As fossil fuels are being depleted, society is looking to renewable resources to provide our energy for the future. Solar energy utilization has become more common in the world today, but mostly in the form of photovoltaics. Solar thermal systems struggle to gain popularity due to, among other factors, the issue of heat loss. The heat is only collected and stored when the sun’s rays are shining on the collectors. Other times the system tends to lose heat to the cooler environment. The focus of this project is to study a potential way of improving solar thermal energy storage by incorporating latent energy storage. A traditional system stores the heat energy by heating water and keeping it in a hot water storage tank. In order to increase the amount of hot water available, the system thermal storage capacity needs to be enhanced. For my project, I am utilizing the latent heat energy as well as low thermal conductivity of phase changing wax to demonstrate that it is an improvement over traditional thermal insulation.
A small prototype was made to test the performance of a hot water tank system with phase changing wax annulus for thermal energy storage and insulation. The phase changing wax selected was paraffin. Paraffin has a melting point of approximately 55-58˚C which is well within the temperature range of a hot water storage tank. Comparisons were conducted with a baseline system, a tank with traditional insulation, and a tank with both a wax annulus and traditional insulation. The overall storage capacity of the wax was calculated as well as the rate of heat loss compared to the baseline.