Waste heat power generation system, photovoltaic and solar thermal hybrid power station, and waste heat power generation method

Abstract

The present application relates to the technical field of waste heat power generation. Provided are a waste heat power generation system, a photovoltaic and solar thermal hybrid power station, and a waste heat power generation method. The waste heat power generation system comprises: a first heat exchanger, which is used for acquiring photovoltaic waste heat to perform primary heat exchange with a first working medium; a second heat exchanger, which is connected to the first heat exchanger and used for acquiring solar thermal waste heat to perform secondary heat exchange with the first working medium; a first turbine, which is connected to the second heat exchanger; a first generator, which is connected to the first turbine and used for power generation; a condenser, which is connected to the first turbine and used for cooling the first working medium; and a first pump, wherein the first pump connects the condenser and the first heat exchanger and is used for conveying the first working medium to the first heat exchanger, thus entering the heat exchange cycle. The waste heat power generation system in the embodiments of the present application can utilize both the photovoltaic waste heat and solar thermal waste heat for power generation, thereby improving the utilization rate of energy, avoiding the waste of resources.

Description

Waste heat power generation system, photovoltaic and solar thermal hybrid power station, and waste heat power generation method

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on January 31, 2024, with application number 2024101389862 and application name “Waste Heat Power Generation System, Photovoltaic and Solar Thermal Hybrid Power Station and Waste Heat Power Generation Method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of waste heat power generation, and in particular to a waste heat power generation system, a photovoltaic and solar thermal hybrid power station, and a waste heat power generation method. Background Art

[0003] A photovoltaic and solar thermal hybrid power station is a site that uses solar energy to generate electricity. It combines photovoltaic power generation and solar thermal power generation technologies.

[0004] In related technologies, both the photovoltaic power generation process and the solar thermal power generation process of a photovoltaic and solar thermal hybrid power station will generate a large amount of medium and low temperature waste heat, of which part of the medium and low temperature waste heat is directly discharged, and part of the medium and low temperature waste heat is cooled.

[0005] However, in the related art, the waste heat is cooled or directly discharged, which causes energy waste.

[0006] Summary of the Invention

[0007] The present application provides a waste heat power generation system, a photovoltaic and solar thermal hybrid power station, and a waste heat power generation method.

[0008] In a first aspect, an embodiment of the present application provides a waste heat power generation system, comprising:

[0009] A first heat exchanger, the first heat exchanger is used to obtain photovoltaic waste heat generated by the photovoltaic power generation system to perform a heat exchange with the first working medium;

[0010] a second heat exchanger, the second heat exchanger being connected to the first heat exchanger, and being used to obtain the waste heat generated by the solar thermal power generation system for secondary heat exchange with the first working medium;

[0011] a first turbine connected to the second heat exchanger, the first turbine being configured to utilize the first working fluid after secondary heat exchange to perform work to generate first mechanical work;

[0012] a first generator connected to the first turbine, the first generator being used to obtain first mechanical work to generate electricity;

[0013] a condenser connected to the first turbine and used to cool the first working medium after being utilized by the first turbine;

[0014] The first pump is connected to the condenser and the first heat exchanger, and is used to transport the cooled first working medium to the first heat exchanger to enter the heat exchange cycle.

[0015] In a second aspect, an embodiment of the present application provides a photovoltaic and solar thermal hybrid power station, comprising:

[0016] Photovoltaic power generation systems and solar thermal power generation systems;

[0017] A waste heat power generation system, which is any waste heat power generation system provided in the first aspect;

[0018] The first heat exchanger of the waste heat power generation system is used to obtain the photovoltaic waste heat generated by the photovoltaic power generation system to perform a heat exchange with the first working medium;

[0019] The second heat exchanger of the waste heat power generation system is used to obtain the waste heat generated by the solar thermal power generation system for secondary heat exchange with the first working medium.

[0020] In a third aspect, an embodiment of the present application provides a waste heat power generation method, which is applied to any waste heat power generation system provided in the first aspect, comprising:

[0021] Acquire photovoltaic waste heat generated by the photovoltaic power generation system to perform heat exchange with the first working medium;

[0022] Acquire the residual heat generated by the solar thermal power generation system to perform secondary heat exchange with the first working fluid;

[0023] utilizing the first working fluid after the secondary heat exchange to perform work to generate first mechanical work;

[0024] obtaining first mechanical work to generate electricity;

[0025] Cooling the first working fluid after being utilized;

[0026] The cooled first working fluid is transported to the first heat exchanger to enter the heat exchange cycle.

