A system and method for realizing zero-power grid connection of a combined heat and power unit by electric heat storage

Abstract

A system for realizing zero-power grid connection of a combined heat and power unit by electric heat storage, comprising a boiler-turbine unit, an electric heat storage unit, a heat supply output unit, a bypass regulation unit, and a heat supply external grid; the bypass regulation unit is arranged between a main steam pipeline and a cold end of a boiler reheater, and is used for regulating the amount of steam input to the turbine; the electric heat storage unit is connected to a power system of a plant, and stores energy by electric heating of a heat storage medium; the heat supply output unit is connected to the boiler-turbine unit and the electric heat storage unit, and is also connected to the heat supply external grid; heat energy is obtained from the boiler-turbine unit and the electric heat storage unit, and is used for heating a heat medium in the heat supply external grid; the system further improves the peak shaving depth of a coal-fired power unit, improves the new energy consumption capacity, and improves the overall income of a coal-fired power enterprise.

Description

Technical Field

[0001] This invention belongs to the field of flexible peak shaving in thermal power plants. It can meet the large-scale and long-term peak shaving needs of the power grid and can be used for all reheat units. It is not limited by heating / non-heating conditions and meets the requirements of new power systems. Specifically, it relates to a system and method for realizing zero-power grid connection of cogeneration units through electric thermal storage. Background Technology

[0002] Upgrading and retrofitting coal-fired power units is an important means to improve the efficiency of coal utilization, reduce coal consumption, and promote the consumption of clean energy. As of the end of 2020, the national installed power generation capacity was 2.2 billion kilowatts, with thermal power accounting for 57% of the installed capacity but generating 68% of the electricity, remaining the mainstay of my country's power supply. In recent years, my country's wind and solar power generation has developed rapidly, with installed capacity increasing year by year, leading to increasingly prominent consumption issues. Wind and solar curtailment has caused significant energy waste and economic losses. To reduce the proportion of wind and solar curtailment while ensuring the stability and security of the power grid, coal-fired power units are gradually shifting from being the main source of electricity to a fundamental source of reliable power and peak-shaving / frequency regulation capabilities. Therefore, higher requirements are placed on the flexible operation of coal-fired power units.

[0003] To encourage thermal power units to participate in regional deep peak shaving, many regions provide certain electricity price compensation to participating units. As the depth of peak shaving increases, the subsidy policies provided by the power grid become more favorable. Therefore, it is necessary to further increase the peak shaving depth of coal-fired power units, improve the capacity for renewable energy absorption, and simultaneously increase the overall profitability of coal-fired power companies. Summary of the Invention

[0004] The purpose of this invention is to maximize the peak-shaving depth that can achieve zero-power grid connection, and to propose a system and method for achieving zero-power grid connection of combined heat and power (CHP) units through electric thermal energy storage. This system has a wide range of applications, requires minimal retrofitting, offers a high return on investment, and boasts high operational reliability, making it suitable for further promotion.

[0005] A system for achieving zero-power grid connection of a combined heat and power (CHP) unit through electric thermal energy storage includes a boiler turbine unit, an electric thermal energy storage unit, a heat output unit, a bypass regulation unit, and an external heating network; characterized in that... The bypass regulating unit is located between the main steam pipeline and the cold end of the boiler reheater, and is used to regulate the amount of steam input to the steam turbine. The electric thermal energy storage unit is connected to the plant's power system and stores energy by electrically heating the thermal storage medium. The heating output unit pipeline connects to the boiler turbine unit and the electric thermal energy storage unit, and also connects to the external heating network; Thermal energy is obtained from the boiler turbine unit and the electric thermal energy storage unit to heat the heat medium in the external heating network.

