Abstract
This study was carried out to compare the thermal performance and operating characteristics of evacuated tubular solar collector(ETSC) with different working fluid. The evacuated tubular solar collectors with different working fluid of heat pipe were investigated in the same operating condition for a indoor experiment equipment. First, the result of working fluid with Water showed that $F_R({\tau}{\alpha})$ was 0.6636 and $F_RU_L$ was -1.8457 Second, Ethanol showed that $F_R({\tau}{\alpha})$ was 0.6147 and $F_RU_L$ was -0.6365. Third, Flutec-pp9 showed that $F_R({\tau}{\alpha})$ was 0.515 and $F_RU_L$ was -3.2313. Finally MA's showed that $F_R({\tau}{\alpha})$ was 0.6572 and $F_RU_L$ was -2.0086.