A procedure for optimizing energy-management of a hospital complex is described, which, starting from hourly load diagrams, derived from the optimal design, allows the determination of the design and the running conditions of a trigeneration plant. The results obtained from the implementation of a mixed integer programming model, described here in detail, demonstrate how a trigeneration plant configuration utilizing heat pumps which are directly fed by a cogenerator, greatly improves energy-management, achieving significant economic, energy and environmental benefits. (c) 2006 Elsevier Ltd. All rights reserved.