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re: concrete solar collector feasibility in pnw?
26 may 1998
elaine gallegos wrote:
>nicksanspam@ece.vill.edu wrote:
>: solar heating a swimming pool from march through october seems like a
>: piece of cake in seattle...
> nick- i almost never disagree with you, but i think you are off base on
>this one. i've never seen no sunshine out her in may much less march.
never seen none, eh? :-) would that your math exceed your english...
maybe you only go outdoors at night? :-) nrel's 30 year weather record
says an average of 1760 btu/ft^2 of sun per day falls on a square foot
of horizontal surface in may in eugene, or, with an uncertainty of 9%
and a standard deviation of 149, and an average outdoor temp of 55.8 f,
and an average daytime high of 67.1.
that means collecting about 1760(450ft^2)0.9 = 713k btu of sun over an 8(?)
hour day, so we'd have something like
713k = 8h(t-56f)450ft^2/r1 for the cover during the day
+ 16h(t-56f)450ft^2/r11 for the cover at night
+ 24h(t-56f)300ft^2/r11 for the sides,
so t = 56 + 713k/(3600+655+655) = 201 f, theoretically-speaking :-)
>it's hard to heat a pool with solar, even in otherwise hot sunny areas.
that's because they have such poorly insulating covers. you might call
this "insulating the pool." i've talked with quite a few "solar pool
heating professionals" (duh) over the last few years, and subscribed to
"pool and spa marketing." i'm sad to say that as a group, these guys seem
arrogant, ignorant, backward and stupid. i spoke with an honest one
this morning, who answered a simple question with "i have no idea..."
nick
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