy distribution unit is controlled according to the plan within the preset time period.

[0015] The flue gas waste heat absorption refrigeration water storage system of this invention integrates flue gas waste heat recovery, absorption refrigeration and large-capacity water storage, and is supplemented by a control method based on multi-source information perception and multi-objective optimization. It converts low-grade flue gas waste heat into high-value cold energy and uses water storage to achieve flexible scheduling of cooling capacity in time and space to match summer cooling demand, solving the problems of the single form of traditional waste heat utilization and mismatch with the demand season.

[0016] Furthermore, the system deeply integrates with the operation of thermal power plants. Its intelligent control strategy can proactively adjust the load, creating a stable and adjustable process heat load for combined heat and power units in summer, fundamentally alleviating the heat and power imbalance and improving the overall energy efficiency and economy of the power plant throughout the year. By embedding electricity price response, predictive optimization, and energy commercialization dispatch logic, the system can minimize operating costs and has the capability to participate in grid demand-side response and regional energy markets. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a flue gas waste heat absorption refrigeration water storage system according to an embodiment of the present invention.

[0018] Figure label: 11-Flue gas heat extraction unit; 12-Absorption refrigeration unit; 13-Cooling capacity distribution unit; 14-Water cold storage unit; 141-Cold storage water body; 142-First heat exchange loop; 143-Second heat exchange loop; 21-Power plant boiler; 22-High-pressure cylinder; 23-Medium-pressure cylinder; 24-Low-pressure cylinder; 25-Generator; 26-Low-pressure heater; 27-Deaerator; 28-High-pressure heater; 29-Chimney; 31 - Cold User. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0020] The following describes, with reference to the accompanying drawings, an embodiment of the flue gas waste heat absorption refrigeration water storage system of the present invention.

[0021] like Figure 1 As shown, the flue gas waste heat absorption refrigeration water storage system of this embodiment includes a flue gas heat extraction unit 11, an absorption refrigeration unit 12, a cooling capacity distribution unit 13, and a water storage unit 14.

[0022] The flue gas heat extraction unit 11 is used to extract waste heat from the flue gas. The absorption refrigeration unit 12 is connected to the flue gas heat extraction unit 11, and the absorption refrigeration unit 12 uses the waste heat of the flue gas to drive a refrigeration cycle to generate cooling capacity.

[0023] The absorption refrigeration unit 12 is connected to the water storage unit 14 and the cold user 31 via the cold energy distribution unit 13. The cold energy distribution unit 13 is configured to selectively distribute the cold energy generated by the absorption refrigeration unit 12 to the water storage unit 14 and / or directly to the cold user 31. The water storage unit 14 is used to store the cold energy generated by the absorption refrigeration unit 12. The water storage unit 14 is connected to the cold user 31 to supply the stored cold energy to the cold user 31.

[0024] Understandably, existing flue gas waste heat utilization technologies are limited to a single form of heat or electricity output, making it difficult to flexibly match the energy-saving cooling demand in summer and unable to resolve the heat-power contradiction in combined heat and power plants during the summer. The embodiments of this invention aim to construct a flexibly dispatchable and value-maximizing cooling supply system by combining the stable, low-grade heat source of medium- and low-temperature flue gas waste heat with the conversion of heat-to-cold energy forms and the transfer of time and space dimensions.

[0025] The system uses an absorption refrigeration unit 12 to convert the low-temperature flue gas heat energy (low-value waste heat) of approximately 120℃-150℃ into low-temperature chilled water cooling capacity (high-value useful cold energy) at 7℃-12℃, following the thermodynamic principles of absorption refrigeration cycles (e.g., the absorption and generation process of lithium bromide-water working fluid pairs). This process achieves the cascade utilization and form conversion of energy quality, transforming waste heat that is difficult to use directly for summer cooling into cold energy that can directly meet the needs of air conditioning and process cooling.

