Concentrating photovoltaic and photo-thermal integrated energy supply system and control method thereof

Abstract

The invention discloses a concentrating photovoltaic and photo-thermal integrated energy supply system and a control method thereof, and relates to the technical field of solar energy supply, and the concentrating photovoltaic and photo-thermal integrated energy supply system comprises a solar energy receiving device, a heat exchanger, a heat supply pipeline, a centrifuge, a thin working medium container, a thick working medium container, a main pipeline, a first branch and a second branch, the heat supply pipeline is connected with the evaporation side of the heat exchanger; the solar energy receiving device comprises a condensing lens, a heat-collecting light-transmitting tube and a photovoltaic module; the condensing lens and the photovoltaic module are respectively positioned on two opposite sides of the heat-collecting light-transmitting tube; the heat collection light-transmitting pipe and the condensation side of the heat exchanger are sequentially arranged on the main pipeline. The end, close to the heat exchanger, of the main pipeline is connected with the centrifuge. The first branch is sequentially connected with the centrifuge, the dilute working medium container and the main pipeline; the second branch is sequentially connected with the centrifuge, the concentrated working medium container and the main pipeline; the heat conduction working medium is a solid-liquid two-phase fluid formed by mixing solid particles and a liquid matrix.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic and thermal integration, and in particular to a concentrated photovoltaic and thermal integration energy supply system and a control method thereof. Background Art

[0002] Oilfield production, gathering, and transportation consume significant amounts of energy. Heavy oil production and transportation, in particular, require significant amounts of heat to reduce crude oil viscosity and improve fluidity. Furthermore, significant amounts of electricity are required to operate various production equipment.

[0003] Traditionally, oilfields have relied primarily on traditional fossil fuels for power and heating, which not only increases carbon emissions but also leads to high operating costs. With the development of renewable energy technologies, solar energy, as a clean energy source, has gradually become a vital supplement to the oilfield sector. Currently, while solar energy technology has been applied in oil and gas extraction and transportation, these applications are typically limited to single-use photovoltaic or solar thermal systems. These solar systems can only meet the single heating or power needs of oilfield production and are unable to adapt to the oilfield's fluctuating energy demands. Consequently, oilfields are forced to rely on additional electricity or electric heating equipment to meet their energy needs, which not only wastes energy but also increases production costs. Furthermore, the demand for electricity and heat in oil and gas production and transportation typically has a specific ratio, which varies with the seasons and the different stages of the production process. Traditional solar photovoltaic and solar thermal systems only provide a fixed ratio of electricity to heat output, making it difficult to achieve flexible adjustment.

[0004] To improve energy efficiency and reduce costs, there is an urgent need to develop a solar energy device that can dynamically match the supply of electricity and heat to the actual needs of the oil field. This device will be able to better adapt to the energy needs of oil field production, reduce dependence on the external power grid, and achieve sustainable energy utilization. Summary of the Invention

[0005] The main purpose of the present invention is to propose a concentrated photovoltaic and solar thermal integrated energy supply system and its control method, aiming to achieve both photovoltaic and solar thermal energy supply and dynamically match the supply of electricity and heat energy according to the actual needs of the oil field, that is, to achieve flexible and adjustable ratio of electricity and heat output.

[0006] To achieve the above-mentioned objectives, the present invention proposes a concentrated photovoltaic and photothermal integrated energy supply system, which includes a solar receiving device, a heat exchanger, a heating pipeline, a centrifuge, a dilute working fluid container, a concentrated working fluid container, a main pipeline, a first branch and a second branch, wherein the heating pipeline is connected to the evaporation side of the heat exchanger; the solar receiving device includes a focusing lens, a heat-collecting transparent tube and a photovoltaic module, and the focusing lens and the photovoltaic module are respectively located on opposite sides of the heat-collecting transparent tube; the heat-collecting transparent tube and the condensing 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 to the centrifuge; the first branch is sequentially connected to the centrifuge, the dilute working fluid container and the end of the main pipeline close to the solar receiving device; the second branch is sequentially connected to the centrifuge, the concentrated working fluid container and the end of the main pipeline close to the solar receiving device; a heat-conducting working fluid is provided in the main pipeline, the first branch and the second branch, and the heat-conducting working fluid is a solid-liquid two-phase fluid formed by a mixture of solid particles and a liquid matrix.

[0007] In one embodiment, the solar energy receiving device further includes a first flow valve and a second flow valve; the first flow valve is arranged in the first branch and is located between the dilute working fluid container and the heat collecting light transmitting tube; the second flow valve is arranged in the second branch and is located between the concentrated working fluid container and the heat collecting light transmitting tube.

