I am a missionary working in Siberia, Russia. I finished an earth sheltered
greenhouse this fall and have had some encouraging observations to share. I wrote the following as a
FaceBook post but I really wanted to share it with you all since I'v learned so much from these forums and wanted to sort of pay it back. Maybe someone building a greenhouse/ barn could find this information and my stats useful!!
We have an
underground (earth sheltered) greenhouse/barn structure thing that I am hoping will prove very effective in year round food production. The barn is about 108 m(2) (1,162 sqr ft) and the green house is about 81 m(2) (872 sqr ft) the combined floor space of the two halves of the structure is about 189 m(2) (2034 sqr ft). Bare with me!!
I've been collecting data this year on its thermal performance. I intended to heat the
greenhouse with two Jean Paine style
compost piles. Each of these piles is capable of producing between 9-12kw/h of heat
energy for between 16-20 months. I had assumed that I would need two such piles to keep the temperature at 10 C (50 F) in the coldest winter days of -50 C ( -58 F).
Due to technical failure of my chipper I was unable to assemble these compost piles. I was really disappointed about this BUT have had the opportunity to gather data on the performance of the structure without any outside heat source.
Currently, without any external heat source, at -42 C (-43.6 F) outside temperature the Greenhouse was -14 C (6.8 F) and the barn was -5 (23 F)!!! This represents an average of about 7.2 kwh worth of heat energy coming from the surrounding earth and the animals!!!
The really cool news is this: The thermal performance of the barn/greenhouse structure as observed this winter is such that, after running the numbers on my thermal model of the facility, it is rather conclusive that 1 Jean Paine pile
should be more than
enough to keep the greenhouse at 10 C (50 F) most of the time and during extremely cold nights such as - 50 C (--58 F) the greenhouse temperature should be no cooler than a balmy 7 C (45 F)!!
NOTE: normally the barn would be MUCH warmer however the design is such that it uses the heat from the barn to warm the greenhouse.
NOTE 2: If you think this is not a big deal then consider how warm an above ground hoop house would be on a cloudy windy day with -40 temperature outside for days on end! Don't have a hoop house? How cold would your house get unheated??
Hopefully we will be using this greenhouse this spring and if all goes well then the underground greenhouse/barn structure concept will become a central piece of our tent making model for rural pastors in small villages!
Here are a few pictures of the 3d computer model i made of the greenhouse barn structure. I'll upload some pictures of the real thing later.
I have learned volumes about what to do better next time and the next Underground Greenhouse barn I build will be a lot better. In fact I am optimistic that with some design modification and a few other tweaks I could get a 2 C (36 F) greenhouse temperature at an outdoor temperature of -50 C (-58 F) WITHOUT ANY EXTERNAL heat, compost or otherwise (not including the sun, of
course). This is extremely ambitious but I think possible and affordable!
Thanks to Mike Ohler, Sola Viva (I don't know the lady's name), Jean Paine, and the Permies Forums
Thanks to Dan Rulison and Jordan Jonas for A LOT of work put into this structure!
Thans to a lot of other folk who donated time and man power along the way!
Thanks to two generous financial contributors who made this experiment possible!!!
Give a man a fish and he eats for a day, teach a man to fish and he eats for a life time!