ALEXANDRIA, Va., March 31 -- United States Patent no. 12,590,738, issued on March 31, was assigned to Energy Recovery Inc. (San Leandro, Calif.).

"Heat pump systems with pressure exchangers" was invented by Azam Mihir Thatte (Kensington, Calif.), Kuo-Chiang Chen (Dublin, Calif.) and Farshad Ghasripoor (Berkeley, Calif.).

According to the abstract* released by the U.S. Patent & Trademark Office: "A system includes a pressure exchanger (PX) configured to receive a first fluid at a first pressure, receive a second fluid at a second pressure, and exchange pressure between the first fluid and the second fluid. The first fluid is to exit the PX at a third pressure and the second fluid is to exit the PX at a fourth pressure. The system further i...