A concentrated photovoltaic and photo-thermal integrated energy supply system and a control method thereof

Abstract

The application discloses a concentrated photovoltaic and light heat integrated energy supply system and a control method thereof, and relates to the technical field of solar energy supply.The concentrated photovoltaic and light heat integrated energy supply system comprises a solar energy receiving device, a heat exchanger, a heat supply pipeline, a centrifugal device, a dilute working medium container, a concentrated working medium container, a main pipeline, a first branch pipeline and a second branch pipeline, and the heat supply pipeline is connected with an evaporation side of the heat exchanger.The solar energy receiving device comprises a condensing lens, a heat collecting and light transmitting pipe and a photovoltaic module, the condensing lens and the photovoltaic module are located on opposite sides of the heat collecting and light transmitting pipe, the heat collecting and light transmitting pipe and a condensation side of the heat exchanger are sequentially arranged on the main pipeline, one end of the main pipeline close to the heat exchanger is connected with the centrifugal device, the first branch pipeline is sequentially connected with the centrifugal device, the dilute working medium container and the main pipeline, the second branch pipeline is sequentially connected with the centrifugal device, the concentrated working medium container and the main pipeline, and the heat conducting working medium is a solid-liquid two-phase fluid formed by mixing solid particles and a liquid matrix.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic and photo-thermal integration, and particularly relates to a concentrated photovoltaic and photo-thermal integrated energy supply system and a control method thereof. BACKGROUND

[0002] Oil fields consume a large amount of energy in oil extraction, gathering and transportation, especially in the process of heavy oil extraction and transportation, which requires a large amount of heat energy to reduce the viscosity of crude oil and improve its flowability. In addition, a large amount of electrical energy is also needed to operate various extraction equipment.

[0003] In traditional technology, oil fields mainly rely on traditional fossil energy for power supply and heat supply, which not only increases carbon emissions but also brings high operating costs. With the development of renewable energy technology, solar energy has gradually become an important supplement in the oil field as a clean energy. Currently, solar technology has been applied to oil and gas extraction and gathering processes, but these applications are usually limited to single forms of photovoltaic or photo-thermal. Such solar systems can only meet the single heat or power supply needs in oil field production, and cannot adapt to the changing energy needs of oil fields. Therefore, oil fields have to rely on additional power or electric heating equipment to meet energy needs during production, which not only leads to energy waste but also increases production costs. Moreover, the demand for electrical and thermal energy in oil and gas production and gathering processes often has a specific ratio, which changes with the seasons and different stages of the production process. Traditional solar photovoltaic and photo-thermal energy supply equipment can only provide a fixed ratio of electrical and thermal output, making it difficult to achieve flexible adjustment.

[0004] In order to improve energy utilization efficiency and reduce costs, it is urgent to develop a solar energy supply device that can dynamically match electrical and thermal energy supply according to the actual needs of oil fields. Such a device will better adapt to the energy needs of oil field production, reduce dependence on external power grids, and achieve sustainable use of energy. SUMMARY

[0005] The main purpose of the present application is to provide a concentrated photovoltaic and photo-thermal integrated energy supply system and a control method thereof, aiming to realize photovoltaic and photo-thermal energy supply and dynamically match electrical and thermal energy supply according to the actual needs of oil fields, i.e. to realize flexible adjustment of the ratio of electrical and thermal output.

[0006] To achieve the above object, the application provides a concentrated photovoltaic and photo-thermal integrated energy supply system, which comprises a solar energy receiving device, a heat exchanger, a heat supply pipeline, a centrifugal device, a dilute working medium container, a concentrated working medium container, a main pipeline, a first branch pipeline and a second branch pipeline, the heat supply pipeline is connected with an evaporation side of the heat exchanger; the solar energy receiving device comprises a concentrated lens, a heat collecting and light transmitting pipe and a photovoltaic assembly, the concentrated lens and the photovoltaic assembly are respectively located on opposite sides of the heat collecting and light transmitting pipe; the heat collecting and light transmitting pipe and a condensation side of the heat exchanger are sequentially arranged on the main pipeline, one end of the main pipeline close to the heat exchanger is connected with the centrifugal device; the first branch pipeline is sequentially connected with the centrifugal device, the dilute working medium container and one end of the main pipeline close to the solar energy receiving device; the second branch pipeline is sequentially connected with the centrifugal device, the concentrated working medium container and one end of the main pipeline close to the solar energy receiving device; heat conducting working medium is arranged in the main pipeline, the first branch pipeline and the second branch pipeline, and the heat conducting working medium is a solid-liquid two-phase fluid formed by mixing solid particles and liquid matrix.

[0007] In an embodiment, the solar energy receiving device further comprises a first flow valve and a second flow valve; the first flow valve is arranged in the first branch pipeline and located between the dilute working medium container and the heat collecting and light transmitting pipe; the second flow valve is arranged in the second branch pipeline and located between the concentrated working medium container and the heat collecting and light transmitting pipe.

