Improving the Performance of a Home Solar Water Heater System Using Porous Materials and Reflectors

Abstract

Solar energy storage is essential in renewable energy systems, considering that solar energy is a periodic energy source that depends on time, so the intensity of solar radiation changes from time to time. Therefore, solar energy systems require storing energy to save it during the night periods or on cloudy days. The current solar heater designs are not feasible and ineffective unless energy storage is utilized (energy retention). The present research addresses improving the home solar water heater (SWH) performance under the atmosphere of Iraq. This study improves the thermal performance of a solar water heater integrated with a thermal storage tank using materials storing heat to achieve the most extended possible period of receding solar radiation. The SWH system performance was experimentally tested in Tikrit-Iraq. Several experiments were performed from 8:30 am to 16:30 hours in February 2022 with a water mass flow rate (\dot{m_w}) of (0.016 kg/s) for the circulation system and with a thermal load on the hot water tank (\dot{m_{th.L}}) of (0.0066 kg/s) for the two porous medium design cases (with and without solar reflectors). The results manifested that the maximum daily thermal efficiency (ηo) of the SWH system was 36.40% for design case 2 (with porous media and reflectors) at a (0.006 kg/s) thermal load compared to the case 1 (with porous medium and without reflectors) of 32.21%. At the same load, the outcomes elucidated that the overall thermal efficacy of the SWH regime in the convection presence provided the uppermost value utilizing porous media and reflectors. Also, the outcomes of the present investigation were compared with the preceding study, and the comparison outcomes were better than the present design circumstances.