Two-Dimensional Mathematical Model of Evacuated Tubular Solar Collector

Analysis of an evacuated tubular solar collector is presented by developing a two-dimensional performance model. The collector uses a thin flat plate spanning its diameter as its absorbing surface. Energy balances are made on collector plate and tube, each considered as a separate unit. It has been found that a zero capacitance model is quite adequate when hourly meteorological data are used, and hence in this study steady state analysis of the collector is made [1]. The overall loss coefficient has been assumed to be constant for the whole plate. The model also includes optical effects. The emphasis of the investigation is to study the two-dimensional effects in the absorber plate housed in evacuated glass cylinders. Performance curves obtained from the two-dimensional model has been compared with that of HW model. It was found that the HW model overestimates the performance.