[0008] In an embodiment, the concentrated photovoltaic and photo-thermal integrated energy supply system further comprises a first working medium pump, a second working medium pump and a third working medium pump; the first working medium pump is arranged on the main pipeline and located between the heat exchanger and the centrifugal device; the second working medium pump is arranged on the first branch pipeline and located between the dilute working medium container and the first flow valve; the third working medium pump is arranged on the second branch pipeline and located between the concentrated working medium container and the second flow valve.

[0009] In an embodiment, the concentrated photovoltaic and photo-thermal integrated energy supply system further comprises a working medium return cylinder, which is arranged on the main pipeline and located between the heat exchanger and the first working medium pump.

[0010] In an embodiment, the concentrated photovoltaic and photo-thermal integrated energy supply system further comprises a premixer, which is arranged on the main pipeline, an input end of the premixer is connected with the first branch pipeline and the second branch pipeline, and an output end of the premixer is connected with the heat collecting and light transmitting pipe.

[0011] In an embodiment, the photovoltaic assembly comprises a photovoltaic panel and a storage battery.

[0012] In an embodiment, the concentrated lens is a Fresnel lens.

[0013] In an embodiment, the light collecting and transmitting tube is a single-layer or multi-layer high light transmittance glass tube.

[0014] The application further provides a control method of the concentrating photovoltaic and photo-thermal integrated energy supply system, which is realized based on the concentrating photovoltaic and photo-thermal integrated energy supply system as described in the above embodiments. The control method of the concentrating photovoltaic and photo-thermal integrated energy supply system comprises the following steps:

[0015] obtaining a demand ratio of electric energy and heat energy required by oilfield production;

[0016] determining a ratio of the opening degree of the first flow valve and the opening degree of the second flow valve according to the demand ratio of electric energy and heat energy required by oilfield production;

[0017] opening the first flow valve and the second flow valve according to the ratio of the opening degree of the first flow valve and the opening degree of the second flow valve.

[0018] In an embodiment, the step of determining the ratio of the opening degree of the first flow valve and the opening degree of the second flow valve according to the demand ratio of electric energy and heat energy required by oilfield production is specifically:

[0019] obtaining a heat collecting efficiency of the light collecting and transmitting tube and a photoelectric conversion efficiency of the photovoltaic module;

[0020] calculating the ratio of the opening degree of the first flow valve and the opening degree of the second flow valve according to the following formula:

[0021]

[0022] wherein, and respectively represent the opening degree of the first flow valve and the opening degree of the second flow valve, is a molar light absorption coefficient of the working medium, is a light path length, is the ratio of electric energy and heat energy, is the photoelectric conversion efficiency of the photovoltaic module, is the heat collecting efficiency of the light collecting and transmitting tube, and respectively represent the working medium concentration in the dilute working medium container and the working medium concentration in the concentrated working medium container.

[0023] The concentrating photovoltaic and photo-thermal integrated energy supply system provided by the application comprises a solar energy receiving device, a heat exchanger, a heat supply pipeline, a centrifugal device, a dilute working medium container, a concentrated working medium container, a main pipeline, a first branch pipeline and a second branch pipeline, the heat supply pipeline is connected with the evaporation side of the heat exchanger; the solar energy receiving device comprises a concentrating lens, a heat collecting and light transmitting pipe and a photovoltaic module, the concentrating lens and the photovoltaic module are respectively located on the opposite sides of the heat collecting and light transmitting pipe; the heat collecting and light transmitting pipe and the condensation side of the heat exchanger are sequentially arranged on the main pipeline, and the end of the main pipeline close to the heat exchanger is connected with the centrifugal device; the first branch pipeline is sequentially connected with the centrifugal device, the dilute working medium container and the end of the main pipeline close to the solar energy receiving device; the second branch pipeline is sequentially connected with the centrifugal device, the concentrated working medium container and the end of the main pipeline close to the solar energy receiving device; the main pipeline, the first branch pipeline and the second branch pipeline are all provided with a heat conducting working medium, and the heat conducting working medium is a solid-liquid two-phase fluid formed by mixing solid particles and liquid matrix. The concentrating photovoltaic and photo-thermal integrated energy supply system can adjust the proportion of the working medium delivered by the dilute working medium container and the concentrated working medium container to the heat collecting and light transmitting pipe according to the required energy supply proportion of electricity and heat in oilfield production, the concentrated and dilute working medium mixed in different proportions has different optical properties, especially the optical transmittance will change. With the change of the concentration of the working medium, the optical transmittance and the absorption rate of the working medium in the heat collecting and light transmitting pipe will also change. In the solar energy receiving device, the sunlight is first converged by the concentrating lens and then passes through the heat collecting and light transmitting pipe, the solar radiation in the spectral absorption range of the working fluid is absorbed and converted into heat energy of the working fluid, and the solar radiation in the spectral transmittance range of the working fluid will pass through the heat collecting and light transmitting pipe and fall on the photovoltaic module and be further converted into electric energy, that is, the change of the concentration of the working medium will change the spectral transmittance characteristics of the working medium, so as to realize the pre-distribution of the energy flow of the solar photoelectric conversion and the photo-thermal conversion, and further realize the regulation of the output proportion of the heat energy and the electric energy, and realize the supply of the photovoltaic and photo-thermal energy and the dynamic matching of the supply of the electric energy and the heat energy according to the actual demand of the oilfield. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and other drawings can also be obtained according to the structures shown in these drawings without any creative labor for those skilled in the art.

