Solar heat collection and natural ventilation air cooling coupled power generation system and method

Abstract

The invention discloses a solar heat collection and natural ventilation air cooling coupled power generation system and method. The system comprises a natural ventilation unit, a solar heat collection unit, an air cooling unit and a power generation unit. The natural ventilation unit adopts a natural ventilation air cooling tower; the solar heat collection unit is arranged at the top of the natural ventilation air cooling tower, the air cooling unit is arranged at the bottom of the natural ventilation air cooling tower, the solar heat collection unit and the air cooling unit are respectively connected with the power generation unit, and the air cooling unit dissipates heat through the natural ventilation air cooling tower. The height of the tower body and the density difference of air inside and outside the tower are utilized to form a draft effect to provide driving force for the heat dissipation process of the air cooling unit; the air density difference inside and outside the tower and the high tower body height of the natural ventilation air cooling tower are utilized to form the draft effect, efficient heat exchange can be achieved without external mechanical driving, and the energy consumption and the operation cost of a solar thermal power generation system are expected to be greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of solar thermal power generation, and in particular to a power generation system and method coupling solar thermal collection with natural ventilation and air cooling. Background Art

[0002] Tower solar power systems are a medium-to-large-scale solar thermal technology. They offer advantages such as high operating temperatures, high solar-to-thermal conversion efficiency, and large power generation capacity, and possess enormous development potential. Furthermore, these systems can also be applied to distributed energy systems, offering strong flexibility and scalability to meet energy application scenarios of varying scales and needs. However, the high construction and maintenance costs of these systems have hindered widespread adoption of tower solar power technology.

[0003] The cooling system is an important component of the thermal power generation cycle and the basis for its efficient and stable operation. Since water resources are relatively scarce in areas with abundant solar energy, existing solar thermal power generation systems generally use air cooling technology. In the air cooling system, the circulating cooling water and the ambient air undergo indirect heat exchange through a fin-tube heat exchanger, which has excellent water-saving performance. The air cooling systems of existing solar thermal power plants generally use mechanical ventilation air cooling towers. Due to the low specific heat capacity of air, fans are required to drive large amounts of air through the air-cooled fin tubes. The cooling process will generate high energy consumption. At present, the high cost of power generation is a key bottleneck restricting the development of tower solar thermal power generation technology. Summary of the Invention

[0004] In response to the problems existing in the existing technology, the present invention provides a power generation system and method that couples solar thermal collection with natural ventilation and air cooling. The buoyancy effect is formed by utilizing the difference in air density inside and outside the tower and the higher tower height of the solar thermal collection tower. Efficient heat exchange can be achieved without the need for external mechanical drive, which is expected to significantly reduce the energy consumption and operating costs of the solar thermal power generation system.

[0005] The technical solutions of the present invention are as follows: In a first aspect of the present invention, a power generation system coupling solar thermal collection and natural ventilation air cooling is provided, comprising a natural ventilation unit, a solar thermal collection unit, an air cooling unit and a power generation unit; the natural ventilation unit adopts a natural ventilation air cooling tower; the solar thermal collection unit is arranged at the top of the natural ventilation air cooling tower, and the air cooling unit is arranged at the bottom of the natural ventilation air cooling tower, the solar thermal collection unit and the air cooling unit are respectively connected to the power generation unit, the solar thermal collection unit provides heat for the power generation unit, and the air cooling unit provides cooling for the power generation unit, and the air cooling unit dissipates heat through the natural ventilation air cooling tower, and utilizes the height of the tower body and the density difference of the air inside and outside the tower to form a suction effect to provide driving force for the heat dissipation process of the air cooling unit. In some embodiments of the present invention, the solar heat collection unit adopts a solar heat collector, and the solar heat collector adopts an annular hollow structure, and the hollow part of the solar heat collector is connected to the top of the natural ventilation air cooling tower. In some embodiments of the present invention, a thermal insulation layer is provided inside the solar thermal collector. In some embodiments of the present invention, the air cooling unit includes a radiator composed of a plurality of air cooling fin tube bundles, wherein the plurality of air cooling fin tube bundles form a circular shape, and high temperature cooling water generated by the power generation unit flows into the air cooling fin tube bundles.

[0006] In some embodiments of the present invention, the power generation unit includes a heat storage tank, a cold storage tank, a steam generator, a steam turbine and a generator. The heat storage tank and the cold storage tank are respectively connected to the outlet and inlet of the solar thermal collection unit through pipelines. The heat storage tank provides heat to the steam generator, and the steam generated by the steam generator is provided to the steam turbine, which drives the generator to generate electricity.

