Development of a Stratified Tank Storage Component for Esp-R with Embedded PCM Modules

Solar domestic hot water systems (SDHW) are very common and are considered an efficient system for exploiting the renewable energy source of the sun, for instance national Italian regulations require the adoption of SDHW systems in new buildings. Water tanks are typical components for such systems, but have a serious drawback since they require a great amount of space in the building. In this paper a new water tank model for the ESP-r code is presented. A new feature has been added to an existent tank model, that is the possibility to include internal Phase Change Materials (PCM) modules. The paper describes the numerical model used to deal with phase change phenomena and the incorporation of the method into the ESP-r source code. The inputs and parameters required to describe the new component are presented as well. To validate the model the results of a test case have been compared with literature data. A typical SDHW system has been simulated in order to study the impact of the PCM modules inside a tank on the energy performance of the system. Two tank sizes have been used to verify the impact of the modules. The results are reported using a global parameter that represents the fractional primary energy saved by using the solar system. Temperature plots with and without PCM have been reported as well.