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
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