[0007] In some embodiments of the present invention, the exhaust steam outlet of the steam turbine is connected to the condenser through a pipeline, and the high-temperature cooling water outlet of the condenser is connected to the air cooling unit, and the cooling water after being cooled by the air cooling unit returns to the condenser again.

[0008] In some embodiments of the present invention, the heat storage medium in the heat storage tank and the cold storage tank is molten salt.

[0009] In some embodiments of the present invention, an air-cooling heat exchanger is provided at the bottom of the natural ventilation air-cooling tower as an air-cooling unit, and the gaps between the fins of the air-cooling heat exchanger serve as the air inlet of the natural ventilation air-cooling tower.

[0010] In a second aspect of the present invention, a method for operating a power generation system coupled with solar thermal collection and natural ventilation cooling is provided, comprising the following steps: The solar thermal collection unit absorbs solar radiation energy and converts it into heat energy to provide to the power generation unit; The high-temperature cooling water generated by the power generation unit is cooled by the air cooling unit, causing the air at the bottom of the natural ventilation air cooling tower to become hot air, forming a density difference with the air outside the natural ventilation air cooling tower. The density difference provides driving force for the cooling process of the air cooling unit, forming a stable suction effect, so that it flows stably in the tower body without relying on the action of external fans.

[0011] In some embodiments of the present invention, the exhaust steam generated by the power generation unit enters the condenser and is cooled into condensed water. The heat released during the condensation process is transferred to the low-temperature cooling water. The low-temperature cooling water absorbs the heat and becomes high-temperature cooling water. The high-temperature cooling water is transported to the air-cooled heat exchanger at the bottom of the solar collector tower to exchange heat with the ambient air. The cooled cooling water returns to the condenser again and acts as a cooling medium.

[0012] One or more technical solutions of the present invention have the following beneficial effects: (1) The present invention couples a solar heat collection tower with a natural ventilation air cooling tower, utilizing the hollow structure of the solar heat collection tower to provide a driving force for the natural ventilation air cooling process, thus eliminating the cost of constructing an additional air cooling tower and the shadow effect that may be caused by the construction of an air cooling tower. At the same time, the inner surface of the solar heat collector is provided with insulation measures, so that the air flow in the tower does not affect the solar heat collection effect. In addition, the hollow structure of the tower body is used as a natural ventilation flow channel, forming a compact layout of "one tower with two functions".

[0013] (2) The present invention appropriately expands the bottom of the solar collector tower according to the heat exchange requirements of the air-cooling unit, which not only provides installation space for the tube bundle, but also minimizes airflow resistance through aerodynamic curved surface transition. The geometric dimensions of the tower body and tower top of the solar collector tower can still be designed based on the technology of the existing tower solar collector system, and can be effectively compatible with the existing tower solar thermal power generation technology.

[0014] (3) The present invention can independently or simultaneously carry out solar heat collection and natural ventilation air cooling processes, and can meet the needs of solar thermal power generation systems for heat collection during the day and power generation at night. For example, when there is sufficient solar radiation, the heat collection unit is operated first to store heat energy (molten salt heat storage); when operating at night to generate heat energy using heat storage, the air density difference inside and outside the tower is used to maintain the suction effect and drive the air cooling unit to continue working. The naturally ventilated air cooling unit does not require electrical drive and can meet the cooling needs of power generation, avoiding the cost pressure of traditional fan operation.

[0015] (4) The natural ventilation air cooling tower of the present invention utilizes the buoyancy effect generated by the air density difference to drive air flow during operation, which can significantly reduce the system's operating energy consumption and improve the operating efficiency of the power generation system. Traditional air cooling systems rely on high-power fans for forced convection, which consumes a lot of energy. The present invention uses the synergistic effect of the tower height and the air density difference to form a stable buoyancy (draft effect): cold air is sucked in from the tower bottom inlet, absorbs heat through the finned tube bundle, and becomes low-density hot air, which continues to rise in the tower and is discharged from the top of the tower. The entire process does not require external energy input.

