Cooling a Yurt in the Midwest

[hippiebikerchick]

I have been working on getting my yurt up for over a year. The yurt was actually gifted to me so I didn't start learning about yurts until I ran up against challenges. I finally got the electric in and on the first hot day, I turned on the AC, it's a portable air conditioner that vents out the wall. Granted it was 90 when I turned it on, but it never cooled down until the sun went down. I know it is better to keep the ac on instead of waiting until it's hot, but the clear

dome

is like trying to cool off the oven while pouring more heat in it. Anyone have any suggestions on the best way to tint the

dome

? The dome is acrylic on a 20' yurt. The AC is rated for 400 square foot and the yurt is a 318.

Any advice would be appreciated.

[hierony]

Look for places where you can get air infiltration, especially where the yurt wall meets your platform. I'd also feel the canvas layers on the inside and outside to get an idea of how much thermal radiation it's absorbing. AC works best when the building/room is sealed, and I know my yurt is not well sealed...

Other than that, I'd suggest what the traditional yurt approach is: get a square flap (say, 5 ft x 5 ft white canvas or shade cloth), tie ropes to the four corners, and use that to cover the dome, tying the ropes to a stake in the ground or an anchor point on your platform. The flap is called an 'urgh' technically. Depending on how you set things up, you can have it completely cover the dome, partially, or just a little.

I think there's been a few people that tack up some shade cloth on the bottom of the crown ring on the inside. If your dome opens, the shade cloth might work with the dome cracked a little. Or the reflective bubblewrap would really help, but it would block the light.

Lots of options. Get creative, see what works. Best of luck!

[hippiebikerchick]

Thanks for your kind thoughts. The dome is the centerpiece and I hope to do something that will add to it's beauty.

[Jafo]

They do make tinted domes that help keep the uv out.

[hierony]

I resisted the urge on the other thread but it's mainly visible & IR radiation, not UV, that transfers most of the energy we feel as heat from the sun. UV on the other hand has a tendency to age materials (higher energy but much lower intensity). Not that it makes much difference for most people...

[Bob Rowlands]

Flap over the top as hierony mentioned would be a quick and cheap check to see if it helps. A massive tarp erected over the yurt to keep the direct sun from soaking the fabric? Hmm.. worth a try perhaps?

My gut tells me that you would need a kick @$$ chiller on a yurt that is sealed up (to hold in the cool) to really get the temp down during a sunny day. But that is just a guess.

My truck gets incredibly hot sitting in the sun with windows up. Air C wide open and recirc on it takes quite a bit to cool off. Same circumstance bomb down the interstate with all windows and rear window open, it cools off fast, THEN turn on AC. Just a thought. I think you'll have to do some experimenting. At least you don't have mold.

[hippiebikerchick]

Lol, Bob! I guess I should have built the yurt on wheels so I could cool it off at the same time as putting the chicken to grill in my dome solar oven!

[thebitmaster]

I've got a 12' yurt on a platform in Austin, Texas. We're about to get into 100+ degrees at 40% humidity, so cooling is paramount. My yurt is covered with recycled billboard vinyl, and currently insulated with comforters and sleeping bags I purchased at the Goodwill Outlet store for $1 each. I've purchased radiant barrier bubblewrap I intend to put between those two layers. I also have pretty thorough tree cover in every direction but straight up. I'm using a Honeywell 10,000 BTU portable AC with the water line plumbed outside. It's rated for 400 sq. ft., and I've got 113. I've got two layers of transparent shower curtain over my roof ring. One is strapped on in four corners and goes over the crown. It keeps out rain but isn't fully air or bug tight. I have another layer of the same taped to a shaped ring that goes between the crown and the roof ring, which are not attached. This forms a more airtight seal. I'm mainly working on reducing airflow out of the yurt where the roof meets that walls and around the floor. I'll be using one of those temperature-difference detection guns to look for leaks. I may look into semi-transparent radiant barrier material for a new crown cover as we get into the summer. Right now I'm able to keep it in the high 70s running the AC during the day. The high today was 87. I'm interested to see how it will go during the summer, though hopefully I'll be on the west coast for much of it.

