Method for heating household water through cold source of steam turbine of thermal power plant

Abstract

The invention relates to the technical field of steam turbine cold source heating, and particularly discloses a method for heating household water by a steam turbine cold source in a thermal power plant, which comprises the following steps: purifying raw water taken from a water source to obtain cold water meeting the basic standard of household water, and storing the cold water; the cold water is introduced into a preheating link, low-temperature waste heat carried by return water of circulating water in a steam turbine system of a thermal power plant is utilized for primary heat exchange, and cold water preheating is completed; the preheated cold water is introduced into a special heat exchange area of a steam turbine condenser and exchanges heat with steam exhausted by a low-pressure cylinder of a steam turbine, and main temperature rising of the cold water is achieved; water subjected to main temperature rise is introduced into an auxiliary heating link, low-temperature waste heat originally discharged through a water cooling tower, a river and the like is converted into a heating heat source for domestic hot water of residents through the collaborative design of a condenser, a resident water part and a preheating heater, idle cold source lost heat in a thermal power system can be greatly recycled, energy waste consumption is reduced, and energy consumption is reduced. And the energy comprehensive utilization rate of the whole thermal power system is improved.

Description

Technical Field

[0001] This invention relates to the field of steam turbine cold source heating technology, and in particular to a method for heating residential water using a steam turbine cold source in a thermal power plant. Background Technology

[0002] As the core power equipment in thermal power plants, the cold-end loss of steam turbines during operation is a major bottleneck restricting the improvement of unit thermal efficiency. According to industry statistics, when steam turbine exhaust steam completes the condensation process in the condenser, the released heat from the cold source accounts for as much as 58.6% of the total heat input of the entire unit. This part of the energy is not effectively utilized and is directly discharged into the environment such as cooling towers, rivers or the sea through the circulating water system.

[0003] On the other hand, with the accelerated urbanization process and the continuous improvement of residents' living standards in my country, the demand for domestic hot water among urban residents is showing a sustained upward trend. Currently, the supply of domestic hot water in China mainly relies on electric heating or gas heating, which heats tap water directly from the water source. The temperature of tap water is basically the same as the ambient temperature, about 20-25℃ in summer and only 5-10℃ in winter, while the required temperature for domestic hot water is usually 30-60℃. To achieve this temperature increase, electric heating or gas heating requires a large amount of electricity or gas, which not only leads to high energy costs for residents but also further increases carbon emissions due to losses during energy conversion, contradicting the current national advocacy of the "dual carbon" goal and the concept of green and low-carbon living.

[0004] Therefore, the energy waste from the cooling loss of steam turbines in thermal power plants and the high energy consumption demand for domestic hot water supply create a stark supply-demand mismatch. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is that: the electric heating or gas heating of tap water consumes a lot of electricity or gas, which not only leads to high energy costs for residents, but also further increases carbon emissions due to losses in the energy conversion process.

[0006] The above-mentioned technical problems are solved by the following technical solution: The present invention proposes a method for heating residential water from the cold source of a steam turbine in a thermal power plant, which includes purifying the raw water taken from the water source to obtain cold water that meets the basic standards for residential water use and storing it. The cold water is introduced into the preheating stage, and the low-temperature waste heat carried by the circulating water return water in the steam turbine system of the thermal power plant is used for preliminary heat exchange to complete the cold water preheating. The preheated cold water is introduced into the dedicated heat exchange area of ​​the steam turbine condenser to exchange heat with the exhaust steam from the low-pressure cylinder of the steam turbine, thereby achieving the main temperature rise of the cold water. The water heated by the main heating element is introduced into the auxiliary heating stage and heated to the temperature required for domestic water use by the auxiliary heat source. After the hot water reaches the required temperature, it is stored and then delivered to residential users.

[0007] In a preferred embodiment of the method for heating residential water from the turbine cold source of a thermal power plant according to the present invention: the raw water from the water source is pressurized by a water replenishment pump and then sent to a water treatment device for purification, and the purified cold water is stored in a cold water storage tank. The cold water in the cold water storage tank is sent to the preheating heater by the cold water supply pump, and exchanges heat with the circulating water return water from the condenser circulating water section, which is pressurized by the circulating water booster pump, to complete the initial preheating of the cold water.