[0016] (5) The present invention solves the problem of high cost and low efficiency of solar power tower cooling systems in arid areas. It has the characteristics of water saving, high efficiency and compact structure, and is suitable for large-scale concentrated solar power stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The overall schematic diagram of the power generation system coupled with solar heat collection and natural ventilation and air cooling of the present invention; Figure 2 A half-section view of the air cooling unit of the present invention; Figure 3 A top view of the solar thermal collection unit of the present invention; Figure 4 Schematic diagram of a natural ventilation air cooling tower coupled with a solar heat collection unit and an air cooling unit according to the present invention; In the figure: 1. Radiator; 101. Heat dissipation tube bundle; 2. Natural ventilation air-cooling tower; 3. Solar collector; 4. Insulation layer; 5. Tower support column; 6. Heat storage tank; 7. Cold storage tank; 8. Steam generator; 9. Steam turbine; 10. Generator; 11. Condenser; 12. Water pump; ①. Circulating water outlet; ②. Radiator air inlet; ③. Radiator air outlet; ④. Circulating water inlet; ⑤. Tower top air outlet. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Example 1 In a typical embodiment of the present invention, a power generation system coupling solar heat collection and natural ventilation cooling is proposed, such as Figures 1-4 As shown, it includes a natural ventilation unit, a solar heat collection unit, an air cooling unit and a power generation unit; the natural ventilation unit adopts a natural ventilation air cooling tower 2; the solar heat collection unit is arranged at the top of the natural ventilation air cooling tower 2, and the air cooling unit is arranged at the bottom of the natural ventilation air cooling tower 2. The solar heat collection unit and the air cooling unit are respectively connected to the power generation unit, the solar heat collection unit provides heat for the power generation unit, and the air cooling unit provides cold for the power generation unit. The air cooling unit dissipates heat through the natural ventilation air cooling tower 2, and utilizes the height of the tower body and the density difference of the air inside and outside the tower to form a suction effect to provide driving force for the heat dissipation process of the air cooling unit.

[0020] The power generation system described above couples solar thermal collection with natural ventilation air cooling. By reusing the tower structure of the natural ventilation air cooling tower 2, it provides both a support platform for the thermal collector and a buoyancy-driven channel for the air cooling unit, achieving the core advantage of "one tower serving two purposes." By leveraging the difference between the natural ventilation air cooling tower's height and air density to create a draft effect, it completely eliminates the energy consumption of mechanical fans (which accounts for over 60% of the power consumption of traditional air cooling systems), thereby improving the overall efficiency of the power station.

[0021] In this embodiment, the solar thermal collection unit utilizes a solar thermal collector 3 having an annular hollow structure. The hollow portion of the solar thermal collector 3 is connected to the top of the natural ventilation air-cooling tower 2. The solar thermal collector 3 utilizes an existing structure capable of converting solar energy into thermal energy. Specifically, a large number of heliostats can reflect and focus sunlight onto the solar thermal collector 3 located at the top of the natural ventilation air-cooling tower 2. The solar thermal collector 3 absorbs solar radiation and converts it into thermal energy.

[0022] The hollow design of the solar collector 3 is creatively and seamlessly connected with the ventilation duct at the top of the tower, forming an integrated "heat collection-ventilation" flow field, which can improve the uniformity of air circulation distribution in the tower and improve the cooling efficiency of the air cooling unit.

[0023] Furthermore, the solar thermal collector 3 is provided with an insulation layer 4. To prevent heat loss from the collector due to airflow within the tower, the insulation layer 4 is provided within the solar thermal collector 3 to reduce heat loss. The insulation layer 4 can be made of a building insulation material with a low thermal conductivity, such as ceramic fiber.

[0024] like Figure 2 As shown, the air-cooling unit includes a radiator 1 consisting of multiple air-cooling finned tube bundles arranged in a circular pattern. High-temperature cooling water generated by the power generation unit flows into these bundles. Multiple heat dissipation tube bundles 101 are arranged at a specific angle. The number of tube bundles is determined by factors such as the base diameter, bundle specifications, and placement angle. The placement angle can be adjusted based on the heat exchange capacity. The gaps between the air-cooling finned tube bundles serve as the air inlet for the natural ventilation air-cooling tower. The circular array of finned tube bundles achieves "maximum heat exchange in a compact space." Compared to traditional rectangular arrays, the annular structure effectively increases the heat exchange area. Furthermore, louvers are installed on the outer periphery of the heat dissipation tube bundles to precisely control the amount of cooling air flowing through the radiator. For example, they can be fully opened in summer to ensure heat dissipation efficiency; in winter, they can be adjusted to prevent pipe freezing (or closed). Air volume is controlled according to load changes for economical operation. They also provide equipment isolation and protection (against dust and debris).

