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Cooling BTU's

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addicted56

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I know most people that build yurts live in climates that require heating. I on the other hand need cooling.

I will be placing a couple ductless mini-split units and I do have the insulation kit on my Colorado yurts.

I will be running a heat pump water heater in the pantry of the 30' yurt (approx 150 SQFT) and we have a 110V 6K AC unit that is filling an old gap that was cut in the yurt from the last owner that had a evaporitive system. This is mainly there in case we have a power outage I can run the 110V unit on the generator and keep at least one place in the house that is not boiling, though I doubt it will actually cool anything in that space.

So I was thinking an 18K BTU unit would be plenty for the 30' yurt and a 12K unit for the 24' yurt. Thoughts or does anyone have any experience in this department?

The 24K BTU unit is only 80 more bucks but I know systems are not as efficient if they are over or under sized.

Also thinking about running one of the portable heat pump units in the bathroom to keep it dry in there and to have something in the 12K BTU range that runs on 110V in case we have any hurricanes this year and we lose power in peak summer. 100 with 90% humidity is not fun.
 
I do not have a definite answer but I will say that yurts breath a lot more than standard structures. I would think more is better (to a degree) with AC. You can always turn an AC down, but it only goes up so high.
 
Cold air sinks to the lowest level within any given space, and secondly if that space is defined by thin cloth walls, you will lose the cooling pretty fast especially on a very hot day. I'd try and seal up the lower wall cover as tight as possible, including running a seperate cloth band around the lower perimeter where the wall meets the floor. Possibly rigging a huge tarp over the top of the yurt will help keep direct sun from heating the yurt cover.
 
Bob,

I like the idea of a huge tarp over the yurts during the day. I should go to the excess equipment yard and pick up some of our camoflauge netting and rig a way that I can unroll/roll it up like you see on R/V's. That would make a huge difference and be nice when the kids want to be on the deck in the afternoon. The trees provide great shade but only before 10 and after 6 in the summer. In the winder we have shade almost all day at least on one portion of the deck.

Jafo,

I think I will oversize. I forget how much they breat and while I have great radiant insulation which works great for blocking the sun and keeping in stove heat, but horrible for the convective heating/cooling we will get from these units without R vlaued insulation.
 
I am having to make the same decision right now for my 30ft yurt. Where we live in Tennessee it can get very hot and humid. We are also in full sun between 10 and 6. I talked with a rep @ minisplitwarehouse and he recommended a 24000 but unit. My only concern is I want to go solar later and I haven't figured out how much more it will cost me in solar panels to run a 2 ton unit. We have a 27' yurt we are going to add later, so I am tempted to try the 18,000 unit for the 30' yurt and if it doesn't do the job i will just move it over to the 27' later. A friend of mine just replaced the refrigerant in his system with propane. It supposed to make it run 60% more efficient. If that is actually the case i will definitely go with the 24000 BTU. I would be curious to here from anyone in a hot weather climate that is using a mini split system and get a report on how it is working.
 
I wish the edit button lasted longer for my posts. I go back and find all of the errors later.

That said glad to know I'm not the only one looking for these answers. Tennessee gets plenty hot in the summer and we are in a very similar boat.

The propane thing is very interesting. All of the mini-splits that I see come pre-charged with 410A so I will just use that. I will have to do some research.

I will not live in these yurts long so I can't invest much into solar panels but I have the same aspirations. Setting up for 220V adds additional cost though. Plus heating and cooling takes significant power. A Fridge, TV, lights are super easy these day. I still have my original plasma from 2002 that I bought in college but our fridge has a linear compressor and we will light with LED's. If we had an LED TV of equivalent size it really does not take that much to run a home these days. Computers like the chrome book are negligible on power consumption and really can just use the I phone for most of our needs. But until then we will have a backup generator for those emergency situations. Heating on the other hand is easy with wood but cooling is a whole different ball of wax.
 
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Well if I stay on track we will be moving in around 1 August. I just ordered a 24K inverter unit for the 30' Yurt a 12K for the 24' yurt and a 14K portable unit that will be in the bathroom on the 24' yurt for heating, cooling, and more importantly dehumidifying.

So in the very hottest month of the year and in full sun for approx 8 hours a day we will find out if 24K BTU's is way overkill or not.

Also purchasing a small Hyundai Generator to run the 110V units in the house i case of power outage. I might need to get a hard start capacitor for the small AC units but at least we will have back up if we get hit with a hurricane or lose power for any other reason this summer.
 
