Effect of Reflector Absorptivity on Radiative Heat Exchange in Case of Solar Receiver Collection Systems

In case of solar central receiver systems, the major portion of incident solar radiation is reflected by the concentrating reflectors or heliostats towards the receiver by specular reflection and minimum portion is received through diffused radiation. In order to know this diffused component of radiation energy transfer, the absorptivity of reflectors as well as shape factors between the reflectors and the central receiver is must. The present chapter is dealing with the estimation of radiative heat/energy exchange between the hot cavity receiver and reflecting collector surface along with the diffused configuration factor computation encompassing in solar reflector-collector systems of various orientations and geometries. The configuration factors have been evaluated using contour integral technique, which has been reported as one of the accurate and faster tools for configuration factor estimation. The integral cum analytical expressions are also demonstrated for configuration factor, and the methodology adopted for exchange of radiative heat between the hot cavity receiver and the reflecting surface of parabolic dish collector is also discussed.