[0027] The embodiments of the present application provide a waste heat power generation system, a photovoltaic and solar thermal hybrid power station, and a waste heat power generation method. The waste heat power generation system can obtain photovoltaic waste heat generated by the photovoltaic power generation system by setting a first heat exchanger, and by setting a second heat exchanger, the second heat exchanger is connected to the first heat exchanger, and the first working fluid after the first heat exchange in the first heat exchanger enters the second heat exchanger, and can continue to obtain the solar thermal waste heat generated by the solar thermal power generation system for secondary heat exchange with the first working fluid, so as to simultaneously obtain photovoltaic waste heat and solar thermal waste heat in the same power generation system, thereby improving the energy utilization rate of the waste heat power generation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings herein are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the description, are used to explain the principles of the embodiments of the present application.

[0029] FIG1 is a system schematic diagram of a photovoltaic and solar-thermal hybrid power station provided in an embodiment of the present application;

[0030] FIG2 is a system schematic diagram of the waste heat power generation system in FIG1 ;

[0031] FIG3 is a flow chart of a waste heat power generation method provided in an embodiment of the present application;

[0032] FIG4 is a system schematic diagram of the thermal storage bypass unit in FIG2 ;

[0033] FIG5 is a system schematic diagram of the temperature control bypass unit in FIG2 .

[0034] Explanation of Reference Numerals: 100 - Waste Heat Power Generation System; 110 - First Heat Exchanger; 120 - Second Heat Exchanger; 130 - First Turbine; 140 - First Generator; 150 - Condenser; 160 - First Pump; 170 - Photovoltaic Waste Heat Recovery Unit; 171 - First Pipeline; 172 - Second Pipeline; 173 - Second Pump; 180 - First Preheater; 200 - Photovoltaic Power Generation System; 300 - Concentrated Solar Power Generation System; 310 - Steam Generator Assembly; 320 - Second Turbine; 330 - Second Generator; 340 - Air Cooling Island; 350 - Third Pump; 400 - Power Storage Device; 500 - Thermal Storage Bypass Unit; 510 - First Main Path; 520 - First Temperature Sensor; 530 - First Control Valve; 540 - First Branch Path; 550 - Thermal Accumulator; 560 - Second Temperature Sensor; 600 - Thermostatic bypass unit; 610 - Third temperature sensor; 620 - Second regulating valve; 630 - Second branch; 640 - Heat pump; 650 - Fourth temperature sensor. The above figures illustrate specific embodiments of the present application, which will be described in more detail below. These figures and descriptions are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0036] In related technologies, both the photovoltaic power generation process and the solar thermal power generation process of a photovoltaic and solar thermal hybrid power station will generate a large amount of medium and low-temperature waste heat, which usually cannot be directly recycled and utilized. Part of the medium and low-temperature waste heat is directly discharged, and part of the medium and low-temperature waste heat is cooled.

[0037] However, in the related art, the waste heat is cooled or directly discharged, which causes energy waste.

[0038] In view of the above technical problems, please refer to Figures 1 and 2. The embodiment of the present application provides a waste heat power generation system, including: a first heat exchanger 110, the first heat exchanger 110 is used to obtain the photovoltaic waste heat generated by the photovoltaic power generation system 200 to perform a primary heat exchange with the first working medium; a second heat exchanger 120, the second heat exchanger 120 is connected to the first heat exchanger 110, and the second heat exchanger 120 is used to obtain the photothermal waste heat generated by the photothermal power generation system 300 to perform a secondary heat exchange with the first working medium; a first turbine 130, the first turbine 130 is connected to the second heat exchanger 120, and the first turbine 130 is used to generate a heat wave. The first working fluid after the secondary heat exchange is used to perform work to generate the first mechanical work; the first generator 140, the first generator 140 is connected to the first turbine 130, and the first generator 140 is used to obtain the first mechanical work to generate electricity; the condenser 150, the condenser 150 is connected to the first turbine 130, and the condenser 150 is used to cool the first working fluid after being used by the first turbine 130; the first pump 160, the first pump 160 is connected to the condenser 150 and the first heat exchanger 110, and the first pump 160 is used to transport the cooled first working fluid to the first heat exchanger 110 to enter the heat exchange cycle.

