Staff Sgt. Nathan Day and Senior Airman Ricky Ball, 2nd Civil Engineer Squadron Heating, Ventilation, Air Conditioning and Refrigeration technicians, review schematics for one of the recently installed chillers on Barksdale Air Force Base, La., June 7. New heating and cooling units are routinely brought in when needed and installed to maintain Barksdale's aging heating and cooling systems. (U.S. Air Force photo/Airman 1st Class Andrew Moua)(RELEASED)