Abstract A numerical study is accomplished to evaluate thermal and fluid-dynamic behaviours of a compact heat exchanger in aluminum foam. LTNE condition are assumed. The purpose of the investigation is to find the heat exchanger dimensions to evaluate a compromise between the heat transfer improvement and the increase in pressure drop. The results are showed in terms of heat and mechanical power ratio. It is found an optimal foam thickness in terms of tube diameter equal to 5. At the end, the Energy Performance Ratio (EPR) is evaluated to determine the efficiency of the metal foam and the best value is obtained for Re=800.