Experimental analysis of solar air collector with PCM-honeycomb combination under the natural convection

Abstract

Phase change material (PCM) is at the head of materials commonly used in latent heat storage. However, usually the main problem is that the heat conductivity of PCMs is low. Therefore, a novel solar air collector (SAC) combined the PCM-Rubitherm RT54HC with aluminum honeycomb was manufactured and investigated the effect of using honeycomb core on the collector thermal performance regarding heat storage with PCM under natural convection conditions. In the experiments, the heat storage material was tested in two forms with 26 kg capacity, PCM with honeycomb core in the first collector (type I) and only PCM in the second collector (type II), and also the third collector (type III) with a flat absorber plate for comparison. The first collector reached the PCM melting point about 50 min ago. Also, when we consider the peak point, an apparent 10 °C advantage is achieved in sensible heat storage in favor of type I. It is observed that the honeycomb core used as a heat transfer enhancer is effective in shortening the charge-discharge times, also a noticeable difference in sensible heat storage during the noon. The production of useful energy in Type I lasted 469 min and 539 min longer than type III, respectively. The thermal efficiencies under daylight were calculated as 10.1%, 10.9% and 13.6%, respectively. As a result, it can be said that the use of honeycomb core as heat conductivity enhancer material is very functional, in particular during the discharge period. © 2019 Elsevier B.V.