Heat Transfer Properties of a Latent Thermal Storage Unit with Flat Microheat Pipe Arrays

Abstract

A thermal storage unit (TSU) with flat microheat pipe arrays (FMHPAs) as heat transfer core is experimentally investigated in this study. A comprehensive evaluation parameter of the TSU defined as thermal power intensity is proposed. The effects of the length proportion of the air side and the phase-change material (PCM) side on the heat transfer properties of TSU are also examined. Phase-change behavior of the PCM, heat transfer characteristics, and thermal resistance distribution are analyzed and discussed. Results show that the FMHPAs greatly enhanced the heat transfer rate between the air and the PCM. The thermal resistance of the air side is nearly three times greater than that of the PCM side. Keeping the length of the storage section 480 mm long and varying the length of the heating and cooling sections from 130 to 160 mm and 190 mm, the best performance was obtained for the length of 160 mm.