Thermal performance evaluation of a new structure hot water tank integrated with phase change materials

The energy consumption of domestic hot water accounts for 10-20% of building energy consumption. Such high energy consumption heightened the need for utilizing energy-efficient technologies in domestic hot water systems. Among existing technology, integrating phase change materials (PCM) into domestic hot water tanks is very attractive due to the fact that adding PCM in tanks would enhance the storage density of the system. Most of these studies encapsulated PCM and then put it on the top of the tank. These studies highlighted the positive aspects of the integration of PCM. However, they suffer from the fact that the capacity of hot water in tanks will be reduced. To address this issue, in this study a new structure hot water tank was proposed with PCM placed on the side of the tank. In order to evaluate the thermal performance of this new tank, experiments were performed based on a cylindrical hot water tank of 150 L capacity. Results show that the integration of PCM can significantly improve the thermal performance of the hot water tank. Compared to a tank without PCM, the time length for water temperature drop from 65 to 40 degrees C at the top of the tank with PCM is over 8.5% longer. Moreover, the change of the amount and the location of PCM results in different water stratification in the tank. (C) 2019 The Authors. Published by Elsevier Ltd.