[0039] The waste heat power generation system 100 provided in this embodiment of the present application is provided with a first heat exchanger 110 to capture waste heat generated by a photovoltaic power generation system 200 and recycle it to avoid energy waste. Furthermore, capturing waste heat by the first heat exchanger 110 can also reduce the temperature of the photovoltaic power generation system 200, thereby improving the photovoltaic conversion efficiency of the photovoltaic power generation system 200.

[0040] Waste heat power generation system 100 is equipped with a second heat exchanger 120 to capture and recycle the waste heat generated by CSP system 300, thus avoiding energy waste. Furthermore, the temperature of the circulating medium in CSP system 300 decreases after secondary use, resulting in a lower cooling medium during CSP system operation.

[0041] In addition, the waste heat power generation system 100 is provided with a first turbine 130, a first generator 140, a condenser 150 and a first pump 160, and the first heat exchanger 110, the second heat exchanger 120, the first turbine 130, the first generator 140, the condenser 150 and the first pump 160 together form an organic Rankine cycle power generation system. The first turbine 130 can use the first working fluid to perform work to generate first mechanical work, and the first generator 140 can obtain the first mechanical work to generate electricity, so that it can use photovoltaic waste heat and solar thermal waste heat to generate electricity. Moreover, the first working fluid can circulate in the organic Rankine cycle power generation system, continuously obtaining photovoltaic waste heat and solar thermal waste heat, so as to improve energy utilization and avoid waste of resources.

[0042] In addition, since photovoltaic waste heat is generally lower in temperature than solar thermal waste heat, the second heat exchanger 120 is connected to the first heat exchanger 110, and the first working fluid after one heat exchange in the first heat exchanger 110 enters the second heat exchanger 120, which can continue to obtain the solar thermal waste heat generated by the solar thermal power generation system 300 for secondary heat exchange with the first working fluid, so as to obtain photovoltaic waste heat and solar thermal waste heat at the same time in the same power generation system, thereby improving the energy utilization rate of the waste heat power generation system 100.

[0043] In some embodiments, referring to FIG2 , the waste heat power generation system 100 further includes a photovoltaic waste heat recovery unit 170 , which includes: a photovoltaic waste heat acquisition component, which includes a first pipe 171 , which is used to connect to the photovoltaic power generation system 200 , and a second working fluid is contained in the first pipe 171 , which is used to acquire photovoltaic waste heat generated by the photovoltaic power generation system 200 ; a second pump 173 , which is connected to the first pipe 171 , and is used to transport the second working fluid after acquiring photovoltaic waste heat to the first heat exchanger 110 for heat exchange with the first working fluid; the photovoltaic waste heat acquisition component further includes a second pipe 172 , which is used to connect the photovoltaic power generation system 200 and the first heat exchanger 110 , so that the second working fluid after heat exchange is transferred to the photovoltaic power generation system 200 to enter the heat exchange cycle.

[0044] In this embodiment, one end of the first pipe 171 is connected to the first heat exchanger 110, and the other end of the first pipe 171 is used to connect to the photovoltaic power generation system 200. The first pipe 171 contains a second working fluid. When the second working fluid is located at the location of the photovoltaic power generation system 200, the second working fluid is heated by the photovoltaic waste heat of the photovoltaic power generation system 200, thereby realizing the acquisition of photovoltaic waste heat.

[0045] The second pump 173 is connected to the first pipe 171. The second pump 173 can transport the second working medium after obtaining photovoltaic waste heat to the first heat exchanger 110 to perform heat exchange with the first working medium, thereby realizing the utilization of photovoltaic waste heat.

[0046] One end of the second pipe 172 is connected to the first heat exchanger 110, and the other end of the second pipe 172 is used to connect to the photovoltaic power generation system 200. The second working fluid after heat exchange with the first working fluid can flow to the photovoltaic power generation system 200 through the second pipe 172 and obtain the photovoltaic waste heat generated by the photovoltaic power generation system 200 again.

[0047] Thus, the second working medium circulates between the photovoltaic power generation system 200 and the first heat exchanger 110 through the first pipe 171 and the second pipe 172. During the heat exchange cycle, the second working medium can continuously obtain photovoltaic waste heat from the photovoltaic power generation system 200 and can continuously transfer the obtained photovoltaic waste heat to the first heat exchanger 110 for power generation.

[0048] It is understandable that the second working fluid can be liquid water.

[0049] In some specific embodiments, the photovoltaic waste heat acquisition component 171 is a daily solar energy frequency division utilization component or a fixed solar energy frequency division utilization component.

