Cooling is very important for space conditioning of buildings in warm and humid regions. Along with the growth of cooling loads in modernbuildings, the peak electricity demand increases during the daylight. This causes problems concerning the energy supply in some countries such asIran, as the demand for air conditioning occurs simultaneously with the maximum electricity demand of industry. The new solar cooling systempresented in this paper takes air from outside by a wind tower, dehumidifies it with a desiccant wheel, cools it by an air to air heat exchanger (heatrecovery system) and then cools it by a direct evaporative cooling system to the desired state of a maximum 100% relative humidity in the inlet airstream. The desiccant must be regenerated by heat. This can be achieved with solar energy from a solar air collector that is installed in the southernwall and roof of the building. In addition the system is mathematically modeled. The model is used to simulate two hot and humid regions of Iranin the north (Babolsar) and south (Bushehr) over one year. The result shows that this solar cooling system with a payback time of 5.5 years canprovide 54% of the annual cooling load in the north and 48% in the south of Iran.