Cooling and heating system based on waste heat recovery of thermal power plant and plant area accessory building

Abstract

The utility model relates to the technical field of energy conservation, in particular to a cooling and heating system based on waste heat recovery of a thermal power plant and a plant area accessory building, which comprises a steam boiler room, a desulfurizing tower, a sewage heat exchanger, an absorption heat pump unit, a heat storage water tank and the plant area accessory building. The generated high-temperature flue gas is sent to a desulfurization tower for desulfurization, the desulfurization tower is connected with a sewage heat exchanger, and heat of the flue gas is released to an intermediate medium; the winter sewage heat exchanger is connected with the absorption heat pump unit to recover heat of an intermediate medium; the summer sewage heat exchanger is connected with the heat storage water tank to store heat of the intermediate medium; the winter factory area auxiliary building is connected with the heat storage water tank and used for building heat supply; the auxiliary building of the factory area in summer is connected with the absorption heat pump unit and used for building cooling. According to the cooling and heating system, the operation efficiency of a thermal power plant is improved, and meanwhile the requirements for heating in winter and cooling in summer of auxiliary buildings in a plant area can be met.

Description

Technical Field

[0001] The utility model relates to the technical field of energy conservation, in particular to a cooling and heating system based on waste heat recovery of a thermal power plant and its ancillary buildings. Background Art

[0002] In recent years, the cogeneration technology, which produces high-temperature and high-pressure steam to drive steam turbines for power generation and uses extraction or exhaust steam for heating, has been widely promoted in northern China due to its significant energy-saving and emission-reduction effects. However, due to the reduction in heating demand in summer and the decrease in steam consumption, the steam load of thermal power plants shows seasonal fluctuations. In addition, when the heat in high-temperature steam is used in a cascade manner, some of the heat is still discharged into the external environment in the form of sewage, flue gas, waste residue, etc., resulting in a waste of waste heat resources. For example, after the circulating water in the desulfurization tower undergoes a chemical reaction with the flue gas for desulfurization, its temperature can reach above 40°C, which has good heat recovery potential.

[0003] On the other hand, in order to improve the utilization rate of waste heat resources, the heat demand of the same grade is sorted out: (1) Ancillary buildings in the factory area, such as office buildings and restaurants, require cooling in summer and heating in winter. The water supply temperature in winter is generally between 35℃ and 55℃. (2) When using municipal tap water for boiler water replenishment, it needs to be preheated to about 20℃ due to the low temperature of tap water in winter. (3) The higher the temperature of boiler desalinated water, the better the desalination effect, but its temperature is only 20℃ in summer.

[0004] Therefore, there is an urgent need for a cooling and heating system based on waste heat recovery from thermal power plants and their ancillary buildings to solve the above problems and improve the operating efficiency of thermal power plants. Utility Model Content

[0005] The purpose of the utility model is to provide a cooling and heating system based on waste heat recovery from a thermal power plant and its ancillary buildings, so as to solve the problems existing in the prior art and to meet the needs of winter heating and summer cooling of the ancillary buildings in the plant while improving the operating efficiency of the thermal power plant.

[0006] To achieve the above purpose, the utility model provides the following solutions: The utility model provides a cooling and heating system based on waste heat recovery from thermal power plants and ancillary buildings in the plant area.

[0007] include:

[0008] Steam boiler room;

[0009] A desulfurization tower, the desulfurization tower is connected to the steam boiler room through a flue, and is used to transport the high-temperature flue gas generated by the steam boiler room to the desulfurization tower;

[0010] A sewage heat exchanger, wherein the water outlet of the desulfurization tower is connected to the left heat exchange coil of the sewage heat exchanger, and is used to indirectly exchange the heat of the circulating water in the desulfurization tower to the intermediate medium, which is then recovered by the absorption heat pump unit or stored in the hot water storage tank;

[0011] An absorption heat pump unit, the absorption heat pump unit comprising:

