Solid desiccant air-conditioning systems can take care of both the sensible and latent load of a conditioned space, as well as of the fresh air requirements, through the use of thermal energy. The development of desiccant systems, competitive to conventional cooling ones, would require the optimization of the parameters which are involved in the design of the systems for a range of ambient conditions the systems will face throughout their lifetime. The present work aims at identifying the main design parameters, and investigates their effect on the performance of the systems. Specific guidelines for the dimensioning of the systems are proposed, on the basis of an easy to implement steady state model. (C) 2011 Elsevier Ltd. All rights reserved.