[0006] A method for achieving zero-power grid connection of a combined heat and power (CHP) unit through electric thermal energy storage, characterized in that: The combined heat and power unit is undergoing deep-adjustment operation. 1-1. When the cogeneration unit is operating under deep adjustment, if the depth of deep adjustment is limited, start the heat output unit and adjust the power generation load through the bypass adjustment unit. 1-2. When the peak shaving depth of the cogeneration unit is further increased, the adjustment through the bypass regulation unit can no longer meet the peak shaving depth requirements. The electric thermal energy storage unit is started to store energy. The heat release of the electric heater is adjusted according to the demand of the deep load, and all the grid-connected electricity is absorbed to achieve zero output operation of the unit. When the deep adjustment is completed and the unit load increases, the bypass unit is taken out of operation; 2-1. When the heat dissipation of the electric thermal energy storage unit can meet the user's needs, the heat output unit obtains thermal energy from the electric thermal energy storage unit to heat the heat medium in the external heating network. 2-2. When the heat dissipation of the electric thermal energy storage unit cannot meet the user's needs, the heat output unit draws air from the steam turbine system to supplement some heat for heating the heat medium in the external heating network. 2-3. When the electric thermal energy storage unit exceeds the user's demand, a portion of the heat from the electric thermal energy storage unit is sent to the turbine condensate system; 2-4. When there is no demand for heat from users, all the heat stored in the electric thermal energy storage unit is sent to the turbine condensate system.

[0007] The beneficial effects of this invention are: Compared with existing technologies, this invention designs a system and method for achieving zero-power grid connection of cogeneration units through electric thermal energy storage. By setting up equipment such as electrode boilers and related piping systems, it further enhances the peak-shaving depth of coal-fired power units, improves the capacity for renewable energy absorption, and simultaneously increases the overall profitability of coal-fired power enterprises. Furthermore, this system has a wide range of applications, enabling the parallel operation of multiple units, significantly reducing the scope of retrofitting and saving on retrofitting costs. This invention has a small retrofitting scope, low investment cost, and high operational reliability, making it suitable for further promotion and application. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the system connections.

[0009] In the diagram: 1. Boiler turbine unit; 2. Plant power supply system; 3. Electric heater; 4. Hot water storage tank; 5. Heat user. Detailed Implementation

[0010] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0011] A system for achieving zero-power grid connection of a combined heat and power (CHP) unit through electric thermal energy storage includes a boiler turbine unit, an electric thermal energy storage unit, a heat output unit, a bypass regulation unit, and an external heating network; characterized in that... The bypass regulating unit is located between the main steam pipeline and the cold end of the boiler reheater, and is used to regulate the amount of steam input to the steam turbine. The electric thermal energy storage unit is connected to the plant's power system and stores energy by electrically heating the thermal storage medium. The heating output unit pipeline connects to the boiler turbine unit and the electric thermal energy storage unit, and also connects to the external heating network; Thermal energy is obtained from the boiler turbine unit and the electric thermal energy storage unit to heat the heat medium in the external heating network.

[0012] Example: Taking a certain generating unit as an example. The system diagram is as follows: Figure 1 As shown: The system includes a boiler turbine unit 1, an electric thermal energy storage unit, a peak operation compensation unit, a heat output unit, and a bypass regulation unit.

[0013] The boiler-turbine unit includes a boiler, a high-pressure cylinder, an intermediate-pressure cylinder, and a low-pressure cylinder. The main steam pipe from the boiler connects to the high-pressure cylinder, and the high-pressure cylinder exhaust pipe connects to the cold end inlet of the boiler reheater. Reheat steam from the hot end outlet of the boiler reheater connects to the intermediate-pressure cylinder, and the intermediate-pressure cylinder exhaust connects to the low-pressure cylinder. The low-pressure cylinder exhaust connects to the turbine condenser.

[0014] The bypass regulating unit includes a high-pressure bypass and a desuperheater. The high-pressure bypass is located between the main steam pipeline and the high-pressure cylinder exhaust pipeline, and the desuperheater is connected to the boiler feedwater system. The high-pressure bypass is also equipped with electrically operated isolation valves (101, 103) and an electrically operated regulating valve (102). The electrically operated isolation valves (101, 103) are used to open or close the high-pressure bypass, and the electrically operated regulating valve (102) is used to regulate the main steam flow in the high-pressure bypass. When the electrically operated isolation valves (101, 103) are opened, the main steam flows through the desuperheater, and after being de-heated and depressurized by the introduced boiler feedwater, it re-enters the high-pressure cylinder exhaust pipeline.

[0015] The electric thermal energy storage unit includes an electric heater and a hot water storage tank. The electric heater and the hot water storage tank are connected by a heating circuit, which is equipped with heating control valves (401 and 402) and a cold water pump (403).

