A system and method for improving the back pressure of an indirect air-cooling unit during summer operation

Abstract

The present invention discloses a system and method for improving the back pressure of an indirect air-cooling unit during summer operation, comprising a steam turbine unit, an air-cooling island, a power cycle unit and a refrigeration cycle unit. The exhaust steam of the unit's steam turbine is first introduced into the evaporator to release heat, and the exhaust waste heat is used to drive the composite circulation system, so as to realize the effective step-by-step utilization of the exhaust waste heat of the steam turbine and improve the overall energy utilization efficiency of the system. The steam turbine exhaust drives the power cycle, which increases the external power supply of the system and improves the power supply capacity of the system. At the same time, the exhaust steam of the steam turbine first enters the evaporator for preliminary cooling, and then enters the condenser, reducing the heat load entering the condenser. The cooling capacity produced by the composite cycle cools the circulating water at the inlet of the condenser, thereby reducing the circulating water temperature at the inlet of the condenser. When the ambient air temperature is high in summer, the heat exchange effect of the condenser can be significantly improved, the operating back pressure of the unit can be improved, the operating efficiency and safety of the steam turbine unit can be improved, and the problem of large exhaust heat loss and low operating efficiency of the indirect air-cooling unit during summer operation can be solved.

Description

Technical Field

[0001] The invention belongs to the technical field of waste heat recovery and relates to a system and method for improving the back pressure of an indirect air-cooling unit during summer operation. Background Art

[0002] In some areas, due to the relative scarcity of water resources, coal-fired units usually use air cooling to cool the exhaust steam or circulating water of the unit. Since its cooling system is a closed cycle, the water consumption is almost zero, which greatly reduces the consumption of water resources in coal-fired power plants. But at the same time, it brings about the problem of high back pressure in the design and operation of the unit, resulting in huge heat loss in the exhaust steam of the unit, affecting the operating efficiency of the unit. Especially in summer operating conditions, the operating back pressure of the unit can even reach 35~40kPa. On the one hand, the high back pressure reduces the operating efficiency of the unit, and on the other hand, it also brings greater hidden dangers to the safe operation of the unit. Summary of the invention

[0003] The purpose of the present invention is to solve the problems in the prior art and to provide a system and method for improving the back pressure of an indirect air-cooling unit during summer operation.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A system for improving the back pressure of an indirect air-cooling unit during summer operation, comprising a steam turbine unit, a condenser, a condensing unit, a first evaporator, a turbine, a heat exchange unit, a condenser, a second evaporator and an absorber;

[0006] The exhaust steam of the steam turbine unit is divided into two paths, one path enters the condenser for cooling and condensation, and the condensed water generated enters the condensed water system, and the circulating water after absorbing heat in the condenser enters the condensing unit for heat exchange; in the condensing unit, the circulating water after heat exchange is divided into two paths, one path returns to the condenser, and the other path enters the second evaporator; the other exhaust steam of the steam turbine unit enters the first evaporator, and enters the condenser after heat exchange with the working medium inside the first evaporator, and the working medium generates superheated steam after absorbing heat and enters the turbine;

[0007] The exhaust steam generated by the turbine first enters the heat exchange unit for heat exchange, and then enters the condenser for condensation from the heat exchange unit. A part of the generated condensed working fluid returns to the first evaporator, and the other part enters the second evaporator for heat exchange; in the second evaporator, the circulating water after heat exchange returns to the condenser, and the working fluid vapor generated by the heat exchange of the condensed working fluid enters the absorber, and the solution in the absorber absorbs the working fluid vapor and then enters the heat exchange unit for heat exchange; in the heat exchange unit, the solution after heat exchange returns to the absorber, and the working fluid vapor precipitated by the solution through heat exchange enters the condenser for condensation.

[0008] A further improvement of the present invention is:

[0009] The heat exchange unit includes a generator and a solution heat exchanger;

[0010] The exhaust steam generated by the turbine enters the generator and the solution heat exchanger in sequence for heat exchange, and then enters the condenser for condensation;

[0011] The solution in the absorber enters the solution heat exchanger and the generator in turn for heat exchange. In the generator, the solution after heat exchange returns to the absorber through the solution heat exchanger, and the working fluid steam precipitated by the solution heat exchange enters the condenser through the solution heat exchanger.