[0026] By introducing a water-based cold storage unit 14 and a cold energy distribution unit 13, the generated cold energy does not necessarily need to be consumed immediately. When the cold energy demand is lower than the cooling capacity produced by the refrigeration unit (such as at night or during transitional seasons) or when electricity costs are high, the cold energy can be preferentially or partially stored in a large-volume cold storage water body 141 (such as an artificial lake, reservoir, or dedicated cold storage pond) through the first heat exchange loop 142. When the peak demand for cold energy arrives (such as in the afternoon in summer) or to reduce operating electricity costs, the stored cold energy can be released to the cold users 31 through the second heat exchange loop 143. This achieves peak shaving and valley filling in terms of time for cold energy production and consumption, and large-scale, low-cost storage in terms of space through a natural or artificial cold storage device—a water body.

[0027] When the system is integrated into a thermal power plant (especially a combined heat and power plant), its operation can proactively serve the overall energy efficiency optimization of the power plant. In summer, by actively adjusting the load of the flue gas heat extraction unit 11, the heat extraction of the tail flue gas can be increased. This is equivalent to creating a stable and adjustable new heat load for the boiler when the demand of the heating network is low, thereby balancing the contradiction of insufficient power generation caused by insufficient heat load in the turbine's heat-driven power generation mode, and improving the unit's operating hours and economy in summer.

[0028] Optionally, such as Figure 1 As shown, the thermal power plant's thermal system includes a power plant boiler 21, a high-pressure cylinder 22, a medium-pressure cylinder 23, a low-pressure cylinder 24, a generator 25, a low-pressure heater 26, a deaerator 27, and a high-pressure heater 28, which are connected in sequence by pipelines.

[0029] The flue gas heat exchange unit 11 is constructed as a corrosion-resistant finned tube heat exchanger. The flue gas heat exchange unit 11 is located in the tail flue of the power plant boiler 21. Flue gas flows through the primary side of the flue gas heat exchange unit 11, and a heat transfer medium flows through the secondary side of the flue gas heat exchange unit 11. The cooling capacity generated by the absorption refrigeration unit 12 is supplied to the equipment cooling points in the thermal system and / or the cooling points of the plant buildings.

[0030] High-temperature flue gas flows through the primary side of the heat exchanger, transferring heat to the heat transfer medium (such as hot water or organic heat transfer oil) circulating on the secondary side. The cooled flue gas is then discharged through chimney 29. The heat transfer medium forms a closed loop under the drive of the pump.

[0031] Optionally, the absorption refrigeration unit 12 is configured as a lithium bromide absorption chiller or an ammonia absorption chiller. For example, it can be a single-effect or double-effect lithium bromide absorption chiller, whose generator inlet is connected to the heat medium outlet of the aforementioned heat medium circulation loop through a pipeline, receiving hot water or steam at approximately 90°C-130°C as a driving heat source, and whose evaporator outlet outputs low-temperature chilled water (e.g., 7°C supply water, 12°C return water).

[0032] Optionally, the cooling capacity distribution unit 13 can be physically embodied as a piping distribution system including a three-way valve, a regulating valve, and a water pump. Its inlet is connected to the chilled water outlet of the absorption refrigeration unit 12, and its two outlets are respectively connected to the water-based cold storage unit 14 and the cold user 31 (such as a plant air conditioning terminal or process cooling equipment). By adjusting the valve opening, stepless distribution of cooling capacity between the two can be achieved.

[0033] Optionally, such as Figure 1 As shown, the water body cold storage unit 14 includes a cold storage water body 141 (such as a natural lake or artificial cold storage pond near the power plant) and two independent heat exchange circuits connected thereto.

[0034] First heat exchange circuit 142 (cold storage circuit): One end is connected to the water side outlet of the cold distribution unit 13, and the other end is in contact with water through a submerged coil or plate heat exchanger, transferring the cold energy of the chilled water to the water body, reducing the water temperature, and completing cold storage.

[0035] The second heat exchange circuit 143 (cooling circuit): one end extracts cold from the low-temperature water body through another heat exchanger, and the other end is connected to the water supply pipeline of the cold user 31. When needed, it extracts the cold energy stored in the water body and supplies it to the cold user 31.

[0036] The flue gas waste heat absorption cooling water storage system of this invention efficiently converts surplus flue gas waste heat in summer (when traditional heating schemes are idle) into urgently needed cooling capacity, realizing energy production based on demand. Compared with traditional electric cooling, it utilizes waste heat to drive the system, significantly reducing the electricity load on the power grid during peak summer periods, and has significant peak-shifting and valley-filling effects as well as primary energy savings.