[0050] As a new solar energy technology, split-frequency solar energy utilization enables the split-frequency utilization of photovoltaic and thermal energy. This technology uses nanofluids and other media to selectively absorb light in frequency ranges with significant thermal effects, while light in other frequency ranges passes through photovoltaic modules to generate electricity. This technology achieves split-frequency solar energy utilization, improving the photovoltaic conversion efficiency of photovoltaic power generation system 200 while also recovering the generated medium- and low-temperature heat energy.

[0051] The solar-powered split-frequency solar utilization system features a photovoltaic module whose orientation changes according to the direction of the sun. It primarily consists of a barrier layer beneath the module and a working fluid pipeline beneath the barrier layer. A split-frequency fluid is injected into the barrier layer to absorb heat from the photovoltaic module layer before transferring it to a secondary working fluid. This split-frequency method maximizes solar power generation and improves resource efficiency.

[0052] Fixed solar frequency-splitting modules utilize fixed-position solar panels, whose orientation cannot be changed. Prisms are primarily composed of prisms, which are positioned around the PV panels to divide the sunlight. By properly positioning and angling the prisms, they focus the solar energy to heat the secondary working medium.

[0053] In other embodiments, please refer to Figure 2, the waste heat power generation system 100 also includes a first preheater 180, which is arranged between the first turbine 130 and the first condenser 150, and the first preheater 180 is also arranged between the first pump 160 and the first heat exchanger 110. The first preheater 180 is used to preheat the first working medium entering the first heat exchanger 110.

[0054] In certain situations, installing first preheater 180 increases the temperature of the first working fluid upon entering first heat exchanger 110, increasing its superheat after evaporation. This increases the enthalpy difference in first turbine 130 and reduces the mass flow rate of the first working fluid, thereby reducing the photoelectric conversion efficiency. The increased temperature of the first working fluid upon entering first heat exchanger 110 reduces the heat transfer temperature difference, thereby reducing exergy losses and increasing exergy efficiency.

[0055] During the day, there is abundant solar energy, and its heat generates a large amount of electricity that cannot be consumed. However, at night, there is no solar energy and no electricity can be generated.

[0056] Furthermore, the photoelectric conversion efficiency is significantly correlated with the temperature of the first working fluid upon entering the first turbine 130, and this relationship follows a generally normal distribution. Specifically, as the temperature of the first working fluid upon entering the first turbine 130 increases, the photoelectric conversion efficiency increases. When the temperature of the first working fluid reaches a first preset temperature, the photoelectric conversion efficiency of the organic Rankine cycle decreases. Therefore, to maintain a high photoelectric conversion efficiency, the temperature of the first working fluid upon entering the first turbine 130 should be equal to or lower than the first preset temperature. It should be noted that the first preset temperature is dependent on the type of the first working fluid and can be set based on the specific type of the first working fluid.

[0057] In response to the above technical problems, in some embodiments, referring to FIG4 , the waste heat power generation system further includes a heat storage bypass unit 500, which includes: a first main path 510, the first main path 510 connecting the second heat exchanger 120 and the first turbine 130, and the first main path 510 can be used to supply the first working medium from the second heat exchanger 120 to the first turbine 130; a first temperature sensor 520, the first temperature sensor 520 is provided on the first main path 510, and the first temperature sensor 520 is used to detect a first temperature of the first working medium at the outlet of the second heat exchanger 120; a first regulating valve 530, the first regulating valve 530 is arranged on the first main path 510, and the first regulating valve 530 is located between the first temperature sensor 520 and the first turbine 130; a first branch 540, one end of the first branch 540 is connected to the first regulating valve 530, and the other end of the first branch 540 is connected to the first main path 510 between the first regulating valve 530 and the first turbine 130, and the first branch 540 is configured to be provided for the first working medium; The first working medium flows from the first regulating valve 530 to the first main path 510; a heat accumulator 550 is arranged on the first branch 540 and is used to obtain heat from the first working medium; a second temperature sensor 560 is arranged between the other end of the first branch 540 and the first turbine 130 and is used to detect a second temperature of the first working medium; a controller (not shown) is communicatively connected to the first temperature sensor 520, the first regulating valve 530, the heat accumulator 550, and the second temperature sensor 560, respectively. The controller is used to control the first regulating valve 530 to open when the first temperature is higher than a first preset temperature, so that the heat accumulator 550 obtains part of the heat of the first working medium and mixes the first working medium from which heat is obtained with the first working medium from which heat is not obtained, so as to reduce the temperature of the first working medium; the controller is also used to control the first regulating valve 530 to increase its opening when the second temperature is higher than the first preset temperature, so that the second temperature is equal to or lower than the first preset temperature.

