Investigations on Vapour Compression Air Conditioner with Direct Contact Desiccant Loop over Condenser and Evaporator

Abstract

Perceived air quality increases when relative humidity is decreased till about 30% in the range of comfort temperature. In the present scenario, humidity is considered as a pollutant. Hence, a controlled environment not only at low temperature but also at low humidity is desired for many applications such as archives, data centers, etc. Either a separate dehumidifier or a precision air conditioning (AC) system needs to be employed for such an application. In fact, the latter forms a reheat AC system which happens to be energy inefficient. In view of this, a vapor compression window air conditioner is investigated with a superimposed liquid desiccant loop harnessing the advantages of both the compression system (high COP) and desiccant system (low humidity). Operation of such a novel system is explained, elucidating the operational feasibility. The results presented consider the characteristics of such a system with respect to changes in the evaporator inlet air temperature and humidity. The change in the specific humidity of air is compared for vapor compression system and the direct contact hybrid system for different values of inlet air temperature.