[0008] In one embodiment, the concentrated photovoltaic and solar thermal integrated energy supply system also includes a first working fluid pump, a second working fluid pump and a third working fluid pump; the first working fluid pump is arranged on the main line and located between the heat exchanger and the centrifuge; the second working fluid pump is arranged on the first branch line and located between the dilute working fluid container and the first flow valve; the third working fluid pump is arranged on the second branch line and located between the concentrated working fluid container and the second flow valve.

[0009] In one embodiment, the concentrated photovoltaic and solar thermal integrated energy supply system further includes a working fluid reflux cylinder, which is provided on the main pipe and located between the heat exchanger and the first working fluid pump.

[0010] In one embodiment, the concentrated photovoltaic and thermal integrated energy supply system further includes a premixer, which is arranged on the main line, the input end of the premixer is connected to the first branch and the second branch, and the output end of the premixer is connected to the heat-collecting transparent tube.

[0011] In one embodiment, the photovoltaic assembly includes a photovoltaic panel and a battery.

[0012] In one embodiment, the focusing lens is a Fresnel lens.

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

[0014] The present invention further provides a control method for a concentrated photovoltaic and thermal integrated energy supply system, which is implemented based on the concentrated photovoltaic and thermal integrated energy supply system described in the above embodiment. The control method for the concentrated photovoltaic and thermal integrated energy supply system includes the following steps: Obtain the required ratio of electrical energy to thermal energy for oil field production; Determining the ratio of the opening of the first flow valve to the opening of the second flow valve according to the demand ratio of electric energy to thermal energy required for oil field production; The first flow valve and the second flow valve are opened according to the ratio of the opening degree of the first flow valve to the opening degree of the second flow valve.

[0015] In one embodiment, the step of determining the ratio of the opening of the first flow valve to the opening of the second flow valve according to the demand ratio of electrical energy to thermal energy required for oil field production is specifically as follows: Obtain the heat collection efficiency of the heat-collecting transparent tube and the photoelectric conversion efficiency of the photovoltaic module; 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:

[0016] in, and Respectively represent the opening of the first flow valve and the opening of the second flow valve, is the molar absorption coefficient of the working fluid, 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 collection efficiency of the heat collecting transparent tube, and They represent the working fluid concentration in the dilute working fluid container and the working fluid concentration in the rich working fluid container respectively.

[0017] The concentrated photovoltaic and photothermal integrated energy supply system proposed in the present invention includes a solar receiving device, a heat exchanger, a heating pipeline, a centrifuge, a dilute working fluid container, a concentrated working fluid container, a main pipeline, a first branch and a second branch, and the heating pipeline is connected to the evaporation side of the heat exchanger; the solar receiving device includes a focusing lens, a heat-collecting transparent tube and a photovoltaic module, and the focusing lens and the photovoltaic module are respectively located on opposite sides of the heat-collecting transparent tube; the heat-collecting transparent tube and the condensation side of the heat exchanger are arranged in sequence on the main pipeline, and the end of the main pipeline close to the heat exchanger is connected to the centrifuge; the first branch is connected in sequence to the centrifuge, the dilute working fluid container and the end of the main pipeline close to the solar receiving device; the second branch is connected in sequence to the centrifuge, the concentrated working fluid container and the end of the main pipeline close to the solar receiving device; a heat-conducting working fluid is provided in the main pipeline, the first branch and the second branch, and the heat-conducting working fluid is a solid-liquid two-phase fluid formed by a mixture of solid particles and a liquid matrix. The present invention's integrated photovoltaic and solar-thermal energy supply system can adjust the ratio of working fluids delivered by dilute and concentrated working fluid containers to the heat-collecting transparent tube according to the ratio of electricity and heat required for oilfield production. Mixing different ratios of concentrated and dilute working fluids results in different optical properties, particularly changes in optical transmittance. As the working fluid concentration changes, the working fluid's optical transmittance and absorptivity in the heat-collecting transparent tube also change. In a solar receiving device, sunlight is first focused by a concentrating lens and then passes through the heat-collecting transparent tube. Solar radiation within the working fluid's spectral absorption range is absorbed and converted into thermal energy by the working fluid. Solar radiation within the working fluid's spectral transmission range passes through the heat-collecting transparent tube and falls on the photovoltaic module, where it is further converted into electrical energy. In other words, changes in working fluid concentration alter the working fluid's spectral transmission characteristics, thereby enabling pre-distribution of energy flows for solar photovoltaic and solar-thermal conversion, and further regulating the ratio of thermal and electrical energy output. This achieves both photovoltaic and solar-thermal energy supply and dynamically matches electrical and thermal energy supply to the actual needs of the oilfield. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0019] Figure 1 This is a structural diagram of an embodiment of a concentrated photovoltaic and thermal integrated energy supply system provided by the present invention; Figure 2 for Figure 1 A partial enlarged view of the solar energy receiving device; Figure 3 Flowchart of the control method of the concentrated photovoltaic and thermal integrated energy supply system provided by the present invention; Figure 4 The spectral transmittance of the PS-PDMS working fluid at different concentrations provided by one embodiment of the present invention; Figure 5 The IV characteristic curves of photovoltaic modules under different working fluid concentrations provided by an embodiment of the present invention; Figure 6 The maximum power generation and fill factor curves of photovoltaic modules under different working fluid concentrations provided by an embodiment of the present invention; Figure 7 This is a table of electrical / heat output ratios corresponding to different working fluid concentrations after mixing provided by an embodiment of the present invention.

