Desiccant systems are useful to remove latent load from ventilation air in HVAC systems. Sometimes, desiccant wheels complement the treatment in dedicated outdoor units. This paper proposes a new system that incorporates two layers of solid desiccant inside each side of a ventilated facade. The regeneration of the desiccant is achieved by passing hot air, given by a solar collector module also incorporated into the facade. A detailed mathematical model, based on the water mass and heat transfer equations, gives the capacity of the system. In a Mediterranean climate, the maximum latent load that can be removed by the system reaches 30 W per linear meter of facade. The main variable that determines the capacity of the system is solar radiation, although the humidity ratio and the dry temperature of the outside air have also to be considered. Finally, a very simple model based on an efficiency is developed. The relative error of the simple model ranges between 10% and 20%, depending on climatic conditions (C) 2014 Elsevier B.V. All rights reserved.