In the Drink; October 1999; Scientific American Magazine; by Holmes; 2 Page(s)

Even on a muggy, 90-degree July day in Ithaca, N.Y., the depths of nearby Cayuga Lake are a nippy 40 degrees. This simple fact has pointed Cornell University, the town's largest economic entity, toward a novel solution to its energy demands for cooling. The university has embarked on a $55-million project called Lake Source Cooling, which by mid-2000 will be using cold water from the lake to reduce Cornell's energy consumption for air conditioning by 80 percent.

To make this happen, the university is laying underground a huge pipeline in two distinct segments. One segment, 1.6 meters (5.25 feet) in diameter, will draw water from Cayuga (the longest of the Finger Lakes) from a depth of 76 meters, raise it to a heat-exchange facility on shore and then discharge it into a shallower part of the lake. A separate line of somewhat smaller underground pipes will carry water downhill from Cornell, about three kilometers (two miles) away, to the heat exchanger and back up again. The Cornell water and the lake water will never mix, but heat will be transferred through stainless-steel plates.