Walipini Roof Angle

Hello there! I want to construct a walipini design greenhouse. I've read as many information as I could but one thing that embarrassed me is the roof angle. I live in a town in Northeastern Bulgaria, 43 degrees latitude. Can you help me calculate my roof angle so that I can maintain an aquaponic system in it through winter and summer. Mind that the average temperature is roughly 11 degrees - 20-35 degrees during warm seasons and 10- -1-,-2 degrees during autumn and winter. I would really appreciate any help & suggestions because this is my first time ever trying such construction. Thank you in advance.

Sez Ko,

I found a ton of great information on a greenhouse for an area a little further north than you are, Calgary I believe.
The builder has a ton of great information and talks about the angle of glazing, size, roof angle, window angle for
your latitude formula.

Designed Greenhouse

Greenhouse Update 2 Years Later

Lots of good information in the comments too.

I also found this post with a ton of information on Walipini Greenhouses from permies. Walipini Information

Also more information, like Walipini's are also called "pit greenhouses", helpful to know the various names when searching for
new or old information, Walipini Googled

Thank you for the helpful suggestions guys! But I figured out that 43 + 23 degrees latitude won't do well for a roof angle. I now have newer information which is 43 +15 = 58 but "However, as long as the glazing angle is within 45 and 75 degrees you will be within 5% of optimum – therefore it often makes more sense to design the building to height restriction and material constraints vs optimal glazing angle. " So my angle can be safely made 50 or 60 degrees. So now I'm thinking about a 50 degree roof angle. What do you think? I plan to make the pit greenhouse at least 3 metres deep on the north side with a 50 degree angle.

Not knowing Bulgaria's weather I have little suggestion of what is best. I guess I always
assumed hoop houses were round because of there construction material. Other houses
roofs were there shape because of "snow load". I can imagine there are better reasons
than these but if your area had a large snow amount you may want to take that into
account.

I thought of another permies thread talking of Winter Greenhouses and you may
want to go there and garner suggestions. I made reference there of a Minnesota
couple that had built a green house on the back of their dairy barn, they buried rocks
in the ground and piped hot air from the ceiling to the rocks to hold in heat. They
also had planned on putting in a wood heater to replace another conventional one
to help with their cold winters. It is a really good article, they use rain gutters stacked
or suspended from each other to maximize growing area.

Here is the thread Winter Greenhouse Information

I was looking around this morning and found this link to a previous Permie's Bermed Greenhouse.
They talk of using patio door frames and doubling up of the windows so they get 4 panes of glass
and three dead air spaces, very nice information. They use separate solar collectors to help heat
the surrounding walls which seems like overkill but you can't argue with the results.
This is a quote of information on his site, the link is below the quote.

The overall dimensions of the greenhouse are 42' X 16'.

The green house is bermed up on the north side with a 6 foot wall. I used recycled patio doors for the glazing.

I heat the concrete walls with the solar panels (that is the tubing in the walls).

When it was -6 F degrees out side it was 46 F inside this past winter.

Bermed Greenhouse