Solar Concentrating Modules With Louvered Heliostats - Advances in Environmental Engineering and Green Technologies
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Published By IGI Global

9781799842767, 9781799842774

In connection with the large-scale development of high-rise building projects recently in Russia and abroad and their significant energy consumption, one of the main principles in designing is the use of effective energy-saving technologies. Also, important aspects are reducing energy consumption and neutralizing the environmental impact of tall buildings. The most promising areas in the field of integration of solar modules (planar and concentrating) in the construction of buildings are development of BIPV technologies (roofing, film, facade materials), the integration of solar energy concentrators that do not require biaxial tracking (medium and low concentrations) on the facades and roofs of buildings (parabolic concentrators, lenses, and Fresnel mirrors), integration of highly concentrated modules on the roofs of buildings.


In connection with the large-scale development of high-rise building projects recently in Russia and abroad and their significant energy consumption, one of the main principles in designing is the use of effective energy-saving technologies. Also important aspects are reducing energy consumption and neutralizing the environmental impact of tall buildings. The most promising areas in the field of integration of solar modules (planar and concentrating) in the construction of buildings are development of BIPV technologies (roofing, film, facade materials), the integration of solar energy concentrators that do not require biaxial tracking (medium and low concentrations) on the facades and roofs of buildings (parabolic concentrators, lenses, and Fresnel mirrors), integration of highly concentrated modules on the roofs of buildings.


Artificial neural network (ANN) is initially used to forecast the solar insolation level and followed by the particle swarm optimisation (PSO) to optimise the power generation of the PV system based on the solar insolation level, cell temperature, efficiency of PV panel, and output voltage requirements. Genetic algorithm is a general-purpose optimization algorithm that is distinguished from conventional optimization techniques by the use of concepts of population genetics to guide the optimization search. Tabu search algorithm is a conceptually simple and an elegant iterative technique for finding good solutions to optimization problems. Simulated annealing algorithms appeared as a promising heuristic algorithm for handling the combinatorial optimization problems. Fuzzy logic algorithms set theory can be considered as a generation of the classical set theory. The artificial neural network (ANN)-based solar insolation forecast has shown satisfactory results with minimal error, and the generated PV power can be optimised significantly with the aids of the PSO algorithm.


Optical schemes and designs of four types of solar modules with louvered heliostats and concentrators with zero shading losses and blocking of solar radiation have been developed. The design of a compact thermal photovoltaic solar radiation detector for a non-tracking parabolic-cylindrical solar concentrator provides the thermal efficiency of the module in the range of 0,6–0,7, the service life of at least 25 years due to the sealing of the photoelectric elements using a two-component polysiloxane gel.


The principles of construction and operation of the main concentrating systems, including non-followable modules, are reviewed, and the work of the concentrators is analyzed. An analytical review of modern facade-integrated photovoltaic technologies was carried out, and their classification was given. The known methods for calculating a flat (two-dimensional) scheme for passing the sun's rays through a louvered heliostat make it impossible to assess the real effectiveness of using louvered heliostats with non-tracking solar concentrators, which makes it necessary to consider the practically important three-dimensional problem of calculating the solar radiation flux on the receiving surface of an unfollowing parabolic-cylindrical solar concentrator with louver heliostat.


The calculations confirm the high efficiency of using louvered heliostats. The maximum annual energy production by non-tracking solar concentrating modules is achieved with a vertical orientation of the concentrator, which is very important when placing solar modules on the southern facades of buildings. The annual amounts of insolation at the receiver for concentrators with a louvered heliostat with an angular aperture of 26° and 18°, respectively, are on average 2 and 3.4 times higher than the total insolation on a flat surface and 1,6 and 2,2 times higher than insolation by blind surface receiving concentrating modules with similar angular aperture values. The cost of electricity produced when using non-glare concentrating modules with louvre is reduced by 40–60% compared to concentrating modules without louver, and thermal energy by 50%.


The developed system of automatic measurement of the main parameters of a solar concentrating module with PV, PVT, and heat receivers allows you to save time during information processing, to obtain data on the dynamics of the processes in the solar concentrating module with the required measurement periodicity. The developed algorithm for calculating the passage of sunlight through the mirror surface of the lamellae and the parabolic cylinder, implemented as a computer program, allows calculating the flow of solar radiation on the receiving surface of the solar concentrator with a relative error of not more than 5%, which is confirmed by experimental data.


A functional relationship was obtained linking the position of the Sun, the step of the mirror lamellae of the heliostat, and their orientation to ensure zero blocking and shading losses in the louvered heliostat. Based on the consideration of a three-dimensional problem, the algorithm for calculating the passage of sunlight through the mirror surface of the lamellae and parabolic cylinder allows calculating the flux of solar radiation on the receiving surface of the solar concentrator. An algorithm for controlling lamellar heliostat mirror lamellas has been developed that significantly increases the efficiency of a solar concentrator—using a louvre heliostat with a constant lamella pitch is equivalent to increasing the angular aperture of the concentrator from 26° to 70° without reducing the concentration ratio.


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