[0058] In this embodiment, the heat accumulator 550 can store the excess photovoltaic waste heat and solar thermal waste heat obtained by the first working fluid during the day, and release it at night to heat the first working fluid. The heated first working fluid enters the first turbine 130 to generate electricity, which can achieve the effect of valley cutting and peak filling.

[0059] This embodiment uses a local cooling method to lower the overall temperature, thereby improving the controllability of the cooling process.

[0060] Specifically, by providing a heat accumulator 550 to capture a portion of the heat of the first working fluid, the temperature of the portion of the first working fluid is reduced. The cooled first working fluid is then mixed with the uncooled first working fluid, causing the overall temperature of the first working fluid to decrease. By providing a second temperature sensor 560, which is communicatively connected to the controller, the second temperature sensor 560 can be used to monitor the second temperature of the mixed first working fluid and promptly and effectively feed the second temperature back to the controller, thereby enabling the controller to promptly adjust the opening of the first regulating valve 530 to increase the opening of the first regulating valve 530 so that the second temperature is equal to or lower than the first preset temperature, thereby ensuring the normal operation of the thermal storage bypass unit 500.

[0061] In this embodiment, the heat in the thermal storage at night may not be enough to raise the second temperature to within the optimal range, resulting in low photoelectric conversion efficiency. Furthermore, the minimum temperature at which the organic Rankine cycle power generation system can generate electricity depends on the type of organic matter. If the second temperature of the first working fluid at night falls below the corresponding minimum temperature, the organic Rankine cycle power generation system will not function properly.

[0062] Therefore, in some other embodiments, referring to FIG5 , the waste heat power generation system further includes a temperature regulating bypass unit 600, which includes: a third temperature sensor 610, which is arranged on the first branch 540, and is used to detect the third temperature of the first working medium at the outlet of the heat accumulator 550; a second regulating valve 620, which is arranged on the first branch 540, and is located between the third temperature sensor 610 and the first turbine 130; a second branch 630, wherein one end of the second branch 630 is connected to the second regulating valve 620, and the other end of the second branch 630 is connected to the first branch 540 between the second regulating valve 620 and the first turbine 130, and the second branch 630 is configured to allow the first working medium to flow from the second regulating valve 620 to the first branch 540; a heat pump 640, which is arranged on the second branch 630, and is used to increase The heat of the first working fluid; a fourth temperature sensor 650, the fourth temperature sensor 650 is arranged on the first branch 540 between the other end of the second branch 630 and the first turbine 130, and the fourth temperature sensor 650 is used to detect the fourth temperature of the first working fluid; the controller is communicated with the third temperature sensor 610, the second regulating valve 620, the heat pump 640 and the fourth temperature sensor 650 respectively, and the controller is used to control the first regulating valve 530 to open when the third temperature is lower than the second preset temperature, so as to guide all the first working fluid into the first branch 540, and control the second regulating valve 620 to open, so that the heat pump 640 increases the heat of at least part of the first working fluid, and mixes the first working fluid with increased heat with the first working fluid without increased heat to increase the temperature of the first working fluid; the controller is also used to control the opening of the second regulating valve 620 to increase when the fourth temperature is lower than the second preset temperature, so that the fourth temperature is greater than or equal to the second preset temperature.

[0063] In this embodiment, when the third temperature of the first working fluid is lower than the second preset temperature, the third temperature of the first working fluid is adjusted to be greater than or equal to the second preset temperature, so that the organic Rankine cycle power generation system can operate normally.

[0064] This embodiment uses a local heating method to increase the overall temperature, thereby improving the controllability of the heating process.

[0065] Specifically, the second regulating valve 620 can divert the first working fluid to facilitate localized temperature increase of the first working fluid; the heat pump 640 adds a portion of the heat to the first working fluid, and the heated first working fluid mixes with the unheated first working fluid, causing the overall temperature of the first working fluid to rise. A fourth temperature sensor 650 is provided, which is communicatively connected to the controller and can be used to monitor the fourth temperature of the mixed first working fluid and promptly and effectively feed the fourth temperature back to the controller, thereby enabling the controller to promptly adjust the opening of the second regulating valve 620 to increase the opening of the first regulating valve 530 so that the fourth temperature is greater than or equal to the second preset temperature, thereby ensuring the normal operation of the temperature control bypass unit 600.

