Operational characteristics of a novel phase change thermal storage device under rotational actuation of the annular plate heat exchanger

A phase change heat storage device based on the rotatable annular plate heat exchanger (PCHS-RAPHE) has been proposed in this paper. Compared to simple methods such as enhancing the thermal conductivity of the phase-change material or installing fins, by applying external force to drive the rotation of RAPHE, the convective heat transfer effect between the solid and liquid phase change material (PCM) can be effectively enhanced. On this basis, the PCHS characteristics of the device under rotating state and the influence rules of different rotational speeds and structural parameters of the RAPHE on the heat storage performance of the device has been studied. Results show that actively rotation can significantly accelerate the melting rate of paraffin, and 30 rpm has been considered as a suitable rotational speed of the RAPHE. Compared to the stationary state, at 30 rpm of the RAPHE, the complete melting time of paraffin can be shortened by approximately 75 %. For the structural parameters of the RAPHE, with the increase of diameter and spacing of the annular plate, the melting rate of paraffin also gradually increases. When the diameter and spacing increases from 50 mm to 300 mm, the melting rate of the paraffin can be decreased by 43.02 % and 67.16 % respectively. However, the effect of further increasing these two parameters on accelerating the melting rate gradually diminishes. It can be speculated that when the structure of the annular plate increases to a certain extent, the influence of further changing the above two parameters on the paraffin melting rate can be ignored.