One advantage of indirect-direct evaporative cooling over packaged air conditioning that is often overlooked is total water usage. Steve Kinkel has pointed out in a recently published article entitlted Four Timely Benefits of Indirect-Direct Evaporative Cooling:
” …Indirect-direct systems use a significantly less amount of water to provide cooling. This may not seem like the case at first glance. However, when the additional electricity needed for standard packaged air conditioning systems is considered, an indirect-direct system can use approximately 50 percent less water. This is because power companies primarily rely on large cooling towers and reservoir water to produce electricity.”
Kinkel went on to say,
“According to the National Renewable Energy Laboratory (NREL TP-550-33905), power plants in Arizona and Nevada require an average of 7.55 gallons of water to produce 1 kWh of electricity. The chart below takes the data from the NREL report and uses it to compare the hydro-footprint between packaged air conditioning and an indirect-direct system for a 100,000-square-foot facility that is 24 feet high.”
Water Usage of Indirect-Direct Evaporative Cooling vs Air Conditioning