Abstract:

In view of the optimization of the dew point indirect evaporative cooler structure, the cooling efficiency under different environmental conditions, the relationship between the air volume ratio and the cooling capacity, and the technical principle, structure, heat and mass transfer characteristics of three different dew point indirect evaporative coolers (composite , cross and countercurrent ) were compared and analyzed. At the same time, the three kinds of dew point indirect evaporative cooler were tested on the wet bulb efficiency, dew point efficiency, temperature drop range, cooling capacity and so on under the laboratory simulation conditions or practical applications. The experimental results show that under dry conditions, the wet bulb efficiency of the three dew point coolers can all reach above 100%, and the dew point efficiency is between 55% and 85%. In terms of the temperature drop range, the average dry-bulb temperature drop of the cross-type and composite dew-point coolers under standard drying conditions (dry bulb temperature of 38°℃and wet bulb temperature of 23℃) is about 15 °℃, and wet bulb temperature drop is at about 5.5 ℃, significantly better than that of the composite dew point cooler. At this point, the countercurrent dew point cooler energy effciency raio is 11.78, reaching the highest level.

Key words: dew point indirect evaporative cooling, heat and mass transfer, heat exchanger core, temperature drop rate, cooling efficiency