Effect of Phase Change Material (PCM) m.p. Distribution on Latent Heat Storage

Charge and discharge heat transfer rates were investigated by using a latent heat storage reservoir with sloped distribution of m.p. The heat storage reservoir consisted of 45 vertical cylindrical capsules. The heat transfer fluid was air and paraffin wax within the capsules was the phase change material (PCM). Melting and solidification time of the PCM were measured for three kinds of m.p. distributions. The charge and discharge heat transfer rates were estimated from the melting and solidification time respectively. Numerical results agreed with the experimental results. For the PCM with constant m.p. the charge and discharge heat transfer rates decreased downstream from the air inlet of the reservoir. The charge and discharge heat transfer rates increased by sloping m.p. distribution. The analytical investigation showed that m.p. distribution with too large or too small slope was not suitable.