[0016] The electric heater (3) is used to heat the heat storage medium in the hot water storage tank. The heat storage medium is water, but other suitable media can also be used.

[0017] The electric heater (3) is powered by the plant's internal power supply system. The output line of the high-voltage transformer of the thermal power unit is connected to the thermal storage transformer (12), and the output line of the thermal storage transformer (12) is connected to the electric heater.

[0018] High-voltage disconnect switches (11, 13) are added to the inlet and outlet lines of the thermal storage transformer (12) respectively, for the connection or disconnection of the thermal storage transformer (12).

[0019] The hot water storage tank is also equipped with an external heating circuit, which is equipped with heating control valves (405 and 406) and a cold water pump (404).

[0020] During the heating process: start the cold water pump (403), open valves (401 and 402), close valves (405 and 406), and stop the hot water pump (404).

[0021] During the heating process: start the hot water pump (404), open valves (405 and 406), close valves (401 and 402), and stop the cold water pump (403).

[0022] The heating circuit has two parallel outlet water lines. One line is connected to the hot water side of the first heat exchanger (61) to heat the turbine condensate. Valves (614, 615) are installed on the hot water side pipeline. The first heat exchanger (61) is a water-to-water heat exchanger. The cold water side of the first heat exchanger (61) is connected to the turbine low-pressure heater system. Two bypass lines are led out on the outlet water pipeline of the No. 2 low-pressure heater of the turbine low-pressure heater system. The bypass lines are connected to the cold water side of the first heat exchanger (61). Electric gate valves (612 and 613) are installed on the bypass lines for the activation or deactivation of the first heat exchanger (61). A regulating valve (611) is installed on the condensate pipeline between the two bypass lines. The outlet water of the No. 2 low-pressure heater is divided into two lines. One line flows into the downstream low-pressure heater, and the other line returns to the turbine low-pressure heater system after being heated by the first heat exchanger (61). The flow distribution ratio of the two lines can be adjusted and controlled by the regulating valve (611).

[0023] The first heat exchanger (61) serves as a peak operation compensation unit.

[0024] The outlet of the heating circuit is connected to the hot water side of the third heat exchanger (63) to heat the circulating water of the heating network. Valves (407, 408) are installed on the hot water side pipeline. The third heat exchanger (63) is a water-to-water heat exchanger. The cold water side of the third heat exchanger (63) is connected to the circulating water of the heating network. Valves (503, 504) are installed on the cold water side pipeline.

[0025] The system also includes a second heat exchanger, which is a steam-water heat exchanger. A heating pipeline is led out from the exhaust pipe of the intermediate pressure cylinder of the steam turbine. The heating pipeline is connected to the steam side of the second heat exchanger (62), and the water side of the second heat exchanger (62) is connected to the circulating water of the heating network. A heating butterfly valve (621) is installed on the heating pipeline.

[0026] When the heating butterfly valve (621) is opened, some of the steam from the intermediate-pressure cylinder enters the steam side of the second heat exchanger (62) to heat the circulating water of the heating network. The steam from the intermediate-pressure cylinder after releasing heat in the steam side of the second heat exchanger (62) generates condensate, which enters the turbine condenser through a pipeline. The condensate pipeline of the second heat exchanger (62) is equipped with a condensate pump (622) and a valve (623).

[0027] The second heat exchanger (62) and the third heat exchanger (63) are both connected to the same heating network. The circulating water of the heating network is heated by the second heat exchanger (62) and the third heat exchanger (63) and then supplied to the heat users.

[0028] The second heat exchanger (62) and the third heat exchanger (63) together constitute the heat output unit.

[0029] The second heat exchanger (62) serves as the main heat output unit, and the third heat exchanger (63) serves as the auxiliary heat output unit.

[0030] The above-described system enables cogeneration units to connect to the grid with zero power. The system's operation includes the following steps: 1. Deep adjustment operation condition of cogeneration unit.

[0031] 1-1. When a combined heat and power (CHP) unit is operating under deep adjustment, if the depth of deep adjustment is limited, start the heat output unit and adjust the load through the bypass unit.

[0032] At this time, the heating load remains stable, and only the second heat exchanger of the main heating output unit is activated.

[0033] Open valves (621, 623), start the heat network drain pump (622), and keep the heat network circulating water system running. Start the heat network circulating water pump (505), open valves (501, 502, 506, 507), and close the valves of the rest of the system.

