Inter-seasonal heat storage and heating peak-shaving system and method coupled with waste heat recovery of thermal power units

Abstract

The present invention relates to an inter-seasonal heat storage and peak-shaving system and method for heat and power generation unit waste heat recovery coupled with a heat and power generation unit. An inter-seasonal heat storage mechanism is provided, and an underground heat storage device and a first heat exchange device are utilized to enable an absorption heat pump in the non-heating season to store waste heat in the underground heat storage device, thereby avoiding excessive idle capacity of the absorption heat pump and solving the problem of insufficient peak-shaving capacity of the cogeneration unit in the non-heating season, especially insufficient capacity of the unit for load reduction and peak-shaving. The system can also serve as a supplementary heat source to secondary heat the heat network water or as a low-temperature water supplement for the absorption heat pump when the cogeneration unit is in peak-shaving operation in the heating season, so as to make up for the external heat supply gap caused by the flexible regulation of the electric load during the peak-shaving of the cogeneration unit.

Description

Technical Field

[0001] The present invention relates to the field of heating technology, and in particular to an inter-seasonal heat storage and heating peak-shaving system and method coupled with waste heat recovery of a thermal power unit. Background Art

[0002] Currently, the primary source of heat for centralized heating in northern cities remains cogeneration, accounting for 49%. Through a series of technological upgrades, some thermal power plants are effectively recovering the low-temperature waste heat previously wasted by cogeneration units and using it to meet the heat needs of external urban heating. This not only reduces coal consumption at thermal power plants but also achieves low-carbon heating.

[0003] However, with the development of clean energy, the role of thermal power generation in my country has fundamentally changed, shifting from a primary power source for power supply security to a flexible, adjustable power source. This has led to the following problems: During the heating season, to increase the grid's ability to absorb renewable energy, CHP units can only operate at low loads for peak load regulation. This results in insufficient external heat supply, especially for thermal power plants that have undergone absorption heat pump waste heat recovery. Because the amount of waste heat available for heat supply during low-load operation is far less than the absorption heat pump's design requirements, this results in excessively high idle capacity and, to a certain extent, wasteful equipment investment costs. During the non-heating season, the CHP units' peak load regulation capacity is insufficient, particularly their ability to reduce loads for peak load regulation. Furthermore, waste heat cannot be effectively utilized, resulting in energy waste.

[0004] Based on this, it is necessary to transform the waste heat recovery system of the thermal power unit to improve the unit's load reduction and peak regulation capabilities and energy utilization rate. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects in the prior art, thereby providing a cross-seasonal heat storage and heating peak-shaving system and method coupled with waste heat recovery of thermal power units.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A cross-seasonal heat storage and peak-shaving system coupled with waste heat recovery from thermal power units, comprising:

[0008] Combined heat and power unit, including steam turbine, condenser, heater and deaerator;

[0009] A heating and supply mechanism, comprising an absorption heat pump and a heat network heater, wherein the absorption heat pump and the condenser constitute a first heat exchange circuit, and the absorption heat pump and the heat network heater constitute a second heat exchange circuit;

[0010] The inter-seasonal heat storage mechanism includes an underground heat storage device, a first heat exchange device, and a second heat exchange device, wherein the first heat exchange device is connected to the heater and / or the deaerator via a third heat exchange loop; the first heat exchange device is connected to the second heat exchange device via a fourth heat exchange loop, the second heat exchange device is connected to the underground heat storage device via a fifth heat exchange loop, the second heat exchange device is connected to the absorption heat pump via a sixth heat exchange loop; and the second heat exchange device is connected to the heat network heater via a seventh heat exchange loop.

[0011] The underground heat storage device is connected to the low-temperature water inlet and low-temperature water outlet of the absorption heat pump respectively to form a low-temperature water circuit, or the underground heat storage device and the second heat exchange device are connected to the low-temperature water inlet and low-temperature water outlet of the absorption heat pump respectively to form a low-temperature water circuit.

[0012] Preferably, the steam turbine includes a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder connected in sequence, and the heater includes a high-pressure heater corresponding to the exhaust port of the high-pressure cylinder, a medium-pressure heater corresponding to the heat recovery extraction port of the medium-pressure cylinder, and a low-pressure heater connected to the heat recovery extraction port of the low-pressure cylinder; the low-pressure heater, the deaerator, the medium-pressure heater and the high-pressure heater are connected in sequence along the flow direction of the boiler feed water.

[0013] Preferably, the first heat exchange device, the deaerator and the medium-pressure heater form the third heat exchange circuit; or,

[0014] The first heat exchange device and the deaerator constitute the third heat exchange circuit; or,

[0015] The first heat exchange device and the medium-pressure heater form the third heat exchange circuit.

[0016] Preferably, the third heat exchange circuit includes a first valve provided at the high-temperature water inlet of the first heat exchange device and a second valve provided at the high-temperature water outlet.

[0017] A feed water circulation pump is provided between the deaerator and the medium-pressure heater, and a first flow valve is provided between the medium-pressure heater and the high-pressure heater.

[0018] Preferably, the heating network heater is connected to the medium-pressure connecting pipe between the medium-pressure cylinder and the low-pressure cylinder through a heating steam extraction pipe, and is turned on during the heating season.

[0019] Preferably, the fifth heat exchange circuit includes a first heat storage branch pipe and a second heat storage branch pipe, the first heat storage branch pipe connecting one inlet and outlet of the low-temperature side of the second heat exchange device and one inlet and outlet of the underground heat storage device, the second heat storage branch pipe connecting the other inlet and outlet of the low-temperature side of the second heat exchange device and the other inlet and outlet of the underground heat storage device, the underground heat storage device is further connected to the low-temperature water outlet of the absorption heat pump, and the first heat storage branch pipe is further connected to the low-temperature water inlet of the absorption heat pump;

[0020] The first heat storage branch pipe is provided with a third valve, a fourth valve and a second circulation pump, and the second heat storage branch pipe is provided with a fifth valve and a sixth valve.

[0021] It also includes a bypass pipeline connected between the first heat storage branch pipe and the second heat storage branch pipe, and a seventh valve is provided on the bypass pipeline. One end of the bypass pipeline is connected between the third valve and the fourth valve, and the other end is connected between the fifth valve and the sixth valve.

