The increase in energy costs has introduced new stringent boundaries to process engineering, involving the need for more and more advanced calculation techniques and a greater accountability on the part of the process designer for the purposes of a financially effective engineering work. The designing and optimization approaches tending to favor minimum investment decisions for the past are now subjected to a careful critical revision under the pressures of this new reality. The process designer can--through such revision process--bring a substantial contribution of his own to the development of a technology oriented toward energy conservation. In view of these considerations and on the basis of newly emerging trends, some examples are introduced to illustrate certain development opportunities in oil-refining and petrochemical industrial processes. Conventional designs covering a refining plant and an oil fractionating unit are compared in details in this review with alternative patterns to which new designing approaches are applied for the purposes of an optimized energy consumption.