[0025] Figure 1 The structure schematic diagram of an embodiment of the concentrating photovoltaic and photo-thermal integrated energy supply system provided by the present application;

[0026] Figure 2 The structure schematic diagram of an embodiment of the concentrating photovoltaic and photo-thermal integrated energy supply system provided by the present application; Figure 1 The local enlarged view of the solar energy receiving device in the embodiment;

[0027] Figure 3The flow chart of the control method of the concentrating photovoltaic and photo-thermal integrated energy supply system provided by the application;

[0028] Figure 4 The PS-PDMS working medium spectral transmittance under different concentrations provided by an embodiment of the application;

[0029] Figure 5 The I-V characteristic curve of the photovoltaic module under different concentrations of working medium provided by an embodiment of the application;

[0030] Figure 6 The maximum power generation and fill factor curve of the photovoltaic module under different concentrations of working medium provided by an embodiment of the application;

[0031] Figure 7 The table of the electricity / heat output ratio corresponding to different concentrations of working medium after mixing provided by an embodiment of the application.

[0032] Explanation of reference signs:

[0033] 100, concentrating photovoltaic and photo-thermal integrated energy supply system;

[0034] 1, main pipeline; 11, solar energy receiving device; 111, concentrating lens; 112, heat collecting and light transmitting pipe; 113, photovoltaic module; 12, heat exchanger; 13, first working medium pump; 14, centrifugal device; 15, pre-mixer; 16, working medium return cylinder;

[0035] 2, first branch; 21, dilute working medium container; 22, first flow valve; 23, second working medium pump;

[0036] 3, second branch; 31, concentrated working medium container; 32, second flow valve; 33, third working medium pump;

[0037] 4, heat supply pipeline.

[0038] The implementation, functional features and advantages of the application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0040] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, motion condition, etc. between components in a certain posture, and if the certain posture changes, the directional indications will also change accordingly.

[0041] In addition, if the embodiments of the present application involve descriptions such as "first", "second", etc., the descriptions of "first", "second", etc. are only for description purposes and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can be explicitly or implicitly included at least one of the features. In addition, "and / or" or "and / or" appearing throughout the text means that the three parallel schemes are included, for example, "A and / or B" includes A scheme, or B scheme, or A and B simultaneously satisfy the scheme. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of the ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor within the scope of protection required by the present application.

[0042] The present application provides a concentrated photovoltaic and photo-thermal integrated energy supply system 100.

[0043] Please refer to Figure 1 and Figure 2 In an embodiment of the present application, the concentrated photovoltaic and photo-thermal integrated energy supply system 100 comprises a solar energy receiving device 11, a heat exchanger 12, a heat supply pipeline 4, a centrifugal device 14, a dilute working medium container 21, a concentrated working medium container 31, a main pipeline 1, a first branch pipeline 2 and a second branch pipeline 3, the heat supply pipeline 4 is connected with the evaporation side of the heat exchanger 12; the solar energy receiving device 11 comprises a condensing lens 111, a heat collecting and light transmitting pipe 112 and a photovoltaic module 113, the condensing lens 111 and the photovoltaic module 113 are respectively located on the opposite sides of the heat collecting and light transmitting pipe 112; the heat collecting and light transmitting pipe 112 and the condensing side of the heat exchanger 12 are sequentially arranged on the main pipeline 1, and the end of the main pipeline 1 close to the heat exchanger 12 is connected with the centrifugal device 14; the first branch pipeline 2 is sequentially connected with the centrifugal device 14, the dilute working medium container 21 and the end of the main pipeline 1 close to the solar energy receiving device 11; the second branch pipeline 3 is sequentially connected with the centrifugal device 14, the concentrated working medium container 31 and the end of the main pipeline 1 close to the solar energy receiving device 11; the main pipeline 1, the first branch pipeline 2 and the second branch pipeline 3 are all provided with a heat conducting working medium, and the heat conducting working medium is a solid-liquid two-phase fluid formed by mixing solid particles and liquid matrix.

