ALEXANDRIA, Va., Dec. 9 -- 7AC Technologies, Beverly, Massachusetts, has been assigned a patent (9,835,340) developed by three co-inventors for "methods and systems for turbulent, corrosion resistant heat exchangers." The co-inventors are Peter F. Vandermeulen, Newburyport, Massachusetts, Mark Allen, Essex, Massachusetts, and Arthur Laflamme, Rowley, Massachusetts. The abstract states: "Disclosed are various turbulent, corrosion-resistant heat exchangers used in desiccant air conditioning system . . .