|
|
re: heat recovery
15 jan 2003
rg wrote:
>actually, a single common pvc pipe inside the greywater drain pipe will only
>raise the temp on the fresh water a few percent at best, even if the pipe
>run were very long. pvc pipe isn't a good heat transfer medium, its
>actually an insulator.
as i recall, it's about r1 per inch, ie 4 btu/h-f-ft^2 for a 1/4" pipe wall,
so a sufficiently long horizontal common pvc pipe inside a larger pipe full
of greywater will make a dandy heat exchanger, approaching 100% efficiency
as the owner's wallet grows thinner.
>a true heat exchanger would consist of an assembly of many thin channeled
>stainless steel baffle plates...
ah, a true heat exchanger...
>the number of baffle plates depends on the maximum volume of heated fluid,
one might imagine it depends on the flow rate.
>there are several commercial uses of heat exchangers, and several variation
>on the construction, but none manufactured for spent home waste water (which
>is not all hot water).
can you say "gfx"?
>capturing the hot water heater exhaust flue heat would be a more
>constant heat source, and more cost effective.
would you have any evidence for this article of faith? how is "capturing"
a heat source? why would we need to heat hot water? :-)
>i believe that a series of small metering vanes (that operate much like a
>common mechanical water meter) could be setup to generate a small amount of
>power ever time greywater passes out of a house or business. this would be
>universal, not dependant on the temperature of the water, and easily
>inverted into household current or battery storage.
this is just fine in concept, but falls apart with a few numbers,
like microhydro using rainwater from a roof.
>hope this was helpful.
not at all. now go away.
nick
|
|