[0008] In a preferred embodiment of the method for heating residential water from a steam turbine cold source in a thermal power plant according to the present invention: the preheated cold water enters the residential water section of the condenser and exchanges heat with the exhaust steam discharged from the low-pressure cylinder of the steam turbine to achieve the main temperature rise of the cold water; The water heated by the main heating is sent to the auxiliary steam heater by the cold water booster pump, where it exchanges heat with the auxiliary steam provided by the auxiliary steam source 16 and is heated to the temperature required for domestic water use. The hot water that has reached the required temperature is stored in the warm water storage tank and then delivered to the residents by the warm water supply pump.

[0009] In a preferred embodiment of the method for heating residential water from a steam turbine cold source in a thermal power plant according to the present invention: the water side of the condenser is divided into two parts, one part being the condenser circulating water section that accommodates most of the heat exchange tube bundle, and the other part being the condenser residential water section that accommodates a small portion of the heat exchange tube bundle; the condenser circulating water section is supplied with circulating water, and the circulating water is driven by a circulating water pump, which operates in a variable frequency mode.

[0010] In a preferred embodiment of the method for heating residential water using a steam turbine cold source in a thermal power plant according to the present invention: the temperature difference between the heat exchange end of the circulating water return and the cold water is controlled at 8 to 12°C, and the required temperature for residential water is 30 to 60°C.

[0011] In a preferred embodiment of the method for heating residential water using a steam turbine cold source in a thermal power plant according to the present invention: the condensation step of the exhaust steam from the low-pressure cylinder of the steam turbine: the exhaust steam discharged from the low-pressure cylinder of the steam turbine enters the steam side of the condenser and exchanges heat with the circulating water in the circulating water section of the condenser and the preheated cold water in the residential water section of the condenser, respectively, and condenses to form condensate water, which is then returned to the thermal system of the thermal power plant.

[0012] In a preferred embodiment of the method for heating residential water from the cold source of a steam turbine in a thermal power plant according to the present invention: the circulating water circulation steps are as follows: the circulating water is pumped into the circulating water section of the condenser, where it absorbs the heat from the exhaust steam of the low-pressure cylinder of the steam turbine, and then pumped into the preheater to exchange heat with the cold water via the circulating water booster pump, and then transported to the cooling tower, river or sea for cooling, thus completing the circulation.

[0013] In a preferred embodiment of the method for heating residential water using a steam turbine cold source in a thermal power plant according to the present invention: the auxiliary steam recovery step: after the auxiliary steam enters the steam side of the auxiliary steam heater and exchanges heat with the water, it condenses to form condensate, which is then recovered to the thermal system of the thermal power plant to realize the recycling of working fluid and heat.

[0014] In a preferred embodiment of the method for heating residential water from the turbine cold source of a thermal power plant according to the present invention: the water levels of the cold water storage tank and the warm water storage tank, the inlet and outlet water temperatures of the preheater, the residential water section of the condenser, and the auxiliary steam heater, as well as the flow rate and pressure of each water pump are monitored in real time through a control and monitoring system consisting of a flow meter, a temperature sensor, a pressure sensor, a frequency converter, and a central control unit. The operating parameters of the circulating water pump, the cold water supply pump, and the warm water supply pump are adjusted by the frequency converter.

[0015] In a preferred embodiment of the method for heating residential water from a steam turbine in a thermal power plant according to the present invention: the purification treatment of the raw water includes filtration, softening and disinfection; the load change of the steam turbine in the thermal power plant is adjusted by frequency conversion to change the speed of the circulating water pump, thereby changing the circulating water flow rate of the condenser circulating water section and maintaining a stable vacuum in the condenser.

[0016] The beneficial effects of this invention are as follows: through the coordinated design of the condenser's domestic water section and the preheater, the low-temperature waste heat originally discharged through cooling towers, rivers, etc., is converted into a heating source for domestic hot water. Based on a domestic annual thermal power generation of 5.7 trillion kilowatt-hours and a thermal power unit ratio of 85.5%, this invention can significantly recover the heat loss from idle cold sources in the thermal power system, reduce energy waste, improve the overall energy utilization rate of the entire thermal power system, break the traditional single mode of thermal power generation and heat dissipation, and achieve cascaded energy utilization.

