The thermal performance of a plant for summer air conditioning of buildings, which use a desiccant wheel with silica gel as a dehumidifying material regenerated by a mass flow heated in a field of solar collectors, is presented in this work. The control strategy adopted makes the outlet specific humidity from the wheel depend on the enthalpy of the necessary mass flow rate for the removal of the total load which acts upon the air-conditioned environment and the temperature and humidity of the outdoor area. With reference to three areas of the Mediterranean area, an energy analysis has been developed with the determination of principal performance indices, such as COP coefficient, solar fraction, dehumidification efficiency and the primary energy efficiency.