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Posted by Tim Williams on July 22, 2008, 4:39 am
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The most obvious and significant problem is infrastructure. Now if you
could pump that water down a street, you might have something. But digging
brand new canals across the city? Never gonna happen.
Maybe, just maybe, a repurposing of the storm drains, for cities that have
seperate storm and sewer lines. But then, what handles the rain?
Underground pipes would have to be pressurized to push enough flow, no storm
grates could remain.
Tim
--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms
>
>
>>Even if all they did was circulate warm condenser cooling water to the
>>city to
>>be used as the heat source for water-source heat pumps, one still has to
>>figure out how to pay for the plumbing. It surely would not compete with
>>simple ground-sourced heat pumps on an economic basis.
>>
>
> I wrote the above as it popped into my head during a previous post. I've
> given it a couple hours' thought and I see some possibilities.
>
> A large power plant has a condenser cooling water flow rate measured in
> the
> millions of gallons per minute. The temperature rise through the
> condensers
> is in the 5 to 15 deg range, typically. Lots of slightly warmed water.
> The
> water is not hot enough to be useful for comfort heating but it DOES
> contain
> lots of low quality energy. A heat pump is a device that takes low
> quality
> heat and turns it back into higher quality heat. An idea is born.
>
> Suppose that a portion of or all of this water were diverted into canals,
> open
> or closed topped, that carry the warmed water to a nearby town. Homes and
> businesses along the canals could pump the water to water-sourced heat
> pumps.
> Or an alternative would be to put the refrigerant coil directly in the
> water
> if the house isn't too far away.
>
> For houses farther away from the main canals, the water is diverted into
> neighborhood feeders. Again, warm water is pumped or siphoned to the heat
> pump or else the refrigerant coils are immersed in the water.
>
> The flow would go through the town and then back into the river or lake.
>
> This could be a very interesting system, depending on some details. Even
> in
> the dead-cold of winter, the condenser cooling water would probably be (or
> could arrange to be by the plant) in the 50s. That is a MUCH more
> suitable
> heat source for a heat pump than trying to pull heat out of below-freezing
> air!
>
> Other features could include cold weather swimming, hot tubs, etc., and
> Venice-like canal navigation around town for those who want to.
>
> A few questions:
>
> - Would this be economically feasible with either concrete-lined or dirt
> canals?
>
> - Would there be too much heat loss with an open canal or would it have to
> be
> covered?
>
> - Would it be economical for the plant to alter its operations such that
> the
> water is allowed to warm more than necessary for optimum plant operation?
> Increasing the condenser temperature and therefore pressure has a negative
> effect on plant efficiency. Given the low cost of fuel, it probably would
> not
> matter much for a nuke but for other plants, it might.
>
> - Would the amount of heat extracted be sufficient to result in too cool
> water
> near the end? Would a "return" canal be necessary? Maybe a divided canal,
> with one side carrying hot water and the other cold.
>
> - Would it be economical to lift-pump the water a few feet to reach
> neighborhoods say, 10, 20, 50 ft above the canal? By "economical" I mean,
> would the energy content of the warm water be sufficient to offset the
> cost of
> pumping?
>
> - Could the system be adequately protected from storm water ingress?
>
> - Would a water velocity too high for swimming or boating be acceptable if
> that was required to minimize the amount of land used for the canals?
>
> - Would this energy be too cheap to meter? That is, would a flat user fee
> adequately compensate the power company for the energy and the operation
> of
> the system?
>
> - Would the NIMBYs favor or fight such a system?
>
> - Would the "have nots" (those too far away or too high in elevation to
> use
> the water) scream and shout and try to stop the system from being built?
> Would
> they succeed?
>
> I'm thinking about my old town of Cleveland, TN. There is a network of
> creeks
> criss-crossing the town, including one behind my parents' old home. (I had
> long wanted to install them a water-sourced heat pump drawing heat from
> the
> creek but they were old-fashioned....) A similar system exists in nearby
> Chattanooga, a city that has the Sequoyah NP not too far from its
> population
> centers. If those paths were carrying hot water from a power plant.....
>
> I guess that I could spend a few hours calculating this out using some
> typical
> numbers but I thought that I'd instead toss out the idea and see what
> others
> have to say.
>
> John
> --
> John De Armond
> See my website for my current email address
> http://www.neon-john.com
> http://www.johndearmond.com <-- best little blog on the net!
> Tellico Plains, Occupied TN
> Better remain silent and be thought a fool than to cite Wikipedia and
> remove all doubt.
>
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