[0017] By employing a condenser water-side partitioning design and variable frequency operation of the circulating water pumps, the vacuum level within the condenser can be maintained stably while utilizing cold source losses, thus avoiding the problems of increased turbine heat consumption and decreased power generation efficiency caused by waste heat utilization. Even under peak shaving and non-full-load operation scenarios, the power generation function can still be ensured to remain unaffected, achieving dual protection for energy recovery and unit output.

[0018] This method utilizes the free waste heat from the turbine's cold source loss as the core heat source, only adjusting the temperature with auxiliary steam in the final stage, replacing the traditional electric and gas heating methods relied upon for residential hot water. Compared to traditional methods that require energy to heat tap water to 30-40℃ in summer and 40-60℃ in winter, this method significantly reduces electricity and gas consumption, directly lowering residential energy costs. It is particularly suitable for densely populated urban peripheries, and long-term use can significantly reduce the burden of living expenses for residents.

[0019] With the buffer design of cold water storage tanks and warm water storage tanks, combined with real-time monitoring and automatic control system, it can cope with the differences in peak and off-peak water consumption, ensure stable hot water temperature and pressure, avoid the problems of slow heating and insufficient water volume of traditional household water heaters, and improve the convenience and comfort of residents' use of hot water.

[0020] Traditional electric heating relies on thermal power generation, and the heating of gas directly emits carbon dioxide. This method, however, utilizes the waste heat of the thermal power system itself, eliminating the need for additional fossil fuel consumption or conversion into electricity, thus reducing carbon emissions in the energy conversion chain. Simultaneously, the condensate from the auxiliary steam can be recovered into the power plant's thermal system, achieving the recycling of the working fluid and heat, further reducing indirect carbon emissions from energy waste. This aligns with the national goal of "carbon peaking and carbon neutrality," providing a feasible path for the low-carbon transformation of thermal power plants.

[0021] Traditional thermal power plants lose cooling energy through circulating water discharge into cooling towers, rivers, or the sea, causing elevated temperatures in surrounding water bodies and air, resulting in environmental thermal pollution and impacting ecosystems. This method recovers a portion of the lost cooling energy, reducing the temperature of the circulating water discharge, decreasing heat input to surrounding water bodies and air, alleviating thermal pollution problems, protecting the ecological environment around the power plant, and achieving coordinated development between industrial production and ecological protection.

[0022] Currently, thermal power units need to undertake grid peak shaving tasks and are often in a non-full-load operation state. The condenser zoning design and variable frequency circulating pump control of this method can flexibly adapt to the load changes of the unit. There is no need to carry out large-scale transformation of the original thermal system of the power plant. Only the condenser tube bundle needs to be optimized by zoning and the addition of residential water-related pipelines and equipment is required. The transformation is simple and the cost is controllable. It is applicable to existing and newly built thermal power units in China and has a wide range of applications.

[0023] By installing water treatment devices, it can be ensured that the raw water taken from the water source meets the hygiene standards for drinking water, avoid water quality problems caused by pipe corrosion and microbial growth during hot water transportation, protect the safety of residents' water use, eliminate water quality concerns during technology promotion, and improve the reliability of technology application. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Wherein: Figure 1 This diagram illustrates the overall structure of a method for heating residential water using a steam turbine cold source in a thermal power plant. Figure 2 A schematic diagram of the condenser section of a method for heating residential water using a steam turbine cold source in a thermal power plant is shown. Figure 3 A schematic diagram of the condenser structure is shown, illustrating a method for heating residential water using a steam turbine cold source in a thermal power plant. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0026] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0027] Reference Figures 1-3 This embodiment provides a method for heating residential water using a steam turbine cold source in a thermal power plant, including purifying the raw water taken from the water source to obtain cold water that meets the basic standards for residential water use and storing it. Cold water is introduced into the preheating stage, and the low-temperature waste heat carried by the circulating water return water in the steam turbine system of the thermal power plant is used for preliminary heat exchange to complete the cold water preheating. The preheated cold water is introduced into the dedicated heat exchange area of ​​the turbine condenser 2 to exchange heat with the exhaust steam 10 of the turbine low-pressure cylinder, thereby achieving the main temperature rise of the cold water. The water heated by the main heating element is introduced into the auxiliary heating stage and heated to the temperature required for domestic water use by the auxiliary heat source. After the hot water reaches the required temperature, it is stored and then delivered to residential users.