[0037] The summer commissioning creates a stable and adjustable process heat load for the power plant. By increasing the amount of waste heat extracted from the flue gas to drive the chiller, the consumption of low-grade heat energy in the power plant's thermal cycle is essentially increased. This helps maintain a higher steam intake and power generation capacity of the turbine during periods of low grid load, thereby improving the power plant's overall energy efficiency and operational economy throughout the year.

[0038] Through the coordinated operation of the cooling capacity distribution unit 13 and the water-based cold storage unit 14, the system can intelligently select various operating modes, such as immediate cooling, cold storage for standby, or cold release supply, based on real-time electricity prices, weather, and user load changes. For example, during off-peak hours at night when electricity prices are low, it can operate at full capacity for cooling and cold storage; during peak daytime air conditioning periods when electricity prices are high, it can primarily rely on cold release from the water body to meet demand, thereby maximizing operational economy. This flexibility is not available in traditional waste heat utilization schemes with fixed output forms.

[0039] The following describes a control method for a flue gas waste heat absorption cooling water storage system according to an embodiment of the present invention. This control method is applicable to the flue gas waste heat absorption cooling water storage system described in the above embodiments.

[0040] The control method of the flue gas waste heat absorption refrigeration water storage system according to the present invention includes: Obtain the real-time operating parameters of the system. The real-time operating parameters include at least the available amount of waste heat from the flue gas, the demand load of the cold user 31, and the cold storage status of the water cold storage unit 14. Based on real-time operating parameters, the system's preset operating mode is determined; The control unit 13 executes a preset operating mode, including at least one of the following: direct cooling mode, cold storage mode, and cold release mode.

[0041] Understandably, the three key state variables that determine the system's operational boundaries—the available waste heat from flue gas (the upper limit on the energy supply side), the demand load of cooling users 31 (the energy demand on the consumption side), and the water body's cooling storage status (the system's energy storage buffer)—are collected and analyzed in real time. By using the system's control unit to simplify the complex multivariate system into a finite state machine based on pre-set mode-switching logic (such as threshold judgment and priority sorting), the system drives the cooling capacity distribution unit 13 to switch or combine between several discrete and efficient baseline operating modes: direct cooling, cooling storage, and cooling release. This constitutes the basic architecture of the entire intelligent control method.

[0042] The control method of this invention ensures that the system can operate safely, stably, and self-consistently based on the most basic supply and demand relationship without human intervention, thus avoiding cooling interruptions or energy waste caused by changes in operating conditions.

[0043] In some embodiments, the step of determining the preset operating mode of the system includes: If the demand load of the cold user 31 is greater than the maximum instantaneous cooling capacity of the absorption refrigeration unit 12 under the current available flue gas waste heat, the release mode is activated, and the direct cooling mode and / or cold storage mode are executed simultaneously. In the cold release mode, the cold energy is extracted from the cold energy storage unit 14 to supplement the supply to the cold user 31 by controlling the cold energy distribution unit 13 and the water cold energy storage unit 14.

[0044] In this embodiment, for situations with instantaneous power shortages, a water-based cold storage unit 14 is introduced as the system's power-type backup capacity. When the real-time monitoring shows that the demand load exceeds the immediate maximum output capacity of the absorption chiller (i.e., supply falls short of demand), the control logic immediately triggers the cold release mode, using the cold energy stored in the water as a supplementary power source to operate in parallel with the chiller. By utilizing the time-shifting capability of energy storage, the contradiction between the rated capacity of the cooling equipment and the peak load of the user is resolved.

[0045] Without expanding the main cooling equipment (absorption chiller), the system's ability to handle peak cooling loads is significantly improved, ensuring the stability of cooling quality and making it suitable for industrial or commercial scenarios with high requirements for cooling reliability. Because water-based cooling storage absorbs part of the peak load, a smaller capacity absorption chiller can be selected, optimizing the system's initial investment.

[0046] In some embodiments, the step of determining the preset operating mode of the system includes: In response to receiving a signal or forecast that electricity prices are at their peak, the cooling mode is activated first to meet the current demand load of cooling users 31. At the same time, control the absorption refrigeration unit 12 to reduce the load or stop it.

