Engineers at the National Renewable Energy Laboratory in Colorado have devised an air conditioning unit that could use up to 90% less energy than a conventional unit.
The new, patented system abandons the power-hungry compressor-driven refrigeration process used in many domestic (and virtually all commercial) air conditioners in favor of a couple of high-efficiency pumps and fans. But it also uses water for evaporative cooling — a concept familiar to many people living in the arid West who have roof-mounted "swamp coolers." Swamp coolers work well when the outside air is dry, as evaporating water carries away heat, cooling and moistening the air that is re-circulated into the house.