Experimental study on desiccant evaporative combined chilled air/chilled water air conditioning systems

Abstract

• A desiccant evaporative combined chilled air/chilled water systems was proposed. • The dynamic characteristics was presented by experimental investigation. • The temperature of the chiller air and the chiller water is below 20℃ and 18℃. • Regeneration temperature and air–water ratio have great impacts on performance. • 70 °C regeneration temperature was recommended in high humidity regions. Evaporative cooling technology is limited by the environmental wet-bulb temperature and is not suitable for humid climates. Desiccant wheels adsorb water vapour, thereby converting high-humidity air into low-humidity air, and they can be regenerated by solar energy or waste heat. In this study, a desiccant evaporative combined chilled air/chilled water air-conditioning system is proposed. The proposed system integrates a desiccant wheel air conditioning system and a direct-evaporative cooler, which can be used for temperature and humidity independent control systems in humid climates. An experimental setup was built and used to test the system performance and important system parameter effects under moderate temperature and humidity (32 °C, 60% RH), moderate temperature and high humidity (32 °C, 80% RH), and high temperature and humidity (36 °C, 80% RH). The results indicated that for the system at a regeneration temperature of 70 °C, the chilled air temperature was lower than 20 °C, the chilled air humidity ratio was lower than 13 g/kg, and the chilled water temperature was lower than 18 °C, which meets the temperature and humidity independent control requirements.