[0047] In this embodiment, external economic signals (time-of-use electricity prices) are internalized as control variables of the system. The water-based cold storage unit 14 is used as value-based energy storage to arbitrage over time. When a signal indicating peak electricity prices is received, the control strategy proactively shifts energy consumption: it commands the high-power-consuming absorption chiller unit 12 to reduce its load or shut down to avoid peak periods, while simultaneously commanding the cooling capacity distribution unit 13 to switch to release mode, using the cheap cold energy previously stored during off-peak hours to meet current demand and achieve valley filling.

[0048] By engaging in arbitrage operations that exploit low storage and high demand, electricity costs during periods of high grid prices are significantly reduced, directly improving the project's overall lifecycle economics. This model automatically reduces grid load during peak hours, effectively shaving off peak loads and contributing to stable grid operation.

[0049] In some embodiments, the step of determining the preset operating mode of the system includes: Acquire operating condition data of the thermal system; In response to the determination that the thermal system is in a low heat load operating state in summer, the operating load of the flue gas heat extraction unit 11 and the absorption refrigeration unit 12 is increased to actively increase the extraction and consumption of flue gas heat.

[0050] In this embodiment, by acquiring operating data from the upstream thermal system, the system intelligently identifies the low summer heat load, a condition that leads to a deterioration in the economic efficiency of combined heat and power (CHP) units. Subsequently, the control strategy operates unconventionally, proactively increasing the heat extraction and cooling loads from the flue gas. This essentially virtualizes the system as a dispatchable process heat load, artificially and controllably increasing the power plant's heat consumption by increasing the consumption of low-grade waste heat. This helps the upstream thermal system alleviate the constraint of heat-driven power generation, achieving more efficient power generation operation.

[0051] Furthermore, if the cooling capacity generated by the absorption refrigeration unit 12 exceeds the sum of the current cooling load demanded by the user 31 and the maximum cooling capacity of the water-based cooling storage unit 14, the control method further includes: Send information about surplus cooling capacity that can be dispatched to external energy networks.

[0052] When an excess of cooling capacity that cannot be used or stored immediately is generated by actively creating heat load for a power plant, this excess cooling capacity can be transformed from waste into a potential tradable commodity by sending information about the surplus cooling capacity available for dispatch to external energy networks (such as regional cooling networks or virtual power plant platforms).

[0053] In some embodiments, the control method of the present invention further includes a prediction and optimization step: Based on historical operational data and weather forecast data, predict the trend of available flue gas waste heat and the demand load trend of cooling users 31 within the future preset time period; Based on the prediction results, a cold storage and release plan for the water body cold storage unit 14 is formulated in advance, and the working mode of the cold energy distribution unit 13 is switched according to the plan within the preset time period.

[0054] In this embodiment, big data and predictive algorithms (such as time series analysis and machine learning) are used to predict key variables (waste heat trends in flue gas on the energy supply side and cooling load trends on the demand side) for future periods based on historical operating data and weather forecasts. Based on the high-confidence prediction results, a refined "cooling storage and release plan" is formulated in advance for the water-based cooling storage unit 14. Essentially, this is a simplified implementation of model predictive control. By anticipating the future, optimal actions are taken in advance, avoiding short-sighted and suboptimal decisions that may result from relying solely on real-time feedback.

[0055] By taking into account energy prices and supply and demand changes over the next 24 hours or longer, a globally optimal operating strategy can be formulated, which is more economical than real-time control that only responds to signals at the current moment.

[0056] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0057] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0058] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0059] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0060] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0061] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A flue gas waste heat absorption refrigeration water storage system, characterized in that, include: A flue gas heat extraction unit, wherein the flue gas heat extraction unit is used to extract waste heat from flue gas; An absorption refrigeration unit is connected to the flue gas heat extraction unit, and the absorption refrigeration unit uses the waste heat of the flue gas to drive a refrigeration cycle to generate cooling capacity. The absorption refrigeration unit is connected to the absorption refrigeration unit, the water storage unit, and the cold users through the cold capacity distribution unit. The cold capacity distribution unit is configured to selectively distribute the cold capacity generated by the absorption refrigeration unit to the water storage unit and / or directly to the cold users. The water storage unit is used to store the cold capacity generated by the absorption refrigeration unit and is connected to the cold users to supply the stored cold capacity to them.

