For improving the performance of heat release unit, porous foam has been offered in this article. To reach the bet ter conduction mode, copper oxide has been mixed with paraffin which its melting point is 28 degrees C. The air flows within the duct and wavy duct was made of aluminum which was full of RT28 in liquid phase at t = 0. For first case, as time rises from 20 to 30 h, solid fraction rises from 0.419 to 0.731 and outlet air temperature declines from 292.83 to 292.14 K. With same change in time for second case, solid fraction augments from 0.731 to 0.959 and temperature of air declines about 0.27%. At t = 15 h, solid fraction for first and second cases are 0.26 and 0.574 and outlet air temperature are 293.09 and 294.64 K, respectively. Amounts of solid fraction after 30 h are 28.9 and 4.98 times greater than those of t = 5 h for first and second cases, respectively. (C) 2020 Elsevier B.V. All rights reserved.