Heat transfer enhancement by flow control with baffle optimization in vertical wall PCM

The aim of this study was to improve heat transfer through flow control via optimized baffles with a gap in a PCM vertical wall system. Numerical simulation, performed for the baffles by varying the height of the PCM section and the gap length, was validated by experimental results. Analysis of the height of the PCM section with 1.5 mm gap showed that single enhanced circulation for each section reduces thermal stratification in the case of small section height, compared to the divided circulation in large section height. The divided flow includes circulation in the molten zone. In the fully molten zone, the temperature gradient was small, and the heat transfer rate was low, compared to those of the partially molten zone. For variations in gap length, the (1.5 and 2) mm gap cases increased the heat transfer rate, while larger gaps resulted in low heat transfer rate by weakened circulating flow. The 21 mm section height and 1.5 mm gap length showed the highest energy absorption rate. The results showed that efficient heat transfer to the PCM could be achieved by applying optimized baffles with a gap that could control the circulating flow and maximize the heat transfer.