Thermal Enhancement of Solar Energy Storage Using Phase Change Materials

Abstract

Solar energy (SE) is a renewable and clean energy source. However, the intensity of solar radiation varies due to seasonal changes, weather conditions, and night and day. Thermal energy storage (TES) has the potential to accumulate energy that can be employed later for various purposes. First of all, this study aimed to improve system efficiency and maintain high water temperature (HWT) for a longer period by utilizing phase change materials to save energy (PCMs). An experimental rig of a flat plate solar water heating system (FPSWHS) with TES based on 17 percent (62 kg) of cylindrical encapsulated paraffin wax type RT42 as a PCM was built. Furthermore, 18 aluminum cylinders were used to increase the surface area of PCM and reduce the time required for charging and discharging PCM. Finally, this research was used to identify a suitable PCM for SWHS based on the climatic conditions in the Erbil-Kurdistan region. Incorporating RT42 in a water-PCM storage tank resulted in electricity savings of up to 4.75 kWh at 50℃ inlet water temperature and 0.1 kg.s-¹ mass flow rate, with a total system energy savings of 30.2 kWh as the operation time of the electric heater was reduced. According to the final results, system efficiency increased by 25%, and the system's average daily carbon footprint was reduced by 27 kg of CO2.