[0012] A generator, the generator is connected to the steam boiler room through a steam pipeline, and is used to drive the evaporator to take heat from the low-temperature heat source and release the heat to the medium-temperature heat source;

[0013] An evaporator, wherein the evaporator is connected to two branches, one branch is connected to the right heat exchange coil of the sewage heat exchanger, and the intermediate medium is used as the low-temperature heat source of the absorption heat pump unit in winter, and the other branch is connected to the auxiliary buildings of the plant area, and the user return water is used as the low-temperature heat source of the absorption heat pump unit in summer;

[0014] absorber and condenser;

[0015] A heat storage tank, wherein the cooling water from the left heat exchange coil of the heat storage tank is sequentially transported to the absorber and the condenser for step heating, and serves as the medium-temperature heat source of the absorption heat pump unit; the water outlet of the heat storage tank is connected to the steam boiler room through a water pipe, and is used to replenish water to the steam boiler room;

[0016] Ancillary buildings in the factory area; the return water from users of the ancillary buildings in the factory area is divided into two branches, one branch is transported to the evaporator, and after releasing heat and cooling, it returns to the ancillary buildings in the factory area for summer cooling; the other branch is transported to the right heat exchange coil of the water storage tank, and after absorbing heat and heating, it returns to the ancillary buildings in the factory area for winter heating.

[0017] Preferably, it further comprises a steam circulation pump, and the steam circulation pump is fixedly installed on the pipeline between the steam boiler room and the absorption heat pump unit.

[0018] Preferably, it also includes a desulfurization tower circulation pump, and the desulfurization tower circulation pump is fixedly installed on the pipeline connecting the water outlet end of the desulfurization tower and the sewage heat exchanger.

[0019] Preferably, it also includes an intermediate medium circulation pump, and the intermediate medium circulation pump is fixedly installed on the outlet pipe of the sewage heat exchanger.

[0020] Preferably, it also includes valve V1, valve V2, valve V3, valve V4, valve V5, valve V6, valve V7 and valve V8, wherein,

[0021] Under winter heating conditions, valves V1 and V2 are respectively provided on the circulation pipeline connecting the outlet end of the sewage heat exchanger and the evaporator, and the valves V1 and V2 are provided on different pipelines; valves V7 and V8 are respectively provided on the circulation loop formed by connecting the auxiliary buildings of the plant area and the hot water storage tank, and the valves V7 and V8 are provided on different pipelines;

[0022] Under the cooling condition in summer, the water outlet of the sewage heat exchanger is connected to the hot water storage tank to form a circulation loop, on which valves V3 and V4 are respectively provided, and the valves V3 and V4 are arranged on different pipelines. The circulation loop formed by connecting the ancillary buildings in the plant area to the absorption heat pump unit is respectively provided with valves V5 and V6, and the valves V5 and V6 are arranged on different pipelines.

[0023] Preferably, it also includes a user-side circulating pump, which is arranged on the user return water pipeline of the ancillary building in the factory area.

[0024] Preferably, it also includes a boiler water supply pump, and the boiler water supply pump is fixedly installed on the pipeline between the steam boiler room and the hot water storage tank.

[0025] The utility model discloses the following technical effects: The cooling and heating system based on waste heat recovery of thermal power plants and ancillary buildings in the plant area of ​​the utility model has the following beneficial effects:

[0026] 1. Compared with the operation mode in the prior art where the auxiliary buildings of the factory area use plate heat exchangers to take heat from the boiler room for heating in winter and use electric cooling units to produce chilled water in summer, the utility model uses a set of absorption heat pump units to achieve winter heating and summer cooling, which simplifies the equipment in the machine room and improves the space utilization rate;

[0027] 2. Since the waste heat of the circulating water in the desulfurization tower is used for heating buildings and preheating boiler water in winter, and the waste heat of the building and the circulating water in the desulfurization tower is used for heating boiler desalted water in summer, the cooling and heating system disclosed in the utility model not only realizes the waste heat recovery of the thermal power plant and the ancillary buildings in the plant area, improves the utilization rate of waste heat resources, but also reduces the energy consumption of heating and cooling of the ancillary buildings in the plant area, and has good energy-saving and carbon-reducing benefits;

