Low-grade heat is available in large amounts across process industry from temperatures of 30-250 degrees C as gases (e.g. flue gas) and/or liquids (e.g. cooling water). Various technologies are available for generating, distributing, utilizing and disposing low-grade energy. Also, conventional desalination technologies are energy intensive and, if the required energy hails from fossil fuel sources, then the freshwater production will contribute to carbon dioxide emission and, consequently, global warming. In this regard, low-grade heat source can be very useful to provide energy to the heat sink by upgrading low-grade energy (e.g. low-pressure steam). The upgrade of low-grade heat can be carried out by desalination technologies through recovering waste heat from various sources. The steam network of site utility system has a suitable potential for the production of low-grade heat. Estimation of cogeneration potential prior to the design of the central utility system for site utility systems is vital to set targets on site fuel demand as well as heat and power production. So, a new cogeneration targeting model has been developed for the integration of steam desalination systems and site utility of process plants. The new procedure for finding optimal integration has been proposed based on new cogeneration targeting. In this paper, evaluation of coupling different desalination systems which included multi-stage flash (MSF), multiple effect distillation (MED), membrane reverse osmosis (RO) and hybrid (MSF/MED-RO) to steam network of site utility system was considered. The integration of desalination systems to a low-grade heat source was performed using the proposed cogeneration targeting method. In addition, a modified Site Utility Grand Composite Curve (SUGCC) diagram was proposed and compared with the original SUGCC. A steam network of the process utility system was considered as a case study. (C) 2012 Elsevier B.V. All rights reserved.