[0020] Description of Figure Numbers: 100. Concentrating photovoltaic and solar thermal integrated energy supply system; 1. Main pipeline; 11. Solar energy receiving device; 111. Concentrating lens; 112. Heat-collecting light-transmitting tube; 113. Photovoltaic module; 12. Heat exchanger; 13. First working fluid pump; 14. Centrifuge; 15. Premixer; 16. Working fluid reflux cylinder; 2. First branch; 21. Diluted working fluid container; 22. First flow valve; 23. Second working fluid pump; 3. Second branch; 31. Concentrated working fluid container; 32. Second flow valve; 33. Third working fluid pump; 4. Heating pipeline.

[0021] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0023] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0024] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0025] The present invention proposes a concentrated photovoltaic and solar-thermal integrated energy supply system 100 .

[0026] See also Figure 1 and Figure 2 In one embodiment of the present invention, the concentrated photovoltaic and thermal integrated energy supply system 100 includes a solar receiving device 11, a heat exchanger 12, a heating pipeline 4, a centrifuge 14, a dilute working medium container 21, a concentrated working medium container 31, a main pipeline 1, a first branch 2 and a second branch 3, the heating pipeline 4 is connected to the evaporation side of the heat exchanger 12; the solar receiving device 11 includes a focusing lens 111, a heat collecting transparent tube 112 and a photovoltaic module 113, the focusing lens 111 and the photovoltaic module 113 are respectively located on opposite sides of the heat collecting transparent tube 112; the heat collecting transparent tube 112 is connected to the evaporation side of the heat exchanger 12; the solar receiving device 11 includes a focusing lens 111, a heat collecting transparent tube 112 and a photovoltaic module 113, and the focusing lens 111 and the photovoltaic module 113 are respectively located on opposite sides of the heat collecting transparent tube 112; 12 and the condensing side of the heat exchanger 12 are sequentially arranged on the main line 1, and the end of the main line 1 close to the heat exchanger 12 is connected to the centrifuge 14; the first branch 2 is sequentially connected to the centrifuge 14, the dilute working fluid container 21 and the end of the main line 1 close to the solar energy receiving device 11; the second branch 3 is sequentially connected to the centrifuge 14, the concentrated working fluid container 31 and the end of the main line 1 close to the solar energy receiving device 11; the main line 1, the first branch 2 and the second branch 3 are all provided with a heat-conducting working fluid, which is a solid-liquid two-phase fluid formed by a mixture of solid particles and a liquid matrix.

[0027] In this embodiment, the integrated concentrated photovoltaic and solar-thermal energy supply system 100 is used to provide electricity and heat for oilfield production, gathering, and transportation, and can dynamically adjust output based on the oilfield's real-time demand ratio for electricity and heat. The system comprises a solar receiver 11, a heat exchanger 12, a heat supply pipeline 4, a centrifuge 14, a dilute fluid container 21, a concentrated fluid container 31, a main pipeline 1, a first branch 2, a second branch 3, and a control unit. The internally circulating heat-conducting working fluid is a nanoparticle dispersion system, i.e., a solid-liquid two-phase fluid composed of solid particles and a liquid matrix, wherein the solid particles are uniformly dispersed in the matrix liquid. The solid particles are characterized by a size of 20 to 500 nm, insolubility in the matrix liquid, and high absorptivity within the spectral response range of the photovoltaic module 113. These particles include, but are not limited to, chemically modified microspheres such as SiO2 and Al2O3, organic particles such as PMMA with dyes added, or core-shell structures coated with various composite materials. The liquid matrix is ​​a clear and transparent liquid that can maintain a high optical transmittance within 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 be kept free of large-scale optical absorption within the wavelength range of 350~1100nm. In this case, pure water, silicone oil, biphenyl-diphenyl ether eutectic, etc. can be selected as the liquid matrix.