[0022] To achieve the above purpose, the present invention also adopts the following technical solutions:

[0023] A cross-seasonal heat storage and heating peak-shaving method coupled with waste heat recovery from thermal power units adopts the above-mentioned system and includes the following steps:

[0024] In the non-heating season, the second heat exchange circuit, the seventh heat exchange circuit and the low-temperature water circuit are closed, and the first heat exchange circuit, the fifth heat exchange circuit and the sixth heat exchange circuit are opened, and the low-temperature waste heat is stored in the underground heat storage device through the absorption heat pump and the second heat exchange device;

[0025] During the heating season, the third heat exchange circuit and the fourth heat exchange circuit are closed, and the first heat exchange circuit and the second heat exchange circuit are connected. The temperature of the first heat exchange circuit is increased by the absorption heat pump to heat the heating network water and realize external heat supply; when the cogeneration unit needs to peak load, the underground heat storage device and the absorption heat pump are connected to supplement the heating network water, and low-temperature water is supplemented to the absorption heat pump through the low-temperature water circuit.

[0026] Preferably, based on the peak load regulation requirements of the cogeneration unit, the following steps are further included:

[0027] In the non-heating season, when the cogeneration unit needs to reduce load and adjust peak load, the third heat exchange circuit and the fourth heat exchange circuit are also turned on to increase the heat recovery steam extraction capacity of the unit, and store it in the underground heat storage device through the deaerator, the heater, the first heat exchange device and the second heat exchange device; and / or

[0028] During the heating season, when the cogeneration unit needs to shave peak load, the underground heat storage device and the absorption heat pump are connected, including: when the cogeneration unit needs to reduce load for peak shaving, the second heat storage branch pipe and the low-temperature water circuit are also connected, and the heat stored in the underground heat storage device is used to supplement the heating network water, and it also serves as supplementary low-temperature water for the absorption heat pump; when the cogeneration unit needs to increase load for peak shaving, the heating steam extraction volume of the unit is reduced to increase the amount of steam used by the unit for power generation. At the same time, the second heat storage branch pipe and the low-temperature water circuit are also connected, and the heat stored in the underground heat storage device is used to supplement the heating network water, and it also serves as supplementary low-temperature water for the absorption heat pump.

[0029] Preferably, the following steps are also included in the non-heating season:

[0030] Based on the peak-shaving efficiency, the third heat exchange circuit in which the first heat exchange device is connected to the deaerator and the medium-pressure heater is selected to perform load-reduced peak-shaving operation of the cogeneration unit in the non-heating season;

[0031] Based on energy-saving requirements, the third heat exchange circuit in which the first heat exchange device is connected to the deaerator is selected to perform load-reducing and peak-shaving operation of the cogeneration unit in the non-heating season.

[0032] Preferably, the method further comprises the steps of:

[0033] During the heating season, if the difference between the temperature of the stored water in the underground heat storage device and the temperature of the water in the heating network is greater than a set value, the seventh heat exchange circuit is connected, the second heat storage branch pipe of the fifth heat exchange circuit is connected, the third valve on the first heat storage branch pipe of the fifth heat exchange circuit is opened, and the fourth valve and the second circulation pump on the first heat storage branch pipe are closed, so that the water inlet of the underground heat storage device and the low-temperature side water outlet of the second heat exchange device are connected to the low-temperature water circuit;

[0034] If the difference between the temperature of the stored water in the underground heat storage device and the temperature of the water in the heating network is less than a set value, or the temperature of the stored water in the underground heat storage device is lower than the temperature of the water in the heating network, the seventh heat exchange circuit is closed, the fifth valve on the second heat storage branch pipe of the fifth heat exchange circuit is opened, the sixth valve is closed, the third valve, the fourth valve and the second circulation pump on the first heat storage branch pipe are closed, and the bypass pipeline is opened so that the water inlet and the water outlet of the underground heat storage device are connected to the low-temperature water circuit, and the stored water in the underground heat storage device flows directly to the low-temperature water inlet of the absorption heat pump.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The cross-seasonal heat storage and peak-shaving system and method for coupled cogeneration unit waste heat recovery provided in the above-mentioned technical solution is equipped with a cross-seasonal heat storage mechanism, in which the underground heat storage device and the second heat exchange device are linked with the heating and supply mechanism, and the absorption heat pump can be activated in the non-heating season to store the waste heat in the underground heat storage device, thereby avoiding excessive idle capacity of the absorption heat pump, increasing the utilization time of the power plant's original absorption heat pump and other major equipment, and to a certain extent improving the economy of the absorption heat pump renovation project; it can also be used as a supplementary heat source to reheat the heat network water or as a low-temperature water supplement for the absorption heat pump when the cogeneration unit is in peak-shaving operation during the heating season, so as to make up for the external heat supply gap caused by the flexible adjustment of the electricity load when the cogeneration unit is in peak-shaving operation; it realizes the efficient utilization of the unit's waste heat throughout the year and the peak-shaving operation during the heating season. At the same time, in the above technical solution, the cross-seasonal heat storage mechanism also includes a first heat exchange device, which forms a third heat exchange circuit with the heater and / or deaerator, which can solve the problem of insufficient peak-shaving capacity of the cogeneration unit in the non-heating season, especially the insufficient capacity of the unit to reduce load and peak-shaving. The excess water supply for the unit's load reduction and peak-shaving is transported to the first heat exchange device, and is stored through the second heat exchange device using the underground heat storage device, so that the cogeneration unit can easily achieve load reduction and peak-shaving in the non-heating season and avoid waste of waste heat.

[0037] In general, based on the systems and methods of the above-mentioned technical solutions, the cogeneration unit can achieve efficient waste heat utilization and load reduction and peak regulation throughout the year, ensuring heating for people's livelihood and realizing cross-seasonal utilization of low-temperature waste heat from power plants in the non-heating season. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 Schematic diagram of the system framework of the first embodiment of the present invention.

[0040] Figure 2 This is a schematic diagram of the conducting pipelines of the system according to the first embodiment of the present invention in the non-heating season.

[0041] Figure 3 This is a schematic diagram of the conducting pipelines of the system in the heating season according to the first embodiment of the present invention.

[0042] Figure 4 This is a schematic diagram of the system framework of the second embodiment of the present invention.

[0043] Figure 5This is a schematic diagram of one type of conducting pipeline of the system in the heating season according to the second embodiment of the present invention.

[0044] Figure 6 This is a piping diagram of the system in the non-heating season according to the third embodiment of the present invention.

[0045] Figure 7 This is a schematic diagram of the piping of the system according to the fourth embodiment of the present invention in the non-heating season.

[0046] Description of reference numerals:

[0047] 100. Cogeneration unit; 101. Boiler; 102. High-pressure cylinder; 103. Medium-pressure cylinder; 104. Low-pressure cylinder; 105. Condenser; 1051. Cooling water circulation pump; 106. Cooling tower; 107. Low-pressure heater; 108. Deaerator; 109. Medium-pressure heater; 110. High-pressure heater; 111. Medium-pressure connecting pipe; 112. Condensate pump; 113. Feedwater circulation pump; 114. First flow valve; 115. Second flow valve.

