What Is Lake Source Cooling?

To understand what Lake Source Cooling (LSC) is, you need to know roughly how Cornell's current system works.

Cornell has a "district chilled water system" in which chilled water is pumped in large pipes to numerous buildings where it absorbs heat in large air conditioning machines. The warmed water is then piped to large "chillers" - essentially, large refrigerators - which cool the water for reuse.

The basic idea of LSC is to replace some of the cooling currently provided by chillers with lake water cooling. In order to do that, Cornell would bring campus water down to the lake shore in large pipes, where it would be cooled by lake water in devices called "heat exchangers," and then pumped back up to campus.

Why are heat exchangers needed? Wouldn't it be simpler just to pipe lake water up to campus?

Cornell treats its campus chilled water with chemicals to prevent corrosion of its piping and air conditioning machines. Lake water can't be poisoned with such chemicals, and therefore cannot be used directly in the campus chilled water system. Cornell would get around this problem by using heat exchangers.

Heat exchangers are devices which transfer heat from one fluid to another while keeping them separate. In the case of LSC, they would allow chemically treated campus water to be cooled by lake water without chemically polluting the lake water.

Does that make it a "closed-loop" or "open-loop" system?

What Cornell proposes to build is "open-loop." Cold lake water would be pumped from a deep water inlet, and warmed lake water would be discharged, miles away, at a shallow water outlet.

Cornell examined the possibility of making LSC "closed-loop" - in which campus water would be circulated through miles of pipe at the bottom of Cayuga Lake - but rejected the idea because it would be too costly and inefficient.

Is Lake Source Cooling a Bad Idea in General?

The basic idea of LSC isn't bad, it's just that there are few places on this planet where it is both economically and environmentally suitable - and Cornell isn't one of them. Because its campus is nearly five miles from the deep, cold lake water needed for LSC to work, Cornell would need to install miles of large, costly, buried pipe - which would make it exorbitantly expensive, and would also degrade efficiency. And Cayuga Lake is simply too environmentally sensitive to be subjected to LSC without suffering significant damage.

So why should Cornell be allowed to build LSC when more energy could be saved at less cost by using conventional alternatives that wouldn't harm Cayuga Lake?

Prepared by the Cayuga Lake Defense Fund (CLDF)
For more information, Call: 275-9054 or 272-7914 or email info@cldf.org