[0028] 3. Since steam is required to drive the absorption heat pump unit under both cooling and heating conditions, compared with conventional thermal power plants, the utility model has an increased steam demand in summer, thereby stabilizing the fluctuation of steam load throughout the year and improving the utilization rate of the absorption heat pump throughout the year;

[0029] 4. Preheat boiler water in winter and heat boiler desalted water in summer, while reducing steam network fluctuations, which helps improve the overall operating efficiency of thermal power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 This is the schematic diagram of the cooling and heating system based on waste heat recovery from thermal power plants and ancillary buildings in the plant area;

[0032] Figure 2 It is a schematic diagram of heat flow in winter operation of the cooling and heating system based on waste heat recovery from thermal power plants and ancillary buildings in the plant area;

[0033] Figure 3 This is a flow chart of the winter operation conditions of the cooling and heating system based on waste heat recovery from thermal power plants and ancillary buildings in the plant area;

[0034] Figure 4 It is a heat flow diagram of the summer operation condition of the cooling and heating system based on waste heat recovery from the thermal power plant and its ancillary buildings;

[0035] Figure 5 This is a flow chart of the summer operation conditions of the cooling and heating system based on waste heat recovery from thermal power plants and ancillary buildings in the plant area.

[0036] Among them, 1. Steam boiler room; 2. Desulfurization tower; 3. Desulfurization tower circulation pump; 4. Sewage heat exchanger; 5. Intermediate medium circulation pump; 6. Steam circulation pump; 7. Absorption heat pump unit; 8. Generator; 9. Condenser; 10. Evaporator; 11. Absorber; 12. Boiler feed water pump; 13. Cooling circulation pump; 14. Heat storage tank; 15. User side circulation pump; 16. Ancillary buildings in the factory area. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0038] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0039] like Figure 1-Figure 5As shown, the utility model provides a cooling and heating system based on waste heat recovery of thermal power plants and ancillary buildings in the plant area, comprising: a steam boiler room 1;

[0040] A desulfurization tower 2, wherein the desulfurization tower 2 is connected to the steam boiler room 1 through a flue, and is used to transport the high-temperature flue gas generated by the steam boiler room 1 to the desulfurization tower 2;

[0041] The sewage heat exchanger 4, the water outlet end of the desulfurization tower 2 is connected to the left heat exchange coil of the sewage heat exchanger 4, which is used to indirectly exchange the heat of the circulating water in the desulfurization tower 2 to the intermediate medium, which is then recovered by the absorption heat pump unit 7 or stored in the hot water storage tank 14;

[0042] Absorption heat pump unit 7, the absorption heat pump unit 7 comprises:

[0043] Generator 8, the generator 8 is connected to the steam boiler room 1 through a steam pipeline, and is used to drive the evaporator 10 to take heat from the low-temperature heat source and release the heat to the medium-temperature heat source;

[0044] The evaporator 10 is connected to two branches, one of which is connected to the right heat exchange coil of the sewage heat exchanger 4, and the intermediate medium in winter serves as the low-temperature heat source of the absorption heat pump unit 7, and the other branch is connected to the auxiliary building 16 of the plant area, and the user return water in summer serves as the low-temperature heat source of the absorption heat pump unit 7;

[0045] absorber 11 and condenser 9;

[0046] The hot water storage tank 14, the cooling water from the left heat exchange coil of the hot water storage tank 14 is sequentially transported to the absorber 11 and the condenser 9 for step heating, and serves as the medium-temperature heat source of the absorption heat pump unit 7; the water outlet end of the hot water storage tank 14 is connected to the steam boiler room 1 through a water pipe, and is used to replenish water to the steam boiler room 1;

[0047] The plant ancillary building 16; the return water from the users of the plant ancillary building 16 is divided into two branches, one branch is transported to the evaporator 10, and after releasing heat and cooling, it returns to the plant ancillary building 16 for summer cooling; the other branch is transported to the right heat exchange coil of the water storage tank 14, and after absorbing heat and heating, it returns to the plant ancillary building 16 for winter heating.

