EVALUATIONS OF THERMOSYPHON SOLAR THERMAL WATER HEATERS PART 1: LONG TERM FIELD TEST OF THREE OPEN CIRCUIT SOLAR WATER HEATERS

Simple thermosyphon solar water heaters (SWHs) which are integrated with solar collectors and storage tanks were widely used in 1970-1980s in Japan. According to the afterward economic development, however, they are rapidly shrinking even though its environmental benefit. In order to rejuvenate the solar thermal systems, this study aims to evaluate its correct performance to show potential users and to propose new ideas to increase its efficiency by manufacturers.