[0028] The raw water from water source 14 is pressurized by water replenishment pump 20 and sent to water treatment device 9 for purification. The purified cold water is stored in cold water storage tank 7. The cold water in the cold water storage tank 7 is sent to the preheater 5 by the cold water supply pump 21, and exchanges heat with the circulating water return water from the condenser circulating water section 3 and pressurized by the circulating water booster pump 19 to complete the initial preheating of the cold water.

[0029] The preheated cold water enters the domestic water section 4 of the condenser and exchanges heat with the exhaust steam discharged from the low-pressure cylinder 1 of the steam turbine to achieve the main temperature rise of the cold water; After the main heating is completed, the water is sent to the auxiliary steam heater 6 via the cold water booster pump 22. It exchanges heat with the auxiliary steam provided by the auxiliary steam source 16 and is heated to the temperature required for domestic water use. The hot water that has reached the required temperature is stored in the warm water storage tank 8 and then delivered to the residents via the warm water supply pump 23.

[0030] The water side of the condenser is divided into two parts: one part is the condenser circulating water section 3, which houses most of the heat exchange tube bundles, and the other part is the condenser residential water section 4, which houses a small portion of the heat exchange tube bundles. Circulating water is introduced into the condenser circulating water section 3, and the circulating water is driven by the circulating water pump 18, which adopts a variable frequency operation mode.

[0031] The temperature difference between the heat exchange ends of the circulating water return and the cold water is controlled at 8-12℃, and the required temperature for domestic water is 30-60℃.

[0032] The condensation process of the exhaust steam from the low-pressure cylinder 1 of the steam turbine: The exhaust steam from the low-pressure cylinder 1 of the steam turbine enters the steam side of the condenser and exchanges heat with the circulating water of the condenser circulating water section 3 and the preheated cold water of the condenser residential water section 4 respectively, and condenses to form condensate 11. The condensate 11 is returned to the thermal system of the thermal power plant.

[0033] The circulation steps of the circulating water are as follows: The circulating water is sent to the condenser circulating water section 3 by the circulating water pump 18. After absorbing the heat of the exhaust steam 10 from the low-pressure cylinder of the steam turbine, it is sent to the preheater 5 by the circulating water booster pump 19 to exchange heat with the cold water. Then it is transported to the cooling tower, river or sea for cooling to complete the circulation.

[0034] Auxiliary steam recovery steps: After auxiliary steam enters the steam side of auxiliary steam heater 6 and exchanges heat with water, it condenses to form condensate 17. Condensate 17 is recovered to the thermal system of the thermal power plant to realize the recycling of working fluid and heat.

[0035] The control and monitoring system, consisting of flow meters, temperature sensors, pressure sensors, frequency converters, and a central control unit, monitors in real time the water levels of cold water storage tank 7 and warm water storage tank 8, the inlet and outlet water temperatures of preheater 5, condenser residential water section 4, and auxiliary steam heater 6, as well as the flow rate and pressure of each water pump. The operating parameters of circulating water pump 18, cold water supply pump 21, and warm water supply pump 23 are adjusted via frequency converters.

[0036] The purification treatment of raw water includes filtration, softening and disinfection. The load changes of the steam turbine in the thermal power plant are adjusted by frequency conversion to change the speed of the circulating water pump 18, thereby changing the circulating water flow rate of the condenser circulating water section 3 and maintaining a stable vacuum in the condenser.

[0037] This implementation method is applicable to 300MW conventional pulverized coal-fired power generating units with an average annual load rate of 60%~80%, which need to meet the daily hot water needs of 50,000 to 100,000 households in the surrounding urban areas. The average daily hot water consumption is about 2,000 m³, and the hot water temperature requirement is 35~45℃. In summer, it can be lowered to 30~38℃, and in winter it can be raised to 40~50℃.