[0048] 200, heating and supply mechanism; 201, absorption heat pump; 202, heating network heater; 203, first heat exchange circuit; 2031, first cooling water branch pipe; 2032, second cooling water branch pipe; 204, second heat exchange circuit; 2041, first heating network water branch pipe; 2042, second heating network water branch pipe; 205, heating network main water pipe; 2051, heating network circulating water pump; 206, heating network water supply main pipe; 207, heating steam extraction pipe;

[0049] 300. Inter-seasonal heat storage mechanism; 301. Underground heat storage device; 302. First heat exchange device; 303. Second heat exchange device; 304. Third heat exchange circuit; 3041. Water supply branch pipe; 3042. Return water branch pipe; 3043. First valve; 3044. Second valve; 3045. Branch line; 3046. Branch valve; 3047. Fourth circulation pump; 305. Fourth heat exchange circuit; 3051. Water inlet branch; 3052. Water outlet branch; 3053. Third circulation pump; 306. Fifth heat exchange circuit; 3061. First heat storage branch pipe; 3062 , second heat storage branch pipe; 3063, third valve; 3064, second circulation pump; 3065, fourth valve; 3066, fifth valve; 3067, sixth valve; 307, sixth heat exchange circuit; 3071, first hot water branch pipe; 3072, second hot water branch pipe; 308, seventh heat exchange circuit; 3081, supplementary heating inlet pipe; 3082, supplementary heating outlet pipe; 309, low-temperature water circuit; 3091, low-temperature water supplementary outlet pipe; 3092, low-temperature water supplementary inlet pipe; 3093, low-temperature water circulation pump; 3010, bypass pipe; 3011, seventh valve. DETAILED DESCRIPTION

[0050] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0051] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0052] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0053] The embodiment of the present invention discloses a cross-seasonal heat storage and heating peak-shaving system coupled with waste heat recovery of thermal power units, comprising a cogeneration unit 100, a heating and heating mechanism 200 and a cross-seasonal heat storage mechanism 300, wherein the cogeneration unit 100 is the original equipment of the power plant, comprising a boiler 101, a steam turbine, a condenser 105, a heater and a deaerator 108, the steam from the boiler 101 enters the steam turbine to perform work, the steam discharged from the steam turbine flows into the condenser 105, the condensate flows back to the deaerator 108 and the heater, and after deoxidation and reflux heating, flows back to the boiler 101; the heating and heating mechanism 200 can be the original equipment of the power plant The original equipment may also be equipment added after upgrading and transformation, including an absorption heat pump 201 and a heat network heater 202. The absorption heat pump 201 and the condenser 105 constitute a first heat exchange loop 203, and the absorption heat pump 201 and the heat network heater 202 constitute a second heat exchange loop 204. The condensate of the condenser 105 flows into the absorption heat pump 201. The low-temperature condensate is used, and the thermal potential difference between a large amount of medium-temperature heat source and a low-temperature heat source is used to produce heat with less heat than the medium-temperature heat source but higher temperature than the medium-temperature heat source. Part of the medium and low-temperature heat energy is transferred to a higher temperature position to heat the heat network water in the second heat exchange loop 204, thereby realizing waste heat utilization.

[0054] During the heating season, the cogeneration unit 100, which serves as a flexible and adjustable power source, can only operate at low load and peak load, which results in insufficient external heat supply capacity of the cogeneration unit 100. In particular, in thermal power plants that have undergone the absorption heat pump 201 waste heat recovery and heating transformation, the waste heat that can be recovered for heating is far less than the waste heat required for the absorption heat pump 201 under the design working conditions, resulting in excessive idle capacity of the absorption heat pump 201; during the non-heating season, the low-temperature waste heat of the cogeneration unit 100 has no other use and can only be discharged and wasted. At the same time, the load reduction and peak load regulation capacity of the cogeneration unit 100 is insufficient, and the energy utilization rate is not high, resulting in low economic benefits of the system.

[0055] Based on this, the system of the embodiment of the present invention adds a cross-seasonal heat storage mechanism 300, including an underground heat storage device 301, a first heat exchange device 302 and a second heat exchange device 303.

[0056] The first heat exchange device 302 is connected to the heater and / or deaerator 108 via a third heat exchange loop 304. When the cogeneration unit 100 needs to reduce the load and peak load in the non-heating season, the excess feed water output after being heated by the deaerator 108 and the heater is input to the first heat exchange device 302 via the third heat exchange loop 304. The first heat exchange device 302 is connected to the second heat exchange device 303 via a fourth heat exchange loop 305. The heat of the excess feed water input to the first heat exchange device 302 is transferred to the second heat exchange device 303. 03 is connected to the underground heat storage device 301 through the fifth heat exchange loop 306, and can transfer the above-mentioned heat to the underground heat storage device 301 for storage; at the same time, the second heat exchange device 303 is connected to the absorption heat pump 201 through the sixth heat exchange loop 307, and can transfer the heat generated by the absorption heat pump 201 through the low-temperature condensate water in the non-heating season to the second heat exchange device 303, and then transfer it to the underground heat storage device 301 for storage; thus, the underground heat storage device 301 can store excess heat during the normal operation and load reduction and peak regulation operation of the cogeneration unit 100.

[0057] At the same time, the second heat exchanger 303 and the underground heat storage device 301 can also be used to directly heat the hot water network during the heating season. As a supplementary heat source, the second heat exchanger 303 and / or the underground heat storage device 301 are also connected to the low-temperature water inlet and low-temperature water outlet of the absorption heat pump 201, respectively, to form a low-temperature water circuit 309. During the heating season, when the combined heat and power unit 100 reduces load and peaks, and the steam and condensate volume of the combined heat and power unit 100 is insufficient, the low-temperature water from the second heat exchanger 303 and the underground heat storage device 301 can also supplement the low-temperature water of the absorption heat pump 201, thereby ensuring that the absorption heat pump 201 fully heats the hot water network in the second heat exchange circuit 204, thereby achieving load reduction and peak regulation of the combined heat and power unit 100 and ensuring heating for the people. Preferably, the sixth heat exchange circuit 307 is connected to the fourth heat exchange circuit 305, sharing some pipelines, simplifying the pipelines and reducing costs. Preferably, the second heat exchange device 303 is connected to the heating network heater 202 via a seventh heat exchange loop 308 .

