A new technique called the enthalpy flow rate technique is developed for the construction of heat exchanger network (HEN) composite Curves by Using stream cumulative enthalpy flow rate as the independent variable. The enthalpy flow rate technique allows the construction of a newly introduced Curve labeled the complement grand composite curve (CGCC). The CGCC is considered a valuable tool for (a) presentation of the temperature differential distribution between the composite curves (CCs), (b) estimation of heat exchanger(HEX) area, and (c) facilitation of HEX area estimation in multiple-utility targeting. Furthermore, an improved numerical technique designated the temperature technique is developed for constructing the HEN CCs by using temperature as the independent variable. The cumulative enthalpy flow rate and temperature techniques provide a full range of information about the CCs and presentation of the GCC and CGCC in a single graph, which can assist the HEN designer during the targeting and design stages. (C) 2008 Published by Elsevier Ltd