[0012] A working medium pump is arranged between the condensed working medium outlet of the condenser and the condensed working medium inlet of the first evaporator; and a first throttle valve is arranged between the condensed working medium outlet of the condenser and the condensed working medium inlet of the second evaporator.

[0013] A solution pump is arranged between the solution outlet of the absorber and the solution inlet of the solution heat exchanger.

[0014] A second throttle valve is arranged between the solution outlet of the solution heat exchanger and the solution inlet of the absorber.

[0015] A first valve is arranged between the exhaust outlet of the steam turbine unit and the steam inlet of the first evaporator, a second valve is arranged between the exhaust outlet of the first evaporator and the steam inlet of the condenser, and a third valve is arranged between the exhaust outlet of the steam turbine unit and the steam inlet of the condenser.

[0016] A circulating water pump is provided between the circulating water outlet of the condenser and the circulating water inlet of the condensing unit, and a sixth valve is provided between the circulating water outlet of the condensing unit and the circulating water inlet of the condenser.

[0017] A fourth valve is provided between the circulating water outlet of the second evaporator and the circulating water inlet of the condensing unit; and a fifth valve is provided between the circulating water inlet of the second evaporator and the circulating water outlet of the condensing unit.

[0018] A compressor is arranged between the outlet of the exothermic working medium steam of the second evaporator and the inlet of the working medium steam of the absorber.

[0019] A method for improving the back pressure of an indirect air-cooling unit during summer operation comprises the following steps:

[0020] The exhaust steam of the steam turbine unit is transported to the condenser, cooled and condensed by the circulating water in the condenser, and the generated condensed water is transported to the condensed water system. The circulating water after absorbing heat is transported to the condensing unit to exchange heat with the air. The circulating water after heat exchange is transported to the condenser in one way and to the second evaporator in the other way;

[0021] The exhaust steam from the steam turbine unit is transported to the first evaporator to exchange heat with the working medium in the first evaporator, and the steam cooled by heat exchange is transported to the condenser. The superheated steam generated by the working medium absorbing the heat of the steam is transported to the turbine, where it expands and does work to drive the generator to generate electricity;

[0022] The exhaust steam generated by the turbine is successively transported to the generator and the solution heat exchanger to release heat and then transported to the condenser for condensation. Part of the generated condensed working fluid is transported to the first evaporator to complete the power cycle, and the other part is transported to the second evaporator.

[0023] The circulating water after heat exchange in the second evaporator is transported to the condenser, and the working fluid steam generated by the heat exchange of the condensed working fluid is transported to the absorber. The solution after absorbing the hot steam in the absorber is transported to the solution heat exchanger and the generator in turn for heat exchange. The solution absorbs the exhaust steam heat generated by the turbine in the generator and then heats up. The heated solution flows to the absorber through the solution heat exchanger. The working fluid steam precipitated by the solution heating up is transported to the condenser through the solution heat exchanger to release heat and condense, thereby realizing a refrigeration cycle.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention discloses a system for improving the back pressure of an indirect air-cooling unit during summer operation, comprising a steam turbine unit, a condenser, a condensing unit, a first evaporator, a turbine, a heat exchange unit, a condenser, a second evaporator and an absorber. The exhaust steam of the steam turbine unit is divided into two paths, one of which enters the condenser for cooling and condensation to generate condensed water which enters the condensed water system, and the circulating water after absorbing heat enters the condensing unit for heat exchange; in the condensing unit, the circulating water after heat exchange is divided into two paths, one of which returns to the condenser and the other enters the second evaporator; the other exhaust steam of the steam turbine unit enters the first evaporator and is mixed with the working medium inside the first evaporator. Heat exchange, the steam after heat exchange enters the condenser, and the working fluid steam enters the turbine; the exhaust steam generated by the turbine first enters the heat exchange unit for heat exchange, and then enters the condenser from the heat exchange unit for condensation. Part of the condensed working fluid generated returns to the first evaporator, and the other part enters the second evaporator for heat exchange; in the second evaporator, the circulating water after heat exchange returns to the condenser, and the working fluid steam generated by the heat exchange of the condensed working fluid enters the absorber. The solution in the absorber absorbs the working fluid steam and then enters the heat exchange unit for heat exchange; in the heat exchange unit, the solution after heat exchange returns to the absorber, and the steam precipitated by heat exchange enters the condenser for condensation. The exhaust steam of the turbine of the unit first enters the first evaporator to release heat, and the exhaust waste heat is used to drive the composite cycle system, realizing the effective cascade utilization of the exhaust waste heat of the turbine, and improving the overall energy utilization efficiency of the system. The turbine exhaust drives the power cycle, increasing the external power supply of the system and improving the power supply capacity of the system. At the same time, the turbine exhaust first enters the first evaporator for preliminary cooling, and then enters the condenser, reducing the heat load entering the condenser. The cold produced by the combined cycle cools the circulating water at the condenser inlet, reducing the circulating water temperature at the condenser inlet. In summer when the ambient air temperature is high, it can significantly improve the heat exchange effect of the condenser, improve the operating back pressure of the unit, and improve the operating efficiency and safety of the steam turbine unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 It is a schematic diagram of the system structure of the present invention.