[hippiebikerchick]

I bought a can of nightshades, a tint spray that is used to darken car lenses, and I put cardboard up on all windows (they are all facing east). The tint on the dome was not enough, so I covered it with cardboard.The yurt gets some shade late afternoon, otherwise it's completely open. I have a 12k btu rated at 400 sq ft, the yurt is 300. Even with all of this, I can't hold the temp. The walls and ceiling have the radiant foil bubble wrap. I'm having the windows tinted and I'm thinking of adding another layer of bubblewrap. I'm not sure what else I can do. Anything thicker and I will have to reorder the top canvas.

[thebitmaster]

It seems like you're trying most of the right things. Unless there is an air gap between then, adding another layer of radiant barrier bubblewrap probably won't help much. It has almost no insulating value, the only thing it really helps with is reflecting rays that penetrate the cover back out, which is vital. It also, unfortunately, keeps heat generated inside there. One thing you might consider is trying the approach of using comforters on a small portion of the roof, then using an infrared thermometer or leak detector gun to compare the temperatures of that portion and the rest. The guns can be used to pinpoint places where air is escaping.

I can totally empathize with wanting to keep the crown ring looking good. It's definitely the prettiest thing in the yurt. Right now it's a huge pain for me to ventilate because to get from sealed to open I have to wrestle my inner plug out of the way *and* go outside to fold over the roof cover. I have plans for something more like a dome with a lift, and a fan in the center, but the need to keep that area looking nice is definitely slowing me down.

Because of this, and the fact that I don't have any screened windows or doorways yet (mosquitos are murder here right now) I've been using the AC at night even though the outside temperature is very comfortable for sleeping. It feels like a betrayal of the entire idea of being more connected to nature and less wasteful of energy. I have a bug screen for the front door coming in today, and I'll be making one for the roof ring also. This should allow me to experiment with leaving the yurt open during the day to prevent heat buildup.

One that that was wasteful but felt really good was running the AC with the roof hole cracked. This felt a lot less stuffy than running the AC with a full seal.

One thing I've never understood about portable AC units. They pull air only from inside the room, but they push air back into the room *and* outside the room. Doesn't that mean that the air pressure in the room should be constantly decreasing? Either that or air is flowing in from somewhere else.

I usually try to escape to Portland, Oregon for the hottest part of the summer, so I don't know if I'll manage to get the radiant barrier installed before I leave. If I do I might do some before-and-after testing and report back.

I think, in general, that it's likely that a cooling solution that doesn't take advantage of the natural airflow out the roof ring may not work. It might be necessary to at least keep the dome cracked and run the AC at the same time. It would be very easy to compare both methods and see the result.

This couple put a fan that fits directly inside the roof ring:

Fouch-o-matic Off Grid FAQ page | Esther Emery

I'm planning on doing something similar.

Some people are having success using these with Tiny Houses:

http://energy.gov/energysaver/ductle...r-conditioners

Another idea I like is a some kind of little tower or cover that floats a few feet above the roof ring to keep out direct sunlight, but still allows in light and airflow from the sides. One idea that Won't Go Away is mirroring the underside so that you can still see nature (and maybe yourself) through the hole.

Scott

Originally Posted by hippiebikerchick

I bought a can of nightshades, a tint spray that is used to darken car lenses, and I put cardboard up on all windows (they are all facing east). The tint on the dome was not enough, so I covered it with cardboard.The yurt gets some shade late afternoon, otherwise it's completely open. I have a 12k btu rated at 400 sq ft, the yurt is 300. Even with all of this, I can't hold the temp. The walls and ceiling have the radiant foil bubble wrap. I'm having the windows tinted and I'm thinking of adding another layer of bubblewrap. I'm not sure what else I can do. Anything thicker and I will have to reorder the top canvas.