[0044] In the embodiment, the concentrating photovoltaic and photo-thermal integrated energy supply system 100 is used to provide electric energy and thermal energy for oil extraction, gathering and other scenes in oil fields, and can dynamically adjust the output according to the real-time demand ratio of electric energy and thermal energy in the oil field. The system is composed of a solar receiver 11, a heat exchanger 12, a heat supply pipeline 4, a centrifugal device 14, a dilute working medium container 21, a concentrated working medium container 31, a main pipeline 1, a first branch pipeline 2, a second branch pipeline 3 and a control unit. The heat-conducting working medium circulating inside is a nano-particle dispersion system, that is, a solid-liquid two-phase fluid formed by mixing solid particles and a liquid matrix. The solid particles are uniformly dispersed in the matrix liquid. The characteristics of the solid particles are that the size is 20-500 nm, and the solid particles cannot be dissolved in the matrix liquid and can maintain a high absorption rate in the spectral response range of the photovoltaic module 113, including but not limited to chemically modified SiO2, Al2O3 microspheres, dye-added PMMA organic particles or various composite-coated core-shell structure particle materials. The liquid matrix is a clear and transparent liquid, which can maintain a high optical transmittance in the spectral response range of the photovoltaic module 113. If a single-crystal silicon photovoltaic cell is used in the photovoltaic module 113, the working fluid should not have a large range of optical absorption in the wavelength range of 350-1100 nm. At this time, the liquid matrix can be selected, for example, pure water, silicone oil, biphenyl-diphenyl ether eutectic, etc.

[0045] Please refer to Figures 4 to 7 In order to verify the adjustment ability of the working medium concentration change on the system electric / thermal output ratio, experiments are carried out. In the experiment, the working medium base liquid uses dimethyl silicone oil (PDMS), and the particles use polystyrene (Polystyrene, PS) microspheres. When the concentration of the mixed working medium changes, the output power of the thermal energy and the electric energy of the solar receiver will also change obviously.

[0046] The solar receiver 11 converts the solar radiation into electric energy and thermal energy, and can "pre-distribute" between the two, including a concentrating lens 111, a heat-collecting and light-transmitting pipe 112 and a photovoltaic module 113. The concentrating lens 111 and the photovoltaic module 113 are located on the opposite sides of the heat-collecting and light-transmitting pipe 112. The concentrating lens 111 converges sunlight to the heat-collecting and light-transmitting pipe 112. The solid-liquid two-phase fluid in the pipe absorbs part of the spectral energy and converts it into thermal energy. The unabsorbed spectrum transmits through the heat-collecting and light-transmitting pipe 112 to the photovoltaic module 113 and is converted into electric energy. By changing the concentration of the solid particles in the fluid, the optical transmittance and absorption rate of the fluid can be changed, so as to adjust the energy distribution ratio of photo-thermal and photo-electric.

[0047] The heat exchanger 12 transmits the high-temperature heat energy carried by the working medium to the heat supply pipeline 4, and then to the heat end of the oil field, such as the crude oil heating coil. The heat supply pipeline 4 is connected with the evaporation side of the heat exchanger 12, and the main pipeline 1 is connected with the condensation side of the heat exchanger 12. It needs to be explained that the working medium in the system condenses at the condensation side of the heat exchanger 12 and transmits heat energy to the heat supply pipeline 4, and the working medium outside the system in the heat supply pipeline 4 evaporates at the evaporation side of the heat exchanger 12 and transmits heat energy to the heat-consuming equipment in the oil field after absorbing heat energy.

[0048] The centrifugal separator 14 separates the solid-liquid two-phase fluid into dilute working medium and concentrated working medium according to the particle concentration by centrifugal force. The dilute working medium container 21 and the concentrated working medium container 31 store the low-concentration and high-concentration solid-liquid two-phase fluid respectively. The first branch 2 is connected with the centrifugal separator 14, the dilute working medium container 21 and the end of the main pipeline 1 close to the solar energy receiving device 11 in sequence; the second branch 3 is connected with the centrifugal separator 14, the concentrated working medium container 31 and the end of the main pipeline 1 close to the solar energy receiving device 11 in sequence, that is, the first branch 2 and the second branch 3 are arranged in parallel. The end of the main pipeline 1 close to the heat exchanger 12 is connected with the centrifugal separator 14, so that the working medium forms a circulation among the solar energy receiving device 11, the heat exchanger 12, the centrifugal separator 14 and the containers.

[0049] The system can control the proportion of the working medium delivered by the dilute working medium container 21 and the concentrated working medium container 31 to the heat-collecting light-transmitting tube 112. The mixed concentrated and dilute working medium with different proportions has different optical properties, especially the optical transmittance changes. With the change of the concentration of the working medium, the optical transmittance and the absorption rate of the working medium in the heat-collecting light-transmitting tube 112 also change. In the solar energy receiving device 11, the sunlight is first converged by the condensing lens 111, and then passes through the heat-collecting light-transmitting tube 112. The solar radiation in the spectral absorption range of the working fluid is absorbed and converted into heat energy of the working fluid, and the solar radiation in the spectral transmission range of the working fluid transmits through the heat-collecting light-transmitting tube 112 and falls on the photovoltaic module 113 and is further converted into electrical energy. That is, the change of the concentration of the working medium changes the spectral transmission characteristics of the working medium, so as to realize the pre-distribution of the energy flow of the solar photoelectric conversion and the photo-thermal conversion, and further realize the regulation of the output proportion of the heat energy and the electrical energy, and realize the supply of the photovoltaic and the photo-thermal energy and the dynamic matching of the electrical energy and the heat energy supply according to the actual demand of the oil field.

