Comparative performance assessment of flat plate and evacuated tube collectors for domestic water heating systems in Kerman, Iran

This study represents a year-round energy performance of two solar water heating (SWH) systems with a 4m2 flat plate collector (FPC) and an evacuated tube collector (ETC) operating under the same weather conditions. The energy performance of the two considered systems was compared on a monthly and yearly basis. The obtained results showed that for an annual total solar insolation of 2056kW.h.m-2, a total of 3577kW.h.y-1 and 4201kW.h.y-1 of heat energy were collected by 4m2 FPC and, ETC systems, respectively. The annual average energy efficiency by the FPC system was 43%, while its annual solar fraction was 50%. The ETC system had 51% energy efficiency with 58% solar fraction. The economic analysis showed that both solar water heating systems are not economically viable under prevailing costs in Iran. Furthermore, according to the obtained results, the FPCs are more favorable than the ETCs due to its economic analysis and energy performance. These results provide useful information for households and policymakers.