Design of heat losses calculation method in elements of double-circuit solar water heating collectors

Abstract

With the increasing interest in the use of renewable energy sources, in particular solar collectors, improving their energy efficiency has become particularly important. One of the key factors affecting the overall performance of such installations is heat losses through structural components. However, in practice, there is a lack of universal methods that allow for accurate assessment of these losses for collectors of different types. This determines the need to develop a flexible approach applicable to installations of different designs, which determines the relevance of this study. The aim of the study was to develop a method for calculating heat losses in elements of solar water heating collectors and to establish factors that directly affect its efficiency and performance. In these studies, computational and analytical research methods and thermodynamic analysis methods were used, and on their basis detailed information on heat losses in the collector elements was obtained. Based on the results of the conducted research, it was established that the main factors influencing the values of heat losses and the efficiency of double-circuit water heating collectors are the solar radiation density, the temperature of the environment and the working water. The obtained results make it possible to calculate the heat losses value through the construction elements of the collector. It was found that the greatest heat losses were observed from the collector's face covering. A heat balance equation was derived, and a thermal diagram of the solar water heating system was presented. Theoretically, changes in the heat transfer coefficient depending on ambient temperature and wind speed were investigated. The results obtained in the course of the study have scientific significance for further development and improvement of solar water-heating collector designs. In particular, the identified dependence of heat losses on the structural features of the collector’s front side enables researchers and engineers to focus on its optimisation in order to reduce convective losses. This creates a foundation for the development of more effective engineering solutions in the design of such systems and can be used in the modelling, calculation, and testing of new solar collector designs