[0058] Based on the above system, an embodiment of the present invention further discloses a cross-seasonal heat storage and heating peak-shaving method coupled with waste heat recovery from a thermal power unit, comprising the following steps:

[0059] In the non-heating season, the second heat exchange loop 204, the seventh heat exchange loop 308 and the low-temperature water loop 309 are closed, and the first heat exchange loop 203, the fifth heat exchange loop 306 and the sixth heat exchange loop 307 are turned on. Then, the condensate of the cogeneration unit 100 can be input into the absorption heat pump 201 through the first heat exchange loop 203, and the absorption heat pump 201 uses the waste heat to release heat. At the same time, the sixth heat exchange loop 307 connects the second heat exchange device 303 and the absorption heat pump 201, thereby transferring the heat of the absorption heat pump 201 to the second heat exchange device 303, and then the second heat exchange device 303 transfers the heat to the underground heat storage device 301 through the fifth heat exchange loop 306 for storage.

[0060] Based on the peak regulation requirement, the flow in the third heat exchange loop 304 is turned on and controlled, that is, when the cogeneration unit 100 performs load reduction peak regulation, the feed water heat exchange of the deaerator 108 and / or the heater is increased, thereby increasing the amount of steam consumed by the deaerator 108 and / or the heater, thereby reducing the amount of steam used by the cogeneration unit 100 for power generation, so that the cogeneration unit 100 achieves load reduction peak regulation. At the same time, the excess feed water output after being heated by the deaerator 108 and / or the heater is input into the first heat exchange device 302 through the third heat exchange loop 304, and the heat is transferred and stored in the underground heat storage device 301 through the fourth heat exchange loop 305 and the second heat exchange device 303; thus, in the non-heating season, the waste heat is stored in the underground heat storage device 301 through the absorption heat pump 201, the first heat exchange device 302 and the second heat exchange device 303;

[0061] During the heating season, the third heat exchange loop 304, the fourth heat exchange loop 305 and the sixth heat exchange loop 307 are closed, and the first heat exchange loop 203 and the second heat exchange loop 204 are connected. Then, the condensate of the cogeneration unit 100 can be input into the absorption heat pump 201 through the first heat exchange loop 203. The absorption heat pump 201 uses the waste heat to release heat, and the temperature of the first heat exchange loop 203 is increased through the absorption heat pump 201 to heat the hot network water.

[0062] When the cogeneration unit needs to be peak-loaded, the underground heat storage device 301 is connected to the absorption heat pump 201 to supplement the heating network water, and the absorption heat pump 201 is supplemented with low-temperature water through the low-temperature water circuit 309. Specifically, when the cogeneration unit needs to reduce the load to be peak-loaded, if the steam volume and condensate volume of the cogeneration unit 100 are insufficient, the low-temperature water of the second heat exchange device 303 and / or the underground heat storage device 301 can also supplement the low-temperature water entering the absorption heat pump 201, thereby ensuring that the low-temperature water input to the absorption heat pump 201 is full. The design quantity required by the design working condition of the absorption heat pump 201 is sufficient. The absorption heat pump 201 works normally to heat the hot network water without increasing the load of the cogeneration unit 100. When the cogeneration unit needs to increase the load for peak regulation, the heating steam extraction amount of the unit is reduced to increase the steam amount used by the unit for power generation. At the same time, the second heat storage branch pipe 3062 and the low-temperature water circuit 309 are connected, and the heat stored in the buried heat storage device 301 is used to supplement the heating network water, and it also serves as supplementary low-temperature water for the absorption heat pump 201.

[0063] In general, based on the system and method of the above technical solution, the cogeneration unit 100 can achieve efficient waste heat utilization and flexible peak regulation throughout the year, ensure heating for people's livelihood, and realize cross-seasonal utilization of low-temperature waste heat of power plants in the non-heating season.

[0064] The following will clearly and completely describe the technical solutions in several embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0065] As attached Figure 1In the illustrated embodiment 1, the steam turbine includes a high-pressure cylinder 102, an intermediate-pressure cylinder 103, and a low-pressure cylinder 104 connected in sequence; the heater includes a high-pressure heater 110 corresponding to the exhaust port connected to the high-pressure cylinder 102, an intermediate-pressure heater 109 corresponding to the extraction port connected to the intermediate-pressure cylinder 103, and a low-pressure heater 107 connected to the heat recovery extraction port of the low-pressure cylinder 104; the cogeneration unit 100 also includes a boiler 101 and a cooling tower 106. Specifically, the main steam outlet of the boiler 101 is connected to the steam inlet of the high-pressure cylinder 102, the exhaust port of the high-pressure cylinder 102 is connected to the cold re-inlet of the boiler 101 and the steam inlet of the high-pressure heater 110, the hot re-outlet of the boiler 101 is connected to the steam inlet of the intermediate-pressure cylinder 103, the heat recovery steam extraction port of the intermediate-pressure cylinder 103 is connected to the steam inlet of the intermediate-pressure heater 109, the exhaust port of the intermediate-pressure cylinder 103 is connected to the steam inlet of the deaerator 108, the exhaust port of the intermediate-pressure cylinder 103 is also connected to the steam inlet of the low-pressure cylinder 104 through the intermediate-pressure connecting pipe 111, and the heat recovery steam extraction port of the low-pressure cylinder 104 is connected to the steam inlet of the low-pressure heater 107 The exhaust port of the low-pressure cylinder 104 is connected to the exhaust steam inlet of the condenser 105. The low-temperature cooling water side of the condenser 105 is connected to the cooling tower 106. Corresponding control valves are installed on the connecting pipelines. A cooling circulating water pump is installed at the cooling water inlet of the condenser 105. The condensate outlet of the condenser 105 is connected to the water inlet of the condensate pump 112. The condensate pump 112 is connected to the low-pressure heater 107. The low-pressure heater 107, deaerator 108, medium-pressure heater 109, and high-pressure heater 110 are connected in sequence along the flow direction of the boiler 101 feed water. The feed water outlet of the high-pressure heater 110 is connected to the feed water inlet of the boiler 101. The above is one of the conventional connection methods for the cogeneration unit 100.

