A new methodological approach for estimating energy savings due to air movement in mixed mode buildings

In recent years, there has been a proliferation of air-conditioning in both residential and commercial buildings in India. Mixed mode buildings are buildings in which a combination of air-conditioning and natural ventilation is used to provide comfortable indoor environments. These buildings are likely to be less energy consuming than fully air-conditioned buildings, and further energy savings can be achieved by using air movement to increase the cooling set-point temperature without jeopardizing occupants’ thermal comfort. The aim of this research was to develop and test on a typical Indian apartment a methodology to quantify these energy savings using dynamic thermal simulations. The core of this method is the definition of the cooling set-point, which varies monthly according to the ASHRAE 55-2013 adaptive model. The results show that the annual energy demand for space cooling can be reduced by as much as up to 70 percent by using air motion devices. Moreover, the indoor thermal conditions during the occupied periods predicted by the model are closer to the values measured in field studies in India.