[0028] Among them: 1-steam turbine unit, 2-condenser, 3-air cooling tower, 4-circulating water pump, 5-first evaporator, 6-turbine, 7-generator, 8-solution heat exchanger, 9-condenser, 10-working fluid pump, 11-first throttle valve, 12-second evaporator, 13-compressor, 14-absorber, 15-solution pump, 16-second throttle valve, 17-first valve, 18-second valve, 19-third valve, 20-fourth valve, 21-fifth valve, 22-sixth valve. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0032] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply 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 terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0033] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0034] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] Among low-temperature waste heat utilization technologies, the organic Rankine cycle (ORC) technology is favored due to its advantages such as simple structure, strong stability, high power generation efficiency and low sealing requirements. The ORC system is a Rankine cycle that uses low-boiling point organic matter such as halogenated hydrocarbons or hydrocarbons as a working fluid. It can effectively utilize a variety of low-grade thermal energy and has broad application prospects in the field of low-temperature waste heat utilization.

[0036] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0037] See also Figure 1 The embodiment of the present invention discloses a system for improving the back pressure of an indirect air-cooling unit in summer operation, comprising a steam turbine unit 1, a condenser 2, a condensing unit, a first evaporator 5, a turbine 6, a heat exchange unit, a condenser 9, a second evaporator 12 and an absorber 14; the exhaust steam of the steam turbine unit 1 is divided into two paths, one path enters the condenser 2 for cooling and condensation to generate condensed water which enters the condensed water system, and the circulating water after absorbing heat in the condenser 2 enters the condensing unit for heat exchange; in the condensing unit, the circulating water after heat exchange is divided into two paths, one path returns to the condenser 2, and the other path enters the second evaporator 12; the other path of the exhaust steam of the steam turbine unit 1 enters the first evaporator 5, exchanges heat with the working medium inside the first evaporator 5, and enters the condenser 2, and the working medium absorbs heat to generate superheated steam which enters the turbine 6;

[0038] The exhaust steam generated by the turbine 6 first enters the heat exchange unit for heat exchange, and then enters the condenser 9 from the heat exchange unit for condensation. A part of the generated condensed working fluid returns to the first evaporator 5, and the other part enters the second evaporator 12 for heat exchange; in the second evaporator 12, the condensed water after heat exchange returns to the condenser 2, and the working fluid steam generated by the heat exchange of the condensed working fluid enters the absorber 14. The solution in the absorber 14 absorbs the working fluid steam and then enters the heat exchange unit for heat exchange; in the heat exchange unit, the solution after heat exchange returns to the absorber 14, and the steam precipitated by heat exchange enters the condenser 9 for condensation.

