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greenhouse floor as a thermal battery  RSS feed

 
Kia Tikaboo
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Dear Toby and Paul,

I am closing in on a 320 sq.ft. greenhouse to go from a three month outdoor growing season to an eight month season on the east slope of the North Cascades.

I'm a considering using the dirt floor as a thermal battery for a rocket stove to bring night time soil temperatures above 50 degrees.

Do you have any tips, ideas, or thoughts.

thanks,

Ruwenzori
 
Brenda Groth
pollinator
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Location: North Central Michigan
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what a great idea..I moved my greenhouse when we installed the pex for an outdoor wood boiler, now it runs right under my greenhouse, we also have 150 ft of pex going to son's house next door, and the snow melts in that long spot so it almost makes a perfect path to his house..other than it goes to the back basement walk out and I don't do stairs well.

can't wait to hear how your rocket stove works with the floor ..keep us up on that.
 
Toby Hemenway
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Coincidentally, I just spent this weekend with Jerome Osentowski, the premier designer of thermal-battery greenhouses in the world. He lives at 7000' in Colorado and grows papayas and bananas in an (mostly) unheated greenhouse. They do get good sun there, but the key is that in the soil are runs of 4-inch perforated pipe laid out in rows that all feed to a central manifold. The manifold, via a big pipe like a chimney, pulls in hot air from the top of the greenhouse and runs it through the soil pipes. At night, the fan keeps running but now the soil pipes are warmer than the air, so warm air is fed from the soil to the greenhouse air. This fixes both of the big drawbacks to greenhouses: they get too hot during the day, so instead of venting off (losing) that hot air, this puts the heat into the soil, keeping the high temps moderated. And greenhouses can chill at night to even colder than outside from radiative heat loss, but this pumps that daytime heat back into the greenhouse air. Hence the bananas in Colorado winter.

Jerome's website is http://crmpi.org and he is also writing a book on these greenhouses. Interesting aside: he's been hired by rich doomers to build enormous thermal-battery greenhouses so they can grow food after the supposed big crash.

So, east of the cascades--do you get reasonable sun (do your daytime greenhouse temps get to 60 or above) to use a thermal battery instead of a lot of wood? The problem I see here with a rocket stove is that if you run the flue pipe underground, the soil may get so cold that the stove won't draw properly. Not sure about that, but it's a concern. Insulating the n and even the e wall of the greenhouse would help too.

Jerome is a genius.
 
Susanna de Villareal-Quintela
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Having a cousin in Crested Butte (I miss Paonia peaches), I understand how fantastic a feat it is to grow bananas in Colorado. Simply amazing!

Thank you for the link to Jerome Osentowski's site. I am hoping to build a greenhouse on the south-side of my house this spring and I've been thinking about various ways encourage a longer growing season here in Michigan. Since my hugel experiment was so successful this past year, my thought has been to build a large hugelbed with putting-stones as retainment and to enclose it within a greenhouse. But, I am concerned heating the soil of this environment would create too much moisture in the air inside the greenhouse. Do you happen to know if soil moisture has been problematic in Mr. Osentowski's design?

Respectfully,

Susanna
 
Maggie Oliver
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I pine for season extenders such as a green house. Living in Colorado Springs really makes my season much shorter than it could be. I do have a great living room that has many windows that face south (little old house that was before such good ideas) so my living room is my green room right now. Not a green house but I am growing some dwarf citrus in here as well as salad greens and house plants. The citrus isn't old enough to let fruit yet, but the smell when they go into flower is worth all the space. They summer outside just fine.
Banana I have not tried yet.... hmmmm
 
Andrew Ray
Posts: 165
Location: Slovakia
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Do you know when that book might be available? Having bananas would be excellent here (east Slovakia), as it is 95% of the time impossible to get organic ones, just occasionally when we happen to go by the Tesco and they happen to have them in stock. Yet, our 8 month old son really loves eating bananas (of course, we do as well).
 
Cory Arsenault
Posts: 55
Location: Ottawa, Canada
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if you're going to use the floor as a heat sink you might want to consider insulating under the floor and along the base of the walls to prevent heat loss.
 
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