 Cornell began operating a closed loop , central chilled water system for air conditioning and laboratory cooling in the 1963 using centralized mechanical <unk> , rather than inefficient , building @-@ specific air conditioners . In 2000 , Cornell began operation of its Lake Source Cooling System which uses the cold water temperature at the bottom of Cayuga Lake ( approx 39 ° F ) to air condition the campus . The system was the first wide @-@ scale use of lake source cooling in North America . 
