Electricity Reduction in Building Climatisation in Hot and Humid Climate Through the use of Solar Desiccant Wheel

摘要

We studied with numerical simulation the amount of energy and costs reduction obtained with the use of a desiccant system combined with other cooling alternatives in the air conditioning of a regular office building in the Brazilian city of Belem, where the climate is hot and humid most of the year. Five different air handling processes using desiccant wheel were analyzed and compared with a standard one, which was assumed as the conventional mechanical compression air conditioner without desiccant wheel. Solar energy was one of the alternatives studied to provide the regeneration heat of the desiccant wheel. Natural gas was chosen as auxiliary heater when the solar energy was not enough to regenerate the wheel. Beside the desiccant wheel, the cooling system also comprised either an evaporative cooling equipment or a mechanical compression system. The results indicated that, although the desiccant system removed the latent heat of the total cooling load, the regeneration energy load was larger than the energy consumption of the mechanical compression system. The use of solar energy to regenerate the desiccant wheel is necessary to guarantee the economical feasibility for the system operation. In this case, the use of a desiccant wheel combined with a mechanical compression refrigeration system and an evaporative cooling equipment was the arrangement with smaller operational cost.