[0028] Please refer to Figures 4 to 7 To verify the ability of working fluid concentration to adjust the system's electrical / thermal output ratio, an experiment was conducted. The working fluid used was dimethyl silicone oil (PDMS) as the base fluid, and polystyrene (PS) microspheres as the particles. When the concentration of the mixed working fluid varied, the thermal and electrical outputs of the solar receiver also varied significantly.

[0029] The solar energy receiver 11 converts solar radiation into both electrical and thermal energy, pre-distributing the two. It comprises a concentrating lens 111, a heat-collecting transparent tube 112, and a photovoltaic module 113. The concentrating lens 111 and photovoltaic module 113 are located on opposite sides of the heat-collecting transparent tube 112. The concentrating lens 111 focuses sunlight onto the heat-collecting transparent tube 112. The solid-liquid two-phase fluid within the tube absorbs a portion of the spectral energy, converting it into heat. The remaining spectral energy passes through the heat-collecting transparent tube 112 and reaches the photovoltaic module 113, converting it into electrical energy. By varying the concentration of solid particles in the fluid, its optical transmittance and absorptivity can be altered, thereby adjusting the energy distribution ratio between solar thermal and photovoltaic energy.

[0030] Heat exchanger 12 transfers the high-temperature heat energy carried by the working fluid to heating pipeline 4, and then to the heat-consuming end of the oilfield, such as the crude oil heating coil. Heating pipeline 4 is connected to the evaporation side of heat exchanger 12, and main pipeline 1 is connected to the condensation side of heat exchanger 12. It should be noted that the working fluid in this system condenses on the condensation side of heat exchanger 12 and transfers heat energy to heating pipeline 4. The working fluid transported from outside the system in heating pipeline 4 evaporates on the evaporation side of heat exchanger 12, absorbs heat energy, and then transfers it to the heating equipment in the oilfield.

[0031] The centrifuge 14 uses centrifugal force to separate the solid-liquid two-phase fluid into a dilute working fluid and a concentrated working fluid according to the particle concentration. The dilute working fluid container 21 and the concentrated working fluid container 31 store low-concentration and high-concentration solid-liquid two-phase fluids, respectively. The first branch 2 is connected in sequence to the centrifuge 14, the dilute working fluid container 21, and the end of the main line 1 close to the solar energy receiving device 11; the second branch 3 is connected in sequence to the centrifuge 14, the concentrated working fluid container 31, and the end of the main line 1 close to the solar energy receiving device 11, that is, the first branch 2 and the second branch 3 are arranged in parallel. The end of the main line 1 close to the heat exchanger 12 is connected to the centrifuge 14, so that the working fluid circulates between the solar energy receiving device 11, the heat exchanger 12, the centrifuge 14, and the container.

[0032] This system can control the ratio of the working fluid delivered from the dilute working fluid container 21 to the concentrated working fluid container 31 to the heat-collecting transparent tube 112. Different ratios of concentrated and dilute working fluids have different optical properties after mixing, especially the optical transmittance. As the working fluid concentration changes, the optical transmittance and absorptivity of the working fluid in the heat-collecting transparent tube 112 will also change. In the solar receiving device 11, sunlight is first concentrated by the focusing lens 111 and then passes through the heat-collecting transparent tube 112. Solar radiation within the spectral absorption range of the working fluid is absorbed and converted into thermal energy of the working fluid. Solar radiation within the spectral transmission range of the working fluid will pass through the heat-collecting transparent tube 112 and fall on the photovoltaic module 113, and further converted into electrical energy. That is, changes in the working fluid concentration will change the working fluid spectral transmission characteristics, thereby achieving pre-distribution of energy flow for controlling solar photovoltaic conversion and photothermal conversion, and then achieving regulation of the output ratio of thermal energy and electrical energy, achieving both photovoltaic and photothermal energy supply and dynamically matching electrical energy and thermal energy supply according to the actual needs of the oil field.

[0033] Further, see Figure 1 In one embodiment of the present invention, the solar energy receiving device 11 further includes a first flow valve 22 and a second flow valve 32; the first flow valve 22 is arranged in the first branch 2 and is located between the lean working fluid container 21 and the heat collecting light transmitting tube 112; the second flow valve 32 is arranged in the second branch 3 and is located between the rich working fluid container 31 and the heat collecting light transmitting tube 112.

