The pvc pipes or plumbed with 12 volt computer fans. Bringing the warm air from the ceiling during the day through the rock mass under the grow bed. I left that out and wondered how long someone would ask! Great spot in that improvement. The fans or hooked to a old solar panel when the sun shines the fans turn exchanging air from the ceiling through the bed. Bob Sharps idea from the Yukon ! Our local food growing expert. http://yukongreenhouse.weebly.com
He's got a lot of great info on greenhouses in harsh climates such as ours !
I kind of suspected that was what the pipe was for. I wasn't able to tell but did you move into the greenhouse last fall and you're sharing the photos now? If so, how well did the hot air storage system work during the winter? Did you use other heat for the greenhouse or was that it? Sorry for all the questions but I'm in the midst of a greenhouse design myself. Thanks for the link it looks like great info so far (still clicking around).
We built last year and planted but to late for a crop.
The heat is of no use to use in the winter really. It's -40 here often I've seen -52c as the coldest. The greenhouse serves more of a buffer to these temps for my workshop. We just don't get enoughsolar gain. 5 hours in December and it's very low on the horizon. Not much to gather. My solar panels or not putting out much. In more moderate climates I could see this to be useful to boast the heat to the attached building. The greenhouse itself does help a lot with wind chill and such usually 10 degree temp difference then outside. -40 outside -30 in the greenhouse 21 in the shop sorry that's in Celsius. The way I see it is that wall only sees +10 more then outside that's 10degrees I don't have to heat!
Keep asking. If I didn't want to share I wouldn't have posted!
I'll give you credit, -52C is pretty cold. I only get to about -32C here... Using the tube and fan to collect warm air spring and fall makes perfect sense. So what are the red pex lines for?
My goal is to have my greenhouse well above freezing all winter without much outside energy. So the fan/tube idea looks like it can help but probably not in the depth of winter.
I'm debating between a climate battery (like your tube idea but bigger fan, more pipes and 6' deep) or a compost heat system. I'm heavily leaning towards compost but trying to do my homework on the climate battery before I decide for sure.
The red tubes or for heating from hot water. Everything I build has them. In this case in the spring before I plant I'm going to heat my water through a thermal electric generator on my wood stove. I don't need the heating in the shop anymore. I also need the return line to be as cool as possible for ultimate electricity production. Sending out the water into the greenhouse spring and fall and pumping through the bed will heat the plants excactly were they need it and have my teg running at full bore. I got a new pump on order just need to hook it up!
In the future I plan on a thermal mass tank like 2000 gal then I can heat the hole property from this. Until then I'll utilize the teg. It's currently hooked up heating my bathroom and boosting my dhw!
The pvc pipe through the bed and hooked to computer fans were free from the local landfill. I have a box of fans from dead computers and the pipe someone got rid of. So I also put that through the bed. These serve two purposes. Pulling the heat of the day through the thermal mass warms the thermal mass but it also tempers the extreme heat of the day and cycles the cool off the mass into the room. Another benefit is getting air flow throughout the greenhouse. I think these or both beneficial to the plants. The fans move very little air but that's allows for the air to spend time in the tube getting max exchange. I haven't any equipment to measure temps throughout the bed but Bob sharp has and he has seen differences proving that it works. If one is patient scrap pipe and computer fans or free! The teg is $$$ put I've got this hooked up heating my dhw and bathroom in the dead of winter and looking to divert heat for the fall and spring that I don't need in he house anymore. Plus I'm looking for max electricity production! Double whammies for all systems. Note these tegs when set up properly or self powered!
Awesome, thanks for the link! I checked out their site and video and sent them some questions.
Unless I do the climate battery for some reason, I think I'll do the pvc pipe in the bed like you did. Seems like a very cheap way to moderate temps in the late spring through early fall without opening vents as much.
I wrote a reply to this but maybe it was the day permies was sort of down and it didn't get posted, I don't know.
I've lived in houses heated only by attached greenhouses for the past 20 winters. We get a lot more solar gain than you because we're only 34N, and high, dry, clear and sunny. Our Jan minimums tend to be -22C or so, ie a lot warmer than yours.
I think that its great to have your south wall exposed only to the milder wind free cold air of the greenhouse than outside.
Eliot Coleman's books have great info about getting the most vegetables and season extension out of your greenhouse. For example a lot of salad crops he grows to size in fall and lets then stand there fresh on their roots for harvesting all winter, even if they don't actually grow in midwinter. This year I followed some of his variety suggestions and it has been GREAT! I had fresh greens every day of this winter, when there hasn't been anything fresh in the market in our region since December when the highway closed for the season.
Two questions. It looks like warm air circulation into the room is only those slot shaped openings, is that right? We have nice big windows and doors to open when greenhouse is warm and close at night. We get a lot of heat gain in the house from this.
Secondly, I'm dubious about heating beds by piping hot air from the top of the greenhouse. Hot air has so much less mass than soil that piping hot air under cold soil might carry negligible heat.
For keeping grow beds warm, Coleman recommends adding covers over beds or plants inside the greenhouse for the coldest months. I don't need to do that because my greenhouse only drops to -5C at worst, and all the leafy greens don't mind too much.
Works at a residential alternative high school in the Himalayas SECMOL.org . "Back home" is Cape Cod, E Coast USA.
Nice looking green house. How is it working a year later? What kind of plastic cover did you use? Looks like you have similar weather to us and not far away. I am looking for ideas to cover the green house I will build this spring.
We or very happy with our greenhouse Tim! The tin on the roof is strategically placed to shade during the intense summer heat but we get full gain during fall and spring. Being attached to a building with a massive concrete slab also stabilizes then temp swings more then I thought. During the hot summer opening then bay door and the door into the greenhouse creates a very interesting air flow keeping the greenhouse from overheating and charging may thermal mass under the shop win win.
We had -45c last night no joke! And during the day we see -25 ish over the last week. But in the greenhouse we're seeing in the +'s. I can't stress enough about how having that south wall gaining so many btus and sheltering from the wind shield effect has complimented the shop!
So for the return for us hasn't been only in groceries!
Ok the negatives is we used suntuff sheets when we should have sourced flat polycarbonate sheets! So hard to seal. Regardless what they say. At any rate I learn from every project. The house will get flat polycarbonate sheets on its attached greenhouse when we build. I've seen flat polycarbonate even with 4 layered air channels between them. Great if your looking to grow year round. This isn't my goal. To much to do in the winters! My goal with this greenhouse was to grow food, temper the environment around the shop, provide a nice space to hang out in on cool evenings and mornings. Not all in that order or course depending on the season. This addition has been huge for the well being of my family, as we spend so much time outside even when it's raining. Moral of the story I figure it's worth just as much as a heater for the south wall, and as warm place to hang out in the greens and sun ☀️ as it does in return in food. I wish I built the greenhouse earlier!!!
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