I put a 36000 btu mini split in our 30 footer with full insulation package. We live near Nashville TN so plenty hot & humid. Heating with it was marginal. New Year's Eve was in the teens and the yurt was 59 degrees in the morning. Cooling has been good so far, but we haven't hit a 100 yet.

My only issue is noise as a 3 ton unit (36000 btu) moves a lot of cfm and that makes noise which bounces off the dome and gets louder. If I had to do it again I would get a mutiple zone unit either 18000 x 2 or 24000 x 2. I was trying to be cheap, paid $2400 for the 3 ton Gree unit installed. Get what you pay for!

Hope this helps. Happy yurting!
 
I noticed my picture shows my groovy yurt but I have the mini split in my 30 foot Yurts of America yurt on a concrete foundation with 6 windows. I wish I had opted for the bronze tinted dome to reduce the heat from sun.
 
addicted56 said:
Bob,

I like the idea of a huge tarp over the yurts during the day. I should go to the excess equipment yard and pick up some of our camoflauge netting and rig a way that I can unroll/roll it up like you see on R/V's. That would make a huge difference and be nice when the kids want to be on the deck in the afternoon. The trees provide great shade but only before 10 and after 6 in the summer. In the winder we have shade almost all day at least on one portion of the deck.
Click to expand...

Rather than a tarp, you might want to look at surplus parachutes.

For example you can get a 28' white parachute for $120 It would almost completely cover your 30' yurt's roof and is already round is shape. Being white it would reflect the sun rather than be heated by it. Russian White Parachute - 28'

Just be sure to leave at least a foot of space between your roof and the parachute/tarp for air flow.
 
I found a container full of surplus woodland camouflage the other day. Cut the lock and it was probably sitting in that container since our first deployment in 2004. It is going to the dumpster or to DRMO if they will even take it. The container was so old it leaked and everything is covered in moisture and probably mold.

Might make good concealment from the flight line we are under as well. I figure I can run a cable to trees on either side, throw in some grommets and a rope on each side and we could easily pull it over and back if we wanted it off. Maybe 20' up so it felt more like the canopy of a forest instead of netting.

Glad to hear that for the most part 36 BTUs was not overkill. It was in the teens for a couple of days this year but I don't mind using a small space heater in the small yurt, and we have a wood stove in the big yurt for those days. Sounds like they should all work quite well.
 
Not really the time of year for cooling anymore, but there is a way to have solar-powered cooling. It's called Adsorption Chillers--works on basic refrigeration principles but the cooling power comes from adsorbing water onto/into an adsorbent (usually zeolite), with the required energy/heat coming from solar (heat). There should be a commercial product somewhere; there have been several well-documented large-scale industrial applications--a school or such in Germany or Zurich I think.

If you're more DIY, this place has some good links as a starting place.
 
hierony said:
Not really the time of year for cooling anymore, but there is a way to have solar-powered cooling. It's called Adsorption Chillers--works on basic refrigeration principles but the cooling power comes from adsorbing water onto/into an adsorbent (usually zeolite), with the required energy/heat coming from solar (heat). There should be a commercial product somewhere; there have been several well-documented large-scale industrial applications--a school or such in Germany or Zurich I think.

If you're more DIY, this place has some good links as a starting place.
Click to expand...

I will have to check it out. I think the fridge in most of your campers runs the same way. Uses the propane heat in the same cycle. Trust me there is plenty of it. We just generally undersized in the small yurt. The 2 ton in the 30' yurt seems plenty even in regards to heating when it is really cold but we have a fireplace as well. The 1 ton in the 24' yurt just can't cut the mustard though. Works its ass off all night and if it is to hot or to cold it just can't keep up. Insulation on the floors and walls and even roof are just no match for that those temps.
 
Yup, very similar to the propane fridges.

I reread some old notes--It was a school & neighboring dance club in Munich, Germany that had ZAE Bayern make an industrial zeolite heating & cooling system driven by communal steam heat. I have a copy of the summary paper if anyone wants.

D. Tchernev did a lot of work on heating/cooling with zeolites. The above-posted webpage has a link to an excellent summary of his zeolite cooler. Unfortunately, he puts 1 ton of cooling power as requiring 1 ton of mordenite in a panel 200 sq ft (~14'x14'). Not something I'd consider a small, cheap DIY project... Might make a good small supplement to your 1 ton unit though.

Out of curiosity, how air-tight are your yurts? Did you ever do the shade-cloth/parachute thing? This company has two cool sunshades and interesting suggestions. Are the evening/nighttime lows cool enough to just do a massive forced air-swap?
 
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