Abstract
A proposal of outdoor testing methods for the thermal performance of solar collectors is presented in this paper. The thermal performance of solar collectors is influenced by ambient temperature, wind speed, incident angle of solar beam to solar collector surface, conditions of cloud etc. This approach is a part of the research which goal is to establish outdoor testing methods for solar collectors. Five types of collectors were used for this study. Two of them are flat plate type collectors. Three of them are evacuated tubular collectors. Those types are representative collectors that have been sold in Japan.
