[Greenbuilding] [BULK] Re: Daylight harvesting progress

[Lawrence Lile]

>Would you believe "40% more than white plastic"?

That makes more sense.  I thought they were claiming to be 40% better
than a clear glass panel.  


>Wal-Mart guards that sort of information carefully. I heard
that the Wal-Mart employee who revealed that secret was fired. 

I read it in an industry trade mag.  

 
Lawrence Lile, P.E., LEED AP


-----Original Message-----
From: greenbuilding-bounces at listserv.repp.org
[mailto:greenbuilding-bounces at listserv.repp.org] On Behalf Of Nick Pine
Sent: Tuesday, March 06, 2007 1:51 PM
To: greenbuilding at listserv.repp.org
Subject: [BULK] Re: [Greenbuilding] Daylight harvesting progress
Importance: Low

"Lawrence Lile" <LLile at projsolco.com> writes:

>> Sunoptics prismatic skylights transmit 40% more light than others, 
>> with no hot spots. 
> 
> A claim I find hard to believe.

Would you believe "40% more than white plastic"? Other skylights
use white pigments alone to diffuse sunlight and avoid hot spots. 
Sunoptics uses lots of tiny molded prisms and a lot less white pigment
to achieve better light uniformity with a higher level of illumination.
They test them in a 32'x32' room with black walls and 21 light meters,
with another meter on the roof to measure sunlight.

California requires a min 3% of large roofs to be skylights, with 
a "90% haze," ie 90% of the light must be diffuse vs direct. 
The "effective" vs actual area is less, about 1.5%, after multiplying 
by the skylight transmittance and lightwell transmission.      
 
> Skylights also sell more soap.  Walmart did a test a number of years
> ago, installed skylights in half a store.  Sales went up by 15% in
that
> half.  Then they swapped the products in the store, suddenly the duds
on
> the other side that weren't selling, also went up 15% on the sunlit
side.

Wal-Mart guards that sort of information carefully. I heard
that the Wal-Mart employee who revealed that secret was fired.

> ... many new Walmarts are starting to go in with skylights.

Over 100,000 Sunoptics skylights in 560 stores so far, with more 
than 340 million skylit square feet. The next step may be skylights 
with constant illumination. A photocell senses the skylight and closes
louvers beneath when it's too bright. So far, Sunoptics has about
10,000 of these in the field, but they have only appeared in two 
Wal-Marts, and all they do there is to close fully at night to avoid 
"light trespass" upon neighbors. 

Nick


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