A solar-powered home inspired by a sunflower
bbc.com
bbc.com
There's an outer shell for the house, that has a bunch of flat solar panels on the roof. The entire shell is moved to change the pitch of the panels. Placing the panels on gimbals (as is usual) would require less power, less time, be easier to repair, and safer.
The entire building then rotates so that the floor to ceiling glass wall in the front tracks the sun for warmth. That's at least partially needed because of the giant outer shell being designed such that it blocks the other three walls, so they can't let sun in to heat the room.
Then you lose realestate because the building is rectangular, but rotates. If the building was circular, with glass right the way around, you'd have a more effective use of space, and wouldn't require heavy mechanics and engineering needed to support a moving building. (Of course you wouldn't get press for making a round glass building with solar panels on the roof, as that's already been done at quite a large scale :D )
From a purely photovoltaic perspective, something that I think am qualified to comment on... Moving/tilting/rotating photovoltaics haven't been economical for a long time. As an example, the ground mount required to put six or nine 300W panels on a sun-tracking mount costs about $1900 in hardware and requires a 4.50" or 6" pipe set into a concrete pier. Figure at least $2400 once built. Nine 60-cell panels is a lot of wind load, it needs to be strong and robust, and there's just no way to do that cheaply.
If you spend that $2400 on additional fixed-mount, fixed tilt PV panels part of a big array, at $0.48/watt, you will produce far more kWh in a month than with an expensive mechanical tilting/swiveling apparatus.
e.g imagine a building with a flat horizontal roof covered in PV panels, vs the roof being angled such that the tangent of the roof is directly to where the sun is at noon at the height of summer (or maybe peak of winter? after all less hours of sun could mean max peak exposure is more important then? I have no idea).
It seems like angled to face the sun would make more power at times when the sun is in the right place, but it seems like such an angled roof would lose sunlight earlier/gain it later during the day, vs a horizontal one.
Clearly that intuition is incorrect as far as actual power output goes (otherwise people wouldn't have angled solar panels :D), but I'm curious what the difference in effective power output is.
The +15-20% returns that you see from having a panel that perfectly tracks the sun from sunrise to sunset are much more costly to build than to add another string of twenty, 72-cell, 360W panels mounted in a more economical fixed method.
If you are extremely space constrained and need the asbolute maximum Wh per square meter of panel per day, then a tracker might be warranted. In which case you should also be looking at super high efficiency mono panels composed of 22.5%+ expensive monocrystalline cells.
In that case you’re not really constrained by existing roof geometry, so what would be the best price/wh trade off?
I could imagine the dumbest thing would be a rotating fixed angle unit, which doesn’t seem like it would (should?) cost that much compared to the total installation cost anyway?
Mostly I’m curious as to what the crossover point between complexity of tracking vs fixed angle looks like.
There are rotating restaurants in various towers and buildings.
It might be some thing as simple as a center section that doesn't rotate.
But I can't see how this would be practical in real life.