[0025] In this embodiment, the power generation unit includes a heat storage tank 6, a cold storage tank 7, a steam generator 8, a steam turbine 9 and a generator 10. The heat storage tank 6 and the cold storage tank 7 are respectively connected to the outlet and inlet of the solar thermal collection unit through pipelines. The heat storage tank 6 provides heat to the steam generator 8, and the steam generated by the steam generator 8 is provided to the steam turbine 9. The steam turbine 9 drives the generator 10 to generate electricity.

[0026] Furthermore, the exhaust outlet of the steam turbine 9 is connected to the condenser 11 through a pipeline, and the high-temperature cooling water outlet of the condenser 11 is connected to the air cooling unit. The cooling water after being cooled by the air cooling unit returns to the condenser 11 again, and the condensed water returns to the steam generator 8 again after being pressurized by the pump.

[0027] In this embodiment, the heat storage medium in the heat storage tank 6 and the cold storage tank 7 is molten salt.

[0028] In this embodiment, a vent for the air cooling unit is provided at the bottom of the natural ventilation air cooling tower 2, and the vent serves as an air inlet. The entire natural ventilation air cooling tower 2 is supported by a plurality of tower support columns 5 to ensure support strength.

[0029] The operation mode of the power generation system coupled with solar heat collection and natural ventilation cooling provided in this embodiment is as follows: The solar thermal unit uses a large number of heliostats to reflect and concentrate sunlight onto the solar collector 3 at the top of the natural ventilation air-cooling tower 2, which absorbs solar radiation and converts it into heat. Low-temperature molten salt from the cold storage tank 7 is pumped to the solar collector 3 at the top of the tower. There, it is heated to a high temperature (typically 465-665°C) before being transferred to the heat storage tank 6. The high-temperature molten salt in the heat storage tank 6 enters the steam generator 8 of the power generation unit, transferring heat to water. The water absorbs the heat and evaporates into steam. The steam acts as the working fluid to drive the steam turbine 9, which in turn drives the generator 10 to generate electricity. After the working fluid in the steam turbine 9 has expanded, the exhaust steam enters the condenser 11, where it is recondensed back into liquid water using circulating cooling water.

[0030] In a solar thermal power generation system, circulating cooling water is generally provided by a cooling tower. In this embodiment, circulating cooling water is provided by an air cooling unit at the bottom of the solar thermal collector tower. The air cooling process is as follows: the high-temperature cooling water at the outlet of the condenser 11 is introduced into the air cooling unit at the bottom of the tower through the water inlet pipe, that is, the high-temperature cooling water is supplied from the cooling tower. Figure 2 The air enters the natural ventilation air cooling tower 2 through the tower bottom, radiator 1 air inlet ②, and radiator 1 air outlet ③. The air comes into full contact with the high-temperature cooling water as it passes through radiator 1. During the heat exchange process, the temperature difference between the air and the high-temperature cooling water causes heat to transfer from the high-temperature medium to the low-temperature medium. The temperature of the high-temperature circulating water gradually decreases, and the air entering the air cooling unit from the environment becomes hot air. The hot air flows upward within the tower and is discharged through the tower top air outlet ⑤.

[0031] After heat exchange, the density of the hot air inside the tower is lower than that of the atmosphere outside, creating a density difference. The coupled solar thermal unit and natural ventilation air-cooling tower 2 are hollow and generally quite tall. Therefore, after the hot air passes through the air-cooling heat exchanger at the bottom of the tower and enters the tower, the height of the hollow solar thermal tower and the density difference between the air inside and outside the tower provide the driving force for the natural ventilation air-cooling process, creating a stable draft effect. This allows for stable flow within the tower without relying on external fans, resulting in a stable natural ventilation heat dissipation process throughout the coupled system.

[0032] Example 2 In a typical embodiment of the present invention, a method for operating a power generation system coupled with solar thermal collection and natural ventilation cooling is provided, comprising the following steps: The solar thermal collection unit absorbs solar radiation energy and converts it into heat energy to provide to the power generation unit; The high-temperature cooling water generated by the power generation unit is cooled by the air cooling unit, causing the air at the bottom of the natural ventilation air cooling tower to become hot air, forming a density difference with the air outside the natural ventilation air cooling tower. The density difference provides driving force for the cooling process of the air cooling unit, forming a stable suction effect, so that it flows stably in the tower body without relying on the action of external fans.

[0033] Furthermore, the exhaust steam generated by the power generation unit enters the condenser and is cooled into condensed water. The heat released during the condensation process is transferred to the low-temperature cooling water. The low-temperature cooling water absorbs the heat and becomes high-temperature cooling water. The high-temperature cooling water is transported to the air-cooled heat exchanger at the bottom of the solar collector tower to exchange heat with the ambient air. The cooled cooling water returns to the condenser again to act as a cooling medium.

