Phase-change heat transfer in flat-plate solar collectors

Abstract The performance of a flat-plate collector, set up in a driving loop, has been studied when some parameters such as the solar irradiance, the saturation temperature or the absorber characteristics vary. A steady-state model of the collector has been studied. The equations are developed for a fluid in which first sensible heat transfer occurs, then boiling. The experimental and theoretical results are compared and it is concluded that the total heat loss conductance cannot be assumed as constant. The collector efficiencies have been calculated for different conditions.