[0034] At this time, the system's peak shaving depth is limited, which can meet the conditions for stable boiler combustion. By opening the high-pressure bypass, that is, opening valves (101, 102, 103), the unit's power output is reduced. By adjusting the opening degree of valve (102), the high bypass flow rate is controlled to adjust the load to meet the deep shaving requirements.

[0035] 1-2. When the peak shaving depth of the cogeneration unit is further increased, the peak shaving depth requirement can no longer be met by adjusting the high-voltage bypass unit alone. The electric thermal energy storage unit is then activated for energy storage.

[0036] After reducing the unit load as much as possible through high-speed bypass, the system has now entered the deep-load lower limit.

[0037] The heating load remains stable and the heat supply to external heat users does not change: valves (621, 623) are opened and the heat network drain pump (622) is started; The heating network circulating water system is kept running. The heating network circulating water pump (505) is started, and the valves (501, 502, 506, 507) are opened. When the system is operating at its peak, the high-pressure bypass is opened, i.e., valves (101, 102, 103) are opened. At this time, in order to further reduce the electrical load, it is necessary to start the electric thermal energy storage unit, start the cold water pump (403), open the cold water supply valve (402) and return water valve (401), close the high-pressure side switch (11) and high-pressure side switch (13), and after the cold water is heated by the electric heater (13), the high-temperature water enters the hot water storage tank (4) for storage.

[0038] The system can adjust the heat output of the electric heater according to the demand of the deep-load load, and theoretically can absorb all the grid-connected electricity, so as to achieve zero-output operation of the unit.

[0039] 2. After the deep adjustment is completed, when the unit load increases, the bypass unit will be taken out of operation.

[0040] The operating modes can be divided into the following types: 2-1. When the heat dissipation of the electric thermal energy storage unit can meet the user's needs, the main heating output unit shuts down and the auxiliary heating output unit starts operating.

[0041] At this point, the bypass unit is shut down, meaning valves (101, 102, 103) are closed; The second heat exchanger (62) is shut off, valves (621, 623) are closed, and the heat network drain pump (622) is shut off. The heating network circulating water system is kept running. The heating network circulating water pump (505) is started, and the valves (501, 502, 506, 507) are opened. When the thermal storage process is shut down, turn off the chilled water pump (403) of the thermal storage system, close the chilled water supply valve (402) and the return water valve (401), and open the high-pressure side switch (11) and the high-pressure side switch (13). Heat is supplied to the heating network circulating water system by the electric heating energy storage unit. At this time, the hot water pump (404) starts, valves (405) and (406) open, valves (407) and (408) open, and valves (614) and (615) close. The high-temperature hot water in the hot water storage tank flows through the third heat exchanger (63) of the auxiliary heating output unit to heat the heating network circulating water and supply heat to the user (5).

[0042] 2-2. When the heat dissipation of the electric thermal energy storage unit cannot meet the user's needs, it is necessary to use the main heating output unit to supplement some heat. At this point, the high-voltage bypass system shuts down, meaning valves (101, 102, 103) are closed; The second heat exchanger (62) of the main heat output unit is put into operation: valves (621, 623) are opened, the heat network drain pump (622) is started, and the heat supply is controlled by adjusting the opening of valve (612) to ensure that all the heat stored in the electric heat storage unit is consumed. The heating network circulating water system is kept running. The heating network circulating water pump (505) is started, and the valves (501, 502, 506, 507) are opened. When the thermal storage process is shut down, turn off the chilled water pump (403) of the thermal storage system, close the chilled water supply valve (402) and the return water valve (401), and open the high-pressure side switch (11) and the high-pressure side switch (13). Heat is supplied to the heating network circulating water system by the electric heating energy storage unit. At this time, the hot water pump (404) starts, valves (405) and (406) open, valves (407) and (408) open, and valves (614) and (615) close. The high-temperature hot water in the hot water storage tank flows through the third heat exchanger (63) of the auxiliary heating output unit to heat the heating network circulating water and supply heat to the user (5).

[0043] 2-3. When the electric thermal energy storage unit exceeds user demand, some heat needs to be sent to the turbine condensate system. The peak operation compensation unit is then activated.

