Keywords: exergy efficiency, energy efficiency, thermal energy storage, TES systems, stratification, efficiency, models, temperature distribution modelling
Application of temperature-distribution models to evaluate the energy and exergy of stratified thermal storages
Vertical stratification occurs in many thermal energy storages, and is often promoted to increase efficiency. Six temperature-distribution models for vertically stratified Thermal Energy Storage (TES) systems are described and applied for determining their energy and exergy efficiencies. The models are Linear, Stepped, Continuous-linear, Basic Three-zone, General Three-zone and General-linear. The models are intended to allow accurate yet relatively simple determinations of TES energy and exergy while providing physical meaning and understanding. An application of the temperature distribution models to a TES is presented. The results are expected to assist in the design and improvement of TES systems.