[0048] Specifically, Figure 1 As shown, the steam boiler room 1 is connected to the desulfurization tower 2 through a flue, and the high-temperature flue gas generated by the steam boiler room 1 is transported to the desulfurization tower 2, and while chemically reacting with the circulating water of the desulfurization tower to remove sulfides in the flue gas, heat is transferred to the circulating water of the desulfurization tower, and the flue gas after cooling and desulfurization is discharged into the atmosphere;

[0049] The heated desulfurization tower circulating water is transported by the desulfurization tower circulating pump 3 to the left heat exchange coil of the sewage heat exchanger 4, and releases heat to the intermediate medium;

[0050] The intermediate medium coming out of the right heat exchange coil of the sewage heat exchanger 4 is divided into two branches, one branch is transported to the evaporator 10 through the intermediate medium circulation pump 5, and is used as a low-temperature heat source for the absorption heat pump unit in winter, and the other branch is transported to the right heat exchange coil of the hot water storage tank 14 through the intermediate medium circulation pump 5, and the heat is stored in the hot water storage tank 14 in summer;

[0051] The steam boiler room 1 is connected to the absorption heat pump unit 7 through a steam pipeline. The high-temperature steam produced by the steam boiler room 1 is transported to the generator 8 by the steam circulation pump 6 as a high-temperature heat source of the absorption heat pump unit, and is used to drive the absorption heat pump unit to extract heat from the low-temperature heat source and release the heat to the medium-temperature heat source together with the heat from the high-temperature heat source;

[0052] The cooling water coming out of the left heat exchange coil of the hot water storage tank 14 is transported by the cooling circulation pump 13 to the absorber 11 and the condenser 9 for step heating in turn, as the medium-temperature heat source of the absorption heat pump unit, that is, the high-temperature heat source is high-temperature steam, the low-temperature heat source is the intermediate medium (in winter) or user return water (in summer), and the medium-temperature heat source is the cooling water flowing through the absorber and condenser. In the entire absorption heat pump, the heat flow path is: the heat of the high-temperature heat source in the generator and the heat of the low-temperature heat source in the evaporator are transferred to the medium-temperature heat source of the absorber and the condenser;

[0053] Municipal tap water or boiler desalted water is connected from the upper end of the heat storage tank 14, and after absorbing heat and heating up in the heat storage tank 14, it is transported to the steam boiler room 1 through the boiler make-up water pump 12, and is used to replenish water for the steam boiler room 1; the user return water coming out of the plant ancillary building 16 is divided into two branches, one branch is transported to the evaporator 10 through the user-side circulating pump 15, and serves as a low-temperature heat source for the absorption heat pump unit in summer, and returns to the plant ancillary building for cooling after releasing heat and cooling down, and the other branch is transported to the right heat exchange coil of the heat storage tank 14 through the user-side circulating pump 15, and returns to the plant ancillary building for heating after absorbing heat and heating up.

[0054] The cooling and heating system disclosed by the utility model replaces the original dispersed heating and cooling systems by adding an absorption heat pump unit, thereby simplifying the layout of the machine room; considering that the circulating water of the desulfurization tower has poor water quality and is easily corroded by being directly sent to the evaporator, a sewage heat exchanger is added to indirectly exchange the heat of the circulating water of the desulfurization tower to the intermediate medium and then be recovered by the evaporator; the high-temperature steam produced by the steam boiler room enters the generator, and is used to drive the absorption heat pump unit to recover the waste heat of the flue gas from the evaporator in winter, and is used to drive the absorption heat pump unit to recover the heat of the auxiliary buildings of the factory area from the evaporator in summer. Steam is consumed in both winter and summer, thereby stabilizing the seasonal fluctuation of the steam pipeline network and increasing the annual operation time of the absorption heat pump unit; the heat absorbed from the absorber and the condenser is stored in a heat storage tank, and in winter, in addition to supplying heat to the auxiliary buildings of the factory area, it is also used to preheat the municipal tap water for boiler replenishment, and in summer, it is used to heat the desalted water of the boiler to enhance the desalination effect. The above measures are conducive to improving the overall operation efficiency of the thermal power plant.

