Capacity factor characteristics for a multi‐tubular sensible energy storage system with wire coil inserts.

Summary: The transient energy storage in a sensible energy storage system (SESS) depends on the rate of energy stored in the system. The rate of energy stored in a sensible energy system is a strong function of spatial temperature distribution that governs the energy distribution in the storage medium. The present study explores the energy and capacity factor characteristics of a wire coil fitted multi‐tubular SESS. A storage system is molded using M30 grade concrete of density (ρc= 2200 kg/m3) and specific heat capacity (Cps= 850 J/kg/K). The inlet temperature of the air, used as heat transfer fluid, is varied from 45°C to 75°C. The pitch to diameter (p/d) ratio of the wire coil insert is varied from 0.25 to 0.75 to examine its effect on energy storage/release and capacity factor. Using a (p/d) ratio of 0.5 for wire coil inserts, the maximum capacity factor of 0.98 is achieved during the charging phase of sensible energy storage at 55°C inlet air temperature and 0.029 kg/s mass flow rate of heat transfer fluid (HTF). With respect to the smooth SESS, the maximum improvement in capacity factor is found to be 29%. [ABSTRACT FROM AUTHOR]