[0044] At this point, the high-voltage bypass system shuts down, meaning valves (101, 102, 103) are closed; The second heat exchanger (62) of the main heating output unit is shut off: valves (621, 623) are closed, and the heat network drain pump (622) is shut off; The heating network circulating water system is kept running. The heating network circulating water pump (505) is started, and the valves (501, 502, 506, 507) are opened. When the thermal storage process is shut down, turn off the chilled water pump (403) of the thermal storage system, close the chilled water supply valve (402) and the return water valve (401), and open the high-pressure side switch (11) and the high-pressure side switch (13). Heat is supplied to the heating network circulating water system by the electric heating energy storage unit. At this time, the hot water pump (404) starts, valves (405) and (406) open, valves (407) and (408) open, and the high-temperature hot water in the hot water storage tank flows through the third heat exchanger (63) of the auxiliary heating output unit to heat the heating network circulating water and supply heat to the user (5).

[0045] Simultaneously, valves (614) and (615) are opened, allowing a portion of the hot water to enter the first heat exchanger (61) of the peak operation compensation unit. The condensate bypass system is activated, and valves (613) and (612) are opened. The amount of heat entering the first heat exchanger (61) is controlled by adjusting the opening degree of valve (611). The stored heat exceeding the heat user's demand is input into the condensate for peak operation compensation.

[0046] 2-4. When there is no demand from heat users, all the stored heat is sent to the turbine condensate system.

[0047] At this point, the high-voltage bypass system shuts down, meaning valves (101, 102, 103) are closed; The second heat exchanger (62) of the main heating output unit is shut off: valves (621, 623) are closed, and the heat network drain pump (622) is shut off; The heating network circulating water system remains operational, but the heating network circulating water pump (505) is shut down, and valves (501, 502, 506, 507) are closed. When the thermal storage process is shut down, turn off the chilled water pump (403) of the thermal storage system, close the chilled water supply valve (402) and the return water valve (401), and open the high-pressure side switch (11) and the high-pressure side switch (13). The condensate system is heated by the electric thermal energy storage unit. At this time, the hot water pump (404) is opened, valves (405) and (406) are opened, and valves (407) and (408) are closed, stopping the electric thermal energy storage unit from supplying heat to the heating network circulating water system.

[0048] Open valves (614) and (615) to allow all hot water to enter the first heat exchanger (61) of the peak operation compensation unit. The condensate bypass system is opened, and valves (613) and (612) are opened. The flow rate into the first heat exchanger (61) is controlled by adjusting the opening of valve (611). All stored heat is input into the condensate for peak operation compensation.

[0049] Electric thermal energy storage units can provide additional energy storage during peak operation, and based on the price difference of electricity at different times, they can supplement peak and off-peak storage, thereby bringing greater production benefits.

[0050] This system can be used in parallel with multiple units. When used in parallel, only the relevant electrical and steam-water piping systems need to be modified, and the principle is basically the same.

[0051] Finally, it should be noted that the above description is merely an explanation of the present invention and is not intended to limit the invention. Although the present invention has been described in detail, those skilled in the art can still modify the technical solutions described above or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A system for achieving zero-power grid connection of a combined heat and power (CHP) unit through electric thermal energy storage, comprising a boiler turbine unit, an electric thermal energy storage unit, a heat output unit, a bypass regulation unit, and an external heating network; characterized in that, The bypass regulating unit is located between the main steam pipeline and the cold end of the boiler reheater to regulate the amount of steam input to the steam turbine. The electric thermal energy storage unit is connected to the plant's power system and stores energy by electrically heating the thermal storage medium. The electric thermal energy storage unit includes an electric heater and a thermal storage tank; The electric heater and the thermal storage tank are connected by a heating circuit through a pipeline. The electric heaters are powered by the factory's internal power supply system; The outlet line of the high-voltage transformer of the thermal power unit is connected to the thermal storage transformer, and the outlet line of the thermal storage transformer is connected to the electric heater. The heating output unit pipeline connects to the heat storage tank in the boiler turbine unit and the electric thermal energy storage unit, and at the same time, the pipeline connects to the external heating network; Heat energy is obtained from the boiler turbine unit and heat storage tank to heat the heat medium in the external heating network; It also includes a peak operation compensation unit; The peak operation compensation unit pipeline is connected to the heat storage tank in the electric thermal energy storage unit, and at the same time, the pipeline is connected to the condensate system; Heat energy is extracted from the thermal storage tank to heat the condensate; The heat storage tank has two parallel outlet water lines. One line connects to the hot water side of the first heat exchanger to heat the turbine condensate, and a valve is installed on the hot water side pipeline. The first heat exchanger is a water-to-water heat exchanger. The cold water side of the first heat exchanger is connected to the turbine low-pressure heater system. Two bypass lines are led out from the outlet water pipeline of the turbine low-pressure heater system No.

