Thermal and economical analysis of central solar heating systems with underground seasonal storage in Turkey

ABSTRACT PhD Thesis THERMAL AND ECONOMICAL ANALYSIS OF CENTRAL SOLAR HEATING SYSTEMS WITH UNDERGROUND SEASONAL STORAGE IN TURKEY Aynur UÇAR Fırat University Graduate School of Natural and Applied Sciences Department of Mechanical Engineering 2005, Page:171 In this study, the long-term performance of a solar assisted house heating system with underground seasonal storage is investigated. Three types of underground storage are chosen: trapeze, cylindrical and prism. The thermal and economical performances of these three types of storage are compared with each other. In the analysis of the solar heating systems, the transient temperature distribution problem in the ground is solved by using a finite element analysis and ANSYS software. By using water and ground temperatures obtained from simulation, the annual solar fractions and savings of system are calculated and the results are presented in the graphical form. The exergy losses in the system are evaluated by applying a general exergy balance over each of the components of the solar heating system. An exergoeconomic method which combined the exergy losses with economic relations is developed for analysis of solar heating systems. Further, the economically optimal dimensions of collector area and storage volume are determined by using the thermo-economical optimization analysis. The simulation results have shown that the annual solar fractions of a trapeze tank system are higher than that of the cylindrical tank system. Therefore, saving of trapeze lank system is higher, compared with the other two tank systems. It is observed from the present results that the central solar heating systems with the seasonal storage in all regions of Turkey are promising both technologically and economically. Keywords: Solar energy, house heating, seasonal storage, economical analysis, exergy analysis, exergo-eceonomic. XX