A novel method to investigate the influence of phase change material orientation in reduction of car cabin temperature

Abstract

Car parked in peak sun light, attains temperature higher than the surroundings. Due to this, the passenger develops discomfort while entering into the car. For the betterment of passenger's thermal comfort, the phase change material (PCM) is employed inside the car. There were many experiments & numerical studies carried out to find the effect of cabin air temperature by placing the phase change material near the roof and also by varying the melting temperature of phase change material. From the understanding obtained from the literature study, the effect of changing the phase change material orientation with respect to the air flow inside the car cabin is not much reported. In this study, a novel method named equivalent specific heat method has been developed. It is conventional to employ 2 phase simulation for phase change material. By employing this novel method, the computational time associated with the 2 phase simulation is drastically reduced as the entire simulation can be carried out as a single phase. The effect of employing different phase change material and their orientation on reducing the car cabin temperature has been studied in detail. 2 phase change material namely OM29 and HS24 along with their 7 orientations have been investigated. Results in terms of the solar load distribution, the temperature distribution due to solar load, air temperature contours, air velocity contours and phase change material temperature contours have been presented and discussed in detail. It is found that the performance of 2 curvatures of PCM (HS24) covering the roof is able to reduce the average car cabin temperature by 10.4 °C when compared to that without PCM. The reduction in average car cabin temperature is found to be 9.5 °C, 9.1 °C, 7.9 °C, 7.2 °C, 4.7 °C and 4.3 °C for 3 curvatures of PCM (HS24), 1 curvature of PCM (HS24), 2 curvatures of PCM (OM29), 1 curvature of PCM (OM29), Flat PCM (OM29) covering the roof and & Flat PCM (OM29) partially covering the roof respectively. This novel method is capable of reducing the computational time for two phase simulation by 90%. The average deviation for the novel single phase simulation and conventional two phase simulation with that of the experiment is found to be 11.38% and 9.93% respectively.