[0066] It should be noted that the controller in the embodiment of the present application is independently provided relative to the first regulating valve 530 and the second regulating valve 620, and can separately control the first regulating valve 530 and the second regulating valve 620. In other embodiments, the first regulating valve 530 and the second regulating valve 620 are both integrated with a controller, and the second regulating valve 620 can operate independently of the first regulating valve 530 at night.

[0067] In the embodiment of the present application, the first working fluid is a dry working fluid, a wet working fluid or an isentropic working fluid.

[0068] Exemplarily, the first working fluid is a dry working fluid, which has a better heat recovery effect.

[0069] Specifically, the dry working fluid can be R245fa, R600, R600a, etc., the wet working fluid can be R134a, etc., and the isentropic working fluid can be R11, R142b, etc.

[0070] Please refer to Figure 1. An embodiment of the present application also provides a photovoltaic and solar thermal hybrid power station, including a photovoltaic power generation system 200, a solar thermal power generation system 300 and a waste heat power generation system 100. The waste heat power generation system 100 is any of the aforementioned waste heat power generation systems 100. The electricity generated by the photovoltaic power generation system 200, the solar thermal power generation system 300 and the waste heat power generation system 100 is all transmitted to the power storage device 400.

[0071] 1 and 2 , the first heat exchanger 110 of the waste heat power generation system 100 is used to obtain the photovoltaic waste heat generated by the photovoltaic power generation system 200 for a primary heat exchange with the first working fluid; the second heat exchanger 120 of the waste heat power generation system 100 is used to obtain the photovoltaic waste heat generated by the solar thermal power generation system 300 for a secondary heat exchange with the first working fluid.

[0072] Specifically, the photovoltaic and solar thermal hybrid power station of this embodiment adopts all the technical solutions of any of the aforementioned waste heat power generation systems 100, and therefore has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described one by one here.

[0073] In some embodiments, referring to Figures 1 and 2, a solar thermal power generation system 300 includes: a heat collection component (not shown), which is used to convert solar energy into thermal energy; a steam generating component 310, which is used to obtain the thermal energy converted by the heat collection component to exchange heat with a third working medium; a second turbine 320, which is connected to the steam generating component 310, and is used to use the third working medium after heat exchange to generate second mechanical work; a second generator 330, which is connected to the second turbine 320, and the second generator 330 is used to generate second mechanical work. The second generator 330 is used to obtain the second mechanical work for generating electricity; the air-cooling island 340, the second heat exchanger 120 connects the second turbine 320 and the air-cooling island 340, the second heat exchanger 120 is used to obtain the heat of the third working fluid after being utilized by the second turbine 320 for secondary heat exchange with the first working fluid, and the air-cooling island 340 is used to cool the third working fluid after heat exchange; the third pump 350, the third pump 350 connects the air-cooling island 340 and the steam generating assembly 310, and the third pump 350 is used to transport the cooled third working fluid to the steam generating assembly 310 to enter the heat exchange cycle.

[0074] In the solar thermal power generation system 300, sunlight is concentrated into a heat medium (usually molten salt) through a reflector or lens. The molten salt can exchange heat with a third working fluid, and the second turbine 320 can use the third working fluid after heat exchange to generate electricity.

[0075] It should be noted that the third working medium can be water, which is liquid water when in liquid state and water vapor when in gaseous state.

[0076] In other embodiments, the hydrodynamic circulation mode of the steam generating component 310 is natural circulation or forced circulation.

[0077] In this embodiment, the steam generating component 310 generally includes a second preheater, an evaporator, a steam drum and a superheater, and the liquid third working medium is heated to a gaseous third working medium through the second preheater, the evaporator, the steam drum and the superheater in sequence. If the liquid third working medium relies solely on density as a power to overcome resistance, it is a natural circulation process. If the liquid third working medium relies on a circulating pump to provide power to overcome resistance, it is a forced circulation process. The natural circulation process has a large circulation ratio and good self-compensation ability, that is, when the heat absorption of the circuit increases, the amount of circulating water increases accordingly, but in order to reduce flow resistance, a steam drum with a larger volume needs to be configured. The forced circulation process can provide sufficient pressure and capacity in startup, shutdown and other working conditions, and has a greater time advantage, but it will increase the system maintenance cost.

