Water source heat pump system based on power plant natural ventilation cooling tower filler and tower pool waste heat

Abstract

The invention belongs to the field of water source heat pumps, and provides a water source heat pump system based on power plant natural ventilation cooling tower filler and tower pool waste heat, which comprises a water source heat pump, a natural ventilation cooling tower, a unit condenser, a heat pump condenser and a heat pump evaporator, the heat pump condenser and the heat pump evaporator are arranged in the water source heat pump; under the refrigeration working condition, water inlet on the water source side of the water source heat pump is cooling water output by the natural ventilation cooling tower, the cooling water is conveyed to the heat pump condenser after being decontaminated, and the cooling water enters the natural ventilation cooling tower again for cooling after absorbing heat in the heat pump condenser to be heated to a set temperature, so that a refrigeration circulation loop is formed; under the heating working condition, water entering the water source side of the water source heat pump is high-temperature water output by the unit condenser, the high-temperature water flows into the heat pump evaporator, and after heat is released in the heat pump evaporator for cooling, the high-temperature water is conveyed to the unit condenser and absorbs heat in the unit condenser for heating, and a heating circulation loop is formed.

Description

Technical Field

[0001] The invention belongs to the field of water source heat pumps, and in particular relates to a water source heat pump system based on natural ventilation cooling tower fillers and tower pool waste heat in a power plant. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Water source units are more energy efficient and more stable than air source units, and their reliability mainly depends on the stability of the water quality on the heat source side. However, the current water source heat pump units have the following problems:

[0004] (1) When the water source is surface water, the temperature of surface water sources such as lake water and river water is highly dependent on the climate, resulting in a lower COP of the heat pump in winter. This is because the incoming water temperature is lower in winter, the evaporation pressure increases, and the evaporation temperature decreases;

[0005] (2) When the water source is groundwater, the amount of groundwater required is large, the initial investment is high, and the recharging of groundwater has always been a major problem. It is difficult to ensure that the water body will not be polluted during the recharging process, and ground subsidence may occur;

[0006] (3) When the water source is seawater, considering the high salt ion content, the corrosion to the pipeline will reduce the life of the pipeline. Therefore, the water source needs to be filtered to remove sodium before entering the pipeline, and the initial investment and subsequent operation and management costs are high. Summary of the invention

[0007] In order to solve at least one technical problem existing in the above-mentioned background technology, the present invention provides a water source heat pump system based on natural ventilation cooling tower filler and tower pool waste heat of a power plant, which can significantly improve the energy efficiency of the water source unit and reduce equipment energy consumption.

[0008] In order to achieve the above object, the present invention adopts the following technical solution:

[0009] A water source heat pump system based on natural ventilation cooling tower filler and tower pool waste heat of a power plant, comprising: a water source heat pump, a natural ventilation cooling tower, a unit condenser, a heat pump condenser and a heat pump evaporator; the heat pump condenser and the heat pump evaporator are arranged in the water source heat pump;

[0010] When the unit is in normal working condition and the water source heat pump system is in cooling condition, the water source side inlet water of the water source heat pump is the cooling water output by the natural ventilation cooling tower. The cooling water is transported to the heat pump condenser after decontamination. After absorbing heat and heating to the set temperature in the heat pump condenser, it re-enters the natural ventilation cooling tower for cooling, forming a refrigeration cycle.

[0011] When the unit is in normal operating conditions and the water source heat pump system is in heating conditions, the water source side of the water source heat pump is high-temperature water output by the unit's condenser. The high-temperature water flows into the heat pump evaporator, releases heat and cools down in the heat pump evaporator, and then is sent to the unit's condenser and absorbs heat and heats up in the unit's condenser, forming a heating cycle.

[0012] As an implementation method, under heating conditions, the air-conditioning circulating water return water on the user side of the water source heat pump is connected to the water source heat pump, filtered and decontaminated, and then output to the heat pump condenser. After absorbing heat and rising in temperature, it is sent to the heat terminal equipment of each air-conditioning system.

[0013] As an implementation method, the cooling water pipeline of the water source heat pump is connected to the circulating water pipeline before the condenser of the unit and the circulating water pipeline after the condenser of the unit respectively.

[0014] As an implementation mode, the water source heat pump is also connected to a first valve and a second valve capable of adjusting the flow direction of the water source.

