LAUSR

Abstract This paper proposes the concept of “sub-wet bulb temperature” for the application of evaporative cooling technology, discusses the principle and implementation approach of the indirect-direct evaporative chiller for producing sub-wet bulb temperature cold water, and puts forward a way to describe the cooling performance of the pre-cooling section of indirect evaporative cooling through “sub-wet bulb efficiency”, using the “cooling efficiency of the water drenching filler on the air side and the water side” to show the cooling performance of the direct evaporative cooling section of the Water drenching filler, and utilizing the “unit's chilled water efficiency” to describe the cooling performance of the whole unit, and then explicit equation for predicting the unit's water supply temperature is derived out. The cooling performance of evaporative cooling chillers under different ambient air pre-cooling types was tested in Xinjiang region. The results showed that the chilled water efficiency of evaporative chillers reached a maximum value of 45.9 under the coil and vertical tube type of indirect evaporative pre-cooling form. At this time, the sub-wet bulb efficiency of the pre-cooling section of indirect evaporative cooling is 52.1%, the cooling efficiency of the water drenching filler on the air side has reached to 59.8%, and the water supply temperature of the unit is 13.7 °C, which is 2.3 °C lower than the wet bulb temperature of ambient air.