The attainable region (AR technique is used to find the optimum process designs for an exothermic reversible reaction system where allowance is made for cooling and heating with a constant temperature utility. The optimum process layout (equipment), which results directly from solving the problem using the AR method, incorporates both a direct and indirect method of cooling material undergoing reaction. The results have shown that direct cooling (cold shot) is favoured at high temperature and indirect cooling (heat exchange) at lower temperature, The values of system parameters were changed and this caused the relative shape and size of the attainable regions to vary. The inclusion of the cost of hearing introduces a new complexity in the process layouts of the AR. In particular the direct cooling (cold shot) is split into two stages: The hot reaction mixture is first cooled by adding preheated feed of varying temperature and this is followed by the addition of cold feed to the reaction mixture.