Experimental Study of the Thermal Performance of a Sensitive Solar Energy Storage System on a Rock Bed (Granite) for a Drying Application

The use of solar energy is hampered by the intermittency of the resource and the constraints of storing the thermal form of this energy. The processes using this resource are therefore faced with problems of continuity of the process. To remedy this, this work proposes to develop a device for the accumulation of solar thermal energy by a sensitive storage system on a rock bed. A solar thermal energy storage system has been developed and experimentally studied with a view to coupling it to a solar dryer. The thermal performance of the system was evaluated in terms of temporal distribution of bed temperature, total energy stored, total energy discharged, charging efficiency, discharging efficiency. The results obtained indicate that the stratification in the storage system decreases in the afternoon due to the reduction of solar radiation and the output temperature of the solar collector. This contributes to a decrease in the thermal performance of the storage system. The charging efficiency obtained is 76.8%, the discharging efficiency 44.4%. The results also indicate that out of 4.7 MJ of total stored energy almost 89% or 4.17% was recovered during the discharge phase which is interesting for solar dryers.