Solar thermal engineering; Transparent insulation material; Solar water heating; Periodic thermal analysis; integrated collector-storage system
This paper presents an analysis of heat transfer processes in a transparent-honeycomb-insulated
solar collector made of such low-energy materials as soil/sand/concrete, which also acts as a heat store. The analysis assumes solar intensity and atmospheric temperature as well as the resultant temperature in the ground and concrete/sand region to be periodic. An explicit expression for the heat flux that can be extracted at constant mass flow rate and at constant heat extraction temperature is derived. Numerical computations corresponding to typical months of June, September and December at New Delhi are presented. The solar conversion efficiency of 30-60% corresponding to a ollection temperature in the range of 40-70°C is reported. The solar gain and heat storage characteristics of the proposed system are
found to be of the right order of magnitude for solar water-heating applications.