Packed-bed Thermocline Testing Facility with Air as HTF for Sensible Thermal Energy Storage
Abstract
Sensible heat from CSP plants or other energy sources can be stored in one-single tank storage system that performs by creating a thermocline between a cold and hot zone. The Thermal Storage Group of CIEMAT has available a testing facility for packed-bed thermocline TES, named ALTAYR, suitable for operating in a wide range of temperatures and flowrates, different solid materials and charge and discharge modes. Such facility is useful for forecasting the behavior of industrial thermocline tanks, especially when it is combined with mathematical models able to count for scale aspects, as well as for different material assessment. In this work, different experimental tests operating with ALTAYR under different conditions are presented. Two types of pebbles have been employed as filler materials and their storage capacity has been compared. The temperatures in both solid and air have been measured independently using four different experimental methodologies to differentiate between them. However, it appears to be no measurable difference. The tank wall thermal conductivity has been obtained from one long duration experimental test in order to characterize the tank and be able to calculate thermal losses through the wall.