We experimentally studied thermal storage in water around a cooling tube placed in an insulated rectangular cavity. The cavity (a thermal storage cavity) was filled with water and very thin copper foils. In order to control time variation of heat flux, the copper foils were installed in the cavity in such a way that a space is provided between them and the cooling tube. The experiments were conducted by filling the cavity with eight different volume fractions of copper foil and water at three different initial temperatures. According to the experimental results, by filling the thermal storage cavity with water and the optimal volume fraction of copper foil, time variation of heat flux can be reduced and thermal storage capacity can be increased even if the amount of water, a phase-change material, decreases. As a result, we have ascertained the effectiveness of using layered copper foils in a thermal storage device.
