Thermal performance analysis of a new multiple flat-plate latent heat storage heat exchanger

This paper proposes a novel latent heat storage heat exchanger integrated heat supply and storage to address the intensity mismatch of renewable energy. Using experimental data in published literature validates the developed two-dimensional mathematical model. The thermal performance of the new device using paraffin RT50 as PCM is studied and analyzed in heat storage mode, simultaneous heat supply and storage mode, and heat release mode. In each operating mode, the heat transfer rates are explored and compared among three cases: not considering the nature convection (NC) of PCM, considering the NC, and both considering the NC and fins. The heat-transfer enhancement by the NC and fins is investigated and compared. The influence of parameters on melting time in heat storage modes is analyzed. The results show that the relative heat-transfer rate in simultaneous heat supply and storage mode is about 50 % higher than in heat storage mode. The heat transfer enhancement promoted by the NC of PCM during melting is more effective than by adding fins and has almost the same effect as fins during solidification. The PCM thickness and fluid inlet temperature considerably affect the melting time. Lengthening the PCM module is more effective than thickening it in increasing thermal storage capacity. Increasing fluid velocity or channel gap can significantly reduce melting time when the fluid flow rate or channel gap is small enough, and vice versa has little effect. The suitable fluid flow rate and channel gap are approximately 0.4 m/s and 3 mm, respectively.