[0015] As an implementation mode, the first valve and the second valve are both connected to a controller, and the controller is used to control the opening and closing states of the first valve and the second valve to control the water source heat pump system to switch between cooling and heating conditions.

[0016] As an implementation mode, when the first valve is opened and the second valve is closed, the water source heat pump system operates in a cooling condition; when the first valve is closed and the second valve is opened, the water source heat pump system operates in a heating condition.

[0017] As an implementation mode, the refrigeration cycle loop when the unit is in a shutdown condition and the water source heat pump system is in a cooling condition is the same as the refrigeration cycle loop when the unit is in a normal condition and the water source heat pump system is in a cooling condition.

[0018] As an implementation method, when the unit is in a shutdown condition and the water source heat pump system is in a cooling condition, the supply and return water temperatures are no greater than 30°C or 35°C.

[0019] As an implementation mode, when the unit is in a shutdown condition and the water source heat pump system is in a heating condition, the water source side water inlet of the water source heat pump is the circulating water output by the condenser of the unit, and the circulating water flows into the heat pump evaporator. After releasing heat and cooling in the heat pump evaporator, it is sent to the bottom tower pool of the natural ventilation cooling tower, absorbs heat from the bottom tower pool of the natural ventilation cooling tower and the circulating water pipeline buried deep underground, and then returns to the condenser of the unit.

[0020] As an implementation method, when the unit is in a shutdown condition and the water source heat pump system is in a heating condition, the supply and return water temperature is not lower than 11°C or 6°C, and the outlet water temperature on the user side is not lower than 45°C or 40°C.

[0021] The beneficial effects of the present invention are:

[0022] (1) Relative to the air temperature, the circulating water temperature in the plant area has the characteristics of being warm in winter and cool in summer within a year, which is an ideal cold and heat source. The unit energy efficiency can be improved by no less than 30% compared with conventional air source heat pumps. The present invention can reduce initial investment and operating costs, and has obvious economic performance. When building a water source heat pump system, the investment in equipment such as boilers and cooling towers can be omitted, which not only saves equipment investment but also reduces floor space. During operation, only a part of the electrical energy is consumed to recover the waste heat resources in the circulating water, reducing investment in energy such as coal and natural gas, and reducing operating costs.

[0023] (2) When the thermal power unit of the present invention is operating normally, the circulating water temperature at the condenser outlet is stable and reliable, not lower than 16°C, and the maximum temperature of the heating water supply of the water source unit is not lower than 60°C, which can be applied to more heat use scenarios.

[0024] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0026] Figure 1 It is a schematic structural diagram of a water source heat pump system based on natural ventilation cooling tower fillers and tower pool waste heat in an embodiment of the present invention.

[0027] Among them, 1. Water source heat pump; 2. Controller; 3. Circulating water pump; 4. First valve; 5. Second valve; 6. Third valve; 7. Natural ventilation cooling tower; 8. Unit; 9. Unit condenser; 10. Circulating water pipeline after the unit condenser; 11. Circulating water pipeline before the unit condenser; 12. Temperature sensor. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0029] It should be noted that the following detailed descriptions are all illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0031] In the present invention, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present invention, and do not specifically refer to any part or element in the present invention and should not be understood as limitations on the present invention.

[0032] In the present invention, terms such as "fixed connection", "connected", "connection", etc. should be understood in a broad sense, indicating that it can be fixedly connected, integrally connected or detachably connected; it can be directly connected or indirectly connected through an intermediate medium. Relevant scientific research or technical personnel in this field can determine the specific meanings of the above terms in the present invention according to specific circumstances, and they should not be understood as limiting the present invention.

[0033] In thermal power plants, the temperature of circulating water used to cool the condenser is a kind of available low-grade waste heat. Compared with the air temperature, it does not fluctuate much with the seasons. Its temperature is higher than the air temperature in winter and lower than the air temperature in summer. This makes the water source heat pump have higher operating efficiency than the air source heat pump system, saving energy and operating costs.

