Living in a greenhouse/solarium

New to posting.  Looking to share a home idea and get thoughts on it.  Perhaps this should be in "greenhouses", not sure.
I live in central Saskatchewan - weather is anything between 90F in summer to -40 in winter.  I've got the idea of a solar greenhouse, something like 30'x40'x18' high, with a glazed south wall, insulated roof, earth-bermed to ~12' high on north side (two-level retaining wall).  Inside this, nestle about 250sqft living quarters, plus another 150sqft bedroom on second level.  Room for future expansion of living quarters.
On the south side of the solarium, overhangs at the roof level and at about 9' high would provide summer shade, but winter sun.  A few windows on the east/west walls and uphill patios on the north side provide balance of light and cross-ventilation.  Also, I'd like to have some of the glazing on the south side removable, and replaceable with screens for the summer season.  
Solarium/greenhouse construction would (likely) be timber frame with straw bale infill.  My neighbors up the road run a sawmill, and there's grain fields for as far as the eye can see up here.  
Whatever the living quarters, they will be insulated from the solarium to maintain comfortable temperatures.  The solarium will be insulated to outside air, with a water-proof insulating skirt extending out at about ground level for several feet.  The solarium will not be insulated against the earth berms.
The idea of the solarium is to provide a semi-conditioned space around the house.  
This space will:
1. moderate the climate in which the house sits,
2. provide a greenhouse heated by the sun AND heat lost from the house,
3. provide space for growing plants and fish year round,
4. provide space for water storage,
5. provide a moderated climate for our composting toilet,
6. provide a moderated "yard" for the kids in winter,
7. provide moderated working area for temporary projects (a shop is definitely in the long-term plan)
8. provide a mosquito-free "yard" in the summer.

Back-of-the-envelope calculations indicate that the solarium would stay above freezing on the coldest days of winter with about 2kW of heat loss from the house.  This is based on average solar gain in Dec for our area and heat loss through all exposed wall/roof areas.  It does assume some sort of nighttime curtain on the glazing to increase insulation.  It doesn't factor in any heat gain from the huge thermal mass of earth below and around the solarium.  I think the average yearly temperature here is about 5C.  
We have two seasons in SK, and they are both fierce: Winter, and Mosquito.  There is about a 2 week shoulder season between them, which is my favorite part of the year.
Some background on my wife and I: We've been living in a 200 sqft single-room cabin for 2 years.  It has an attached, unheated, uninsulated garage that's a little bigger than the house, which we use for storage and (for part of the year) a workspace.  We have an outhouse that we use year-round (yes, for real! another thread, anyone?), that composts about 4 months out of the year.  No running water in the cabin - we run exclusively off rainwater and water hauled from town by the 50gal barrel.  We have about 100 gallons of water storage inside the house.
We were both born and raised in climates without snow.  I've got a background in engineering (and in "southern engineering").
One aspect of this plan is to use rougher building techniques in the solarium than we'd like in the house - cheap, salvage, somewhat experimental - AND have less demand on the house construction system than if it were exposed to the elements completely (no wind, no rain exposure).  The first winter, living quarters might simply be an RV or a skid shack pulled inside the greenhouse.  

Views in the living quarters would be by design.  A strip of salvaged windows in the solarium's south wall at the right height would provide southern views. Similar height, judiciously placed windows in the east and west walls will provide similar views.  Careful design of these and the living quarters' windows would hopefully allow us to mitigate the lack of outside views from the living quarters.  

I've got lots more thoughts on the concept, but I think this gives the basic idea.  Let me know if I've neglected some important information (likely).  
Ideas? Comments? Obvious problems?
Thoughts on ways to insulate the roof of the solarium would be appreciated.  I do like green roofs, and I've noticed the rafter spacings in Rob Roy's "Earth Sheltered Houses..." book would be the right size for decking it with wooden pallets.... perhaps rough lumber from the sawmill is a better idea.
Thank you for your thoughts in advance!

Have you read Anna Edey's book Solviva?  It is about living in greenhouse-like spaces.  http://www.solviva.com/

No, I hadn't!  Thank you kindly!  Looks very helpful.

There is also a you tube clip or even clips of folks with such houses in Norway I think , I may have posted on on this very site but no time at the moment to look Monday maybe

David

 found it

Thanks David, I have seen those.  There's another within the arctic circle that used a geodesic.  Very expensive wrapping a whole house in a glass greenhouse, but it illustrates the concept.
I can't figure why they've used transparent walls everywhere, though. Why not just the south side and get some insulation or earth against the other three and the roof.  You're losing massive amounts of heat otherwise, and thermal storage.

I think its a trade off regarding sunlight as remember the higher latitudes in the summer have very long days plus it might mitigate against possible damp and humidity issues .
Pity not a house like this near us we can have a look at

David

On your south facing walls, you might consider setting up the lower half of the walls as solar thermosyphon heaters... which are kind of like windows but have a thermal mass and/or heat conductive materials directly behind the glass, air intakes at the bottom, and air outflows at the top.

See http://www.iedu.com/Solar/Panels/index.html for detailed information on building them.

The physics make sense but I have not built one yet (I'm actually going to build a simple one this afternoon once I finish fixing the car).

The basic idea is that the conductive material behind the glass heats up from available sun light causing the air inside to rise... which creates a vacuum that pulls cold air in through the bottom air intake... which is then heated up causing the process to repeat. To prevent reverse operation at night one could either close the air intake/outtake or build an air gate in the back of the panel.

Add a thermal mass behind the conductive materials (say black water filled containers, cob, soap stone, brick, etc.) and the heating should continue for a few hours after the sun goes down.

Anywise, I'm (slowly) working on a cob green house living space and planning to provide extra heat via both thermosyphon panels and (for the wet cloudy winters here) a rocket stove (free wood from pressed sawdust received from local saw mills) to provide extra heat when needed.

Once I have the initial panels working (and verify that they work as anticipated) I'll be working on optimizing them and combining them with other functions (heating collected water, etc.).

Great stuff on this thread. My little 2 cents is that I recall a Massachusettes based project that was raising tilapia in nothing more than a pool covered with a plastic dome in the 70s and the thermal mass of the water alone was keeping the habitat in the high 60s farenheight even in the dead of Winter with no other imputs..and Massachusettes can or used to get pretty cold. I hope the details are enough for you to research some articles. Best of luck.Mike

I grew up in an "envelope house", which is a similar idea. In our case, the basement was where excess heat ended up getting stored.

Joseph Lofthouse wrote:
I grew up in an "envelope house", which is a similar idea. In our case, the basement was where excess heat ended up getting stored.

Joseph,  if you get some time,  could you explain this in greater detail.  Sounds very interesting.

Passive solar envelope house. Favorite single family home I ever lived in.  I loved living in a monastery more, but for different reasons...  

The solarium on the envelope house was astonishingly warm and delightful in the winter when warmth and sunshine is so rare.

The worst time of year was about March, when it was cloudy out for days on end, and the heat stored all summer had become exhausted.

Joseph Lofthouse wrote:Passive solar envelope house. Favorite single family home I ever lived in.  I loved living in a monastery more, but for different reasons...  

The solarium on the envelope house was astonishingly warm and delightful in the winter when warmth and sunshine is so rare.

The worst time of year was about March, when it was cloudy out for days on end, and the heat stored all summer had become exhausted.

Thanks for posting that.  What a cool idea.

One design feature I forgot to mention is the insulated roof over the solarium, and the vertical windows. That made it so that almost no sunshine came into the solarium during the summer months, thus avoiding overheating.