[0038] The thermal power plant has a complete steam turbine thermal system, including the normally operating steam turbine low-pressure cylinder 1, condenser, circulating water pump 18, cooling tower and auxiliary steam pipeline network; The water quality of water source 14 meets the standards for drinking water sources and can reach the hygienic standards for drinking water through conventional purification treatment. Hot water transmission pipelines with diameters of DN400 to DN600 have been laid between the power plant and residential users, with a heat loss rate of ≤5% / km for the pipeline insulation layer.

[0039] Raw water purification and cold water storage Start the water supply pump 20 to pressurize the raw water from the water source 14 to 0.5MPa and send it into the water treatment device 9; The raw water passes through quartz sand filtration, activated carbon adsorption, ion exchange softening and ultraviolet disinfection in sequence in the water treatment device 9. The treated water meets the hygiene standards for drinking water. The purified cold water is sent into the cold water storage tank 7 through pipelines. The liquid level in the storage tank is maintained between 30% and 80% and is monitored in real time by a liquid level gauge. When the liquid level is below 30%, the water replenishment pump 20 is automatically started; when it is above 80%, the water replenishment pump 20 is automatically stopped.

[0040] Start the cold water supply pump 21 to pressurize the cold water in the cold water storage tank 7 to 0.6MPa and send it into the tube side of the preheater 5; Meanwhile, the circulating water 12 is driven by the circulating water pump 18 and enters the condenser circulating water section 3 to absorb the heat of the exhaust steam 10 of the low-pressure cylinder 1 of the turbine. It becomes circulating water return water at a temperature of 38°C, and is then pressurized to 0.3MPa by the circulating water booster pump 19 and sent to the shell side of the preheater 5. Cold water and circulating water return water undergo countercurrent heat exchange in the preheating heater. The temperature of the cold water rises from 25℃ / 10℃ to 32℃ / 17℃, with the temperature difference controlled at 8~10℃, completing the initial preheating. The temperature of the circulating water return water drops from 38℃ to 33℃, and then is transported to the cooling tower 13 through pipelines for cooling. After cooling, it returns to the inlet of the circulating water pump, completing the circulating water circulation.

[0041] The preheated cold water at 32℃-17℃ enters the residential water section 4 of the modified condenser 2 through the pipeline, accounting for 15% of the tube bundle. At this time, the low-pressure exhaust steam 10 discharged from the low-pressure cylinder 1 of the turbine is introduced into the steam side of the condenser at a temperature of 45℃ and a pressure of 5kPa. The preheated cold water and low-pressure exhaust steam exchange heat in the condenser's residential water section 4: the low-pressure exhaust steam condenses into condensate 11 at a temperature of 42℃, which is then returned to the power plant's thermal system for recycling; the cold water absorbs the condensation heat of the exhaust steam, and its temperature rises from 32℃-17℃ to 40℃-25℃, completing the main temperature rise. During this process, the flow rate of circulating water in the condenser circulating water section 3 is controlled by the frequency conversion regulation of the circulating water pump 18, ensuring that the vacuum degree in the condenser 2 is stable at -95~-97kPa, without affecting the normal operation of the steam turbine.

[0042] Start the cold water booster pump 22 to pressurize the water after the main heating is 40℃ / 25℃ to 0.5MPa and send it into the tube side of the auxiliary steam heater 6; Auxiliary steam at a pressure of 1.0 MPa and a temperature of 250°C is drawn from the auxiliary steam network 16 of the power plant and sent to the shell side of the auxiliary steam heater 6 to exchange heat with the water in the tube side: the water absorbs the heat of the steam, and its temperature rises from 40°C-25°C to 45°C-40°C to meet the temperature required for residential hot water; the auxiliary steam condenses into condensate 17 at a temperature of 95°C, and returns to the power plant's condensate 17 recovery system through the condensate 17 pipeline, realizing the recycling of working fluid and heat; After meeting the standards, the hot water at 45℃ / 40℃ is piped into the warm water storage tank 8. The storage tank is equipped with a temperature monitoring and insulation system: when the temperature is lower than the set value, such as below 40℃ in winter, the auxiliary steam heater 6 is triggered to increase the steam supply; when the temperature is higher than the set value, such as above 45℃ in summer, the steam supply is reduced; the liquid level in the storage tank is maintained at 40%~90% to cope with peak water usage periods.

