Semi-open Sorption (IMAGE) DOE/Oak Ridge National Laboratory Caption A new class of gas-fired heat pump water heaters, based on a novel semi-open sorption concept, could replace the evaporator in a traditional devices with a vapor-permeable membrane that more efficiently absorbs and transfers heat for residential applications. Credit ORNL Usage Restrictions None License Licensed 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.