Study on Thermal Performance of Solid Heat Storage System combined with Air Heating Type of Solar Collector

The characteristics of thermal behavior of solid heat storage tank (Rock Bed) combined with air heating type of solar collector were investigated theoretically by applying the heat transfer model considering for rock-air convection heat transfer, thermal conduction as a void parameter, and heat loss to the environment, and experimentally by cylindrical rock-beds connecting with the ref-lamp simulation system of the solar collector. The solar collector characteristics is the most significant parameter for this system, so the heat absorbed efficiency η_c is based on the simultaneous solutions for the energy balancing equation between the wall and glass elements coupled with the energy equation of heated air in the collector channel. The storage energy equations were discretized by the control volume method and solved numerically by Guess-Seidel iteration full implicit technique by using the above derived collector performance η_c depending on the temperature difference in the rock and surroundings. The behaviors of storage performance have been discussed for various parameter under the condition of (1) the air flow rate per unit of face area, (2) solar incident intensity q_inc, and (3) storage and discharge air flow mode