This paper deals with an optimization problem about thermal exchanges between a reactive porous environment and two networks of heat pipes together enclosed in a chemical heat pump reactor. Because all physico-chemical features of the reactive matter are fixed (actually the reactor contains a patented chemical mixture), the only way to optimise the quality of these exchanges, is to find an optimal location within the reactor for the heat pipes using ozone friendly fluid as the working fluid. Two numerical approaches, the first quantitative by the finite element method and the second based on the heat conduction hyperbolic theory, enabled us to obtain the same optimization results.