[0039] The heat exchange unit includes a generator 7 and a solution heat exchanger 8; the exhaust steam generated by the turbine 6 enters the generator 7 and the solution heat exchanger 8 in turn for heat exchange, and then enters the condenser 9 for condensation; the solution in the absorber 14 enters the solution heat exchanger 8 and the generator 7 in turn for heat exchange, in the generator 7, the solution after heat exchange returns to the absorber 14 through the solution heat exchanger 8, and the working fluid steam precipitated by the solution heat exchange enters the condenser 9. A solution pump 15 is provided between the solution outlet of the absorber 14 and the solution inlet of the solution heat exchanger 8. A second throttle valve 16 is provided between the solution outlet of the solution heat exchanger 8 and the solution inlet of the absorber 14. A first valve 17 is provided between the exhaust outlet of the steam turbine unit 1 and the steam inlet of the first evaporator 5, a second valve 18 is provided between the exhaust outlet of the first evaporator 5 and the steam inlet of the condenser 2, and a third valve 19 is provided between the exhaust outlet of the steam turbine unit 1 and the steam inlet of the condenser 2. A circulating water pump 4 is provided between the exhaust outlet of the condenser 2 and the steam inlet of the condensing unit, and a sixth valve 22 is provided between the circulating water outlet of the condensing unit and the circulating water inlet of the condenser 2. A working medium pump 10 is provided between the condensing working medium outlet of the condenser 9 and the condensing working medium inlet of the first evaporator 5; a first throttle valve 11 is provided between the condensing working medium outlet of the condenser 9 and the condensing working medium inlet of the second evaporator 12. A fifth valve 21 is provided between the circulating water inlet of the second evaporator 12 and the circulating water outlet of the condensing unit. A compressor 13 is provided between the working medium steam outlet of the second evaporator and the working medium steam inlet of the absorber 14. A fourth valve 20 is provided between the circulating water outlet of the second evaporator 12 and the circulating water inlet of the condenser 2. The condensing unit includes an air-cooling island 3.

[0040] The present invention also discloses a method for improving the back pressure of an indirect air cooling unit during summer operation, which specifically comprises the following steps:

[0041] The exhaust port of steam turbine unit 1 is connected to the inlet of condenser 2. The exhaust steam entering condenser 2 is cooled by circulating water and condensed before entering the unit condensate system. The circulating water, which has been heated by absorbing the heat of the exhaust steam, is pressurized by circulating water pump 4 and enters air cooling tower 3, where it exchanges heat with ambient air and cools down, and then returns to condenser 2.

[0042] The exhaust port of the steam turbine unit 1 is connected to the inlet of the first evaporator 5 . The exhaust steam entering the first evaporator 5 first transfers part of its heat to the organic working medium in the first evaporator 5 for preliminary cooling, and then enters the condenser 2 .

[0043] The first evaporator 5, turbine 6, generator 7, solution heat exchanger 8, condenser 9, and working fluid pump 10 constitute a power circulation unit. The specific working steps of the power circulation unit are:

[0044] The organic working fluid absorbs the exhaust heat of the steam turbine unit 1 in the first evaporator 5 to become superheated steam, and then enters the turbine 6 to expand and do work to drive the generator to generate electricity. The exhaust steam of turbine 6 enters the generator 7 and the solution heat exchanger 8 in turn to release heat, and then enters the condenser 9 to condense. The partially condensed working fluid at the outlet of the condenser 9 is pressurized by the working fluid pump 10 and then returned to the first evaporator 5.

[0045] The generator 7, the solution heat exchanger 8, the condenser 9, the first throttle valve 11, the evaporator 12, the compressor 13, the absorber 14, the solution pump 15 and the second throttle valve 16 constitute a refrigeration cycle unit. The specific working steps of the refrigeration cycle unit are as follows:

[0046] The dilute solution at the outlet of the absorber 14 is pressurized by the solution pump 15 and then enters the solution heat exchanger 8, where it exchanges heat with the concentrated solution and working fluid steam from the generator 7 to initially increase its temperature, and then enters the generator 7 to absorb the waste heat of the exhaust steam from the turbine 6 to further increase its temperature, causing the working fluid steam to precipitate and transform into a concentrated solution. The concentrated solution returns to the solution heat exchanger 8 to release heat, and then is throttled by the second throttle valve 16 and then returns to the absorber 14. The precipitated working fluid steam enters the condenser 9 to release heat and condense, and then is throttled by the first throttle valve 11 and enters the evaporator 12 to absorb heat and turn into steam again, and then is pressurized by the compressor 13 and returns to the absorber 14 to be absorbed by the solution.

