Subject: Re: black 80%-solar-absorbing shadecloth, Was: AC Short Cycling

From: [email-masked] (Nick Pine)
Date: 12 Jun 1996 00:28:23 -0400

Meir Laker <[email-masked]> wrote:
    
> PS: Lent 700 ft^2 of 13.9 cent/ft^2 black 80%-solar-absorbing shadecloth to
> the local newspaper... so they could see how their comfort and AC bills
> change when they hang it over their barn red south wall with R11 insulation
> and 84 ft^2 of double pane windows. 
 
>Why black, solar absorbing cloth?  Wouldn't white reflective cloth
>keep the sun "away" and therefore keep the building cooler?
 
Yes, but that black is what I happened to have around... And they plan to put
some transparent polycarbonate siding over their shadecloth in the fall, to
make a huge inexpensive solar air heater. For that, a dark color is better.

For summer shading, black is cool, as long as there is an air gap behind it
and at the top. They would like red, eventually. Shadecloth comes in black,
red, green, gunmetal gray, white, aluminized, sandlewood, etc. Home Depot
sells a nice ~100% black furry polypropylene shadecloth ("landscape fabric") 
that is still fairly porous to air, made by DeWitt (800) 888-9609, for $78
for a 4' wide x 250' long roll, with no hems or grommets, but it would not
let much light in through windows, unlike 80%, which looks like a window
screen from the inside, or makes a moire pattern if there is already a
window screen in place..

Nick