Cooling a Yurt in the Midwest

[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.

[hippiebikerchick]

You have several good points. One mistake I made was going off of floor square footage. I oversized it by 25%, but I didn't take into consideration that it has a high ceiling and poor

insulation

. I used a btu calculator that used both of those variables and it calculated 20k btu instead of 12k. I'm going to temporarily test this by adding another ac unit and if that solves it, I will purchase a mini split. We are also consider another layer of bubble wrap. Even without a space in between the layers, it will increase the R factor by 3.

Originally Posted by 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:

Ductless Mini-Split Air Conditioners | Department of Energy

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