[0050] Further, please refer to Figure 1 In an embodiment of the present application, the solar energy receiving device 11 further comprises a first flow valve 22 and a second flow valve 32; the first flow valve 22 is arranged in the first branch 2 and located between the dilute working medium container 21 and the heat-collecting light-transmitting tube 112; the second flow valve 32 is arranged in the second branch 3 and located between the concentrated working medium container 31 and the heat-collecting light-transmitting tube 112.

[0051] In the embodiment, the first flow valve 22 is used to adjust the flow of the dilute working medium into the light collecting and light transmitting pipe 112, and the second flow valve 32 is used to adjust the flow of the concentrated working medium into the light collecting and light transmitting pipe 112. Through independent control of the opening degrees of the two valves by the control unit, the mixing ratio of the dilute working medium and the concentrated working medium can be continuously changed in the range of 0-100%, so that the solid phase concentration in the light collecting and light transmitting pipe 112 is accurately adjusted, and then the rapid and fine matching of the photo-thermal and photo-electric output ratios is realized. Exemplarily, the first flow valve 22 and the second flow valve 32 can both be electric ball valves, the valve body material is selected to be stainless steel CF8, the valve core is a full-bore ball, the actuator is a 24 V DC switching quantity or a 4-20 mA analog quantity input, and the full opening to full closing action time is less than or equal to 5 seconds, which can meet the requirement of rapid adjustment on site.

[0052] Further, please refer to Figure 1 In an embodiment of the present application, the concentrated photovoltaic and photo-thermal integrated energy supply system 100 further comprises a first working medium pump 13, a second working medium pump 23 and a third working medium pump 33; the first working medium pump 13 is arranged on the main pipeline 1 and located between the heat exchanger 12 and the centrifugal separator 14; the second working medium pump 23 is arranged on the first branch pipeline 2 and located between the dilute working medium container 21 and the first flow valve 22; and the third working medium pump 33 is arranged on the second branch pipeline 3 and located between the concentrated working medium container 31 and the second flow valve 32.

[0053] In the embodiment, the first working medium pump 13, the second working medium pump 23 and the third working medium pump 33 are additionally arranged in the system. The first working medium pump 13 is located between the heat exchanger 12 outlet and the centrifugal separator 14 inlet of the main pipeline 1, and provides kinetic energy required for the mixed working medium to enter the centrifugal separator 14, so as to ensure the solid-liquid separation efficiency. The second working medium pump 23 is installed between the dilute working medium container 21 outlet and the first flow valve 22 of the first branch pipeline 2, and maintains the forward flow of the dilute working medium to prevent particle deposition and reverse flow. The third working medium pump 33 is installed between the concentrated working medium container 31 outlet and the second flow valve 32 of the second branch pipeline 3, and maintains the forward flow of the concentrated working medium to prevent particle deposition and reverse flow. Exemplarily, the above three working medium pumps can all be selected to be magnetic drive centrifugal pumps, and the pump body and impeller are made of high-temperature resistant materials to adapt to high-temperature working medium.

[0054] Further, please refer to Figure 1 In an embodiment of the present application, the concentrated photovoltaic and photo-thermal integrated energy supply system 100 further comprises a working medium backflow cylinder 16, which is arranged on the main pipeline 1 and located between the heat exchanger 12 and the first working medium pump 13.

[0055] In the embodiment, considering the fluctuation of the outlet flow and temperature of the heat exchanger 12, the first working medium pump 13 suction inlet pressure is unstable, cavitation and particle erosion, affecting the pump and centrifugal 14 life. The embodiment solves this problem by setting the working medium reflux cylinder 16, which plays a role in stabilizing and buffering. Exemplarily, the working medium reflux cylinder 16 can adopt a vertical cylindrical structure, the top is provided with an exhaust valve, the bottom is provided with a blowdown valve, the inlet is tangentially connected, and the injected working medium flows along the cylinder wall and then flows into the bottom of the cylinder, playing a buffering role. The outlet is located at the bottom of the side of the cylinder and is arranged in a staggered manner with the inlet.

[0056] Further, please refer to Figure 1 In an embodiment of the present application, the concentrated photovoltaic photothermal integrated energy supply system 100 further comprises a premixer 15, which is arranged on the main pipeline 1, the input end of the premixer 15 is connected with the first branch 2 and the second branch 3, and the output end of the premixer 15 is connected with the heat collecting and light transmitting pipe 112.

