Atmosfēras fizikālo parametru ietekme uz saules enerģijas izmantošanu dažādos saules kolektoros = Influence of physical parameters of atmosphere on use of solar energy in several solar collectors
Authors:   ,   Latvia University of Agriculture, Pelece Ilze 
Published: June 2022

Along with running out of fossil fuel, and recognizing of the impact of burning of fossil fuel on climate, more attention to use of solar energy in many countries and also in Latvia has been paid. The current constructions of solar collectors in Latvia and other northern countries incompletely use the solar energy; therefore, it is necessary to improve them, or to elaborate new constructions of solar collectors. There is simple methodology of calculation of solar energy received by any surface depending on its shape and orientation elaborated in this work grounded on knowledge in physics, meteorology and astronomy. Also methods for taking into account the impact of clouds are improved and new ones are elaborated. This methodology is appropriate for elaborating and evaluating of new constructions of solar collectors. The work consists of four chapters. The first chapter contains the analysis of the today’s situation of use of solar energy in the world and in Latvia, based on available scientific publications. The second chapter is methodology of calculation of solar energy received by some surface depending on its shape and orientation, improved or elaborated by the author. The methodology consists of three steps. The first step is calculation of solar coordinates at every moment. There are not any formulae for such calculations available in literature; therefore, the author has developed them from astronomical considerations. The second step is calculation of the energy received by the surface, using improved and combined well-known formulae. The third step is evaluating of the impact of clouds, using more appropriate models from literature and developing new ones. There are experimental investigations outlined in the third chapter. There is a new construction of solar collectors – the solar collector with semi-spherical absorber – used in this work for verifying of the methodology outlined in previous chapters. Such solar collector has been manufactured, and measurements of energy gained from the collector have been carried out. The construction of the semi-spherical solar collector has been patented. It has been found out that the measured energy gain from the solar collector corresponds to the calculated one. The calculations show that the energy gain from the semi-spherical solar collector is comparable with this from tracking to the sun flat plate solar collector. However, the semi-spherical solar collector does not use the tracking system, therefore, there are not movable parts in the collector. The semi-spherical solar collector is more durable against wind and with better appearance not only in comparison with the tracking to sun flat plate solar collector, but also in comparison with the fixed flat plate collector. There are practical recommendations for manufacturing of the semi-spherical solar collector as well as economical calculations given in the fourth chapter. The work has been written in Latvian. It contains 123 pages, 82 figures and 9 tables.