[0047] The working fluid vapor separated out from the generator 7 is first introduced into the solution heat exchanger 8 for preliminary cooling, and then enters the condenser 9 for condensation, thereby reducing the heat load of the condenser 9.

[0048] The circulating water, after being cooled by heat exchange with the ambient air, enters the evaporator 12 , exchanges heat with the working medium to cool down, and then enters the condenser 2 .

[0049] The power cycle and refrigeration cycle use the same organic working fluid.

[0050] Preferably, R1234ze and R1234yf are recommended as the organic working fluid, and ionic liquid [HMIM][Tf2N] is recommended as the absorbent solution.

[0051] When the ambient temperature is high in summer and the back pressure of the unit is poor, open the first valve 17, the second valve 18, the fourth valve 20, and the fifth valve 21, and close the third valve 19 and the sixth valve 22. The exhaust steam of the steam turbine unit 1 first enters the first evaporator 5 for preliminary cooling, and then enters the condenser 2 to be cooled and condensed by the circulating water, reducing the heat load entering the condenser. At the same time, the circulating water at the outlet of the air cooling tower 3 first enters the evaporator 12 for cooling, and then enters the condenser 2 for heat exchange, which reduces the temperature of the circulating water at the inlet of the condenser 2 and improves the heat exchange effect of the condenser 2.

[0052] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A system for improving the back pressure of an indirect air-cooling unit during summer operation, characterized in that: It comprises a steam turbine unit (1), a condenser (2), a condensing unit, a first evaporator (5), a turbine (6), a heat exchange unit, a condenser (9), a second evaporator (12) and an absorber (14); The exhaust steam of the steam turbine unit (1) is divided into two paths, one path enters the condenser (2) for cooling and condensation, and the condensate generated after condensation enters the condensate system, and the circulating water after absorbing heat in the condenser (2) enters the condensing unit for heat exchange; in the condensing unit, the circulating water after heat exchange is divided into two paths, one path returns to the condenser (2), and the other path enters the second evaporator (12); the other path of the exhaust steam of the steam turbine unit (1) enters the first evaporator (5), exchanges heat with the working medium inside the first evaporator (5), and enters the condenser (2), and the working medium absorbs heat to generate superheated steam and enters the turbine (6); The exhaust steam generated by the turbine (6) first enters the heat exchange unit for heat exchange, and then enters the condenser (9) from the heat exchange unit for condensation. A portion of the generated condensed working fluid returns to the first evaporator (5), and the other portion enters the second evaporator (12) for heat exchange. In the second evaporator (12), the circulating water after heat exchange returns to the condenser (2), and the working fluid steam generated by the heat exchange of the condensed working fluid enters the absorber (14). The solution in the absorber (14) absorbs the working fluid steam and then enters the heat exchange unit for heat exchange. In the heat exchange unit, the solution after heat exchange returns to the absorber (14), and the working fluid steam precipitated by the solution during heat exchange enters the condenser (9) for condensation. The heat exchange unit comprises a generator (7) and a solution heat exchanger (8); a working fluid pump (10) is provided between the condensed working fluid outlet of the condenser (9) and the condensed working fluid inlet of the first evaporator (5); and a solution pump (15) is provided between the solution outlet of the absorber (14) and the solution inlet of the solution heat exchanger (8).