[0057] In the embodiment, if the low-concentration working medium flowing from the first branch 2 and the high-concentration working medium flowing from the second branch 3 are not sufficiently and uniformly mixed before entering the heat collecting and light transmitting pipe 112, a concentration gradient will be formed in the pipe, causing a sudden change in spectral absorption or transmission characteristics, and then causing unstable light-thermal and photoelectric distribution ratio, affecting the control precision of the system. Therefore, the premixer 15 is arranged on the main pipeline 1 in the embodiment, the dilute and concentrated working medium is forced to be uniformly mixed in the premixer 15, and then the solid-liquid two-phase fluid with uniform concentration is sent into the heat collecting and light transmitting pipe 112, so as to ensure the constant axial optical performance of the pipe section. Exemplarily, the premixer 15 is a static mixing element, the shell is a stainless steel short pipe with the same diameter as the main pipeline 1, the two ends are welded with flanges, the inside is provided with staggered spiral blades or corrugated plates, the blades are fixedly welded with the pipe wall, the fluid is divided, turned and combined multiple times in the static spiral blades, the uniform dispersion of the solid particles in the liquid is realized, the optical characteristics of the mixed fluid are only determined by the final concentration, and the local overheating or subcooling phenomenon caused by stratification is eliminated. The static mixer has no rotating parts, and the temperature resistance and pressure resistance are consistent with the main pipeline 1, so the maintenance amount is low; if the space is limited, a dynamic mixer with a stirring shaft can also be selected, but the sealing element and the driving element need to be increased.

[0058] Specifically, in an embodiment of the present application, the photovoltaic assembly 113 comprises a photovoltaic panel and a battery.

[0059] In this embodiment, the technical role of the photovoltaic panel is to directly convert light energy into direct current electrical energy to power oilfield equipment or charge the battery. The structural features of the photovoltaic panel are generally standard solar panels composed of multiple photovoltaic cell units connected in series or parallel, with encapsulated surfaces and wiring terminals. Photovoltaic panel technology is relatively mature and can be selected according to needs in existing technology, such as single-crystal silicon, polycrystalline silicon, or thin-film type, perovskite, or other photovoltaic panels that can convert light energy into electrical energy through the photovoltaic effect.

[0060] The technical role of the battery is to store excess electrical energy generated by the photovoltaic panel and release electrical energy during periods of insufficient or no light (such as at night or on cloudy days) or during peak demand for electrical energy to ensure the continuity and stability of power supply for oilfield equipment. Its structural features are energy storage devices with positive and negative electrodes, electrolytes, and casings. Possible options include lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and more advanced lithium-ion batteries, flow batteries, etc. In this embodiment, considering the higher requirements of oilfields on energy density, cycle life, and low-temperature performance, lithium iron phosphate (LiFePO4) batteries are preferred. This type of battery has good safety, long cycle life, and a wide operating temperature range, making it suitable for use in field environments. Its basic function is chemical storage and release of electrical energy.

[0061] The coordination between the photovoltaic panel and the battery is reflected in the dynamic balance of energy supply and demand. Specifically, the direct current generated by the photovoltaic panel first passes through a charge controller (not separately shown in the figure, but usually included in the control unit), which is responsible for managing the charging process based on the output power of the photovoltaic panel and the state of charge (SOC) of the battery to prevent overcharging or overdischarging and protect the battery. When the electrical energy generated by the photovoltaic panel is greater than the immediate power demand of the oilfield, the excess electrical energy is stored in the battery via the charge controller. When the electrical energy generated by the photovoltaic panel is insufficient to meet the demand of the oilfield, or at night when there is no light, the battery supplies power to the oilfield load via an inverter (if the oilfield equipment requires alternating current) or directly (if the equipment uses direct current). This coordination allows the entire energy supply system not only to generate electrical energy using solar energy, but also to smooth the output power through the energy storage function of the battery, to cope with intermittent solar resources, to improve the reliability and self-sufficiency of power supply, to reduce dependence on external power grids, and to further reduce operating costs and carbon emissions.

[0062] Further, please refer to Figure 2 In an embodiment of the present application, the condensing lens 111 is a Fresnel lens.

[0063] In the embodiment, the condensing lens 111 is a Fresnel lens. The lens is a composite structure of a plane and a tooth shape, which is composed of a transparent high polymer sheet integrally formed by a concentric annular ridge and a plane base. The lens not only retains the condensing ability of a convex lens, but also significantly reduces the thickness and weight, facilitating modular installation and low-cost replacement. Under sunlight conditions, the annular ridge refracts and converges the parallel sunlight to the center of the heat-collecting light-transmitting tube 112, significantly improving the condensing efficiency compared with traditional lenses or mirrors.

[0064] Further, in an embodiment of the present application, the heat-collecting light-transmitting tube 112 is a single-layer or multi-layer high-transmittance glass tube.

[0065] It should be noted that multi-layer refers to two or more layers. In the embodiment, high-transmittance glass tubes are selected to maximize the transmittance of sunlight, ensuring that as much light energy as possible can reach the heat transfer medium or subsequent photovoltaic panels inside the tube, thereby improving the photo-thermal or photo-electric conversion efficiency. Glass materials have good weather resistance, corrosion resistance, and high mechanical strength, making them suitable for long-term stable operation in complex outdoor environments. For example, high-transmittance quartz glass tubes or organic glass tubes can be used.