[0034] The present invention takes the thermal power unit adopting wet or indirect air cooling as an example. The temperature of the circulating water flowing through the steam turbine condenser is usually between 16 and 37°C. Even during the commissioning of the power plant or when two units are shut down at the same time, when the circulating water is not heated by the condenser, the temperature of the circulating water in winter can be maintained above 10°C. Although the energy efficiency of the unit is reduced at this time, it can still operate safely. The natural ventilation cooling tower filler and tower pool of the power plant are used as circulating water cooling facilities of the power plant. The outlet water temperature in summer is not higher than 32°C, which can be used as the incoming water source of the water source unit; in winter, the circulating water outlet after flowing through the steam turbine condenser is used as the incoming water on the heat source side of the water source heat pump, which is not only safe and reliable, but also can upgrade the low-grade waste heat in the condenser cooling water drainage to high-grade thermal energy through the water source heat pump, which has positive significance for energy saving and environmental protection for the recovery of condensation waste heat in the power plant. The water source unit is combined with the natural ventilation cooling tower filler and tower pool of the existing power plant, which can significantly improve the energy efficiency of the water source unit and reduce the energy consumption of the equipment.

[0035] like Figure 1As shown, a water source heat pump system based on natural ventilation cooling tower filler and tower pool waste heat of a power plant according to an embodiment of the present invention comprises: a water source heat pump 1, a natural ventilation cooling tower 7, a unit condenser 9, a heat pump condenser and a heat pump evaporator; the heat pump condenser and the heat pump evaporator are arranged in the water source heat pump 1;

[0036] When the unit is in normal working condition and the water source heat pump system is in cooling condition, the water source side inlet water of the water source heat pump 1 is the cooling water output by the natural ventilation cooling tower. The cooling water is transported to the heat pump condenser after decontamination. After absorbing heat and heating to the set temperature in the heat pump condenser, it re-enters the natural ventilation cooling tower for cooling, forming a refrigeration cycle.

[0037] When the unit is in normal operating conditions and the water source heat pump system is in heating conditions, the water source side inlet water of the water source heat pump 1 is the high-temperature water output by the unit's condenser. The high-temperature water flows into the heat pump evaporator, releases heat and cools down in the heat pump evaporator, and then is sent to the unit's condenser 9 and absorbs heat and heats up in the unit's condenser 9, forming a heating cycle.

[0038] In this embodiment, under heating conditions, after the user-side air-conditioning circulating water return of the water source heat pump 1 is connected to the water source heat pump, it is filtered and decontaminated and then output to the heat pump condenser. After absorbing heat and rising in temperature, it is sent to the heat terminal equipment of each air-conditioning system.

[0039] The cooling water pipeline of the water source heat pump 1 is connected to the circulating water pipeline 10 after the unit condenser and the circulating water pipeline 11 before the unit condenser respectively.

[0040] In the specific implementation process, the water source heat pump 1 is also connected to a first valve 4 and a second valve 5 that can adjust the flow direction of the water source. The first valve 4 and the second valve 5 are both connected to a controller 2, and the controller 2 is used to control the opening and closing states of the first valve 4 and the second valve 5 to control the water source heat pump system to switch between the cooling condition and the heating condition.

[0041] When the first valve 4 is opened and the second valve 5 is closed, the water source heat pump system operates in a cooling condition; when the first valve 4 is closed and the second valve 5 is opened, the water source heat pump system operates in a heating condition.

[0042] Under normal operating conditions of thermal power units:

[0043] Taking the 660MW unit as an example, under the annual average meteorological conditions, the cooling tower outlet water temperature (condenser inlet water temperature) is calculated to be 20.77℃ and the average back pressure is 4.75kPa.

[0044] Under the meteorological condition of frequency 10%, the cooling tower outlet water temperature is 26.27℃, which does not exceed the average equivalent back pressure of 7.85kPa of the turbine under TRL (summer) working condition.

[0045] 1) Refrigeration conditions:

[0046] During summer cooling, the chilled water process of the water source heat pump system in summer working conditions is consistent with that of conventional water-cooled chillers. The cold water return water (12°C) of the ventilation and air-conditioning system is sent to the water collector of the water source heat pump 1, filtered and decontaminated by the comprehensive water treatment device, and pumped into the heat pump condenser by the circulating water pump. After cooling to 7°C, it enters the water distributor and is then sent to the terminal equipment of each ventilation and air-conditioning system. The water source side of the heat pump cooling system in summer working conditions uses cooling water output from the natural ventilation cooling tower. Before entering the water source heat pump 1, close the second electric valve 5, open the first valve 4, and the heat pump cooling water pipeline is connected to the circulating water pipeline 10 after the condenser and the circulating water pipeline 11 before the condenser.

