Concrete based high temperature thermal energy storage system: Experimental and numerical studies

Abstract

This paper presents the concept of developing a cost-effective Concrete based Thermal Energy Storage (CTES) system by performing extensive experimental studies and numerical simulations. A stand-alone experiment facility to study the performance of high-temperature thermal energy storage system which operates up to 500 °C using air as the heat transfer fluid has been developed. The CTES module is made of shell and tube configuration, where concrete is filled in the shell side, and 22 air passages are provided on the tube side. The inlet air temperature and velocity are the decision parameters used for analyzing the thermal behaviour of the CTES module. From the spatial variations of temperature, it is observed that the heat transfer rate is uniform and faster along all radial planes, whereas, the heat transfer rate drops gradually along the length of the CTES module due to drop in Heat Transfer Fluid (HTF) temperature. The parametric investigation conducted shows that the charging and discharging times were reduced by approximately 48% and 29%, respectively, with a change in inlet temperature of 40 °C at a fixed air velocity of 2 m/s. A 3-D model for CTES module developed using the finite element method has been validated with experimental results. The temperature contours plotted from 3-D simulation describes the spatial variation of CTES temperature at different inlet air temperatures. Further, a 1-D dynamic model has been developed, which is fast and accurate with a maximum error of ±4.9 °C with reference to real-time experiments and also provides a substantial scope of integrating the CTES with industrial applications. The outcomes of the present studies conclude that the developed CTES module is highly recommended for the high-temperature applications.