[0034] In this embodiment, the first flow valve 22 is used to adjust the flow of the dilute working fluid into the heat-collecting light-transmitting tube 112, and the second flow valve 32 is used to adjust the flow of the concentrated working fluid into the heat-collecting light-transmitting tube 112. By independently regulating the opening of the two valves by the control unit, the mixing ratio of the dilute and concentrated working fluids can be continuously changed within the range of 0–100%, thereby precisely adjusting the solid phase concentration within the heat-collecting light-transmitting tube 112, thereby achieving rapid and precise matching of the photothermal and photovoltaic output ratios. For example, both the first flow valve 22 and the second flow valve 32 can be electric ball valves, with the valve body made of stainless steel CF8, the valve core being a full-bore sphere, the actuator being a 24 V DC switch or a 4–20 mA analog input, and the full-open to full-close action time being ≤5 s, which can meet the needs of rapid on-site adjustment.

[0035] Further, see Figure 1 In one embodiment of the present invention, the concentrated photovoltaic and solar thermal integrated energy supply system 100 also includes a first working fluid pump 13, a second working fluid pump 23 and a third working fluid pump 33; the first working fluid pump 13 is arranged on the main line 1 and is located between the heat exchanger 12 and the centrifuge 14; the second working fluid pump 23 is arranged on the first branch line 2 and is located between the dilute working fluid container 21 and the first flow valve 22; the third working fluid pump 33 is arranged on the second branch line 3 and is located between the concentrated working fluid container 31 and the second flow valve 32.

[0036] In this embodiment, the system is additionally provided with a first working fluid pump 13, a second working fluid pump 23 and a third working fluid pump 33. The first working fluid pump 13 is located between the outlet of the heat exchanger 12 of the main line 1 and the inlet of the centrifuge 14, providing the kinetic energy required for the mixed working fluid to enter the centrifuge 14, thereby ensuring the efficiency of solid-liquid separation. The second working fluid pump 23 is installed between the outlet of the dilute working fluid container 21 of the first branch line 2 and the first flow valve 22, maintaining the forward flow of the dilute working fluid and preventing particle deposition and reverse flow. The third working fluid pump 33 is installed between the outlet of the concentrated working fluid container 31 of the second branch line 3 and the second flow valve 32, maintaining the forward flow of the concentrated working fluid and preventing particle deposition and reverse flow. For example, the above three working fluid pumps can all be magnetically driven centrifugal pumps, and the pump body and impeller are made of high-temperature resistant materials to adapt to high-temperature working fluids.

[0037] Further, see Figure 1 In one embodiment of the present invention, the concentrated photovoltaic and solar thermal integrated energy supply system 100 further includes a working fluid reflux cylinder 16 , which is provided on the main line 1 and located between the heat exchanger 12 and the first working fluid pump 13 .

[0038] In this embodiment, considering the fluctuations in the outlet flow and temperature of the heat exchanger 12, the pressure at the suction port of the first working fluid pump 13 is unstable, cavitation occurs, and particle scouring occurs, which affects the life of the pump and the centrifuge 14. This embodiment solves this problem by providing a working fluid reflux cylinder 16, which plays a role in stabilizing pressure and buffering. For example, the working fluid reflux cylinder 16 can adopt a vertical cylindrical structure, with an exhaust valve provided at the top and a sewage valve provided at the bottom. The inlet is connected tangentially, and the injected working fluid flows along the cylinder wall and then flows into the bottom of the cylinder, which plays a buffering role. The outlet is located at the bottom of the side of the cylinder, and is offset from the inlet.

[0039] Further, see Figure 1 In one embodiment of the present invention, the concentrated photovoltaic and thermal integrated energy supply system 100 also includes a premixer 15, which is arranged on the main line 1, and the input end of the premixer 15 is connected to the first branch 2 and the second branch 3, and the output end of the premixer 15 is connected to the heat collecting transparent tube 112.

[0040] In this embodiment, if the low-concentration working fluid flowing from the first branch 2 and the high-concentration working fluid flowing from the second branch 3 are not fully and evenly mixed before entering the heat-collecting, light-transmitting tube 112, a concentration gradient will form within the tube, resulting in abrupt changes in spectral absorption or transmission characteristics. This in turn causes an instability in the light-heat and light-photoelectric distribution ratio, impacting system control accuracy. Therefore, this embodiment provides a premixer 15 on the main line 1. In this premixer 15, the dilute and concentrated working fluids are forcibly and evenly blended to form a solid-liquid two-phase fluid with consistent concentrations before being introduced into the heat-collecting, light-transmitting tube 112, thereby ensuring constant axial optical performance of the tube section. Exemplarily, the premixer 15 is a static mixing element. Its outer shell is a short stainless steel tube of the same diameter as the main line 1, with welded flanges at both ends. Staggered spiral blades or corrugated plates are installed internally, fully welded to the tube wall. The fluid is repeatedly divided, flipped, and merged within the static spiral blades to achieve uniform dispersion of solid particles in the liquid phase. The optical properties of the mixed fluid are determined solely by the final concentration, eliminating local overheating or overcooling caused by stratification. The static mixer has no rotating parts, and its temperature and pressure resistance are consistent with the main line 1, and the maintenance requirement is low. If space is limited, a dynamic mixer with a stirring shaft can also be selected, but it is necessary to pay attention to adding seals and drive parts.