[0055] Example 1

[0056] like Figure 2 As shown, the direction of heat flow of the cooling and heating system based on waste heat recovery from the thermal power plant and its ancillary buildings during winter operation is: Ignoring the heat loss of the pipeline and the heat input by the water pump, the cooling and heating system, driven by high-temperature steam, recovers the waste heat of the circulating water in the desulfurization tower and uses it for heating the ancillary buildings in the plant and preheating the municipal tap water for boiler replenishment.

[0057] The specific process is as follows Figure 3 As shown, valves V1, V2, V7 and V8 are open, and valves V3, V4, V5 and V6 are closed. Furthermore, the operation process of the cooling and heating system under winter heating conditions includes user heating cycle, waste heat recovery cycle, cooling cycle, steam cycle and boiler water supply cycle. The process of each cycle stage is as follows:

[0058] Waste heat recovery cycle process: In the steam boiler room 1, coal combustion will release a large amount of heat to heat the water in the boiler to produce high-temperature steam. At the same time, high-temperature flue gas containing sulfide will also be produced in the process. The high-temperature flue gas is transported from the steam boiler room 1 to the desulfurization tower 2 through the flue, and directly contacts the desulfurization tower circulating water in the desulfurization tower 2. While the two undergo chemical reaction and desulfurization, the heat in the high-temperature flue gas is transferred to the desulfurization tower circulating water. Further, the heated desulfurization tower circulating water is transported by the desulfurization tower circulating pump 3 to the heat exchange coil on the left side of the sewage heat exchanger 4 for heat release, and the heat released is absorbed by the intermediate medium in the heat exchange coil on the right side of the sewage heat exchanger 4. After the intermediate medium absorbs heat and rises in temperature, it is transported to the evaporator 10 through the intermediate medium circulating pump 5 as a low-temperature heat source for the absorption heat pump unit, and driven by the high-temperature steam in the generator 8, the heat is released from the absorber 11 and the condenser 9 to the cooling water, realizing the waste heat recovery of the desulfurization tower circulating water.

[0059] Steam cycle process: The high-temperature steam produced in the steam boiler room 1 is transported to the generator 8 through the steam circulation pump 6 as the high-temperature heat source of the absorption heat pump unit, driving the absorption heat pump unit 7 to operate.

[0060] The cooling cycle process: the cooling water coming out of the heat exchange coil on the left side of the hot water storage tank 14 is transported to the absorber 11 and the condenser 9 in sequence through the cooling circulation pump 13 to absorb heat, and then returns to the hot water storage tank 14 after absorbing heat and heating up, so as to heat the hot water storage tank 14.

[0061] The process of user heating cycle: the low-temperature return water from the plant ancillary building 16 is transported to the heat exchange coil on the right side of the hot water storage tank 14 through the user-side circulation pump 15, and after being heated to the water supply temperature by the hot water storage tank 14, it returns to the plant ancillary building 16 for user heating.

[0062] The process of boiler water replenishment circulation: municipal tap water enters from the upper water inlet of the hot water storage tank 14, absorbs heat and rises in temperature, and then flows out from the upper water outlet of the hot water storage tank 14, and is transported to the steam boiler room 1 by the boiler water replenishment pump 12 for boiler water replenishment.

[0063] Example 2

[0064] like Figure 4 As shown, the direction of heat flow of the heating and cooling system based on waste heat recovery from thermal power plants and ancillary buildings in the summer is as follows: ignoring the heat loss of the pipeline and the heat input by the water pump, the cooling and heating system, driven by high-temperature steam, recovers the building heat of the ancillary buildings in the plant to achieve building cooling, and at the same time combines the waste heat of the circulating water of the desulfurization tower to preheat the boiler desalted water. The preheated desalted water finally enters the boiler as part of the boiler make-up water.