[0066] The embodiment can set the heat-collecting light-transmitting tube 112 as a multi-layer structure, mainly to enhance the thermal insulation performance and improve the impact resistance and mechanical strength while ensuring high transmittance. When the heat-collecting light-transmitting tube 112 is used in large-scale heat-collecting light-transmitting devices, the length and size of the heat-collecting light-transmitting tube 112 are relatively large. In this case, using a multi-layer tube structure and vacuumizing or filling inert gas in the interlayer can significantly reduce the heat loss of the heat transfer medium or photovoltaic panels after absorbing heat. Compared with single-layer glass tubes, multi-layer structures (especially if the inner layer is thin and the outer layer is thick or has been strengthened) generally have better impact resistance and overall mechanical strength, and can better resist external impacts such as hail, flying stones, and accidental damage during transportation and installation, thereby prolonging the service life of the equipment.

[0067] The present application also proposes a control method for the concentrating photovoltaic and photo-thermal integrated energy supply system 100, which is based on the concentrating photovoltaic and photo-thermal integrated energy supply system 100 as described in the above embodiment. The control method for the concentrating photovoltaic and photo-thermal integrated energy supply system 100 includes the following steps:

[0068] Obtain the demand ratio of electrical energy and thermal energy required for oilfield production;

[0069] Determine the ratio of the opening of the first flow valve 22 to the opening of the second flow valve 32 according to the demand ratio of electrical energy and thermal energy required for oilfield production;

[0070] Open the first flow valve 22 and the second flow valve 32 according to the ratio of the opening of the first flow valve 22 to the opening of the second flow valve 32.

[0071] In the present embodiment, S1: the ratio of the demand for electric energy and thermal energy required for oilfield production is obtained in real time.

[0072] This ratio reflects the demand intensity of the oilfield for the two forms of energy at a specific moment. For example, in winter or when processing high-viscosity heavy oil, the demand for thermal energy can be much greater than the demand for electric energy; while in some highly automated links, the demand for electric energy can dominate. Obtaining this ratio can be achieved by monitoring the load of each electrical equipment and heating equipment in real time, or by estimating according to the preset production plan and working condition model.

[0073] S2: According to the obtained ratio of the demand for electric energy and thermal energy, the ratio of the opening of the first flow valve 22 and the opening of the second flow valve 32 is determined.

[0074] Adjusting the ratio of the opening of the first flow valve 22 and the opening of the second flow valve 32 can control the proportion of the working medium delivered by the dilute working medium container 21 and the concentrated working medium container 31 to the heat-collecting light-transmitting tube 112. Different proportions of concentrated and dilute working medium mixed together have different optical properties, especially the optical transmittance will change. With the change of the concentration of the working medium, the optical transmittance and absorptivity of the working medium in the heat-collecting light-transmitting tube 112 will also change. The change of the concentration of the working medium will change the spectral transmittance characteristics of the working medium, thereby realizing the pre-distribution of the energy flow of solar photoelectric conversion and photothermal conversion, and further realizing the regulation of the proportion of thermal energy and electric energy output, achieving the consideration of photovoltaic and photothermal energy supply and dynamic matching of electric energy and thermal energy supply according to the actual demand of the oilfield.

[0075] S3: According to the determined ratio of the opening of the first flow valve 22 and the opening of the second flow valve 32, the first flow valve 22 and the second flow valve 32 are opened.

[0076] The specific opening ratio calculated in step S2 is not the specific opening value, and the specific opening value can be selected according to the opening ratio calculated in step S2 and further considering the pressure range to be controlled for safe operation of the system and the relationship between the photothermal or photoelectric conversion efficiency and the flow rate, but the consideration of system safe operation and photoelectric conversion efficiency is the common knowledge in the field, therefore the present embodiment only limits the ratio of dilute working medium and concentrated working medium, that is, the opening of the first flow valve 22 and the opening of the second flow valve 32 are controlled according to the specific opening ratio calculated in S2.

[0077] In an embodiment, the step of determining the ratio of the opening of the first flow valve 22 and the opening of the second flow valve 32 according to the ratio of the demand for electric energy and thermal energy required for oilfield production is specifically:

[0078] Obtaining the heat collection efficiency of the heat-collecting light-transmitting tube 112 and the photoelectric conversion efficiency of the photovoltaic module 113;

[0079] The ratio of the opening of the first flow valve 22 to the opening of the second flow valve 32 is calculated according to the following formula:

[0080]

[0081] wherein, and respectively represent the opening of the first flow valve 22 and the opening of the second flow valve 32, is the molar absorption coefficient, is the optical path length, is the ratio of electric energy to heat energy, is the photoelectric conversion efficiency of the photovoltaic module 113, is the heat collecting efficiency of the light-transmitting heat collecting tube 112, and respectively represent the working medium concentration in the dilute working medium container 21 and the working medium concentration in the concentrated working medium container 31.

[0082] In the embodiment, according to the Lambert-Beer law, the light transmittance of the mixed working medium is:

[0083]

[0084] The power generation of the photovoltaic is:

[0085]

[0086] wherein is the light condensing efficiency of the light condensing lens 111.

