Large, seasonally dismantable greenhouse

Hi folks.

I live in a frigid winter - warm summer climate.
Lows in winter can reach -20 and highs in summer +40 Celsius but usual winter lows are -8 ... -15 and usual summer highs +28 ... +32 Celsius.

I'm dreaming of a large, dug in the hill, partially underground, south exposure, greenhouse.
I have the land that's just right for this.

The digging in the hill combined with proper glazing should take care of the cold.
Proper glazing over here can only be twinwall polycarbonate as the PE films available are not up to the task by a long shot.

The problem with this glazing is that the space inside will overheat during summer.
As such, one could just dismantle the sides and hope there will be a draft to cool things.
But how to dismantle these sides ?

Another option would be to take the whole thing apart from the framing and let the inside be outside, good if you have rains during summer like we do.
But taking apart huge 2x6m panels ain't my idea of fun.
Besides, taking them apart enough times will just break them sooner, besides needing a place to store them.

Any brainstorming on this matter ?

Great! I live in a place with very cold winters and warm summers, and we heat our houses only with attached seasonal greenhouses. I think it's great to be able to remove the greenhouse for the summer. I've been in houses here with permanent greenhouses, that get roasting hot in the summer. We get -23C most January nights, and 28C or rarely 30C in summer.

Eliot Coleman's wonderful books about producing vegetables year-round in greenhouses recommends 1:7 as the ratio of open end : length. My climate is probably much sunnier than his in summer, and I doubt that ratio would be enough to prevent cooking plants in summer. His books also have several designs for greenhouses with openable ends.

Thanks Rebecca.

Your way of doing things made me think again about this issue.

The sheet plastic you use is also available here but it's lifespan is short, maybe 3 years, and not that cheap by comparison.
Besides, it's insulation properties are not great.
You mentioned -23C on January nights but what about the days ?
We're frozen -15C during days on end, maybe weeks with nights going lower a little.
That plastic sheet won't help a lot, i know from some friends.
They are good if you have some winter sun but in my climate that is a random occurrence.
You might get some or you might get none.

I also see your GH i not that big.
I want mine larger, at least 6m wide and at least 11m long.
Working with unwrapping plastic film on that scale is not great, i've talked to some nursery guy who does this regularly on a large scale.

Considering these aspects, twinwall polycarbonate is my best bet allround.
I just have to find a way to either take it apart or make it "open" window/door style.

I'll try to take a look at what Elliott talks about.

I agree, it's not easy to handle very large polyfilm. But yes, polyfilm should be available inUV resistant types. We used to get 160 GSM stuff that would last 7 or more years, but more recently the supplier started selling 120 GSM stuff and it is lasting only 3 or 4, I think.

Yes, our climate is ideal for a solar greenhouse, because we get -25C on January nights, but days are usually sunny and not very cold, like maybe -5C. And we are only 34N so the winter sun is stronger than it is in Europe.

So I agree, you might do well with rigid glazing, and some system for either removing it for summer, or opening the ends and many vents in the top.

Good luck!