Investigation of dew point evaporative cooling with vacuum membrane dehumidification

The vacuum membrane dehumidification and dew point evaporative cooling are potential technologies to handle the latent and sensible heat of the air, respectively. This paper proposes a hybrid system of vacuum membrane dehumidifier and dew point evaporative cooler for air conditioning. A horizontal counter-flow dew point evaporative cooler was designed and developed. The transient and steady-state characteristics of the cooler were judiciously examined. The cooling potential of the cooler itself and the combined system with a membrane dehumidifier were then investigated and compared. Key findings that emerged from this study include: (1) the dew point evaporative cooler alone delivers the product air temperature at 24.8 °C under the hot and humid condition, with the wet bulb effectiveness of 1.05; (2) the hybrid cooling system is able to reduce the ambient humidity to 8.2 g/kg, and the ambient temperature is cooled to below 18.5 °C.