Design and analysis of PCM based radiant heat exchanger for thermal management of buildings

Abstract

The present study focuses on the thermal performance of encapsulated phase change material (PCM) based heat exchanger for thermal management of building in Indian conditions. Heat transfer characteristics of the encapsulated PCM based heat exchanger is investigated experimentally and compared vis-à-vis thermally activated roof and radiant panel systems. Experiments are performed on a scaled down concrete cubical test chamber with a window facing the north direction. It is found that the encapsulated PCM based heat exchanger is able to reduce heat gain of the test chamber by approximately 50% as well as mean air temperature by more than 6 °C. The encapsulated PCM based heat exchanger is found more beneficial in flattening the peak for longer duration and reducing the fluctuation in mean air temperature of the test chamber. The developed building simulation model is validated with the experimental results, which is used in parametric studies to identify the effect of different parameters on the average air temperature in the test chamber. The duration of stabilization period can be kept constant by increasing PCM thickness linearly with the increment in thermal load of the test chamber. The inlet water temperature to the PCM based heat exchanger is found to be the most influential parameter affecting the mean air temperature of the test chamber, whereas thermal conductivity of walls and length of pipe in heat exchanger have minimal effect comparatively. Further, a ground heat exchanger is incorporated with the encapsulated PCM based heat exchanger to investigate the effectiveness of ground heat exchanger in discharging the heat load carried by the working fluid.