2011-07-30

How to keep warm - a lesson from the Chukchi's



This guy sleeps in a Chukchi dwelling. He says it reached -60 at night. At the beginning of the clip he stands in what looks very similar to a Mongolian ger. Then there's a tent made of reindeer skins inside the ger. He says it's -30 outside and close to -30 inside. Inside the inner tent there is no blanket or sleeping bag, but only a candle and his body heat. How could he "stay warm as toast"? A dwelling inside a dwelling and body heat. In the previous minutes (in part 10) he was in another Chukchi ger with a fire where they were cooking. Even though he sleep well, they admitted it was a "difficult life" there reindeer herding.


So what can we learn? He slept comfortably through -60 in a tent inside a tent and nothing more except 2 candles and body heat. When he first entered, the ger was cold, about as cold as outside. The inner tent wasn't big, but it wasn't small. Air locks? Insulation and a little thermal mass and sunlight should go a long way in an earthship.

2011-07-29

Thermal Wrap - Use Straw Bales underground as insulation?

The global model earthship has that very nice development of putting insulation behind the tires about 4 feet or so. This is very much needed in a cold climate like Mongolia where it can be -40F or below in winter. The rammed earth in the tires has thermal mass, but heat can escape beyond the tires. The frost depth in Mongolia is something like 3 meters deep. A water line has to be that deep to avoid freezing in the coldest times in winter. In Mongolia rivers are ice blocks in winter until early April. I saw some people, like Dan Richfield's Earthship Blog , put the insulation down to the flat level. I would put the insulation deeper than the flat level at the floor. 

I wondered if straw bale could be substituted for expensive insulation. The obvious risk is that the straw gets wet and doesn't work as insulation and rots. While reading, somebody said that straw covered with clay, then 1cm coating of cement after a few stacked bales. If we did a thick wall of straw, coated and waterproofed with plastic over it all, that would have to be sufficient. Then I would do insulation on the top cap that runs back to the roof and completely cover the straw bale wall.


On the global model the roof is north facing. That means the water is coming back to the gutter into cisterns right near the straw bale insulation wall, so it must work. If the cisterns overflow, they should drain with a pipe to the front of the earthship, not into the cracks of the straw bale.

The savings on insulation should be substantial of a few thousand dollars. If we feel that the straw bales somehow failed, it is possible to dig up most of the wall and replace it anyway, since it's behind the house in the berm. So I feel confident on using this approach.  

Solar Ovens - 2

I thought more about solar ovens. This morning is a very sunny day in late July in Mongolia suitable for cooking. Though our current apartment is not an earthship, it has windows facing directly south. At 9AM the sun was directly east and didn't reach even in the corner of the windows, though it was full sunshine outside. 

So in order to use a solar oven, it has to be facing the sun probably outside unless there is wide window almost facing directly to the sun with a table of some sort. If you have regular windows that are about 1 meter wide, it still would be challenging to catch nearly full sunlight indoors over the course of an hour. With very wide earthship windows maybe it's very likely in the middle of the day until afternoon, but not if it's 7AM or even 5PM in summer, unless it works at low level with non-direct sunlight. The obvious solution is to carry it outside. 

One guy on youtube has a cardboard box on a cart. He got temps as high as 290F with ordinary aluminum foil and a cardboard box around 19F. That means with quality materials it might have been hotter. There was another youtube video of a woman in Michigan who cooked caserole in late December in a pot. It worked throughout the whole day. In Mongolia it can easily be -30F outside in January, thought usually not at noon. It could be below 0F for a week or 2. From late October to early April it's basically below freezing 99% of the time. One point is that to cook and even try to use an oven outside, you have to go outside when it's -20F or even 0F. But if it's warm months and we're in an earthship and we go outside in the front yard, it's entirely possibly for most meals, except cooking french fries. Also, if the cook is not enthusiastic about it, it might not work if the cook has habitual ideas about cooking. But if it's January not only is the cooking time more limited, but even if you can cook outside in -20F, but you have to go outside to attend to it. Also, there will be cloudy times when we need to cook that we need an alternative. Even during the day, and even if it worked well enough in -30F (let's say very good model), there will be dark cloudy moments and times at 11PM when people want to cook. We just need different stoves. Hopefully we can run a little off the solar batteries like say 30 minutes a day to augment or use propane gas or a regular wood/coal stove.