[0065] The specific process is as follows Figure 5As shown, valves V3, V4, V5 and V6 are open, and valves V1, V2, V7 and V8 are closed. Furthermore, the operation process of the cooling and heating system under the summer cooling condition includes user cooling cycle, waste heat recovery cycle, cooling cycle, steam cycle and boiler water supply cycle; and the cooling cycle and steam cycle under the summer cooling condition are the same as those under the winter heating condition, which will not be repeated here. Each cycle process is as follows:

[0066] The process of user cooling cycle: the high-temperature return water from the plant ancillary building 16 is transported to the evaporator 10 through the user-side circulation pump 15 as the low-temperature heat source of the absorption heat pump unit, and then sent back to the plant ancillary building 16 for user cooling after heat release and cooling.

[0067] The process of waste heat recovery cycle is similar to the winter operating conditions, but the difference is that after the intermediate medium absorbs heat in the heat exchange coil on the right side of the sewage heat exchanger 4, it is transported to the heat storage tank 14 through the intermediate medium circulation pump 5 to store heat, completing the waste heat resource recovery of the desulfurization tower circulating water.

[0068] The process of boiler water replenishment cycle: boiler desalted water enters from the upper water inlet of the hot water storage tank 14, absorbs heat and rises in temperature, and then flows out from the upper water outlet of the hot water storage tank 14, and is transported by the boiler water replenishment pump 12 to the steam boiler room 1 to replenish the boiler desalted water. The boiler water replenishment cycle realizes the preheating of the boiler desalted water and improves the desalination effect of the boiler desalted water, thereby better removing scale and salt.

[0069] In addition, when the cooling and heating system based on waste heat recovery from thermal power plants and ancillary buildings in the plant area needs to adjust the load, the mass adjustment method is adopted. The specific steps are as follows:

[0070] Under heating conditions, since the heating efficiency of the absorption heat pump unit is higher than the cooling efficiency, after selecting the absorption heat pump unit according to the cooling load of the auxiliary buildings in the factory area in summer, its heating capacity will be greater than the building heat load, and the excess heat will be used for preheating the boiler feed water. The boiler feed water flow and the user water supply flow are based on meeting the heating design flow. If the indoor load fluctuates, the user water supply flow will not be changed, and only the supply and return water temperature of the cooling water entering the absorption heat pump unit will be adjusted, so that the heating capacity of the absorption heat pump unit can meet the building heat load demand and the boiler feed water preheating demand at the same time.

[0071] Under cooling conditions, the outlet temperature of the cooling water of the absorption heat pump unit is adjusted according to the return water temperature fed back from the user's return pipe, so that the cooling capacity of the absorption heat pump unit can meet the cooling load demand of the building.

[0072] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the descriptions of the terms "low temperature" and "high temperature" are relative and cannot be understood as a specific temperature value.

[0073] The embodiments described above are only descriptions of the preferred methods of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope determined by the claims of the present invention.