[0066] In this embodiment, the absorption heat pump 201 in the heating and supply mechanism 200 is a second-class absorption heat pump 201, the heat network heater 202 is a heat exchanger, and the first heat exchange circuit 203 includes a first cooling water branch pipe 2031, a second cooling water branch pipe 2032 and a corresponding control valve. Specifically, the low-temperature water outlet of the absorption heat pump 201 is connected to the cooling water inlet of the condenser 105 through the first cooling water branch pipe 2031, and a cooling water circulation pump 1051 is provided at the cooling water inlet of the condenser 105. The low-temperature water inlet of the absorption heat pump 201 is connected to the cooling water inlet of the condenser 105 through the second cooling water branch pipe 2032. The water outlet is connected; the second heat exchange circuit 204 is connected to the heat network water main pipe 205 and the heat network water supply main pipe 206. Specifically, the second heat exchange circuit 204 includes a first heat network water branch pipe 2041, a second heat network water branch pipe 2042 and a corresponding control valve. The heat network water main pipe 205 is provided with a heat network circulating water pump 2051, and its water outlet end is connected to the high-temperature water inlet of the absorption heat pump 201 through the second heat network water branch pipe 2042. The high-temperature water outlet of the absorption heat pump 201 is connected to the water inlet of the heat network heater 202 through the first heat network branch pipe, and the water outlet of the heat network heater 202 is connected to the heat network water supply main pipe 206.

[0067] More preferably, the heat network heater 202 is connected to the exhaust pipe of the medium pressure cylinder 103 through the heating steam extraction pipe 207, and the steam inlet of the heat network heater 202 is connected through the exhaust pipe of the heating steam extraction pipe 207 (i.e., the medium pressure connecting pipe 111), and the heating steam extraction pipe 207 and the medium pressure connecting pipe 111 are also respectively provided with corresponding control valves.

[0068] The inter-seasonal heat storage mechanism 300 includes an underground heat storage device 301, a first heat exchange device 302, and a second heat exchange device 303. The first heat exchange device 302 is connected to the heater and the deaerator 108 through a third heat exchange loop 304. Specifically, the third heat exchange loop 304 includes a water supply branch 3041 and a return water branch 3042. The water supply branch 3041 is connected to the high-temperature water inlet of the first heat exchange device 302 and the water supply outlet of the medium-pressure heater 109. A first valve 3043 is provided on the water supply branch 3041. The return water branch 3042 is connected to the high-temperature water inlet of the first heat exchange device 302 and the water supply outlet of the medium-pressure heater 109. The high-pressure water outlet of the first heat exchange device 302 is connected to the water outlet of the deaerator 108 and the water outlet of the low-pressure heater 107. The water outlet of the low-pressure heater 107 is connected to the water inlet of the deaerator 108. The high-temperature water outlet of the first heat exchange device 302 is provided with a second valve 3044. The feed water circulation pump 113 is connected between the water outlet of the deaerator 108 and the water inlet of the medium-pressure heater 109. The condensate pump 112 is arranged between the condensate outlet of the condenser 105 and the water inlet of the low-pressure heater 107. The flow valve includes a first flow valve 114 arranged between the medium-pressure heater 109 and the high-pressure heater 110.

[0069] The first heat exchange device 302 and the second heat exchange device 303 are connected through the fourth heat exchange circuit 305. Specifically, the fourth heat exchange circuit 305 includes an inlet branch 3051, an outlet branch 3052 and corresponding control valves and a third circulation pump 3053. The inlet branch 3051 is connected to the low-temperature water outlet of the first heat exchange device 302 and the high-temperature water inlet of the second heat exchange device 303, and is provided with at least one control valve and a third circulation pump 3053. The outlet branch 3052 is connected to the low-temperature water inlet of the first heat exchange device 302 and the high-temperature water outlet of the second heat exchange device 303, and is provided with a control valve.

[0070] The second heat exchange device 303 is connected to the underground heat storage device 301 through the fifth heat exchange loop 306, and the second heat exchange device 303 is connected to the absorption heat pump 201 through the sixth heat exchange loop 307; specifically, the fifth heat exchange loop 306 includes a first heat storage branch pipe 3061 and a second heat storage branch pipe 3062, the first heat storage branch pipe 3061 connects one inlet and outlet on the low-temperature side of the second heat exchange device 303 and one inlet and outlet of the underground heat storage device 301, the second heat storage branch pipe 3062 connects another inlet and outlet on the low-temperature side of the second heat exchange device 303 and another inlet and outlet of the underground heat storage device 301, the first heat storage branch pipe 3061 is provided with a third valve 3063 and a second circulation pump 3064, and the second heat storage branch pipe 3062 is provided with a fifth valve 3066.

[0071] The second heat exchange device 303 is connected to the absorption heat pump 201 via a sixth heat exchange loop 307. Specifically, the sixth heat exchange loop 307 includes a first hot water branch pipe 3071 and a second hot water branch pipe 3072. The first hot water branch pipe 3071 connects the high-temperature water outlet of the absorption heat pump 201 and the water inlet branch pipe of the fourth heat exchange loop 305. The water inlet branch pipe of the fourth heat exchange loop 305 is equipped with two control valves, one upstream and one downstream of the connection between the first hot water branch pipe 3071 and the water inlet branch pipe. The third circulating pump 3053 is located downstream of the connection between the first hot water branch pipe 3071 and the water inlet branch pipe, near the high-temperature water inlet of the second heat exchange device 303. The second hot water branch pipe 3072 connects the high-temperature water inlet of the absorption heat pump 201 and the high-temperature water outlet of the second heat exchange device 303 and is equipped with a control valve.

[0072] Preferably, a seventh heat exchange loop 308 is formed between the second heat exchange device 303 and the heat network heater 202. Specifically, the seventh heat exchange loop 308 includes a supplementary heating inlet pipe 3081, a supplementary heating outlet pipe 3082 and a corresponding control valve. The supplementary heating inlet pipe 3081 is connected to the second heat network water branch pipe 2042 and the high-temperature water inlet of the second heat exchange device 303, and the supplementary heating outlet pipe 3082 is connected to the first heat network water branch pipe 2041 and the high-temperature water outlet of the second heat exchange device 303.

[0073] The second heat exchange device 303 and / or the underground heat storage device 301 are also connected to the low-temperature water inlet and low-temperature water outlet of the absorption heat pump 201, respectively, to form a low-temperature water circuit 309; Figure 3 As shown, the water inlet of the underground heat storage device 301 is also connected to the low-temperature water outlet of the absorption heat pump 201, that is, the low-temperature water replenishment outlet pipe 3091 of the low-temperature water circuit 309, and the first heat storage branch pipe 3061 connected to the low-temperature side water outlet of the second heat exchange device 303 is also connected to the low-temperature water inlet of the absorption heat pump 201, that is, through the low-temperature water replenishment inlet pipe 3092 of the low-temperature water circuit 309 and the low-temperature water inlet of the absorption heat pump 201, and the low-temperature water replenishment inlet pipe 3092 is also provided with a low-temperature water circulation pump 3093 and a corresponding control valve, and the low-temperature water replenishment outlet pipe 3091 is also provided with a corresponding control valve.

