Abstract:
The subject of our thesis presents a realization and study of two parabolic trough collectors with and without glass cover. The aim is to increase the heat flux at the absorber, as well as the elimination of the cosine effect to obtain a good thermal storage in the tank. the solar field of this city has been studied, before installing the concentrators in Ghardaïa city. The experimental results obtained are validated by three mathematical models with the data base of the radiometric station of Ghardaïa city. The first parabolic trough collector is characterized by a variable focus axis, which allowed to have a range of different concentrations imposed on the absorber. Consequently, it has found that the best heat exchange is achieved when all or a quarter of the absorber tube is exposed to solar radiation. In addition, two types of heat transfer fluids (water and thermal oil Seriola 320) was compared for their thermal storage efficiencies inside the tank during the evening, where it has shown that thermal storage with water is more efficient and effective than thermal oil. Based on the achieved above results, constructed a second parabolic trough collector oriented perpendicularly to the sun, from the morning till the evening, for a whole one year. Temperature measurements are obtained using an automatic solar tracking electronic circuit, using Raspberry Pi3 and Arduino boards for collecting data. In addition, our prototype has been protected by a glass cover; this envelop protects the entire concentrator against the undesirable effects of dust and rain. Also, it contributes to increase the heat transfer of the absorber and to reduce convective thermal losses and radiative to the environment.
