In order to evaluate the energy efficiency of a dew point evaporative cooler from the views of “quantity” and “quality” of energy, based on the second law of thermodynamics, the influence of intake air temperature, air flow velocity and relative humidity on the distribution and variation of thermal exergy, chemical exergy, mechanical xergy, and exergy efficiency in the wet and dry channels of the cooler was studied by exergy analysis. The results show that the exergy efficiency of the cooler increases from 10.6% to 36.7% with the increase of the intake air temperature, and decreases from 21.8% to 9.5% with the increase of the relative humidity of the intake air and decreases from 18.2% to 9.1% with the increase of the air flow velocity. By studying the exergy efficiency under different conditions, it is known that the cooler still has a great energy saving potential. Combined with the exergy efficiency, the weak points of energy saving of the dew point evaporative cooler can be clearly known, thereby finding a method for reducing energy loss.
Keywords dew point evaporative cooler; thermal exergy; chemical exergy; mechanical exergy; exergy efficiency