[0074] Based on the above structure, the corresponding circuit is opened or closed by controlling the corresponding valve on each circuit.

[0075] Specifically, as attached Figure 2 As shown, in the non-heating season, the cogeneration unit 100 operates normally, the control valves on the first heat exchange circuit 203 are all turned on, the first heat exchange circuit 203 is turned on, the cooling water of the condenser 105 is input to the absorption heat pump 201, the control valves on the second heat exchange circuit 204 are all closed, the second heat exchange circuit 204 is turned off, and at the same time, the fourth heat exchange circuit 305 and the sixth heat exchange circuit 307 are turned on, and the high-temperature water of the absorption heat pump 201 enters the second heat exchange device 30 3. The fifth heat exchange loop 306 is turned on. The first heat storage branch pipe 3061 of the fifth heat exchange loop 306 is the outlet pipe of the underground heat storage device. The second heat storage branch pipe 3062 is the inlet pipe of the underground heat storage device. The third valve 3063, the fifth valve 3066 and the second circulation pump 3064 are working normally. The low-temperature water loop 309 is closed. As a result, the heat of the absorption heat pump 201 is transferred and stored in the underground heat storage device 301. The cogeneration unit 100 needs to reduce the load. When the load is at peak, the first valve 3043 and the second valve 3044 can be opened to increase the flow of the feed water circulation pump 113 and the condensate pump 112, increase the feed water heat exchange of the deaerator 108 and the medium pressure heater 109, and then increase the steam consumption of the deaerator 108 and the medium pressure heater 109, thereby reducing the steam consumption of the cogeneration unit 100 for power generation, so that the cogeneration unit 100 can achieve load reduction and peak regulation. The excess water output after heating enters the first heat exchange device 302 through the water supply branch pipe 3041 and exchanges heat with the second heat exchange device 303 through the fourth heat exchange loop 305. The two streams of high-temperature water are mixed and enter the second heat exchange device 303 for heat exchange and storage with the underground heat storage device 301. At this time, the high-temperature water volume is large, the water temperature is high, and the heat exchange efficiency is high. All the excess heat of the cogeneration unit 100 can be stored in the underground heat storage device 301 for long-term storage.

[0076] As attached Figure 3 As shown, during the heating season, the cogeneration unit 100 operates normally, the control valves on the first heat exchange loop 203 are all turned on, the first heat exchange loop 203 is turned on, the cooling water of the condenser 105 is input into the absorption heat pump 201, the control valves on the second heat exchange loop 204 are all turned on, the second heat exchange loop 204 is turned on, the third valve 3063 and the second circulation pump 3064 on the first heat storage branch 3061 of the fifth heat exchange loop 306 are closed, the second heat storage branch 3062 serves as the water inlet pipe of the buried heat storage device, the fifth valve 3066 on it operates normally, the low-temperature water loop 309 is turned on, and the third heat exchange loop 304, the fourth heat exchange loop 305 and the sixth heat exchange loop 307 are closed at the same time. When the user's heat demand is low, the seventh heat exchange circuit 308 is turned on, and the heat stored in the underground heat storage device 301 is used to supplement the heating of the heating network water. The control valve on the heating steam extraction pipe 207 is not opened, and the absorption heat pump 201 works normally. When the user's heat demand increases, the heating network water is heated again by the absorption heat pump 201. At the same time, the control valve on the heating steam extraction pipe 207 is opened, and the heating network heater 202 heats the heating network water again through the heating steam extraction pipe 207, so that the temperature of the heating network water is further increased to meet the heating requirements. When the cogeneration unit 100 needs to reduce the load for peak regulation, the steam volume and the cooling water volume of the condenser 105 are insufficient, the heat supply of the absorption heat pump 201 is insufficient, and the extraction volume of the heating steam extraction pipe 207 is also insufficient. At this time, the low-temperature water of the second heat exchange device 303 is input into the low-temperature water side of the absorption heat pump 201 through the low-temperature water circuit 309, and serves as a supplementary low-temperature heat source for the absorption heat pump 201, so that the absorption heat pump 201 can generate enough heat to make up for the insufficient heating steam extraction volume and the waste heat of the circulating water when the cogeneration unit 100 reduces the load for peak regulation. The gap in external heat supply caused by insufficient heat; when the cogeneration unit needs to increase the load for peak regulation, the heating steam extraction volume of the unit is reduced to increase the amount of steam used by the unit for power generation. At the same time, the second heat storage branch pipe 3062 and the low-temperature water circuit 309 are connected, and the heat stored in the underground heat storage device 301 is used to supplement the heating network water. At the same time, it is also used as supplementary low-temperature water for the absorption heat pump 201 to make up for the heating gap caused by the unit reducing the heating steam extraction volume to increase the load of the unit, thereby realizing the load reduction and peak regulation of the unit and ensuring the heating supply for people's livelihood.

[0077] It should be noted that the water inlet and outlet of the underground heat storage device 301 are interchangeable in the heating season and the non-heating season. Figure 2 and attached Figure 3 As shown in .

[0078] As attached Figure 4The second embodiment shown differs from the first embodiment in that the fifth heat exchange circuit 306 further includes a bypass line 3010 connected between the first heat storage branch 3061 and the second heat storage branch 3062, the first heat storage branch 3061 is provided with a third valve 3063, a fourth valve 3065, and a second circulation pump 3064, the second heat storage branch 3062 is provided with a fifth valve 3066 and a sixth valve 3067, the bypass line 3010 is provided with a seventh valve 3011, one end of the bypass line 3010 is connected between the third valve 3063 and the fourth valve 3065, and the other end is connected between the fifth valve 3066 and the sixth valve 3067.

[0079] Based on this, the underground heat storage device 301 can be controlled more flexibly. Specifically, during the heating season, if the difference between the temperature of the stored water in the underground heat storage device 301 and the temperature of the water in the heating network is greater than a set value, the seventh heat exchange circuit 308 is connected, the second heat storage branch pipe 3062 of the fifth heat exchange circuit 306 is connected, the third valve 3063 on the first heat storage branch pipe 3061 of the fifth heat exchange circuit 306 is opened, and the fourth valve 3065 and the second circulation pump 3064 on the first heat storage branch pipe 3061 are closed, so that the water inlet of the underground heat storage device 301 and the low-temperature side water outlet of the second heat exchange device 303 are connected to the low-temperature water circuit 309, and the low-temperature water circulation pump 3093 and the corresponding control valve in the low-temperature water circuit 309 are turned on;

[0080] If the difference between the temperature of the stored water in the underground heat storage device 301 and the temperature of the water in the heating network is less than the set value, or the temperature of the stored water in the underground heat storage device 301 is lower than the temperature of the water in the heating network, the seventh heat exchange loop 308 is closed, the fifth valve 3066 on the second heat storage branch pipe 3062 of the fifth heat exchange loop 306 is opened, the sixth valve 3067 is closed, the third valve 3063, the fourth valve 3065 and the second circulation pump 3064 on the first heat storage branch pipe 3061 are closed, and the bypass line 3010 is opened, so that the water inlet and outlet of the underground heat storage device 301 are connected to the low-temperature water circuit 309, and the stored water in the underground heat storage device 301 flows directly to the low-temperature water inlet of the absorption heat pump 201, as shown in the attached figure. Figure 5 shown.

