Experimental study of solidification of PCM in cold storage heat exchanger units for novel refrigerated trucks

Abstract This study experimentally investigates the solidification performance of phase change material (PCM) RT5 HC in a cold storage heat exchanger for novel refrigerated trucks, comparing two thermal enhancement methods: finned tubes (to increase heat transfer area) and open-cell Al foam impregnation (to improve PCM thermal conductivity). Four test configurations were examined: (1) a baseline unenhanced sample, (2) a transverse finned tube arrangement, (3) a longitudinal finned tube arrangement, and (4) an open-cell Al foam-filled sample. The effects of heat transfer fluid (HTF) temperature and flow rate on the PCM solidification process were systematically analyzed. The results indicated that lowering the refrigeration unit operating temperature proved more effective in reducing PCM solidification time than increasing the HTF flow rate. Within fixed geometry constraints, finned tube implementations demonstrated superior performance in accelerating solidification at equivalent storage capacities. Notably, longitudinal and transverse fin orientations showed nearly identical enhancement effects, with marginal solidification time differences of just 2-6 minutes for equivalent heat transfer areas. These results provide practical insights for optimizing thermal design in mobile cold storage applications.