The U.S. Department of Energy’s National Renewable Energy Laboratory has developed a new air conditioning process with the potential of using 50 to 90 percent less energy than the best current units.
The process uses a unique combination of membranes, evaporative cooling and liquid desiccants. It uses the desiccant (highly concentrated aqueous salt solutions of lithium chloride or calcium chloride) to create dry air using heat and then uses evaporative cooling to make the dry air cold.
Engineers have known for decades the value of desiccants in air conditioning but, because of the complexity of desiccant cooling systems, they have traditionally only been used in industrial drying processes. To create a device simple enough for easy installation and maintenance, the NREL engineers used thin membranes that simplify the process of integrating air flow, desiccants and evaporative cooling. The air is cooled and dried from a hot-humid condition to a cold and dry condition all in one step.
Because the system uses salt solutions rather than refrigerants, there are no harmful chlorofluorocarbons (CFCs) or hydrochlorofluorocarbons (HCFCs).
The air conditioner uses very little electricity and can be powered by natural gas or solar electricity and will work in all climates.