| David Williams 2007-07-13, 1:25 pm |
| -> I live in a conventional suburban neighborhood, but on a recliamed
-> sand pit land. This forms a fairly large lake of about 20 acres and
-> 25' deep. My house - a conventional wood framed brick venier job,
-> backs up to the water. I live in Texas, and of course it is hot a
-> large part of the year. The interesting part is that the deep lake
-> has a very cold layer of water in the bottom. Not sure of the exact
-> temp but I can get a reading fairly easily. One guy dove to the
-> bottom in a wet suit & scuba gear and claimed it was very cold - in
-> the summer. Lets say mid 40's or 50 degrees.
-> I had an idea of using the cold deep lake water to cool a fluid and
-> pump it up into the house, to the 3rd level mounting of all the
-> current evaporator, then through some sort of heat exchangers and back
-> down to the lake.
-> My initial excitement was dampened by the difficulty of pumping water
-> from the lake would likely use about the same amount of energy as the
-> air conditioner itself.
-> Any thoughts from the community?
If the lake is sufficiently large and deep, the water at its bottom is
probably at the temperature of maximum density, about 4 degrees C.
Your idea is used on a large scale here in Toronto. Cold water from
deep in Lake Ontario is used to cool a lot of commercial buildings
downtown. It is certainly economically viable on that scale. I don't
think any other fluid is used, apart from air. The cold water is piped
to the offices in the buildings, and goes through some pipes with
heat-exchanging fins, over which air is blown. Of course, the air gets
cold. Any condensed water is piped away to drains.
dow
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