An experimental study on the performance evaluation of a combined sensible‐latent heat thermal energy storage

Abstract

SummaryThermal energy storage (TES) is one of the significant technologies for reducing the discrepancy between ever‐increasing energy demand and utilization. Sensible and latent heat based TES concepts are the most widely implemented technologies for thermal applications. However, these two storage technologies have drawbacks of lower energy storage ability, higher thermocline degradation for sensible heat storage and lower thermal conductivity of the phase change material (PCM) causing higher charge and discharge times for latent heat storage. To counter these issues, a novel combined sensible‐latent heat storage system has been proposed. The concept of combined sensible‐latent thermal storage is to place the latent heat storage media above the sensible storage media in the storage container. In the present experimental study, an experimental investigation of the proposed storage system and conventional sensible storage system was performed during charge and discharge cycles. The proposed storage system used concrete spheres as sensible storage media and paraffin encapsulated capsules having the same diameter of 38 mm, as a latent heat storage media. A comparative assessment has been made for two different configurations based on temperature profile, storage capacity, charge and discharge times, energy transferred, and energy recovered. The experimental results reveal that the novel combined sensible‐latent heat storage has lower thermocline degradation during discharge and higher energy storage capacity relative to the sensible storage system. The discharge time and energy utilization is prolonged by adding the PCM capsules above the concrete spheres and also the temperature drop at outlet of the storage system has been reduced than the sensible storage. Based on the analysis, the novel combined sensible‐latent heat storage was found to have a better performance compared with the conventional sensible heat storage system.