Steady as it goes and flows (IMAGE) DOE/Oak Ridge National Laboratory Caption Oak Ridge National Laboratory researchers developed a device called a piezoelectric-driven magnetic actuator, or PEDMA, that can be inserted into the header of a microchannel heat exchanger to keep refrigerants flowing evenly and the HVAC unit running efficiently. Credit ORNL, U.S. Dept. of Energy Usage Restrictions None License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.