Thermal management of using crystallization-controllable supercooled PCM in space heating applications for different heating profiles in the UK

Abstract

Supercooled sodium acetate trihydrate (SAT) allows the latent heat can be released when it is externally triggered regardless of the supercooling degree. Thus, the implementation of SAT into heating systems can eliminate the negative effects of weather variation and increase the utilization of solar energy by storing the heat for days. However, supercooled PCMs can lose a serious amount of latent heat when their temperature falls to ambient temperature. Moreover, the poor heat conductivity of the SAT can cause providing insufficient temperature in the houses for different heating profiles which require auxiliary heating. In this study, the dynamic thermal behaviour of a supercooled PCM-immersed storage tank for heating different dwellings is investigated based on different activation orders of the PCM tubes. The controlled PCM activation order shows that the hot water supply temperature can be increased compared to the activation of all tubes at midnight. Controlled triggering resulted in performance improvement in all heating profiles by an increment of 1.5 °C, but it is more promising for the Eco-house heating profile as it reaches 4.3 °C. Moreover, this method reduces the daily heat loss from the PCM storage tank by up to 1.3 kWh. It is also found that the PCM loses its 35% of latent energy after three days of storage.