Morris,
From personal experience, solar intensity is anything but constant. Even
on a clear day the input (and therefore the output) varies noticeably
from minute to minute. I heated a home in Minnesota for over a decade
with a Jøtul fireplace/stove) and the heat varied from tree to tree of
the same species.
Ok, I'm following your thinking there.
The invitation to visit the shop (just 150 mi east of Omaha) is still
open. DIY skills are easily acquired, and I might be able to offer a few
suggestions and bit of useful show-and-tell to bolster confidence. If
it's any comfort to you, I started building panels without much
experience - but there seems to be only one way to get it...
That would have to be a summer trip; I'm in the very west part of the
state and am still trying to get by with only my motorcycle. I don't
think I've ever been accused of having a lack confidence, but I am
looking at an active system for "summer heat" use reasons and it seems
to me that it may not be my skills as much as anything with moving
parts can break or wear out.
Hmm - yes. I chose not to join the Yahoo! solar-thermal group because of
Yahoo's Terms of Service, and pretty well lost interest in the group
when, after suggesting venetian blind slats for absorber construction to
one of its members, he quoted the private e-mail to the group and
reported that /I/ was building absorbers with venetian blinds. I decided
that I couldn't afford to be associated with such folk. If you happen to
run across this dufus, you might point him at
http://www.iedu.com/DeSoto/Misc/Coil(320x240).jpg
I agree that there are lots of people who don't want to see anyone
helped and will trash any idea that isn't theirs, the solar-thermal
group has its share of pin-heads as does any group, but there are some
helpful ideas out there and like here, I read there every morning.
I don't post much there because any help I could offer would be on
concentration and what I know about collection comes from that group
and BIS to begin with, and that group is mostly focused on collection,
as am I now.
(There are some folks who just plain aren't worth trying to
help.) Although I would tend to trust anything Gary Reysa told me, I'd
still want to check it out carefully Agreed.
I think there may be a lot of difference between space heating and water
heating. My not-very-refined measurements indicated a final efficiency
in the 85% ballpark for a fairly well-refined passive solar panel
incorporated into the structure wall. My largest loss came from
non-ideal transmissivity of the UV-protected twin-wall polycarbonate
glazing - a loss that I was willing to accept in trade for longevity,
improved safety, and significant reduction of other losses.
I carefully stayed away from fluid-heating systems and anything that
required non-solar power for operation. One of my quirks is that I like
machines without moving parts - another is that I like systems that do
their job reliably, silently, and efficiently without supervision.
There seems to be an on-going spiting match between the passive and
active advocates on that yahoo solar-thermal group where both side
think they have the right plan in all circumstances, and in all
circumstances the other plan is wrong. They seem to believe that the
square pegs and round holes are not an issue as much as the size on
the hammer you're using is.
Heh - did you know that purely passive systems aren't eligible for an
Energy-Star rating? There's gotta be a joke in there somewhere... :-/
In my view, the Energy-Star rating is more about helping consumers
consume than helping consumers conserve.
Drove across Nebraska (W to E) Friday. Very much warmer than what I'd
experienced at 11,000' in Colorado. Sunny - a great solar day all across
the Cornhusker State.
So far the whether has been nice, I don't expect that to last much
longer.
Thanks,
Curbie