[0043] Based on residents' water demand, the flow rate is 120 m³ / h during peak hours (18:00-22:00) and 60 m³ / h during off-peak hours. Two to three warm water supply pumps 23 are started to pressurize the hot water in the warm water storage tank 8 to 1.2 MPa. Hot water is delivered to residential user 15 through an insulated pipeline network. Pressure and temperature monitoring points are set up along the pipeline network: when the pressure is lower than 0.8MPa, the backup hot water supply pump is started; when the temperature loss exceeds 5℃, the insulation layer of the pipeline network is checked for damage. Residential users can adjust the hot water temperature to a suitable temperature, such as 30-35℃ for washing and 40-45℃ for showering, through their household water heaters or mixing valves, thus completing the entire heating and supply process.

[0044] The water temperatures of the cold water storage tank 7, the inlet and outlet of the preheater 5, the inlet and outlet of the condenser's domestic water section 4, the inlet and outlet of the auxiliary steam heater 6, and the warm water storage tank 8 are collected in real time by temperature sensors; the pressure of each water pump outlet and the inlet and outlet of the heat exchanger is collected by pressure sensors; the water flow rate of each link is collected by flow meters; and the liquid level of the cold water storage tank 7 and the warm water storage tank 8 is collected by level gauges. Based on the collected data, the central control unit performs the following automatic adjustments: Circulating water pump frequency conversion regulation: Adjusts the circulating water flow rate according to the unit load signal to maintain the vacuum of condenser 2; Auxiliary steam flow regulation: Controls the opening of the auxiliary steam valve according to the temperature of the warm water storage tank 8 to stabilize the hot water temperature; Pump start-stop control: Automatically starts and stops the standby pumps of the make-up water pump 20, cold water supply pump 21, and warm water supply pump 23 according to the tank level and pipeline pressure; Alarm and protection: When the following abnormal conditions occur, the system triggers an audible and visual alarm and executes protection actions: Condenser 2 vacuum is lower than -92kPa: Automatically increases the flow rate of circulating water pump 18. If it does not recover within 10 minutes, triggers the unit load reduction signal; Warm water storage tank 8 temperature is lower than 35℃: Automatically fully opens the auxiliary steam valve. If the temperature still does not rise, starts the standby auxiliary steam heater 6; Cold water storage tank 7 level is lower than 20%: Triggers a raw water supply fault alarm for ground 14 and simultaneously reduces the flow rate of cold water supply pump 21 to prioritize the supply of hot water to residents.

[0045] Taking a 300MW unit operating for 6000 hours per year and a daily hot water demand of 2000m³ for residents as an example, the effects of this implementation method are as follows: The annual heat loss from the steam turbine cooling source is approximately 1.2 × 10⁻⁶. 9 This translates to a saving of 410 tons of standard coal, calculated based on the standard coal calorific value of 29.3 MJ / kg; and a reduction in residential hot water electric heating energy consumption of approximately 3.5 × 10⁻⁶ tons. 5 The system delivers kWh of electricity, reducing residential water costs; the condenser vacuum remains within the design range, the turbine heat rate remains unchanged, and the normal power generation of the unit is not affected; the effluent from the water treatment device 9 meets the hygiene standards for drinking water, there is no secondary pollution during hot water transportation, and the water quality qualification rate for residential use is 100%; the system has been running continuously for 300 days without failure, and can cope with unit load fluctuations and a peak-to-valley difference of 3:1 for residential water use, with hot water temperature and pressure fluctuations within the range of ≤±2℃ and ±0.1MPa, respectively, meeting the requirements for stable supply.

[0046] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A method for heating residential water using a steam turbine cold source in a thermal power plant, characterized in that: include, The raw water taken from the water source is purified to obtain cold water that meets the basic standards for residential water use and then stored. The cold water is introduced into the preheating stage, and the low-temperature waste heat carried by the circulating water return water in the steam turbine system of the thermal power plant is used for preliminary heat exchange to complete the cold water preheating. The preheated cold water is introduced into the dedicated heat exchange area of ​​the steam turbine condenser to exchange heat with the exhaust steam from the low-pressure cylinder of the steam turbine, thereby achieving the main temperature rise of the cold water. The water heated by the main heating element is introduced into the auxiliary heating stage and heated to the temperature required for domestic water use by the auxiliary heat source. After the hot water reaches the required temperature, it is stored and then delivered to residential users.

