Study of the cooling performance of an anti-condensation radiant cooling unit with an infrared-transparent silicon wafer

Abstract

Radiant cooling systems consume a low amount of energy and provide high thermal comfort; however, the risk of condensation in hot and humid areas limits their cooling capacity and is not conducive to their application. To solve the contradiction between condensation problems and the cooling demand, this study proposes a novel anti-condensation radiant cooling unit (RCU) that uses an infrared-transparent silicon wafer (ISW) with a good mechanical strength to separate the cooling radiant panel from the humid air, thus avoiding condensation. A heat transfer model of the anti-condensation RCU was established, and experimental tests were conducted under different indoor air temperatures, humidities, and vacuum degrees in the interlayer. At a temperature of 26 °C in 50 % relative humidity, the maximum cooling capacity of the anti-condensation RCU reached 103.66 W/m2, which was 60.88 % higher than the performance of conventional RCU. When the vacuum degree of the interlayer was 0.06 Mpa, the air-contacting surface outside the ISW was approximately 1.2 °C higher than that of atmospheric pressure. The results demonstrate that the anti-condensation RCU overcomes the limitation of the dew-point temperature on the cooling capacity to a certain extent and expands its applicability in high-humidity environments.