2. A system for improving the back pressure of an indirect air-cooling unit during summer operation according to claim 1, characterized in that: The exhaust steam generated by the turbine (6) enters the generator (7) and the solution heat exchanger (8) in sequence for heat exchange, and then enters the condenser (9) for condensation; The solution in the absorber (14) sequentially enters the solution heat exchanger (8) and the generator (7) for heat exchange. In the generator (7), the solution after heat exchange returns to the absorber (14) through the solution heat exchanger (8), and the working fluid vapor precipitated by the solution heat exchange enters the condenser (9) through the solution heat exchanger (8).

3. A system for improving the back pressure of an indirect air-cooling unit during summer operation according to claim 2, characterized in that: A first throttle valve (11) is provided between the condensed working medium outlet of the condenser (9) and the condensed working medium inlet of the second evaporator (12).

4. A system for improving the back pressure of an indirect air-cooling unit during summer operation according to claim 1, characterized in that: A second throttle valve (16) is provided between the solution outlet of the solution heat exchanger (8) and the solution inlet of the absorber (14).

5. A system for improving the back pressure of an indirect air-cooling unit during summer operation according to claim 4, characterized in that: A first valve (17) is provided between the exhaust outlet of the steam turbine unit (1) and the steam inlet of the first evaporator (5), a second valve (18) is provided between the exhaust outlet of the first evaporator (5) and the steam inlet of the condenser (2), and a third valve (19) is provided between the exhaust outlet of the steam turbine unit (1) and the steam inlet of the condenser (2).

6. A system for improving the back pressure of an indirect air-cooling unit during summer operation according to claim 4, characterized in that: A circulating water pump (4) is provided between the circulating water outlet of the condenser (2) and the circulating water inlet of the condensing unit, and a sixth valve (22) is provided between the circulating water outlet of the condensing unit and the circulating water inlet of the condenser (2).

7. A system for improving the back pressure of an indirect air-cooling unit during summer operation according to claim 6, characterized in that: A fourth valve (20) is provided between the circulating water outlet of the second evaporator (12) and the circulating water inlet of the condensing unit; and a fifth valve (21) is provided between the circulating water inlet of the second evaporator (12) and the circulating water outlet of the condensing unit.

8. A system for improving the back pressure of an indirect air-cooling unit during summer operation according to any one of claims 1 to 7, characterized in that: A compressor (13) is provided between the heat releasing working medium vapor outlet of the second evaporator (12) and the working medium vapor inlet of the absorber (14).

9. A method for improving the back pressure of an indirect air-cooling unit during summer operation according to the system of claim 2, characterized in that: The following steps are involved: The exhaust steam of the steam turbine unit (1) is transported to the condenser (2) through one path, and is cooled and condensed by the circulating water in the condenser (2). The generated condensed water is transported to the condensed water system. The circulating water after absorbing heat is transported to the condensing unit to exchange heat with air. The circulating water after heat exchange is transported to the condenser (2) through another path, and is transported to the second evaporator (12) through another path. The exhaust steam from the steam turbine unit (1) is transported to the first evaporator (5) to exchange heat with the working medium in the first evaporator (5), and the steam cooled by heat exchange is transported to the condenser (2). The superheated steam generated by the working medium absorbing the heat of the steam is transported to the turbine (6), and expands in the turbine (6) to generate work and drive the generator to generate electricity; The exhaust steam generated by the turbine (6) is sequentially transported to the generator (7) and the solution heat exchanger (8) to release heat and then transported to the condenser (9) for condensation. A portion of the generated condensed working fluid is transported to the first evaporator (5) to complete the power cycle, and the other portion is transported to the second evaporator (12). The circulating water after heat exchange in the second evaporator (12) is transported to the condenser (2), and the working fluid steam generated by the heat exchange of the condensed working fluid is transported to the absorber (14). The solution after absorbing the hot steam in the absorber (14) is transported to the solution heat exchanger (8) and the generator (7) in sequence for heat exchange. The solution absorbs the exhaust steam heat generated by the turbine (6) in the generator (7) and is heated. The heated solution flows to the absorber (14) through the solution heat exchanger (8). The working fluid steam precipitated by the heated solution is transported to the condenser (9) through the solution heat exchanger (8) to release heat and condense, thereby realizing a refrigeration cycle.

Images