[Greenbuilding] [BULK] Re: Air Conditioning for Phoenix

[Keith Winston]

Hi there,
> I'm going to push the limits of what he can handle as it is.  A metal
> roof makes a lot of sense in Phoenix, and that is the second part of
> this project that I didn't mention.  Living roofs are great, but involve
> structural mods that I'm not willing to consider on someone else's
> house.  
>   
What about: put your metal roof on purlins (not all mftrs allow it, but 
some do) to create an air channel underneath, vented top and bottom 
(hopefully it's a simple roof -- include insect barriers in the vents). 
Use a radiant barrier under it, pointing up.

Insulate the roof from within the attic with spray foam, in the meantime 
sealing up the attic so if there are any ducts in there they are inside 
the envelope. Sorry, he has to move the nesting dolls. Check with your 
local foam contractor to see how willing/able he/she is to work around 
crap, but probably it needs to be empty. Hire a few young people to 
clean it out! Leave the insulation that is probably already on the 
floor, to make the attic a lightly conditioned space. Then you get the 
reflective metal roof, a radiant barrier properly installed, a 
convective air space to keep the whole assembly from getting TOO hot, a 
tightly insulated roof, interior ductwork... have I missed anything?

Say, did you ever find indirect evaporative coolers? We can't really use 
them here in DC, too humid. I see that Mastercool has an indirect 
modification available http://www.adobeair.com/masterCool.html, I can't 
find it on their website but call and ask them. The other one is here: 
http://www.oasysairconditioner.com/, which looks impressive.

Another possibility is a Freus water cooled evaporative air conditioner, 
quite different from a direct or indirect/2 stage evaporative cooler. It 
is a compression-cycle machine that uses a spray of water on the 
condenser coils to improve performance.

http://www.freus.com/

They don't have a good website. You'll probably gain more information here:

http://www.toolbase.org/TechInventory/TechDetails.aspx?ContentDetailID=793&BucketID=6&CategoryID=6
http://ezinearticles.com/?Evaporative-Water-Cooler---This-Water-Cooled-Condensing-Unit-Is-No-Swamp-Cooler&id=269729
http://www.ecosmartinc.com/productdocs/1-Freus-Overview.pdf

I'm not sure whether it makes more sense to use less electricity, or 
spray the Ogalala into the air to be whisked away...

Also, I have used/installed the Fujitsu 12RLQ mini-split heat pumps, 
which are 21 SEER units. If you have an open floor plan and can get away 
with just one or two sources, it's a good prospect. Of course, you may 
need to consider ventilation, though with swamp cooling it's part of the 
picture. See if an HRV is justified in there, it might remove a bunch of 
the moisture while still cooling makeup air. I like the Venmar units.

Warmly, Keith