[0047] The design supply and return water temperature of the heat pump system cooling water is 32℃ / 37℃. In summer, the 32℃ circulating water cooled by the natural ventilation cooling tower 7 is sent to the water source heat pump 1, filtered and decontaminated by the integrated water treatment unit, pressurized by the circulating water pump 3 and pumped into the heat pump condenser. After absorbing heat in the heat pump condenser, it is heated to 37℃ and sent to the heat pump condenser outlet pipe, and re-enters the natural ventilation cooling tower of the power plant for cooling.

[0048] 2) Heating conditions:

[0049] During winter heating, the water source side of the water source heat pump 1 uses high-temperature water output from the unit condenser, and the summer cooling water pipeline is used. Before entering the water source heat pump 1, the second valve 5 is opened and the first valve 4 is closed to adjust the water flow direction. The circulating water at the outlet of the power plant condenser is sent to the heat pump evaporator to release heat. After releasing heat and cooling down in the heat pump evaporator, it is sent to the unit condenser and absorbs heat and heats up in the unit condenser.

[0050] The design supply and return water temperature of the water source side of the heat pump system is 16℃ / 11℃. After entering the heat pump evaporator to release heat, the water is cooled down and then transported to the inlet of the unit condenser to absorb the heat released by the unit condenser. The 40℃ circulating water return water of the air conditioner on the user side of the heat pump system is connected to the heat pump system, filtered and decontaminated, and then pumped into the heat pump condenser by the heat pump system circulating water pump. After absorbing heat and heating to 50℃, it is sent to the heat-using terminal equipment of each air conditioning system.

[0051] Specifically, under shutdown conditions:

[0052] At present, the number of generating hours of thermal power plants is generally between 4,000 and 5,000 hours. When the thermal power generating unit is in shutdown state, the circulating water system is stagnant and no longer enters the condenser. The heat pump system needs to meet the cooling and heating needs of the power plant throughout the year. A 3-frequency circulating water pump with a head of not less than 30 meters is configured on the cold (heat) source side to ensure that the circulating water entering the unit can be sent to the natural ventilation cooling tower.

[0053] The refrigeration cycle when the unit is in shutdown condition and the water source heat pump system is in cooling condition is the same as the refrigeration cycle when the unit is in normal condition and the water source heat pump system is in cooling condition. When the unit is in shutdown condition and the water source heat pump system is in cooling condition, the supply and return water temperature shall not exceed 30℃ or 35℃.

[0054] When the unit is in shutdown condition and the water source heat pump system is in heating condition, the water source side of the water source heat pump is the circulating water output by the unit condenser, and the circulating water flows into the heat pump evaporator, releases heat and cools down in the heat pump evaporator, and then is sent to the bottom tower pool of the natural ventilation cooling tower, absorbs heat from the bottom tower pool of the natural ventilation cooling tower and the circulating water pipeline buried deep underground, and then returns to the unit condenser. When the unit is in shutdown condition and the water source heat pump system is in heating condition, the supply and return water temperature shall not be lower than 11°C or 6°C, and the user-side outlet water shall not be lower than 45°C or 40°C.

[0055] In the intelligent control mode, the controller 2 monitors the outdoor ambient temperature based on the temperature sensor 13. When the ambient temperature is greater than 20°C, the signal is transmitted to the controller 2, and the controller 2 remotely opens the first valve 4 and closes the second valve 5; when the ambient temperature is less than 20°C, the signal is transmitted to the controller 2, and the controller 2 remotely closes the first valve 4 and opens the second valve 5.

[0056] The controller 2 monitors the operating status of the circulating water in the power plant. When the circulating water system stops running, the third valve 6 is opened to allow the circulating water pump 3 to run at full power under refrigeration conditions to ensure that the circulating water can be delivered to the packing layer of the cooling tower. Under heating conditions, the circulating water pump 3 runs at 30% power, and the circulating water does not go to the cooling tower, but only passes through the cooling tower pool; when the circulating water system operates normally, the third valve 6 is closed, and the circulating water pump 3 runs at 30% power to meet the normal circulation of the circulating water. The third valve 6 is set on the bypass pipe of the water inlet pipe of the natural ventilation cooling tower.

