Experimental and numerical study of an evaporator with integrated latent heat storage for a compressed air dryer

In the current work, a latent heat storage system with organic phase change material is integrated in a plate-and-fin evaporator for air dehumidification, embedded in a refrigerated compressed air dryer. The effect of the phase change material type, evaporator geometry and dew point range on the fluctuations of the air temperature at the evaporator outlet and on the compressor cycle duration is experimentally investigated at partial loads. The addition of a paraffin phase change material allows to keep the air dew point temperature variations within the desired range at partial loads and to cut the energy consumption at the compressor up to 40% at 30% partial load. A two-dimensional model for simulating the dynamic behaviour of the plate-and-fin evaporator with latent heat storage is developed in Matlab®. The model aims at predicting the temporal variations of the dew point and phase change material temperatures inside the evaporator and the compressor ON/OFF cycle durations. The numerical results are compared with the experimental data, showing that the model is able to reproduce the performance of the evaporator at partial loads. A parametric study is carried out to analize the effect of the evaporator geometry and type of phase change material on the system performance.