This aspect is solved in my mind. If we move, then maybe we'll take the door frame we bought recently and make a solar pizza oven like in that video.

2011-07-28

Solar ovens

I realized I needed to learn more about solar power and PV panels. This will work great for lights, computer(s), charging things like cell phones, etc.. The main issue seems to be cooking. Mike Reynolds seems to prefer natural gas to cook and get solar heated warm water a little hotter. It wasn't clear to me how costly such a system would be. For months we've been getting by on one electric heating element. (The electric stove my wife's Mongolian relatives let us borrow stopped working. Folks I'm an American living in Mongolia hoping to get land and build an earthship.) On the bottom it says 1200w. My desktop computer says 500w. I understand that to mean it consumes 1200 watts of power in one hour (on high?). My laptop says something like 220w. Maybe 500 watts for the desktop is some kind of peak power load and actual consumption is much lower. 

I debated: Could one (or 2) heating elements be served by a solar system? I'd have to do the numbers. Mongolians traditionally cook everything over a fire (or stove), like soup. Web sites are warning that it puts too much demand and that this is not the best way. On the other hand some high draw appliances that you run for 2 minutes seem to be OK, so maybe the issue is if you could cook soup for a whole hour, then have to cook other stuff too, or 2-3 items at the same time. But if I'm on the computer for 6 hours, nobody seems to think that's a problem in the solar power web sites. Once I get solar panels, I'll try to see how long it takes to drain the batteries to see how bad it is. 

Then it occurred to me to check out solar ovens, which are hardly mentioned in the Earthship Biotecture literature, though mentioned in a recently posted Guatemala video. I haven't seen these function in real life. Actually I didn't see much of any of this stuff work in person. I don't recall knowing anybody in person relying mainly on solar panels for household needs. I started checking out various solar ovens. It seems they need a little attention. They need to face the sun. It seems they don't fry. It seems the better the reflective material is and the better seal it has in the chamber, the better it will work. I'm 100% sold on the concept and want to build one in the face of earthship wherever the kitchen area is. I was impressed with people on youtube taking simple boxes with aluminum foil and glass getting water to boil. I'm living in Mongolia now. It can get very cold in winter, but it's often sunny. Multiple cloudy days are rare. I saw one site Climatological Information for Ulaanbaatar, Mongolia that calculated the average sunny hours per day for UB over 30 years. Throughout the year, UB got 7.65 hours of "Daily Sunshine Duration" every day on average. Let's assume throughout the year that on average there are 12 hours of daylight, then based on their data (there is varying data out there and what "sunshine" is exactly is open to debate), UB gets something like 233 whole days of 12 hours of "sunshine." Actually this makes Mongolia a suitable place for earthships, because there is lots of open land getting lots of sunshine. 

So, I want to exploit as MUCH SOLAR potential as possible, so PV panels, a solar oven, and try a solar toilet. I realize that it is not always sunny, so if it's night time or dark, then we'll just use an alternate method, like a gas stove. We have a small camping type gas stove. Here many stores sell the little cans. My opinion is the gas stoves are too expensive to run here for most people everyday. They might be good enough in a pinch. I will test running a single heating stove element off solar batteries or research that more just in a pinch, like if we cook at 11PM, not everyday. I'm pleased with all the youtube videos I've seen. 

What are other ways to cook off grid in an earthship? Mongolians typically use wood and coal burning stoves. UB has a terrible air pollution problem due to this use. I'd rather not contribute to bad air pollution. I can see burning garbage paper and wood. In winter we may have to have a stove. I hope not. Maybe if we minimize the use to late at night, but I'd like to avoid that if possible. Just adjusting and cooking and eating during sunny hours might work somewhat. At some point we have to cook during night time. My opinion is that natural gas is somewhat too expensive and is NOT a renewable resource, though it burns clean. This is not 100% resolved in my mind, except that I am planning 100% on getting a decent solar oven.

Discussing various points of earthship building

I'll be posting comments here about the pluses and minuses of various earthship techniques as I try to design my own earthship. http://mongoliaearthship.blogspot.com/  Feel free to correct or comment.