[0057] The above description is only a preferred embodiment of the present invention and is 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 water source heat pump system based on natural ventilation cooling tower filler and tower pool waste heat in a power plant, characterized in that: include: Water source heat pump, natural ventilation cooling tower, unit condenser, heat pump condenser and heat pump evaporator; The heat pump condenser and the heat pump evaporator are arranged in the water source heat pump; When the unit is in normal working condition and the water source heat pump system is in cooling condition, the water source side inlet water of the water source heat pump is the cooling water output by the natural ventilation cooling tower. The cooling water is transported to the heat pump condenser after decontamination. After absorbing heat and heating to the set temperature in the heat pump condenser, it re-enters the natural ventilation cooling tower for cooling, forming a refrigeration cycle. When the unit is in normal operating conditions and the water source heat pump system is in heating conditions, the water source side of the water source heat pump is high-temperature water output by the unit's condenser. The high-temperature water flows into the heat pump evaporator, releases heat and cools down in the heat pump evaporator, and then is sent to the unit's condenser and absorbs heat and heats up in the unit's condenser, forming a heating cycle.

2. The water source heat pump system based on natural ventilation cooling tower filler and tower pool waste heat of a power plant as claimed in claim 1, characterized in that: Under heating conditions, the air-conditioning circulating water return water on the user side of the water source heat pump is connected to the water source heat pump, and then output to the heat pump condenser after filtering and decontamination treatment. After absorbing heat and rising in temperature, it is sent to the heat terminal equipment of each air-conditioning system.

3. The water source heat pump system based on natural ventilation cooling tower filler and tower pool waste heat of a power plant as claimed in claim 1, characterized in that: The cooling water pipeline of the water source heat pump is connected to the circulating water pipeline before the unit condenser and the circulating water pipeline after the unit condenser respectively.

4. The water source heat pump system based on natural ventilation cooling tower filler and tower pool waste heat of a power plant as claimed in claim 1, characterized in that: The water source heat pump is also connected to a first valve and a second valve which can adjust the flow direction of the water source.

5. The water source heat pump system based on natural ventilation cooling tower filler and tower pool waste heat of a power plant as claimed in claim 4, characterized in that: The first valve and the second valve are both connected to a controller, and the controller is used to control the opening and closing states of the first valve and the second valve to control the water source heat pump system to switch between a cooling condition and a heating condition.

6. The water source heat pump system based on natural ventilation cooling tower filler and tower pool waste heat of a power plant as claimed in claim 5, characterized in that: When the first valve is open and the second valve is closed, the water source heat pump system operates in a cooling condition; when the first valve is closed and the second valve is open, the water source heat pump system operates in a heating condition.

7. The water source heat pump system based on natural ventilation cooling tower filler and tower pool waste heat of a power plant as claimed in claim 1, characterized in that: The refrigeration cycle loop when the unit is in a shutdown condition and the water source heat pump system is in a cooling condition is the same as the refrigeration cycle loop when the unit is in a normal condition and the water source heat pump system is in a cooling condition.

8. The water source heat pump system based on natural ventilation cooling tower filler and tower pool waste heat of a power plant as claimed in claim 7, characterized in that: When the unit is in shutdown condition and the water source heat pump system is in cooling condition, the supply and return water temperatures shall not exceed 30°C or 35°C.

9. The water source heat pump system based on natural ventilation cooling tower filler and tower pool waste heat of a power plant as claimed in claim 1, characterized in that: When the unit is in a shutdown condition and the water source heat pump system is in a heating condition, the water source side of the water source heat pump is the circulating water output by the condenser of the unit. The circulating water flows into the heat pump evaporator, releases heat and cools down in the heat pump evaporator, and then is sent to the bottom tower pool of the natural ventilation cooling tower, absorbs heat from the bottom tower pool of the natural ventilation cooling tower and the circulating water pipeline buried deep underground, and then returns to the condenser of the unit.

10. The water source heat pump system based on natural ventilation cooling tower filling and tower pool waste heat of a power plant as claimed in claim 9, characterized in that: When the unit is in shutdown condition and the water source heat pump system is in heating condition, the supply and return water temperature shall not be lower than 11°C or 6°C, and the outlet water on the user side shall not be lower than 45°C or 40°C.

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