Battelle Memorial Institute

New and more efficient cooling methods are needed to reduce building energy consumption and environmental impact. Buildings currently account for 72% of the nation's electricity use and 40% of our carbon dioxide (CO2) emissions each year, 5% of which comes directly from air conditioning. The refrigerants used in air conditioners are potent greenhouse gases (GHGs) that may contribute to global climate change. Because most cooling systems run on electricity, and most U.S. electricity comes from coal-fired power plants which produce CO2, there is a pressing need to support improvements that increase the efficiency of these technologies and reduce the use of GHG refrigerants.

Battelle Memorial Institute is developing a new air conditioning system that uses a cascade reverse osmosis-based absorption cycle. Analyses show that this new cycle can be as much as 60% more efficient than vapor compression, which is used in 90% of air conditioners. Traditional vapor-compression systems use polluting liquids for a cooling effect. Absorption cycles use benign refrigerants such as water, which is absorbed in a salt solution and pumped as liquid—replacing compression of vapor. The refrigerant is subsequently separated from absorbing salt using heat for re-use in the cooling cycle. Battelle is replacing thermal separation of refrigerant with a more efficient reverse osmosis process. Research has shown that the cycle is possible, but further investment will be needed to reduce the number of cascade reverse osmosis stages and therefore cost.

If successful, Battelle would provide an efficient cooling cycle.