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

Fri Feb 2 22:39:30 CST 2007

Thank you for the kind words.
I enjoy learning from everyone else's posts, it's great to get different 
perspectives on subjects.
Sorry I have been so quiet lately, busy working, health problems, 
fighting the legacy of Jerry Brown's reign of terror as Oakland Mayor.

Lawrence Lile wrote:
> As usual George, you have very excellent and detailed suggestions!
>
>  
>  
> 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 George J.
> Nesbitt
> Sent: Tuesday, January 30, 2007 11:14 PM
> To: Keith Winston
> Cc: Greenbuilder list
> Subject: [BULK] Re: [Greenbuilding] [BULK] Re: Air Conditioning for
> Phoenix
> Importance: Low
>
> *GREEN COOLING*
>     Fix the *building shell* first as much as possible.
>        1. Cool roof would be high on my list, but if you need "approval"
>
> then it might not happen. If you insulated the roof underneath then the 
> benefit is too society in reducing the "heat island effect".
>        2. Radiant Barrier, if you have to have a darker roof and if you 
> don't insulate the roof, than I absolutely recommend a radiant barrier 
> (help keep the attic and ducts cooler). Roofing is starting to be made 
> in darker coolers that have reasonable cool roof properties.
>        3. Insulate the roof, to bring the attic and ducts into 
> conditioned space, either by placing rigid (polyisocyanerate) on the 
> roof deck, or spraying foam (cellulose would also work in phoenix) on 
> the underside of the roof deck.
>        4. Windows, add low e film, overhangs, trees, replace, etc. to 
> reduce unwanted summer heat gain.
>        5. Air leakage reduction never hurts. Build tight, ventilate
> right.
>        6. Paint the house walls a light color.
>        7. Insulate the walls if they aren't already.
> Now for the *mechanical.
>        1. *Manual J or ASHREA 90 room by room load calculation
> (accurate).
>        2. Manual S equipment sizing calculation, don't add size, if 
> anything the load calculation is as much as 1/3 to large. Don't
> oversize.
>        3. Manual D duct design.
>        4. Manual T grill/register design.
> Now for the *equipment.
>        *1. Swamp cooler, the oasis is the best, direct, indirect 
> evaporative cooling. Developed with funding from the California Energy 
> Commission, and Davis Energy Group.
>        2. There is another one, but can't think of it's name at the
> moment.
>        3. Split system refrigerant cooling. Forget SEER, it is tested at
>
> 82deg F outside temperature, and 50% RH, you want a high EER, tested at 
> 95 deg F (still cool for Phoenix). The higher the outdoor temperature 
> the lower the EER (or SEER for that matter). Stay away from the 2 stage 
> condensers, they aren't as efficient on high. (better to under size and 
> let it run longer). Install an air handler (furnace?) with a ECM 
> variable speed motor. Install a return duct to the outside for fresh 
> air, and run air handeler 24/7 (or a percentage of the time) on low 
> speed (60-80 Watts).
>        4. Water cooled split system. Consider the Freus, and there is at
>
> least one other, hight EER even at higher outdoor temperatures (although
>
> some loss).
>        5. No HFC, HCFC refrigerants, use R-410A (Puron is one trade 
> name). The Freus is R-22.
> Now for the *Installation*.
>        1. R-8 duct insulation, especially if the ducts are in the attic,
>
> R-4 if they are in conditioned space.
>        2. Insulate the plenum's, and the air hander too.
>        3. Install the ducts and test to less than 6% of design airflow 
> (400cfm/Ton cooling, ie 12,000 BTU's).
>        4. Test the airflow with a Trueflow to check for 400-450cfm/Ton 
> cooling.
>        5. Braze the refrigerant lines with an oxy-acetylene torch, using
>
> 15% silver solder, and run nitrogen in the lines.
>        6. Put the refrigerant lines under a vacuum to 500 microns, and 
> not less than 800 after 15 minuets.
>        7. Verify the charge using Subcooling (install a TXV).
> Now for the *operation.
> *       1. Use a programmable thermostat, try to live with not less than
>
> a 78deg F indoor temperature.
>        2. Enjoy comfort without breaking the bank, or killing the
> planet.
>
>
>
> Keith Winston wrote:
>   
>> 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=7
> 93&BucketID=6&CategoryID=6
>   
> http://ezinearticles.com/?Evaporative-Water-Cooler---This-Water-Cooled-C
> ondensing-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
>>
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>>   
>>     
>
>
>   