OAK RIDGE, Tenn. - Research at the U.S. Department of Energy's (DOE's) Oak Ridge National Laboratory (ORNL) is helping to design a more practicable and energy efficient heat exchange unit in air conditioning systems for buildings.

Ed Vineyard of the laboratory's Engineering Science and Technology Division heads a team designing a natural gas-powered 10-ton micro channel heat exchange unit that can correct uneven refrigerant flow - or maldistribution - through an air conditioning system powered by generators and microturbines. Maldistribution reduces heat exchanger capacity that reduces an air conditioning system's energy efficiency and contributes to higher costs for a unit.

Working with United Technologies Research Center, Modine Manufacturing, Southwest Gas Corp., and DuPont, researchers are evaluating maldistribution with the use of a thermal imaging camera in ORNL's Heat Transfer Test Laboratory to determine steps necessary to correct the unevenness. The goal is to produce a heat exchange unit that will have a reduced profile on top of a building and operate more efficiently than conventional systems.