[0078] Referring to FIG. 3 , an embodiment of the present application further provides a waste heat power generation method, which is applied to any of the aforementioned waste heat power generation systems 100 , comprising:

[0079] S100: Obtain photovoltaic waste heat generated by a photovoltaic power generation system to perform heat exchange with a first working medium.

[0080] S200: Acquire the waste heat generated by the solar thermal power generation system to perform secondary heat exchange with the first working medium.

[0081] S300: Utilize the first working fluid after the secondary heat exchange to perform work to generate first mechanical work.

[0082] S400: Obtain first mechanical work to generate electricity.

[0083] S500: Cooling the first working fluid after use.

[0084] S600: transport the cooled first working medium to the first heat exchanger to enter a heat exchange cycle.

[0085] It should be noted that the waste heat power generation method of this embodiment is applied to any of the aforementioned waste heat power generation systems, and therefore has at least all the beneficial effects brought about by the technical solutions of the aforementioned embodiments, which will not be described one by one here.

[0086] It should be understood that the embodiments of the present application are not limited to the precise structures described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A waste heat power generation system, characterized in that: include: a first heat exchanger, wherein the first heat exchanger is used to obtain photovoltaic waste heat generated by the photovoltaic power generation system to perform a heat exchange with the first working medium; a second heat exchanger, the second heat exchanger being connected to the first heat exchanger, and the second heat exchanger being used to obtain waste heat generated by the solar thermal power generation system for secondary heat exchange with the first working medium; a first turbine connected to the second heat exchanger, the first turbine being configured to utilize the first working fluid after secondary heat exchange to perform work to generate first mechanical work; a first generator connected to the first turbine, the first generator being configured to obtain the first mechanical work to generate electricity; a condenser connected to the first turbine, the condenser being used to cool the first working medium after being utilized by the first turbine; A first pump is connected to the condenser and the first heat exchanger, and is used to transport the cooled first working medium to the first heat exchanger to enter a heat exchange cycle.

2. The waste heat power generation system according to claim 1, characterized in that: It also includes a photovoltaic waste heat recovery unit, which includes: A photovoltaic waste heat acquisition component, the photovoltaic waste heat acquisition component comprising a first pipe, the first pipe being used to connect to the photovoltaic power generation system, the first pipe containing a second working fluid, the second working fluid being used to acquire photovoltaic waste heat generated by the photovoltaic power generation system; a second pump connected to the first pipeline, the second pump being used to transport the second working fluid after obtaining the photovoltaic waste heat to the first heat exchanger for performing a heat exchange with the first working fluid; The photovoltaic waste heat acquisition component also includes a second pipeline, which is used to connect the photovoltaic power generation system and the first heat exchanger so that the second working medium after heat exchange is transmitted to the photovoltaic power generation system to enter the heat exchange cycle.

3. The waste heat power generation system according to claim 2, characterized in that: The photovoltaic waste heat acquisition component is a daily solar energy frequency division utilization component or a fixed solar energy frequency division utilization component.

4. The waste heat power generation system according to claim 1, characterized in that: It also includes a first preheater, which is arranged between the first turbine and the first condenser, and the first preheater is also arranged between the first pump and the first heat exchanger, and the first preheater is used to preheat the first working medium leaving the first pump.

5. The waste heat power generation system according to any one of claims 1 to 4, characterized in that: The system further includes a heat storage bypass unit, the heat storage bypass unit including: a first main path, the first main path connecting the second heat exchanger and the first turbine, and the first main path being configured to allow the first working medium to flow from the second heat exchanger to the first turbine; a first temperature sensor, the first temperature sensor being disposed on the first main path and configured to detect a first temperature of the first working medium at an outlet of the second heat exchanger; a first regulating valve, the first regulating valve being disposed on the first main line and located between the first temperature sensor and the first turbine; A first branch, one end of which is connected to the first regulating valve, and the other end of which is connected to the first regulating valve. The first branch is connected to the first main road between the first regulating valve and the first turbine, and is configured to allow the first working medium to flow from the first regulating valve to the first main road; a heat accumulator, the heat accumulator being arranged on the first branch and being used to obtain heat of the first working medium; a second temperature sensor, disposed between the other end of the first branch and the first turbine, the second temperature sensor being configured to detect a second temperature of the first working medium; a controller, the controller being communicatively connected to the first temperature sensor, the first regulating valve, the heat accumulator, and the second temperature sensor, respectively; the controller being configured to, when the first temperature is higher than a first preset temperature, control the first regulating valve to open so that the heat accumulator captures a portion of the heat of the first working fluid and mixes the first working fluid from which heat is captured with the first working fluid from which heat is not captured, thereby lowering the temperature of the first working fluid; and the controller being further configured to, when the second temperature is higher than the first preset temperature, control the first regulating valve to increase its opening so that the second temperature is equal to or lower than the first preset temperature.