[0081] As attached Figure 6The third embodiment shown is different from the first embodiment in that the third heat exchange circuit 304 in which the first heat exchange device 302 is connected to the deaerator 108, that is, the third heat exchange circuit 304 includes a feed water branch 3041 and a return water branch 3042, the feed water branch 3041 connects the high-temperature water inlet of the first heat exchange device 302 and the feed water outlet of the deaerator 108, and is provided with a first valve 3043 and a fourth circulation pump 3047, the return water branch 3042 connects the high-temperature water outlet of the first heat exchange device 302 and the feed water outlet of the low-pressure heater 107, the feed water outlet of the low-pressure heater 107 is connected to the feed water inlet of the deaerator 108, the high-temperature water outlet of the first heat exchange device 302 is provided with a second valve 3044, the feed water circulation pump 113 is connected between the feed water outlet of the deaerator 108 and the feed water inlet of the medium-pressure heater 109, and the flow valve includes a second flow valve 115 arranged between the medium-pressure heater 109 and the deaerator 108.

[0082] During the non-heating season, when cogeneration unit 100 needs to reduce its load for peak shaving, first valve 3043 and second valve 3044 are opened, increasing the flow rate of condensate pump 112 and the feed water heat exchange rate of deaerator 108. Excess feed water heated by deaerator 108 then flows through feed water branch pipe 3041 into first heat exchange device 302. Because deaerator 108 consumes relatively low heating power, it is suitable for long-term load reduction and peak shaving of cogeneration unit 100, resulting in higher economic efficiency.

[0083] Of course, in other embodiments, the third heat exchange circuit 304 connecting the first heat exchange device 302 and the medium-pressure heater 109, i.e., the feedwater branch 3041 and the return water branch 3042 are connected upstream and downstream of the medium-pressure heater 109, respectively, and the feedwater circulation pump 113 is provided at the feedwater inlet of the medium-pressure heater 109. During the non-heating season, when the cogeneration unit 100 needs to reduce load for peak load regulation, the first valve 3043 and the second valve 3044 are opened to increase the flow rate of the condensate pump 112 and the feedwater circulation pump 113, thereby increasing the feedwater heat exchange capacity of the medium-pressure heater 109. The excess feedwater output after heating by the medium-pressure heater 109 enters the first heat exchange device 302 through the feedwater branch 3041. Due to the high heating efficiency of the medium-pressure heater 109, rapid peak load regulation can be achieved, resulting in higher peak load regulation efficiency.

[0084] Furthermore, as attached Figure 7The fourth embodiment shown can be combined with the first and third embodiments. The third heat exchange circuit 304 includes a water supply branch pipe 3041, a return water branch pipe 3042 and a branch pipe. The water supply branch pipe 3041 connects the high-temperature water inlet of the first heat exchange device 302 and the water supply outlet of the medium-pressure heater 109, and is provided with a first valve 3043. The return water branch pipe 3042 connects the high-temperature water outlet of the first heat exchange device 302 and the water supply outlet of the low-pressure heater 107. The water supply outlet of the low-pressure heater 107 is connected to the outlet of the high-temperature water outlet of the low-pressure heater 107. The water supply inlet of the deaerator 108 is connected, the high-temperature water outlet of the first heat exchange device 302 is provided with a second valve 3044, the water supply circulation pump 113 is connected between the water supply outlet of the deaerator 108 and the water supply inlet of the medium-pressure heater 109, and the branch road 3045 connects the water supply branch pipe 3041 and the water outlet of the water supply circulation pump 113, which is provided with a branch valve 3046. At the same time, the second flow valve 115 is set between the water outlet of the water supply circulation pump 113 and the water supply inlet of the medium-pressure heater 109. If the first valve 3043 and the second valve 3044 are turned on and the branch valve 3046 is closed, the third heat exchange circuit 304 connects the first heat exchange device 302 with the deaerator 108 and the medium-pressure heater 109. When in use, the flow of the second flow valve 115 and the water circulation pump 113 needs to be increased, and the flow of the first flow valve 114 needs to be reduced; if the branch valve 3046 and the second valve 3044 are turned on and the first valve 3043 is closed, the third heat exchange circuit 304 connects the first heat exchange device 302 with the deaerator 108. When in use, the flow of the water circulation pump 113 needs to be increased, and the flow of the first flow valve 114 and the second flow valve 115 needs to be reduced.

[0085] Based on the above structure, in the non-heating season, the system can select a suitable third heat exchange circuit 304 to be connected according to the peak-shaving requirements. Specifically, based on the peak-shaving efficiency, the third heat exchange circuit 304 in which the first heat exchange device 302 is connected to the deaerator 108 and the medium-pressure heater 109 is selected; based on the energy-saving requirements, the third heat exchange circuit 304 in which the first heat exchange device 302 is connected to the deaerator 108 is selected. There are more choices and more flexible adjustments.

[0086] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A cross-seasonal heat storage and peak-shaving system coupled with waste heat recovery from thermal power units, characterized in that: include: Combined heat and power unit, including steam turbine, condenser, heater and deaerator; A heating and supply mechanism includes an absorption heat pump and a heating network heater, wherein the absorption heat pump and the condenser constitute a first heat exchange circuit, and the absorption heat pump and the heating network heater constitute a second heat exchange circuit, and the second heat exchange circuit can be connected to the heating network water main pipe and the heating network water supply main pipe; The inter-seasonal heat storage mechanism includes an underground heat storage device, a first heat exchange device, and a second heat exchange device, wherein the first heat exchange device is connected to the heater and / or the deaerator via a third heat exchange loop; the first heat exchange device is connected to the second heat exchange device via a fourth heat exchange loop, the second heat exchange device is connected to the underground heat storage device via a fifth heat exchange loop, the second heat exchange device is connected to the absorption heat pump via a sixth heat exchange loop; and the second heat exchange device is connected to the heat network heater via a seventh heat exchange loop. The underground heat storage device is connected to the low-temperature water inlet and low-temperature water outlet of the absorption heat pump respectively to form a low-temperature water circuit, or the underground heat storage device and the second heat exchange device are connected to the low-temperature water inlet and low-temperature water outlet of the absorption heat pump respectively to form a low-temperature water circuit.

