Thermohydraulic Performance of a Packed Bed Solar Energy Storage System

In the present scenario, solar energy is one of the sustainable solutions to limit the greenhouse gases emitted by conventional energy systems. But solar energy is intermittent. So in order to use solar energy when it is not available, energy storage is required. Packed bed generally represents the most suitable energy storage unit for air-based solar energy systems. Packing of small-sized particles results in a large pressure drop, which causes a large amount of energy consumption to propel air through the bed. An experimental study on packed bed solar energy storage with five different shapes of large-sized storage elements of concrete was used in earlier experiments. Sphericity was used to describe the shapes of the elements, and the elements were placed in the packed bed with different void fraction. The results on Nusselt number and friction factor provided were used to investigate thermohydraulic parameter in order to determine the thermal and fraction characteristics. Thermohydraulic performance is found to be maximum corresponding to spherical elements and minimum void fraction.