2. The bypass lines are connected to the cold water side of the first heat exchanger, and an electric gate valve is installed on the bypass lines for starting or stopping the first heat exchanger. A regulating valve is installed on the condensate pipeline between the two bypass lines. The outlet water of the No. 2 low-pressure heater is divided into two lines. One line flows into the downstream low-pressure heater, and the other line returns to the turbine low-pressure heater system after being heated by the first heat exchanger. The flow distribution ratio of the two lines can be adjusted and controlled by the regulating valve. The first heat exchanger serves as a peak operation compensation unit. The outlet of the hot storage tank is connected to the hot water side of the third heat exchanger to heat the circulating water of the heating network. A valve is installed on the hot water side pipeline. The third heat exchanger is a water-to-water heat exchanger. The cold water side of the third heat exchanger is connected to the circulating water of the heating network. A valve is installed on the cold water side pipeline. The system also includes a second heat exchanger, which is a steam-water heat exchanger. A heating pipeline is led out from the exhaust pipe of the intermediate pressure cylinder of the steam turbine and connected to the steam-water side of the second heat exchanger. The steam-water side of the second heat exchanger is connected to the circulating water of the heating network. The second heat exchanger and the third heat exchanger are both connected to the same heating network. The second heat exchanger and the third heat exchanger together constitute a heating output unit. The second heat exchanger serves as the main heating output unit, and the third heat exchanger serves as the auxiliary heating output unit.

2. The system for achieving zero-power grid connection of a combined heat and power unit through electric thermal storage according to claim 1, characterized in that, The bypass regulating unit includes a high-pressure bypass and a desuperheater. The high-pressure bypass is located between the main steam pipeline and the high-pressure cylinder exhaust pipeline, and the desuperheater is connected to the boiler feedwater. A regulating valve is also installed on the high-pressure bypass to regulate the main steam flow in the high-pressure bypass.

3. The system for achieving zero-power grid connection of a combined heat and power unit through electric thermal storage according to claim 1, characterized in that, The heat storage medium in electric heaters and heat storage tanks is water or other heat transfer media.

4. A method for operating a system for achieving zero-power grid connection of a combined heat and power unit based on the electric thermal storage of claim 1, characterized in that: The combined heat and power unit is undergoing deep-adjustment operation. 1-1. When the cogeneration unit is operating under deep adjustment, if the depth of deep adjustment is limited, start the heat output unit and adjust the power generation load through the bypass adjustment unit. 1-2. When the peak shaving depth of the cogeneration unit is further increased, the adjustment through the bypass regulation unit can no longer meet the peak shaving depth requirements. The electric thermal energy storage unit is started to store energy. The heat release of the electric heater is adjusted according to the needs of the deep load, and all the grid-connected electricity is absorbed to achieve zero-output operation of the unit.

5. The operating method according to claim 4, characterized in that: When the deep adjustment is completed and the unit load increases, the bypass unit is taken out of operation; 2-1. When the heat dissipation of the electric thermal energy storage unit can meet the user's needs, the heat output unit obtains thermal energy from the electric thermal energy storage unit to heat the heat medium in the external heating network. 2-2. When the heat dissipation of the electric thermal energy storage unit cannot meet the user's needs, the heat output unit draws air from the steam turbine system to supplement a portion of the heat, which is used to heat the heat medium in the external heating network.

6. The operating method according to claim 5, characterized in that: Further includes: 2-3. When the electric thermal energy storage unit exceeds the user's demand, a portion of the heat from the electric thermal energy storage unit is sent to the turbine condensate system; 2-4. When there is no demand for heat from users, all the heat stored in the electric thermal energy storage unit is sent to the turbine condensate system.

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