2. The system according to claim 1, wherein The steam turbine includes a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder connected in sequence, and the heater includes a high-pressure heater corresponding to the exhaust port of the high-pressure cylinder, a medium-pressure heater corresponding to the heat recovery extraction port of the medium-pressure cylinder, and a low-pressure heater connected to the heat recovery extraction port of the low-pressure cylinder; the low-pressure heater, the deaerator, the medium-pressure heater and the high-pressure heater are connected in sequence along the flow direction of boiler feed water.

3. The system according to claim 2, wherein: The first heat exchange device, the deaerator and the medium-pressure heater form the third heat exchange circuit; or, The first heat exchange device and the deaerator constitute the third heat exchange circuit; or, The first heat exchange device and the medium-pressure heater form the third heat exchange circuit.

4. The system according to claim 3, wherein: The third heat exchange circuit includes a first valve provided at the high-temperature water inlet and a second valve provided at the high-temperature water outlet of the first heat exchange device. A feed water circulation pump is provided between the deaerator and the medium-pressure heater, and a first flow valve is provided between the medium-pressure heater and the high-pressure heater.

5. The system according to claim 2, wherein: The heating network heater is connected to the medium-pressure connecting pipe between the medium-pressure cylinder and the low-pressure cylinder through a heating steam extraction pipe and is turned on during the heating season.

6. The system according to claim 1 or 5, characterized in that The fifth heat exchange circuit includes a first heat storage branch pipe and a second heat storage branch pipe, the first heat storage branch pipe connecting one inlet and outlet of the low-temperature side of the second heat exchange device and one inlet and outlet of the underground heat storage device, the second heat storage branch pipe connecting the other inlet and outlet of the low-temperature side of the second heat exchange device and the other inlet and outlet of the underground heat storage device, the underground heat storage device is further connected to the low-temperature water outlet of the absorption heat pump, and the first heat storage branch pipe is further connected to the low-temperature water inlet of the absorption heat pump; The first heat storage branch pipe is provided with a third valve, a fourth valve and a second circulation pump, and the second heat storage branch pipe is provided with a fifth valve and a sixth valve. It also includes a bypass pipeline connected between the first heat storage branch pipe and the second heat storage branch pipe, and a seventh valve is provided on the bypass pipeline. One end of the bypass pipeline is connected between the third valve and the fourth valve, and the other end is connected between the fifth valve and the sixth valve.

7. A cross-seasonal heat storage and heating peak-shaving method coupled with waste heat recovery of thermal power units, characterized in that: The system according to any one of claims 1 to 6 comprises the following steps: In the non-heating season, the second heat exchange circuit, the seventh heat exchange circuit and the low-temperature water circuit are closed, and the first heat exchange circuit, the fifth heat exchange circuit and the sixth heat exchange circuit are opened, and the low-temperature waste heat is stored in the underground heat storage device through the absorption heat pump and the second heat exchange device; During the heating season, the third heat exchange circuit and the fourth heat exchange circuit are closed, and the first heat exchange circuit and the second heat exchange circuit are connected. The temperature of the first heat exchange circuit is increased by the absorption heat pump to heat the heating network water and realize external heat supply; when the cogeneration unit needs to peak load, the underground heat storage device and the absorption heat pump are connected to supplement the heating network water, and low-temperature water is supplemented to the absorption heat pump through the low-temperature water circuit.

8. The method according to claim 7, wherein Based on the peak load regulation requirements of the cogeneration unit, the following steps are also included: In the non-heating season, when the cogeneration unit needs to reduce load and adjust peak load, the third heat exchange loop and the fourth heat exchange loop are also turned on to increase the heat recovery steam of the unit, and the heat recovery steam is stored in the underground heat storage device through the deaerator, the heater, the first heat exchange device and the second heat exchange device; and / or During the heating season, when the cogeneration unit needs to shave peak load, the underground heat storage device and the absorption heat pump are connected, including: when the cogeneration unit needs to reduce load for peak shaving, the second heat storage branch pipe and the low-temperature water circuit are also connected, and the heat stored in the underground heat storage device is used to supplement the heating network water, and it also serves as supplementary low-temperature water for the absorption heat pump; when the cogeneration unit needs to increase load for peak shaving, the heating steam extraction volume of the unit is reduced to increase the amount of steam used by the unit for power generation. At the same time, the second heat storage branch pipe and the low-temperature water circuit are also connected, and the heat stored in the underground heat storage device is used to supplement the heating network water, and it also serves as supplementary low-temperature water for the absorption heat pump.

9. The method according to claim 8, wherein In the non-heating season, the following steps are also included: Based on the peak-shaving efficiency, the third heat exchange circuit in which the first heat exchange device is connected to the deaerator is selected to perform load-reduced peak-shaving operation of the cogeneration unit in the non-heating season; Based on energy-saving requirements, the third heat exchange circuit in which the first heat exchange device is connected to the deaerator is selected to perform load-reducing and peak-shaving operation of the cogeneration unit in the non-heating season.

10. The method according to claim 8, wherein The following steps are also included: During the heating season, if the difference between the temperature of the stored water in the underground heat storage device and the temperature of the water in the heating network is greater than a set value, the seventh heat exchange circuit is connected, the second heat storage branch pipe of the fifth heat exchange circuit is connected, the third valve on the first heat storage branch pipe of the fifth heat exchange circuit is opened, and the fourth valve and the second circulation pump on the first heat storage branch pipe are closed, so that the water inlet of the underground heat storage device and the low-temperature side water outlet of the second heat exchange device are connected to the low-temperature water circuit; If the difference between the temperature of the stored water in the underground heat storage device and the temperature of the water in the heating network is less than a set value, or the temperature of the stored water in the underground heat storage device is lower than the temperature of the water in the heating network, the seventh heat exchange circuit is closed, the fifth valve on the second heat storage branch pipe of the fifth heat exchange circuit is opened, the sixth valve is closed, the third valve, the fourth valve and the second circulation pump on the first heat storage branch pipe are closed, and the bypass pipeline is opened so that the water inlet and the water outlet of the underground heat storage device are connected to the low-temperature water circuit, and the stored water in the underground heat storage device flows directly to the low-temperature water inlet of the absorption heat pump.

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