[0087] When the working medium scattering coefficient is small, the optical absorption rate of the working medium can be considered as , and thus the heat energy output power of the photo-thermal part is:

[0088]

[0089] The electric / heat output ratio is:

[0090]

[0091] According to the above four formulas, the relationship between and can be derived as:

[0092]

[0093] The above only describes exemplary embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made according to the technical concept of the present application, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A concentrating photovoltaic-photothermal integrated energy supply system, characterized in that, The concentrating photovoltaic and photo-thermal integrated energy supply system comprises a solar energy receiving device, a heat exchanger, a heat supply pipeline, a centrifugal device, a dilute working medium container, a concentrated working medium container, a main pipeline, a first branch pipeline and a second branch pipeline, and the heat supply pipeline is connected with the evaporation side of the heat exchanger; The solar energy receiving device comprises a concentrating lens, a heat collecting and light transmitting pipe and a photovoltaic assembly, and the concentrating lens and the photovoltaic assembly are respectively located on the opposite sides of the heat collecting and light transmitting pipe. The heat collecting and light transmitting pipe and the condensation side of the heat exchanger are sequentially arranged on the main pipeline, and one end of the main pipeline close to the heat exchanger is connected with the centrifugal device; The first branch pipeline is sequentially connected with the centrifugal device, the dilute working medium container and one end of the main pipeline close to the solar energy receiving device; The second branch pipeline is sequentially connected with the centrifugal device, the concentrated working medium container and one end of the main pipeline close to the solar energy receiving device; The main pipeline, the first branch pipeline and the second branch pipeline are all provided with a heat conducting working medium, and the heat conducting working medium is a solid-liquid two-phase fluid formed by mixing solid particles and liquid matrix; The solar energy receiving device further comprises a first flow valve and a second flow valve; The first flow valve is arranged in the first branch pipeline and located between the dilute working medium container and the heat collecting and light transmitting pipe; The second flow valve is arranged in the second branch pipeline and located between the concentrated working medium container and the heat collecting and light transmitting pipe.

2. The concentrating photovoltaic photothermal integrated energy supply system of claim 1, wherein, The concentrating photovoltaic and photo-thermal integrated energy supply system further comprises a first working medium pump, a second working medium pump and a third working medium pump; The first working medium pump is arranged on the main pipeline and located between the heat exchanger and the centrifugal device; The second working medium pump is arranged on the first branch pipeline and located between the dilute working medium container and the first flow valve; The third working medium pump is arranged on the second branch pipeline and located between the concentrated working medium container and the second flow valve.

3. The concentrating photovoltaic photothermal integrated energy supply system of claim 2, wherein, The concentrating photovoltaic and photo-thermal integrated energy supply system further comprises a working medium return cylinder, which is arranged on the main pipeline and located between the heat exchanger and the first working medium pump.

4. The concentrating photovoltaic photothermal integrated energy supply system of claim 1, wherein, The concentrating photovoltaic and photo-thermal integrated energy supply system further comprises a premixer, which is arranged on the main pipeline, the input end of the premixer is connected with the first branch pipeline and the second branch pipeline, and the output end of the premixer is connected with the heat collecting and light transmitting pipe.

5. The concentrating photovoltaic photothermal integrated energy supply system according to any one of claims 1 to 4, characterized in that, The photovoltaic assembly comprises a photovoltaic panel and a storage battery.

6. The concentrating photovoltaic photothermal integrated energy supply system according to any one of claims 1 to 4, characterized in that, The concentrating lens is a Fresnel lens.

7. The concentrating photovoltaic photothermal integrated energy supply system according to any one of claims 1 to 4, characterized in that, The heat collecting and light transmitting pipe is a single-layer or multi-layer high light transmittance glass pipe.

8. A control method of a concentrating photovoltaic and photo-thermal integrated energy supply system, implemented based on the concentrating photovoltaic and photo-thermal integrated energy supply system according to any one of claims 1 to 7, characterized in that, The control method of the concentrating photovoltaic and photo-thermal integrated energy supply system comprises the following steps: obtaining the demand ratio of electric energy and heat energy required by oilfield production; determining the ratio of the opening degree of the first flow valve to the opening degree of the second flow valve according to the demand ratio of electric energy and heat energy required by oilfield production; opening the first flow valve and the second flow valve according to the ratio of the opening degree of the first flow valve to the opening degree of the second flow valve. 9.The control method of the CPV-PV-PT integrated energy supply system according to claim 8, wherein, The step of determining the ratio of the opening degree of the first flow valve to the opening degree of the second flow valve according to the demand ratio of electric energy and heat energy required by oilfield production is specifically: obtaining the heat collecting efficiency of the heat collecting and light transmitting pipe and the photoelectric conversion efficiency of the photovoltaic assembly; The ratio of the opening of the first flow valve to the opening of the second flow valve is calculated according to the following formula: wherein, and respectively represent the opening degree of the first flow valve and the opening degree of the second flow valve, is the molar absorption coefficient, is the optical path length, is the ratio of electrical energy to thermal energy, is the photoelectric conversion efficiency of the photovoltaic module, is the heat collecting efficiency of the heat collecting and light transmitting tube, and respectively represent the working medium concentration in the dilute working medium container and the working medium concentration in the concentrated working medium container.

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