Theoretical Analysis of Alloys as Thermal Storage Media

Abstract

Alloy materials are suggested as storing media to realize the optimum performance of the thermal energy storage system. The storage capacity and thermal energy stored inside the suggested storing media are obtained through a transient one-dimensional mathematical model for the present system. The finite difference method and Thomas algorithm solver are used to solve the present model. A cylindrical tank is filled with the suggested storing media to form beds as heat absorbers. The bed is thermally charged with hot air flowing axially through the storing media, then the heat exchange occurs between the hot air and the storing media. The suggested alloy materials (M al ) are alumgsi, duralumin, brass, al-bronze, wrought iron, carbon steel and cast iron, as metallic-alloys. Solutions are obtained for the storing media properties (ρ, C p and K). Energy stored comparison is done between the suggested storing media, rock and porcelain. The results show that increasing either the density, ρ, or specific heat, C p , increases the storage capacity and energy stored for the system. On the other hand, increasing of thermal conductivity, K, is found to markedly increase the energy stored inside the bed up to a certain time during charging, beyond which this trend completely reverses. The highest amount of energy stored inside the suggested storing media are arranged as M al6 > M al5 > M al4 > M al3 > M al7 > M al2 > M al1 > rock > porcelain.