Pilot facility for the study of thermal energy storage: Experiments and Theoretical model
Abstract
Thermal energy storage is a widely used solution to address the mismatch problems between energy availability and demand. However, research in this topic is still necessary to optimise the benefits of energy storage. For this purpose, many research groups have designed and built pilot facilities that allow the study of small pilot tanks for further optimization of storage parameters. Here, we present an experimental setup to study the charging and discharging of thermal energy in a storage tank intended for refrigeration. The facility consists of a chiller which cools down the heat transfer fluid (water/glycol mixture), an 80-litres inertia bath to enhance the chiller's cooling capacity, and a storage tank of 60 litres. A three-way valve allows to control the inlet storage tank temperature, and an electric heater is used with the purpose to study the tank discharging process. A theoretical model representing the energy balance equations for each pilot’s components is also presented to rationalise the experimental results. The model reproduces satisfactorily the operation of the system and shows that even minimal thermal losses must be accounted for. Finally, the energy stored in the tank is calculated, showing that up to 30% of the inlet energy is dissipated to the environment, which was also represented by the developed theoretical model.