Claims

1. A cooling and heating system based on waste heat recovery from thermal power plants and ancillary buildings in the plant area, characterized in that: include: Steam boiler room (1); A desulfurization tower (2), the desulfurization tower (2) being connected to the steam boiler room (1) via a flue, and being used for conveying high-temperature flue gas generated by the steam boiler room (1) into the desulfurization tower (2); A sewage heat exchanger (4), wherein the water outlet end of the desulfurization tower (2) is connected to the left heat exchange coil of the sewage heat exchanger (4), and is used to indirectly exchange the heat of the circulating water in the desulfurization tower (2) to the intermediate medium, which is then recovered by the absorption heat pump unit (7) or stored in the hot water storage tank (14); An absorption heat pump unit (7), the absorption heat pump unit (7) comprising: A generator (8), the generator (8) being connected to the steam boiler room (1) via a steam pipeline and used to drive the evaporator (10) to take heat from the low-temperature heat source and release the heat to the medium-temperature heat source; An evaporator (10), the evaporator (10) being connected to two branches, one branch being connected to the right heat exchange coil of the sewage heat exchanger (4), and the intermediate medium being used as the low-temperature heat source of the absorption heat pump unit (7) in winter; and the other branch being connected to the plant ancillary building (16), and the user return water being used as the low-temperature heat source of the absorption heat pump unit (7) in summer; absorber (11) and condenser (9); A heat storage tank (14), wherein cooling water from the left heat exchange coil of the heat storage tank (14) is sequentially transported to the absorber (11) and the condenser (9) for stepwise heating, and serves as a medium-temperature heat source for the absorption heat pump unit (7); a water outlet of the heat storage tank (14) is connected to the steam boiler room (1) via a water pipe, and is used to replenish water for the steam boiler room (1); The plant ancillary building (16); the return water from the users of the plant ancillary building (16) is divided into two branches, one branch is transported to the evaporator (10), and after releasing heat and cooling, returns to the plant ancillary building (16) for summer cooling; the other branch is transported to the right heat exchange coil of the water storage tank (14), and after absorbing heat and heating, returns to the plant ancillary building (16) for winter heating.

2. The cooling and heating system based on waste heat recovery from thermal power plants and ancillary buildings in the plant area according to claim 1 is characterized in that: It also includes a steam circulation pump (6), which is fixedly installed on the pipeline between the steam boiler room (1) and the absorption heat pump unit (7).

3. The cooling and heating system based on waste heat recovery from thermal power plants and ancillary buildings in the plant area according to claim 1 is characterized by: It also comprises a desulfurization tower circulation pump (3), and the desulfurization tower circulation pump (3) is fixedly installed on the pipeline connecting the water outlet end of the desulfurization tower (2) and the sewage heat exchanger (4).

4. The cooling and heating system based on waste heat recovery from thermal power plants and ancillary buildings in the plant area according to claim 1 is characterized in that: It also comprises an intermediate medium circulation pump (5), wherein the intermediate medium circulation pump (5) is fixedly mounted on the water outlet pipe of the sewage heat exchanger (4).

5. The cooling and heating system based on waste heat recovery from thermal power plants and ancillary buildings in the plant area according to claim 1 is characterized in that: It also includes valve V1, valve V2, valve V3, valve V4, valve V5, valve V6, valve V7 and valve V8, wherein: Under winter heating conditions, valves V1 and V2 are respectively provided on the circulation pipeline connecting the outlet end of the sewage heat exchanger (4) and the evaporator (10), and the valves V1 and V2 are arranged on different pipelines; valves V7 and V8 are respectively provided on the circulation loop formed by connecting the auxiliary building (16) of the plant area and the hot water storage tank (14), and the valves V7 and V8 are arranged on different pipelines; Under the cooling condition in summer, the outlet end of the sewage heat exchanger (4) is connected to the heat storage tank (14) to form a circulation loop, on which valves V3 and V4 are respectively provided, and the valves V3 and V4 are arranged on different pipelines. The factory ancillary building (16) is connected to the absorption heat pump unit (7) to form a circulation loop, on which valves V5 and V6 are respectively provided, and the valves V5 and V6 are arranged on different pipelines.

6. The cooling and heating system based on waste heat recovery from thermal power plants and ancillary buildings in the plant area according to claim 1 is characterized in that: It also comprises a user-side circulation pump (15), wherein the user-side circulation pump (15) is arranged on a user return water pipeline of the factory ancillary building (16).

7. The cooling and heating system based on waste heat recovery from thermal power plants and ancillary buildings in the plant area according to claim 1 is characterized in that: It also includes a boiler water supply pump (12), and the boiler water supply pump (12) is fixedly installed on the pipeline between the steam boiler room (1) and the hot water storage tank (14).

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