shop-talk supported in part by Fat Chance Garage
http://fatchancegarage.com
On Sat, Nov 05, 2005 at 07:56:21AM -0800, Randall wrote:
>
>
> shop-talk supported in part by Fat Chance Garage
> http://fatchancegarage.com
>
> > Keep in mind
> > that the SA240 appears to be mounted vertically instead of at an angle so
>the
> > available energy will be somewhat less.
>
> Possibly quite a bit less. That map assumes a fixed angle from horizontal
>equal
> to the latitude, which for Montana is 44 - 49 degrees. Assuming that's
>optimum,
> mounting the collector vertically reduces available insolation by 30%.
>
> > Let's assume you'll use this heater from October through March and
> > over that time
> > you're able to average 9-10KWh output per day (the collector is about
> > 2.6 square meters).
>
> Perhaps I missed it, but haven't you left out collector efficiency ?
Yep. To cut down on the length of my post, I ignored collector efficiency.
Thanks for pointing that out. Even with my unrealistically-optimistic
figures, the payoff is way, way down the road. Maybe I'm short-sighted or
impatient (or both) but I have a hard time buying into anything that doesn't
have a payoff within 3-5 years.
Jimmie
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