6. The waste heat power generation system according to claim 5, characterized in that: The system further includes a temperature regulating bypass unit, the temperature regulating bypass unit including: a third temperature sensor, the third temperature sensor being disposed on the first branch and configured to detect a third temperature of the first working medium at the outlet of the heat accumulator; a second regulating valve, the second regulating valve being arranged on the first branch and located between the third temperature sensor and the first turbine; a second branch, one end of the second branch being connected to the second regulating valve, the other end of the second branch being connected to the first branch between the second regulating valve and the first turbine, the second branch being configured to allow the first working fluid to flow from the second regulating valve to the first branch; a heat pump, the heat pump being arranged on the second branch and being used to increase the heat of the first working medium; a fourth temperature sensor, disposed on the first branch between the other end of the second branch and the first turbine, and configured to detect a fourth temperature of the first working medium; The controller is communicatively connected to the third temperature sensor, the second regulating valve, the heat pump and the fourth temperature sensor respectively. The controller is used to control the first regulating valve to open when the third temperature is lower than the second preset temperature to guide all of the first working fluid into the first branch, and to control the second regulating valve to open so that the heat pump increases the heat of at least part of the first working fluid and mixes the first working fluid with increased heat with the first working fluid without increased heat to increase the temperature of the first working fluid; the controller is also used to control the opening of the second regulating valve to increase when the fourth temperature is lower than the second preset temperature so that the fourth temperature is greater than or equal to the second preset temperature.

7. The waste heat power generation system according to any one of claims 1 to 4, characterized in that: The first working fluid is a dry working fluid, a wet working fluid or an isentropic working fluid.

8. A photovoltaic and solar thermal hybrid power station, characterized in that: include: Photovoltaic power generation systems and solar thermal power generation systems; A waste heat power generation system, wherein the waste heat power generation system is the waste heat power generation system according to any one of claims 1 to 7; The first heat exchanger of the waste heat power generation system is used to obtain the photovoltaic waste heat generated by the photovoltaic power generation system to perform a heat exchange with the first working medium; The second heat exchanger of the waste heat power generation system is used to obtain the waste heat generated by the solar thermal power generation system to The first working medium undergoes secondary heat exchange.

9. The photovoltaic and solar thermal hybrid power station according to claim 8, characterized in that: The solar thermal power generation system comprises: A heat collection component, wherein the heat collection component is used to convert solar energy into thermal energy; a steam generating assembly, the steam generating assembly being used to obtain heat energy converted by the heat collecting assembly to exchange heat with a third working medium; a second turbine connected to the steam generating assembly, the second turbine being configured to utilize the third working fluid after heat exchange to perform work to generate second mechanical work; a second generator connected to the second turbine, the second generator being configured to obtain the second mechanical work to generate electricity; an air-cooling island, wherein the second heat exchanger connects the second turbine and the air-cooling island, the second heat exchanger is used to obtain heat from the third working fluid after being utilized by the second turbine for secondary heat exchange with the first working fluid, and the air-cooling island is used to cool the third working fluid after heat exchange; The third pump is connected to the air-cooling island and the steam generating assembly, and is used to transport the cooled third working medium to the steam generating assembly to enter a heat exchange cycle.

10. The photovoltaic and solar thermal hybrid power station according to claim 9, characterized in that: The hydrodynamic circulation mode of the steam generating assembly is natural circulation or forced circulation.

11. A waste heat power generation method, applied to the waste heat power generation system according to any one of claims 1 to 7, characterized in that: include: Acquire photovoltaic waste heat generated by the photovoltaic power generation system to perform heat exchange with the first working fluid; Acquire the waste heat generated by the solar thermal power generation system to perform secondary heat exchange with the first working fluid; utilizing the first working fluid after the secondary heat exchange to perform work to generate first mechanical work; obtaining the first mechanical work to generate electricity; cooling the first working fluid after being utilized; The cooled first working fluid is transported to the first heat exchanger to enter a heat exchange cycle.

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