PCM SOLAR AIR HEAT EXCHANGER AND ITS VENTILATION PREHEATING EFFECTIVENESS

This article presents a PCM solar air heat exchanger integrated into ventilated window developed to maximize the use of the solar energy to pre-heat the ventilated air. The system is designed to improve the indoor air quality and thermal comfort by continuous pre-heated air supply at a reduced energy use through the capturing and storing of solar energy. This study examines the thermodynamic behavior of the system both experimentally and numerically. This entails a full-scale experiment in climate boxes to study the thermal storage and heat release ability of the facility. Accordingly, a numerical model combining heat transfer and buoyancy derived laminar flow and nonlinear thermal properties of the PCM is built and validated with the experimental data. The model is then used for configuration optimization of the PCM solar air heat exchanger to maximize the solar energy storage and the ventilation pre-heating effectiveness. The results show that for a 6-h solar charging period, the optimum PCM plate depth is 90 mm and the optimum air gap thickness is 6 mm. The same configuration can be used for both summer night cooling and winter solar energy storage applications. The total stored/released latent heat after one charging period is 93.31 MJ/m3