[0041] Specifically, in one embodiment of the present invention, the photovoltaic assembly 113 includes a photovoltaic panel and a battery.

[0042] In this embodiment, the technical function of the photovoltaic panel is to directly convert sunlight into DC electricity, which can be used to power oilfield equipment or charge batteries. The structural features of a photovoltaic panel are generally similar to those of a standard solar panel, consisting of multiple photovoltaic cells connected in series or parallel, with a sealed surface and wiring terminals. Photovoltaic panel technology is relatively mature, and existing technologies can be selected based on needs. For example, photovoltaic panels can be made of single-crystal silicon, polycrystalline silicon, thin-film, perovskite, or other materials that can convert sunlight into electricity through the photovoltaic effect.

[0043] The technical function of batteries is to store excess electricity generated by photovoltaic panels and release it during periods of low or no sunlight (such as at night or on cloudy days) or during peak electricity demand, ensuring the continuity and stability of electricity supply to oilfields. Their structural characteristics include an energy storage device with positive and negative electrodes, an electrolyte, and a casing. Possible options include lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and more advanced lithium-ion batteries and flow batteries. In this embodiment, considering the high energy density, cycle life, and low-temperature performance requirements that oilfields may have, lithium iron phosphate (LiFePO4) batteries are preferred. These batteries offer excellent safety, a long cycle life, and a wide operating temperature range, making them suitable for use in field environments. Their basic function is the chemical storage and release of electrical energy.

[0044] The collaborative relationship between photovoltaic panels and batteries is reflected in the dynamic balance of energy supply and demand. Specifically, the DC power generated by the photovoltaic panels first passes through a charge controller (not shown separately in the figure, but typically included in the control unit). This controller manages the charging process based on the PV panel's output power and the battery's state of charge (SOC), preventing overcharging or over-discharging and protecting the battery. When the power generated by the photovoltaic panels exceeds the oilfield's immediate power demand, the excess power is stored in the battery via the charge controller. When the power generated by the photovoltaic panels is insufficient to meet the oilfield's needs, or at night when there is no sunlight, the battery supplies power to the oilfield loads via an inverter (if the oilfield equipment requires AC power) or directly (if the equipment uses DC power). This collaborative relationship enables the entire energy supply system to not only generate electricity from solar energy but also, through the battery's energy storage function, smooth the output power and cope with intermittent solar resources. This improves power supply reliability and self-sufficiency, reduces dependence on the external grid, and further reduces operating costs and carbon emissions.

[0045] Further, see Figure 2 In one embodiment of the present invention, the focusing lens 111 is a Fresnel lens.

[0046] In this embodiment, the concentrating lens 111 uses a Fresnel lens. This lens has a composite structure of a flat surface and a toothed shape, composed of a transparent polymer sheet integrally formed with concentric annular ridges and a flat base. This lens retains the light-gathering ability of a convex lens while significantly reducing thickness and weight, facilitating modular installation and low-cost replacement. Under sunny conditions, the annular ridges refract parallel sunlight and converge it at the center of the heat-collecting and transparent tube 112, significantly improving light-gathering efficiency compared to traditional lenses or reflectors.

[0047] Furthermore, in one embodiment of the present invention, the heat-collecting light-transmitting tube 112 is a single-layer or multi-layer high-transmittance glass tube.

[0048] It should be noted that multi-layer refers to two or more layers. In this embodiment, high-transmittance glass tubes are selected to maximize the transmittance of sunlight, ensuring that as much light energy as possible reaches the heat transfer medium within the tube or the subsequent photovoltaic panels, thereby improving the efficiency of photothermal or photoelectric conversion. Glass materials inherently possess excellent weather resistance, corrosion resistance, and high mechanical strength, making them suitable for long-term stable operation in complex outdoor environments. For example, highly transparent quartz glass tubes or organic glass tubes can be used.

