Dan Handeen, of the University of Minnesota College of Design's Center for Sustainable Building Research explains the blueprints for the new Farm Scale Deep Winter Greenhouse design that will soon be released to the public.
If, as you state, the Chinese are "light years ahead of us" in greenhouse design why are we not using some of the concepts that they use? There is also a Canadian who has done some fabulous work regarding unheated greenhouse design. What about using solar thermal to aid in heat storage? And who are you guys really working for? The manufacturers or the Creators? $20k to$60k for a building that is 1/4 the size of a postage stamp seems a bit excessive. Although the farm scale design does seem to be heading in a better direction. Mr Finch's design uses 2 different forms of geothermal heat transfer, one which recirculates air in the greenhouse, the other pulls in fresh air. To me the idea of pulling in fresh air seems like a great idea. I'll stop here. While I may seem a bit sarcastic in this reply I do appreciate the work you all have done.
Agreed about copying the Chinese design. A nighttime thermal blanket is key to the effectiveness of the Chinese system. It could be incorporated inside the glazing for convenience and protection from snow.
So most commercial greenhouses in Canada are designed to optimize light because the days get so short. It’s been more economical to do a full glazing oriented North-South and heat with (until last year) cheap natural gas.
Thanks for sharing a great design. Regarding air flow through the rock bed. I would expect that the warm air would rise as it enters the rock bed before descending to the outlet pipe. If that is the case, then the temperature in the rock bed will tend to stratify being colder at the bottom. That could reduce the efficiency of heat storage. I suggest that a hybrid system may be better where you have alternating input and output transfer pipes between manifolds. I look forward to seeing the temperature data published. Cheers, Julien.
Regarding the "holy grail" that he speaks of at around 1:10:00, there is a guy on RU-vid who has what seems like a solution to me. He's a Canadian farmer doing a Chinese greenhouse with a thermal barrier outside of the glazing, as is traditional, and then he has another greenhouse frame outside of that. So, he has the benefits of the exterior thermal blanket, without the problems of wind and snow affecting it. His name is Dong Jianyi. Here is a link to his RU-vid channel - ru-vid.com/show-UCgs_cmCc-3Nczf6_RQpqmYg
too fidderly, especially when it comes to replacing polythene. I would go for a roll-up thermal barrier under the roof. summer conditions. I would possibly be able to reduce the thickness of the thermal mass, so as to use it as shading from strong sunlight.
Uve all gotta dig deeper into this subject bcuz there's real rumours that an ice age may be here already but can get much worse. The need for good greenhouse cud become so great in the next few years. There's a great opportunity for some to learn how to build good greenhouses, potential in the near future cud be massive.
Rock may prove to be a radon source, I would advise monitoring radon levels permanently. We tried this in northern Vermont in residential construction in the 70's envelope houses. All of which had the ductwork sealed once the news on radon broke. Perhaps scrap iron could play this role but at 30 cents a pound ...
this looks a bit iffy. I am surprised that they never replied to your comment. I did hear that polycarbonate was being used. yet with polycarbonate, the glazing bars run up and down, not horizontally, like what they are showing here. with horizontal bars, rain ingress due to polycarbonate expanding, and retracting from temperature variations is a sure thing. Also, there will definitely be an algae buildup
