This work is aimed at the development of a systematic procedure for energy conservation through the integrated design of trigeneration systems (combined cooling, heating, and power - "CCHP") while incorporating solar energy as a renewable form of energy with low GHG emissions. The focus is on developing preliminary screening and targets that guide the conceptual design of a trigeneration system. Absorption refrigeration is used to utilize excess process heat and external energy in the form of fossil and solar energy. To account for the seasonal fluctuation in collected solar energy, the decision-making horizon is discretized into multiple periods. An extended transshipment representation is developed to embed design configurations. Next, a nonlinear programming formulation is developed. The solution of the optimization formulation determines the optimal levels of power, external heating, external cooling, heat integration, mix of fossil/solar energy forms to be supplied to the process, and the scheduling of the system operation. (C) 2011 Elsevier Ltd. All rights reserved.