A novel empirical model for predicting the heat accumulation of a thermal energy storage medium for solar thermal applications

Abstract

The complex design procedure of the thermal energy storage system is a major factor limiting the commercial deployment of the system for solar thermal applications, especially for distributed generation. Obtaining the amount of heat energy that can be accumulated for a field location is critical in the design process of a solar thermal energy storage system. Available models to aid the design process are typically limited to the specific system design and without prior consideration of the feasible amount of heat energy obtainable from a field location. This sometimes results in design incompatibility, performance deficiencies, and economic loss. Therefore, in this paper dimensional analysis is applied to obtain the sets of parameters that influence the heat accumulation of a thermal energy storage medium. To bridge the gap in literature toward reducing the complex procedures in the design process and predicting the feasible amount of heat energy that can be accumulated in a system operating environment, an empirical heat accumulation model is proposed. Results showed that solar irradiance and the volume of storage medium are significant measures for obtaining and improving the heat accumulation of a thermal energy storage medium. Results also showed that the specific heat capacity of the heat transfer fluid, collector area, and environmental temperature is critical in proper design scaling of the thermal energy storage medium to the specific amount of heat energy needed for a system application.