[0049] In this embodiment, the heat-collecting and light-transmitting tube 112 can be configured as a multi-layer structure. This is primarily to enhance thermal insulation, impact resistance, and mechanical strength while maintaining high light transmittance. When used in large-scale heat-collecting and light-transmitting devices, the length and dimensions of the heat-collecting and light-transmitting tube 112 are relatively large. In this case, adopting a multi-layer tube structure and evacuating or filling the interlayer with an inert gas can significantly reduce heat loss from the heat transfer medium within the tube or the photovoltaic panel absorbing heat. Furthermore, compared to single-layer glass tubes, multi-layer structures (especially if the inner layer is thinner and the outer layer is thicker or reinforced) generally have better impact resistance and overall mechanical strength, making them more resistant to external impacts such as hail and flying rocks, as well as accidental damage during transportation and installation, thereby extending the service life of the equipment.

[0050] The present invention further provides a control method for a concentrated photovoltaic and thermal integrated energy supply system 100. Based on the concentrated photovoltaic and thermal integrated energy supply system 100 in the above embodiment, the control method for the concentrated photovoltaic and thermal integrated energy supply system 100 includes the following steps: Obtain the required ratio of electrical energy to thermal energy for oil field production; 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 electric energy to thermal energy required for oil field production; The first flow valve 22 and the second flow valve 32 are opened according to the ratio of the opening degree of the first flow valve 22 to the opening degree of the second flow valve 32 .

[0051] In this embodiment, S1: obtaining the demand ratio of electric energy to thermal energy required for oil field production in real time.

[0052] This ratio reflects the intensity of the oilfield's demand for the two energy sources at a given moment. For example, in winter or when processing high-viscosity heavy oil, thermal energy demand may far exceed electrical energy demand. In certain highly automated processes, electrical energy demand may dominate. This ratio can be obtained by real-time monitoring of the loads of various electrical and heating equipment, or by estimating it based on pre-set production plans and operating condition models.

[0053] S2: Determine the ratio of the opening of the first flow valve 22 to the opening of the second flow valve 32 according to the acquired demand ratio of electric energy to thermal energy.

[0054] By adjusting the ratio of the opening of the first flow valve 22 to the opening of the second flow valve 32, the ratio of the working fluid delivered by the dilute working fluid container 21 and the concentrated working fluid container 31 to the heat-collecting transparent tube 112 can be controlled. The mixture of concentrated and dilute working fluids of different ratios has different optical properties, especially the optical transmittance will change. As the concentration of the working fluid changes, the optical transmittance and absorptivity of the working fluid in the heat-collecting transparent tube 112 will also change. The change in the working fluid concentration will change the spectral transmittance characteristics of the working fluid, thereby achieving the pre-distribution of the energy flow for controlling solar photovoltaic conversion and photothermal conversion, and then achieving the regulation of the output ratio of heat energy and electrical energy, realizing the balance of photovoltaic and photothermal energy supply and dynamically matching the supply of electrical energy and heat energy according to the actual needs of the oil field.

[0055] S3: opening the first flow valve 22 and the second flow valve 32 according to the determined opening ratio of the first flow valve 22 and the second flow valve 32 .

[0056] The specific opening ratio calculated in step S2 is not the specific opening value. The specific opening value can be selected based on the opening ratio calculated in step S2 and further considering the pressure range to be controlled for the safe operation of the system and the relationship between the photothermal or photoelectric conversion efficiency and the flow rate. However, the consideration of system safe operation and photoelectric conversion efficiency is common knowledge in this field. Therefore, this embodiment only limits the ratio of the dilute working fluid and the concentrated working fluid, that is, the opening of the first flow valve 22 and the second flow valve 32 is controlled according to the specific opening ratio calculated by S2.

[0057] In one embodiment, the steps of determining the ratio of the opening of the first flow valve 22 to the opening of the second flow valve 32 according to the required ratio of electrical energy to thermal energy required for oil field production are specifically as follows: Obtaining the heat collection efficiency of the heat collection and light transmission tube 112 and the photoelectric conversion efficiency of the photovoltaic module 113; 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:

[0058] in, and Respectively represent the opening of the first flow valve 22 and the opening of the second flow valve 32, is the molar absorptivity, is the optical path length, is the ratio of electrical energy to thermal energy, is the photoelectric conversion efficiency of the photovoltaic module 113, is the heat collection efficiency of the heat collection transparent tube 112, and They represent the working fluid concentration in the lean working fluid container 21 and the working fluid concentration in the rich working fluid container 31 respectively.

[0059] In this embodiment, according to the Lambert-Beer law, the transmittance of the mixed working fluid is:

[0060] The photovoltaic power generation capacity is:

[0061] in is the focusing efficiency of the focusing lens 111.