[0034] The above-mentioned entire working method utilizes the buoyancy effect generated by the difference in air density to drive air flow. Compared with the existing structure, there is no need to set up corresponding fans to drive air flow, which can greatly reduce the energy consumption of system operation, improve the operating efficiency of the power generation system, and at the same time save the cost of building additional air cooling towers.

[0035] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A power generation system that couples solar heat collection with natural ventilation and air cooling, characterized in that: It includes a natural ventilation unit, a solar heat collection unit, an air cooling unit and a power generation unit; the natural ventilation unit adopts a natural ventilation air cooling tower; the solar heat collection unit is arranged at the top of the natural ventilation air cooling tower, and the air cooling unit is arranged at the bottom of the natural ventilation air cooling tower. The solar heat collection unit and the air cooling unit are respectively connected to the power generation unit, the solar heat collection unit provides heat for the power generation unit, and the air cooling unit provides cold for the power generation unit. The air cooling unit dissipates heat through the natural ventilation air cooling tower, and utilizes the height of the tower body and the density difference of the air inside and outside the tower to form a suction effect to provide driving force for the heat dissipation process of the air cooling unit.

2. The power generation system coupled with solar heat collection and natural ventilation cooling according to claim 1, characterized in that: The solar heat collection unit adopts a solar heat collector, and the solar heat collector adopts an annular hollow structure. The hollow part of the solar heat collector is connected to the top of the natural ventilation air cooling tower.

3. The power generation system coupled with solar thermal collection and natural ventilation cooling according to claim 2, characterized in that: A heat-insulating layer is provided inside the solar heat collector.

4. The power generation system coupled with solar heat collection and natural ventilation cooling according to claim 1, characterized in that: The air cooling unit includes a radiator composed of a plurality of air cooling fin tube bundles, wherein the plurality of air cooling fin tube bundles are arranged in a circular shape, and high temperature cooling water generated by the power generation unit is passed into the air cooling fin tube bundles.

5. The power generation system coupled with solar thermal collection and natural ventilation cooling according to claim 1, characterized in that: The power generation unit includes a heat storage tank, a cold storage tank, a steam generator, a steam turbine and a generator. The heat storage tank and the cold storage tank are respectively connected to the outlet and inlet of the solar thermal collection unit through pipelines. The heat storage tank provides heat to the steam generator, and the steam generated by the steam generator is provided to the steam turbine, which drives the generator to generate electricity.

6. The power generation system coupled with solar thermal collection and natural ventilation cooling according to claim 5, characterized in that: The exhaust steam outlet of the steam turbine is connected to the condenser through a pipeline, and the high-temperature cooling water outlet of the condenser is connected to the air cooling unit. The cooling water after being cooled by the air cooling unit returns to the condenser again.

7. The power generation system coupled with solar thermal collection and natural ventilation cooling according to claim 5, characterized in that: The heat storage medium in the heat storage tank and the cold storage tank is molten salt.

8. The power generation system coupled with solar thermal collection and natural ventilation cooling according to claim 1, characterized in that: An air-cooling heat exchanger is provided at the bottom of the natural ventilation air-cooling tower as an air-cooling unit, and the gap between the fins of the air-cooling heat exchanger serves as an air inlet of the natural ventilation air-cooling tower.

9. An operating method of a power generation system coupled with solar thermal collection and natural ventilation cooling according to any one of claims 1 to 8, characterized in that: The following steps are involved: The solar thermal collection unit absorbs solar radiation energy and converts it into heat energy to provide to the power generation unit; The high-temperature cooling water generated by the power generation unit is cooled by the air cooling unit, causing the air at the bottom of the natural ventilation air cooling tower to become hot air, forming a density difference with the air outside the natural ventilation air cooling tower. The density difference provides driving force for the cooling process of the air cooling unit, forming a stable suction effect, so that it flows stably in the tower body without relying on the action of external fans.

10. The operating method of the power generation system coupled with solar thermal collection and natural ventilation and air cooling according to claim 9, characterized in that: The cooling process of the air-cooling unit includes: the exhaust steam generated by the power generation unit enters the condenser and is cooled into condensed water. The heat released during the condensation process is transferred to the low-temperature cooling water. The low-temperature cooling water absorbs the heat and becomes high-temperature cooling water. The high-temperature cooling water is transported to the air-cooled heat exchanger at the bottom of the solar collector tower to exchange heat with the ambient air. The cooled cooling water returns to the condenser again to act as a cooling medium.

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