Solar panels

Telegraph_Sam

Why is it that no one appears to have come up with the idea of rotatable panels designed to make max use of the daylight hours? Not 360°, may be just a limited turn taking account of local conditions.

tacpot12

They have! Look up "Solar Follower" or "Solar Tracker". 

Making rooftop solar panels follow the sun isn't a thing because of how unsightly a large movable structure on your roof would look, plus its a mechanical system which means it is prone to breaking down, and the cost makes an already expensive system prohibitively so. Also, the extra electricty gained doesn't cover the cost of the extra parts or maintenance needed. 

eddddy

"Solar Tracker" systems exist, that do what you describe, and they can increase the amount of electricity generated.

They are sometimes used in large commercial projects, but generally not regarded as economic for home installations.

Static panels are simply bolted to the roof. If you want a solar tracking system, you have to add sensors plus motors or hydraulics, plus a control system, etc.

That's a lot of extra complexity, a lot of extra cost, and likely to be lot of extra maintenance over the years. So most people don't feel the cost justifies the benefit, at the moment.

Telegraph_Sam

I could appreciate that the economics might not be viable. What I was visualizing was a system where the rotational travel was limited. Like having one position in the morning which was changed to a different one in the afternoon. A simple motor yes, plus a simple timer,  but no need for AI or a sensor,  unless one anticipates the sun changing its route from one day to another.

matt_drummer

Telegraph_Sam said:

I could appreciate that the economics might not be viable. What I was visualizing was a system where the rotational travel was limited. Like having one position in the morning which was changed to a different one in the afternoon. A simple motor yes, plus a simple timer,  but no need for AI or a sensor,  unless one anticipates the sun changing its route from one day to another.

It does!

The sun isn't in the same place in the sky today as it will be in June, or even tomorrow!

Qyburn

Cost and space effectiveness. For example I have 20 panels in a block, four rows each of five panels with virtually no space between them. If you set each one on a motorised mount then as soon as they angle E or W they would start shading each other. To avoid that they'd need to be widely spaced, meaning fewer panels in the same space.

Vaguely related I did see a write up of a ground mounted system where the vertical angle could be manually adjusted. The idea was he'd move it every month or so to optimise for Summer, Winter or in between.

debitcardmayhem

You also have to factor in declination at your latitude and the seasons etc. , pitch of roof 
Basically not worth the effort/cost for domestic uses. https://www.pveducation.org/pvcdrom/properties-of-sunlight/declination-angle

QrizB

debitcardmayhem said:

You also have to factor in declination at your latitude and the seasons etc. , pitch of roof 
Basically not worth the effort/cost for domestic uses. https://www.pveducation.org/pvcdrom/properties-of-sunlight/declination-angle

And, from the complete lack of tracking on UK solar farms, not worth it for commercial applications in the UK either.

If you have tracking you need to leave gaps between the panels, to stop them interfering, overlapping and shading. It's cheaper and more productive to fill the field with fixed ones.

Trackers made sense when panels were scary expensive and land was cheap. Neither of those conditions apply in the UK now.

wrf12345

With 400W panels at £60, more panels are going to be cheaper than a system that changes their position

Telegraph_Sam

As I said, a mental what-if exercise rather than a practical plan. More realistic would be to mount half the panels a few degrees different from the others  to make a better if not perfect job of "following" the sun. No sensor, no motor, no movement, no servicing. Not perfect but an improvement on a static flat arrangement.

matt_drummer

Telegraph_Sam said:

As I said, a mental what-if exercise rather than a practical plan. More realistic would be to mount half the panels a few degrees different from the others  to make a better if not perfect job of "following" the sun. No sensor, no motor, no movement, no servicing. Not perfect but an improvement on a static flat arrangement.

No, some would produce more and some would produce less, the average would be the same.