Need feedback on a solar greenhouse - cold weather, low heating reqmt

[WookinPaNub]

I drafted this out on paper, but have been trying to model in Sketchup to show what it would look like with the sun / shade during different times of the year to vet out the design I was describing. Unfortunately I am obviously a slow Sketchup learner Give me a little more time and I'll try to get that up and running.

 

[WookinPaNub]

Allright, never mind. I can't even make a window in a wall in sketchup. And I work with computers every day, sheesh.....

NOTE: I managed to reverse the FT (fish tank) and GB (grow bed) in the drawing - assume the fish are on the bottom.

So here is my low grade workup on paper. I've plotted a side profile of the solarium, assume south is to the right. I've got two sets of bays, each 4 ft high and 4 feet wide - one at the front of the space and one at the rear.

There are two windows, one located on the roof roughly 3-4 ft tall, and another in the wall at roughly 5-6 feet tall. For simplicity I've documented sun profiles at 67 degrees (summer), 45 (spring / fall) and 22 (winter).

The thought is:
1) Summer Sun (67 deg): The summer sun is the strongest, therefore I want that directed into the space but not directly on the beds - hence the ceiling window allows the direct light onto the aisle separating the bays so each bed receives indirect lighting. In the front the light can shine directly in to the front portion of the bed, however given the angle of incidence on the glass being so steep it should dampen it down quite a bit in strength.
2) Spring / Fall (45 deg): I want as much of this direct sunlight on both beds as I possibly can. Both the roof and wall window allow in as much of the direct sunlight right on to the beds at that angle.
3) Winter (22 deg): At this point the ceiling window gets the aforementioned patch of insulation and closed off to save heat. The larger front window (and architected roof overhang length) allow the winter sun angle to shine in on both beds directly. At night curtains or shades are pulled to keep in as much heat as possible.

So that is my thought in more detail. Roof pitch is shallow, window length and position calculated to maximize desireable sun across seasons. Let me know your thoughts on that, I'll be curious for feedback.

Another alternative I was kicking around, and don't laugh, is a heliostat type approach that completely eliminates the window in the roof. The idea is instead of investing in the window in the roof, instead place a mirror outside the solarium, and mirrors on the ceiling inside the solarium. The ceiling mirrors would be fixed, the external would have 3 positions - one for summer angle , one for spring / fall angle, and one for winter angle. Each position would be optimized to reflect sunlight onto the ceiling mirrors and back down to the grow beds. The benefit is the removal of a heat losing window space, the con is having to reposition the external mirror 4x / year.

I'm sure most folks reading this will scoff and ask why bother with all this effort - and for a standard greenhouse I would agree. But I want to try to maintain production through all seasons, in a minimally maintenance required way, and minimal / no fossil fuel heating costs.

Again, thoughts are appreciated. Outside of the costs (which I recognize and accept) why would these approaches NOT work?

 

[brandylorton]

Very good information there regarding the greenhouse there. It would help guys like me who are quite new to this field practically. Keep going on and keep sharing the nice information.