This paper describes the development of mesh-shaped PCM for the recovery of intermittently released, high temperature heat from LD steelmaking converter and its systematic design for utilizing the recovered heat in the methanol production heat. Experiments were performed mainly to examine the effect of coating material and its film thickness on strength of the PCM. Copper, with a melting point of 1,356 h, was selected as the PCM. The results showed that the PCM coated doubly with Cr and Ni had enough strength in a heating test at 1,473 K. The heat and mass balances model showed the possibility that by using the developed PCM reactor, 25% of methanol required in Japan can be synthesized with only 25% of exergy consumption of conventional method.