Subject: Re: McCarthy's observations (Re: Wind power to expensive!!)

From: [email-masked] (Nick Pine)
Date: 26 Sep 1995 01:15:41 -0400

Joe Dlhopolsky  <[email-masked]> wrote:

>I don't know about anyone else, but in my house (one-story ranch), the 
>insulation is in the ceiling of the living area.

That's like my attic.

>If I had the money to invest, I'd cover my entire 60 x 40 feet
>of sun-exposed roof with solar panels.

I got my 32' x 20' steep south attic roof replaced this summer with clear
polycarbonate plastic. So now the south side of the attic is transparent,
a 600 ft^2 solar air heater, which should have a peak power collection of
about 40 kW (thermal) at about 75% efficiency. It looks great from the
inside, with a 32' x 24' floor with wide pine floorboards and stone endwalls,
and conventional from the outside, unless I turn on a light at night. The
cost for labor (at $40/hour) and materials was $2200, including a couple
of large vents with operable doors underneath, near the roof peak. 

Nick

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From: [email-masked] (Nick Pine)
Date: 28 Sep 1995 06:35:28 -0400

Joe Dlhopolsky  <[email-masked]> wrote:
>[email-masked] (Nick Pine) wrote:

>>a 600 ft^2 solar air heater,

>How do you keep from cooking in the summer?

There's 8" of cellulose insulation under the wide pine floorboards, and
4 open windows in the stone walls, and 2 1' vents near the ridge, 14'
above the floor. The vents have some hinged and weatherstripped doors
underneath that are open now, but they will be closed in the winter. 

Still, it gets very hot up there on a sunny day, and quite warm on a
cloudy day. At the moment, I just use the attic for storage, altho
sometimes I sleep up there in a hammock strung from the collar beams,
and look out at the stars, after the sun goes down...

Nick

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From: [email-masked] (Nick Pine)
Date: 28 Sep 1995 07:05:33 -0400

Ken Fischer <[email-masked]> wrote:
 
>         It is possible to place an overhang above south facing
>passive collectors so that the natural position of the Sun in
>summer does not let _any_ sun in.

Adaptable overhangs seem nice, since a fixed overhang that admits the
low-angle sun in April and May will also admit the low-angle sun in
August and September, when extra heat is unwanted.

An excellent $5 book about solar overhangs is _Sun Angles for Design_, 
published by Robert Bennett/6 Snowden Road/Bala Cynwyd, PA 19004. 
Mr. Bennett is a Registered Architect and Professional Engineer (with
a degree in space physics :-) and a former National Coordinator of the
American Section of the International Solar Energy Society. I believe
he now lives in Virginia.

Closable vents also help in the summer, as do deciduous trees, trumpet vines,
automatic insulated garage doors, clematis, runner beans or grapes. Vine-wise,
twiners are less damaging and more controllable than clingers. Perhaps grape
pruning and harvesting would be easier with a movable rope trellis over the
glazing, suspended from a board at the top which is in turn suspended from
an eave by a couple of ropes and pulleys.  

Nick

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From: [email-masked] (Nick Pine)
Date: 28 Sep 1995 07:05:33 -0400

Nick

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From: [email-masked] (Nick Pine)
Date: 28 Sep 1995 07:30:58 -0400

<[email-masked]> wrote:
>[email-masked] ([email-masked]) wrote:
 
>> An overhang above the roof?
 
>Why not?  Trees provide a natural overhang...and are commonly used to 
>control solar gain.

I used to have a cherry tree that overhung my attic roof. The trunk is still
there, about 3' in diameter. It died. I had it removed a few years later,
very carefully. One of the long branches that overhung the roof was about
a foot in diameter. A tree would be safer shading a wall than a roof.

>An artificial one would be even more efficient, though if not designed
>properly it would be UGLY.

An artificial tree? Seems like it would have to drop its leaves in winter
to work... (?) People now make cellular telephone base station antennas
that look like trees, large fiberglass structures with co-linear array
antennas inside, I think. About $50K...

Nick