Thermal energy storage system operating with phase change materials for solar water heating applications: DOE modelling

Phase change materials have gathered wide acceptance globally due to its effective and economically efficient storage properties. It is emerging to find potential applications in both renewable and fossil energy systems. This paper analyzes the performance and models an experimental design for heat transfer enhancement of a thermal energy storage system by using honey and paraffin waxes. Experiments were conducted in a fabricated thermal energy storage cylindrical tank embedded with copper tubes that in turn filled with these waxes in a liquid state. This non-isothermal system was fabricated to improve the water heat transfer rate from the solar tank unit to waxes in the thermal chamber. The conservation of heat energy was achieved through implementation of this system, this offer a better solution to a conventional storage tank. Performance appraisal of results from experimentation during the processes of charging and discharging of phase change materials has been performed and examined. Good thermal energy storage characteristics of heat transfer, absorption and rejection were observed. The design of experiments modelling work- artificial neural network showed good agreement with experimental results. Mainly, it was found that the factor time has contributed more than 40% of the heat improvement in this storage system during charging and discharging process of paraffin and honey waxes. On the other side, the least number of residuals was observed for the honey wax heat absorption during charging process.