[0062] When the scattering coefficient of the working fluid is small, the optical absorption rate of the working fluid can be considered to be , from which the thermal output power of the photothermal part can be obtained as:

[0063] The electrical / heat output ratio is:

[0064] According to the above four formulas, we can deduce and The relationship:

[0065] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformation made by utilizing the contents of the present invention's description and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A concentrated photovoltaic and thermal integrated energy supply system, characterized in that: The concentrated photovoltaic and thermal integrated energy supply system includes a solar energy receiving device, a heat exchanger, a heating pipeline, a centrifuge, a dilute working fluid container, a concentrated working fluid container, a main pipeline, a first branch pipeline, and a second branch pipeline. The heating pipeline is connected to the evaporation side of the heat exchanger. The solar energy receiving device includes a concentrating lens, a heat-collecting light-transmitting tube, and a photovoltaic module, wherein the concentrating lens and the photovoltaic module are respectively located on opposite sides of the heat-collecting light-transmitting tube; The heat collecting light-transmitting tube and the condensing side of the heat exchanger are sequentially arranged on the main pipe, and one end of the main pipe close to the heat exchanger is connected to the centrifuge; The first branch is connected in sequence to the centrifuge, the dilute fluid container, and one end of the main line close to the solar energy receiving device; The second branch is connected in sequence to the centrifuge, the concentrated working medium container, and the end of the main line close to the solar energy receiving device; Heat-conducting medium is provided in the main line, the first branch line and the second branch line. The heat-conducting medium is a solid-liquid two-phase fluid formed by a mixture of solid particles and a liquid matrix.

2. The concentrated photovoltaic and thermal integrated energy supply system according to claim 1, characterized in that: The solar energy receiving device further includes a first flow valve and a second flow valve; The first flow valve is provided on the first branch and is located between the lean working medium container and the heat collecting light-transmitting tube; The second flow valve is provided on the second branch and is located between the concentrated working medium container and the heat-collecting light-transmitting tube.

3. The concentrated photovoltaic and thermal integrated energy supply system according to claim 2, characterized in that: The concentrated photovoltaic and thermal integrated energy supply system further includes a first working fluid pump, a second working fluid pump and a third working fluid pump; The first working fluid pump is provided on the main pipe and located between the heat exchanger and the centrifuge; The second working fluid pump is provided on the first branch and is located between the lean working fluid container and the first flow valve; The third working medium pump is provided on the second branch and is located between the concentrated working medium container and the second flow valve.

4. The concentrated photovoltaic and thermal integrated energy supply system according to claim 3, characterized in that: The concentrated photovoltaic and thermal integrated energy supply system further includes a working fluid reflux cylinder, which is arranged on the main pipe and located between the heat exchanger and the first working fluid pump.

5. The concentrated photovoltaic and thermal integrated energy supply system according to claim 1, characterized in that: The concentrated photovoltaic and thermal integrated energy supply system also includes a premixer, which is arranged on the main line. The input end of the premixer is connected to the first branch and the second branch, and the output end of the premixer is connected to the heat-collecting transparent tube.

6. The concentrated photovoltaic and thermal integrated energy supply system according to any one of claims 1 to 5, characterized in that: The photovoltaic assembly includes a photovoltaic panel and a battery.

7. The concentrated photovoltaic and thermal integrated energy supply system according to any one of claims 1 to 5, characterized in that: The focusing lens is a Fresnel lens.

8. The concentrated photovoltaic and solar thermal integrated energy supply system according to any one of claims 1 to 5, characterized in that: The heat-collecting light-transmitting tube is a single-layer or multi-layer glass tube with high light transmittance.

9. A control method for a concentrated photovoltaic and solar thermal integrated energy supply system, implemented based on the concentrated photovoltaic and solar thermal integrated energy supply system according to any one of claims 2 to 8, characterized in that: The control method of the concentrated photovoltaic and thermal integrated energy supply system comprises the following steps: Obtain the required ratio of electrical energy to thermal energy for oil field production; Determining the ratio of the opening of the first flow valve to the opening of the second flow valve according to the demand ratio of electric energy to thermal energy required for oil field production; The first flow valve and the second flow valve are opened according to the ratio of the opening degree of the first flow valve to the opening degree of the second flow valve.

10. The control method of the concentrated photovoltaic and solar thermal integrated energy supply system according to claim 9, characterized in that: The step of determining the ratio of the opening of the first flow valve to the opening of the second flow valve according to the demand ratio of electric energy to thermal energy required for oil field production is specifically as follows: Obtain the heat collection efficiency of the heat-collecting transparent tube and the photoelectric conversion efficiency of the photovoltaic module; 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: in, and Respectively represent the opening of the first flow valve and the opening of the second flow valve, is the molar absorptivity, 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 collection efficiency of the heat collecting transparent tube, and They represent the working fluid concentration in the dilute working fluid container and the working fluid concentration in the rich working fluid container respectively.

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