2. The flue gas waste heat absorption refrigeration water storage system according to claim 1, characterized in that, The system is integrated with the thermal system of the power plant. The flue gas heat exchange unit is constructed as a heat exchanger and is located in the tail flue of the power plant boiler. Flue gas flows through the primary side of the flue gas heat exchange unit, and a heat transfer medium flows through the secondary side of the flue gas heat exchange unit. The cooling capacity generated by the absorption refrigeration unit is supplied to equipment cooling points in the thermal system and / or cooling points of plant buildings.

3. The flue gas waste heat absorption refrigeration water storage system according to claim 1 or 2, characterized in that, The absorption refrigeration unit is constructed as a lithium bromide absorption chiller or an ammonia absorption chiller. The generator of the absorption refrigeration unit is connected to the flue gas heat extraction unit to form a heat medium circulation loop.

4. The flue gas waste heat absorption refrigeration water storage system according to claim 1, characterized in that, The water-based cold storage unit includes a cold storage water body, a first heat exchange circuit, and a second heat exchange circuit. The first heat exchange circuit is located between the absorption refrigeration unit and the cold storage water body and is used to store cold energy in the cold storage water body. The second heat exchange circuit is located between the cold storage water body and the cold user and is used to provide the cold energy stored in the cold storage water body to the cold user.

5. A control method for a flue gas waste heat absorption refrigeration water storage system according to any one of claims 1-4, characterized in that, include: The system obtains real-time operating parameters, which include at least the available amount of waste heat from flue gas, the demand load of cold users, and the cold storage status of the water-based cold storage unit. Based on the real-time operating parameters, the system's preset operating mode is determined; The cold energy distribution unit is controlled to execute the preset operating mode, including at least one of the following: direct cooling mode, cold storage mode, and cold release mode.

6. The control method for the flue gas waste heat absorption refrigeration water storage system according to claim 5, characterized in that, The steps to determine the system's preset operating mode include: In response to the cold user demand load being greater than the maximum instantaneous cooling capacity of the absorption refrigeration unit under the current available flue gas waste heat, the cold release mode is activated, and the direct cooling mode and / or cold storage mode are executed simultaneously. In the aforementioned cooling release mode, by controlling the cooling capacity distribution unit and the water-based cooling storage unit, the stored cooling capacity is extracted from the water-based cooling storage unit to supplement the supply to the cooling users.

7. The control method for the flue gas waste heat absorption refrigeration water storage system according to claim 5, characterized in that, The steps to determine the system's preset operating mode include: In response to receiving a signal or forecast that electricity prices are at their peak, the cooling mode is activated first to meet the current cooling demand load of users. At the same time, the absorption refrigeration unit is controlled to reduce its load or shut down.

8. The control method for the flue gas waste heat absorption refrigeration water storage system according to claim 5, characterized in that, The steps to determine the system's preset operating mode include: Acquire operating condition data of the thermal system; In response to the determination that the thermal system is in a low heat load operating state in summer, the operating load of the flue gas heat extraction unit and the absorption refrigeration unit is increased to actively increase the extraction and consumption of flue gas heat.

9. The control method for the flue gas waste heat absorption refrigeration water storage system according to claim 8, characterized in that, If the cooling capacity generated by the absorption refrigeration unit exceeds the sum of the current cooling user demand load and the maximum cooling capacity of the water-based cold storage unit, the control method further includes: Send information about surplus cooling capacity that can be dispatched to external energy networks.

10. The control method for a flue gas waste heat absorption refrigeration water storage system according to any one of claims 5-9, characterized in that, It also includes prediction and optimization steps: Based on historical operational data and weather forecast data, predict the trend of available flue gas waste heat and the demand load trend of cooling users within the future preset time period; Based on the prediction results, a cold storage and release plan for the water body cold storage unit is formulated in advance, and the working mode switching of the cold energy distribution unit is controlled according to the plan within the preset time period.

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