2. The method for heating residential water using a steam turbine cold source in a thermal power plant according to claim 1, characterized in that: The raw water from the water source is pressurized by a water replenishment pump and then sent to a water treatment device for purification. The purified cold water is then stored in a cold water storage tank. The cold water in the cold water storage tank is sent to the preheating heater by the cold water supply pump, and exchanges heat with the circulating water return water from the condenser circulating water section, which is pressurized by the circulating water booster pump, to complete the initial preheating of the cold water.

3. The method for heating residential water using a steam turbine cold source in a thermal power plant according to claim 2, characterized in that: The preheated cold water enters the residential water section of the condenser and exchanges heat with the exhaust steam discharged from the low-pressure cylinder of the steam turbine to achieve the main temperature rise of the cold water; The water heated by the main heating pump is sent to the auxiliary steam heater via a cold water booster pump. It exchanges heat with the auxiliary steam provided by the auxiliary steam source and is heated to the temperature required for domestic water use. The hot water that has reached the required temperature is stored in a warm water storage tank and then delivered to residents via a warm water supply pump.

4. The method for heating residential water using a steam turbine cold source in a thermal power plant according to claim 3, characterized in that: The water side of the condenser is divided into two parts: one part is the condenser circulating water section that houses most of the heat exchange tube bundles, and the other part is the condenser residential water section that houses a small portion of the heat exchange tube bundles. The condenser circulating water section is supplied with circulating water, which is driven by a circulating water pump that operates in a variable frequency mode.

5. The method for heating residential water using a steam turbine cold source in a thermal power plant according to claim 4, characterized in that: The temperature difference between the heat exchange end of the circulating water return and the cold water is controlled at 8-12℃, and the temperature required for domestic water is 30-60℃.

6. The method for heating residential water using a steam turbine cold source in a thermal power plant according to claim 5, characterized in that: The condensation process of exhaust steam from the low-pressure cylinder of the steam turbine: The exhaust steam from the low-pressure cylinder of the steam turbine enters the steam side of the condenser and exchanges heat with the circulating water in the condenser's circulating water section and the preheated cold water in the condenser's residential water section, respectively, and condenses to form condensate. The condensate is then returned to the thermal system of the thermal power plant.

7. The method for heating residential water using a steam turbine cold source in a thermal power plant according to claim 6, characterized in that: The circulation steps of circulating water are as follows: Circulating water is pumped into the condenser circulating water section by the circulating water pump. After absorbing the heat of the exhaust steam from the low-pressure cylinder of the steam turbine, it is pumped into the preheater by the circulating water booster pump to exchange heat with the cold water. Then it is transported to the cooling tower, river or sea for cooling to complete the circulation.

8. The method for heating residential water using a steam turbine cold source in a thermal power plant according to claim 7, characterized in that: The auxiliary steam recovery process involves the auxiliary steam entering the steam side of the auxiliary steam heater and exchanging heat with water. The steam then condenses to form condensate, which is then recovered to the thermal power plant's thermal system, thus achieving the recycling of the working fluid and heat.

9. The method for heating residential water using a steam turbine cold source in a thermal power plant according to claim 8, characterized in that: The control and monitoring system, which includes flow meters, temperature sensors, pressure sensors, frequency converters, and a central control unit, monitors in real time the water levels of cold water and warm water storage tanks, the inlet and outlet water temperatures of the preheater, the residential water section of the condenser, and the auxiliary steam heater, as well as the flow rate and pressure of each water pump. The operating parameters of the circulating water pump, cold water supply pump, and warm water supply pump are adjusted by the frequency converter.

10. The method for heating residential water using a steam turbine cold source in a thermal power plant according to claim 8, characterized in that: The raw water purification treatment includes filtration, softening and disinfection. The load changes of the steam turbine in the thermal power plant are adjusted by frequency conversion to change the speed of the circulating water pump, thereby changing the circulating water flow rate of the condenser circulating water section and maintaining a stable vacuum in the condenser.

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