A new type of photovoltaic system using flat cylindrical lenses for low magnification focusing is proposed by unifying solar power generation and solar heating. The solar energy is focused on a single crystal silicon cell to generate electricity, and the focused heat is transferred to the heat storage system – the heat island – to achieve cogeneration. A closed space is formed between the flat cylindrical lens and the thermal strip to prevent heat loss, Maximizing the utilization of thermal energy.
This paper elaborates on the design concept of an intelligent household photovoltaic photovoltaic heat generation comprehensive utilization system for cogeneration, and the main work is as follows:
(1) Through the study of traditional household solar energy systems, a new type of concentrator – irregular cylindrical flat lens – was designed, and a biaxial solar light tracking device was optimized. It can solve the problems of difficult production, uneven focusing, high cost, and low photoelectric conversion rate of traditional solar energy concentrator systems. By comparing with traditional fixed silicon solar cell systems, experiments were conducted to verify the design in this paper, which can improve power generation efficiency by 62%, At the same time, silicon photocells reduce usage by 80%.
(2) We have completed the design and experimental verification of low magnification concentrated solar panels. Through the study of traditional lenses, polycarbonate plastic was selected for the production of concentrated lenses. After experimental verification, the design fully meets the design requirements of intelligent household photovoltaic systems, achieving the effect of ultra white glass material. Moreover, the overall structure is simple and stable, solving the problem of high magnification concentrated solar system battery temperature and the need to add a cooling system The problem of low photoelectric conversion efficiency and high cost. Considering that the entire system designed in this article needs to work stably in remote areas for a long time, its RAMS and LLC are optimal.
(3) For the northern region of China, research has been conducted on heat storage devices, circulating cooling heat transfer systems, and a new CPV/T system thermal system has been designed. After theoretical analysis and derivation calculations, it has been concluded that in the northern region of China, using heat island thermal storage not only does not increase renovation costs, but also achieves the advantages of heat generation and storage of the solar energy system proposed in this article.
(4) Based on the CPV/T system, this article conducts research on islanding effects on the user side, analyzes different detection methods for islanding effects, and proposes the use of correlation function synchronous sampling method to detect unplanned islanding through model derivation. This method has high reliability and can avoid pollution to the power grid without affecting power supply quality.
(5) A design of three-phase rotating active solar inverters is proposed to address the serious electromagnetic pollution, high cost, and high safety risks of active solar inverters. Similar to ordinary generators, when the voltage and frequency are close, when the phase is synchronized and integrated into the grid, it will be pulled into synchronization by the grid. Even if the grid fails, it will not have catastrophic consequences and can completely solve the above shortcomings.
We have built an experimental platform for the comprehensive utilization of low magnification photovoltaic heating in smart households, and conducted experimental research under different conditions. The ultimate goal is to provide comprehensive solutions to energy problems in rural areas, especially remote areas, in China, and to master intelligent household low magnification concentrated solar cogeneration technology with independent intellectual property rights. If this goal can be achieved, it can greatly improve the quality of life in rural areas, especially in remote areas, and greatly promote the goal of achieving carbon neutrality and peak carbon emissions. Based on this goal, there are two major follow-up tasks that need to be done:
1.Further optimize and improve the completed intelligent household photovoltaic photovoltaic thermal comprehensive utilization system.
(1) Conduct year-round experimental research on the intelligent household photovoltaic photovoltaic heat generation comprehensive utilization system with low magnification, accumulate experimental data under different meteorological conditions and seasons, and conduct comparative research.
(2) Conduct an economic analysis on the comprehensive utilization system of low magnification concentrated light for intelligent household photovoltaic photovoltaic heating, and compare it with other similar systems.
(3) Improve the processing technology of cylindrical flat lenses. The polycarbonate board carving process currently used to produce flat cylindrical lenses has the advantages of flexible processing and convenient modification, but the processing cost is high, which is not conducive to large-scale production. Further research is needed to produce polycarbonate cylindrical flat lenses using extrusion methods; Or design new rolling processes to produce ultra white glass cylindrical flat lenses, making quality more guaranteed and cost lower.
2.Preliminary design of small-scale networking for the comprehensive utilization system of photovoltaic and photovoltaic heating for subsequent smart households, and establishment of a demonstration area for cogeneration utilization of 100 households.
(1) Build a 220 volt residential power grid environment in the laboratory and test the performance of three-phase rotating active solar inverters.
(2) Concentrate the electricity produced by small-scale networking on the grid, further optimize household grid equipment, and make full use of grid equipment to reduce the cost of household photovoltaic photovoltaic heating comprehensive utilization system.
(3) Further research and optimize the detection methods for islanding effects, and move the detection points to the grid side.
(4) Establish centralized heat storage stations, timely utilize thermal energy, and further avoid thermal energy storage losses.
(5) Add remote control equipment and adjust the tracking system of the sun more intelligently to achieve the goal of fully utilizing solar energy, while also observing and collecting more solar operation data.
(6) Summarize actual operating data, establish mathematical models, and develop planning and design software for the comprehensive utilization system of household photovoltaic heat generation with low magnification, providing theoretical guidance and auxiliary tools for future large-scale applications.