Experimental Investigation of Desiccant Wheel Assisted MAC System

In this paper, the application of the separate sensible and latent cooling (SSLC) technology to the mobile air conditioning (MAC) system was investigated. Conventional MAC systems utilize a low evaporating temperature to cool down the cabin air temperature and to remove moisture from humid air. In order to remove the moisture, the supply air temperature has to be below the dew point temperature of the cabin air. Therefore, a reheating process is necessary to increase the air temperature to an appropriate and comfortable level. However, energy is wasted in this reheating process, which results in the reduction of the fuel efficiency. Since the SSLC technology can provide an appropriate solution to these issues of conventional systems, it is proposed to apply the SSLC technology to the MAC system, which can eventually reduce the fuel consumption of the MAC system. In the proposed SSLC MAC system, the desiccant wheel is dedicated to handle most of latent load while the vapor compression cycle handles the remaining latent load and sensible load. To evaluate the performance of the desiccant wheel assisted SSLC system, the test facility was constructed. When the SSLC concept was applied under summer rainy conditions, the total power input was reduced by 20%, and condensate from the evaporator was reduced by 46.6%.