I'm currently putting trusses across two containers 16' apart. Each container is 8' wide with a 16' space between. 40' long. Trusses are 32' long to allow a rain overhang. It is sloped with no peak.
My intent was to take the sun load off the top of the containers. There will also be double doors on each end of the space to be able to enclose the inside. I intend to put a swamp cooler in each container.
I was wondering if I put a recirculating water pump to flow water over the roof and outside vertical east and west sides if that would cool it very much. I'm probably going to have to just try it. I get ag water, so there's no problem about added cost.
There was a hot dog restaurant (Rutt's Hut) in NJ that my family frequented YEARS (50's & 60's) ago. The place is still there and quite well known.
I didn't really care for their hot dogs, they appeared burned to me but my fascination with the place was that the building was partially cooled by water that run over the roof (from ridge to eave), collected by rain gutters and recirculated.
Whether this will work or not depends on your local weather conditions, temperature of water source & cost of water.
If oyu get water out of the ground at 60 degrees you can cool your roof quite nicely but it will take a lot of water. Let's say you can heat the water from 60 to 75 F as it travels over the roof. That means each gallon (~8.3 pounds) will remove about 125 btu.
Not too bad but to rely on water cooling alone, no evap, will require about 1 gallon per sq ft per hour. :(
If your local relative humidity is low, you can get the additional bonus of evaporative cooling..... every pound of water you evaporate takes ~1000 btu's with it. :)
So a gallon removes about 8000 btu's.
Evaporate 12 pounds per hour and you've got a 1 ton "air conditioner".
Depending on the temperature changes, day to night, a swamp cooler might give you moisture issues but maybe not.
Around here, a white plastic tarp (30 x 20 ft) costs about $30 at home despot.
My first thought was to cover the roof with something like that. Something very white, that could be put up and taken down quickly.
I'm thinking that having it suspended a few inches over the roof surface somehow - with stand-offs or something - would be better at keeping the roof cool vs having the cover in direct physical contact with the roof.
A couple of the sides of my roof can't really be seen from the ground. I really wouldn't mind painting those shingles with some sort of white glossy paint - assuming there is such a paint that has a good record for durability in that application.
Anyone know how much of a temperature reduction I'd get by painting the shingles white, vs suspending a white tarp a few inches over them?
A person in our neighborhood tried water cooling on his house roof. Minerals in the water leached out onto his shingles causing major white streaks & splotches. Looked like 10,000 pigeons roosted there. Worse eyesore in the neighborhood until he re-roofed.
I had a 20 x 12' carport sized house peak shaped tarp on a frame shading the middle of the containers. It was tied down to a welding table made of 2" x
2" x 1/4" angle iron. The table was four feet wide, ten feet long, and 32" high. The wind took the tarp cover, frame, AND welding table and flew them to a landing spot 30 feet away never touching the ground until the landing. At least 200#.
We don't do tarps where we live. My 480 sf steel awning at the rear of my house is engineered for 104 mph winds. Everything must be made of steel, telephone posts, or some other very sturdy materials. And every once in a while, that is not enough.
A person in our neighborhood tried water cooling on his house roof. Minerals in the water leached out onto his shingles causing major white streaks & splotches. Looked like 10,000 pigeons roosted there. Worse eyesore in the neighborhood until he re-roofed.
reply:
I just posted some links to HVAC projects that use these, and had better luck than I would have ever suspected. Some are complicated systems with heat sensors that control on/off valves to different areas of the roof as needed. I do suppose, tho, that the roof is the key to the whole thing, as applying the water is a no brainer.
The material you are wetting is the key. In driving around, I see roofs of all manner of decay. Some look like they wouldn't hold up to a decent rain or even a good wind, and some are down to the plywood/particle board.. Keeping them wet would just speed up the decay process, plus go down into underlayment, decking, trusses, insulation, drywall, et al. I am using Fabral steel sheeting. It has eleven layers and is made for weather exposure. I'm going to use a gutter seal on the seams that I can only get from my professional gutter guy. There will be no degradable material, save for rusting, and that can be dealt with.
I'm jazzed, as putting the roof over the containers was to take the sun load off. The studies claim a 25 degree reduction of temperature. Add two swamp coolers, and I should have a nice cool shop.
As always, I am documenting on camera, and will post when done.
What about painting them with a more expensive but much more durable coating -- I'm thinking aircraft-type aluminum paint. I've thought of doing that with the part of my roof that is flat EPDM-or-similar membrane.
Used some of that on a job I did at Hoover Dam. Interesting stuff, but still has an absorption by the steel under the paint. It looks like this sprinkler sprayer concept is leading so far. Those studies provided by Steve W. were impressive. Hope to get the trusses up tomorrow, and start decking soon. Probably get it done when the weather cools off. Figgers.
Steve
Heart surgery pending?
formatting link
Heart Surgery Survival Guide Now on facebook, too.
============ Insul Cool-Coat is a high build 100% acrylic elastomeric roof coating based on the latest chemical technology and fortified with Hy-Tech insulating ceramic microspheres. This bright white high build formula is designed to insulate, seal, repel moisture, deaden sound, and protect. The thick rubber-like ceramic reinforced shield expands and contracts with varying hot and cold temperatures plus resists thermal shock. Insul Cool-Coat offers superior mildew resistance, soundproofing, UV ray reflectivity, corrosion resistance and a beautiful insulating finish.
Spread Rate- 100-150 sq.ft/gal Dry to touch- 2-4 hours Recoat-12 hours...Cure Time 5-7 days Sizes: 1 Gal., 5 Gal. $28.50 Per Gallon...5 Gallon $142.50 (no deal) ===========
Example pictures:
formatting link
See also:
formatting link
formatting link
"Now, the Federal government has created tax incentives for energy-saving improvements, including cool roof coatings. Many states are now offering incentives to contractors and homeowners who use cool roof coatings, so you'll receive another benefit for choosing one of the most effective roof coatings available today."
================
formatting link
09-08-2010, 02:43 PM Holy crap, Batman! I coated my dark shingled shop over the weekend, and got an honest 40 degree drop in temps inside! Put it on right over the shingles, some guys said OK, some said not to. It's as cool in there as my carport is in the shade. No more 130 degree sweatbox, and I can store my paints in there now. I bought the good 12 year stuff, we'll see how long it lasts. =================
=================
formatting link
You can paint asphalt roof shingles with any acrylic (water-based) paint. I tested part of my roof and it's holding up fine. You need to water it down a bit so that it covers the texture more easily without brushing over and over. I'm about to paint my entire roof using 5 shades of green, and painting each individual shingle. Don't know how long this will take, but my stone cottage needs a jewel-like roof to crown it properly. The part I tested is on top of a sun porch, which I painted gloss white so the summer sun will reflect off of it. I've painted a whole lotta things in my life, and I've come to the conclusion that people worry too much... just go ahead and paint. I've even painted some of the corner stones on my cottage with flat "terra cotta" colored paint, and it looks like that's what they are made of. Life is short... just do it. ================
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.