Using Mirrors for Solar Panels

[Mike Norman]

Theoretically mirrors could double power generation. What do you think?

[Joe Blake]

Hi Mike,

This link may provide you with some answers.

http://theconversation.com/can-mirrors-boost-solar-panel-output-and-help-overcome-trumps-tariffs-90663

Joe

[Mike Norman]

Thanks for the link, the article says they increased efficiency of solar panels with mirrors by 30%.

[Bill von]

Theoretically mirrors could double power generation. What do you think?
They can. But the Carrizo solar plant tried that back around 1990 - and the result was browned panels; the EVA was damaged by the intense heat generated. So you have to be careful going that route (i.e. do it only in winter or when weather is cool)

With solar currently averaging about 50 cents/watt, I would think mirrors wouldn't be as cost effective.

[Don Kornelson]

A better option for increasing power might be a solar tracker which they say can increase power by up to 40%. Maybe a cheap arduino based tracker like this,https://circuitdigest.com/microcontroller-projects/arduino-solar-panel-tracker

I'm putting together a 1Kw test system this spring using arduino controlled gear motors on the horizontal axis and manual control on the seasonal vertical axis.

It sounds doable?.

[Rob Beckers]

Regarding trackers: We get more than a few customers asking for a tracker. They used to be popular and were installed over here in massive numbers in the early days of the Ontario Feed-In-Tariff program, when solar panels cost $4/Watt and payback was CAD$0.802/kWh. With those numbers it made financial sense; a dual-axis tracker at our latitude can in theory increase production to just over 150% vs. a regular south-facing array.

Fast-forward to today, with retail solar going for about $0.72/Watt (US$0.53/Watt), and in hindsight the experience that trackers require annual maintenance and expensive repairs (a popular German-made brand had and has widespread elevation motor failures, and they don't come cheap!). It just doesn't make sense any more, unless you have very restrictive conditions (maximum size in kW of panels, limited space, VERY expensive electricity etc.).

The beauty of solar PV is that warranties are 25 year on panels, because they rarely fail, and in practice will likely live for 30+ years, coupled with literally zero-maintenance for most places on this planet (if you have rainfall). It's one of the few things in life that "just work".

Now add a mechanical tracker to the mix: It will break and require repairs. It will need regular maintenance. Besides, trackers are not cheap! This negates the huge benefit of solar PV, requiring no work or maintenance.

So my advise to nearly everyone is: If you need more energy production, just add more panels. If you really want to, install them on a seasonably adjustable ground mount, so (over here) you can put them at 30 degrees from March through September, and 60 degrees from September through March. That will add 5% to the total (105% energy production vs. fixed 40-degree tilt-angle), and shed snow better in winter. It's really that last part that helps. For simplicity, a regular fixed 45-degree tilt-angle ground mount in our area will shed snow reasonably well, and produce well in summer and winter.

That's my 2 cts about trackers.

-RoB-

[Ralph Day]

My house panels are divided into 3 arrays of 4 panels. 1 array is on an old 10foot satellite dish and it tracks. So far (in 16 years) I've had to replace the tracking control once and the actuator motor 2 times. Good thing there's lots of old satellite dish equipment around. It still needs it's seasonal angle adjusted a couple of times a year (single axis only).

I agree with Rob, not worth the hassle. Cost wise only the controller cost me money, all other things were gifted to me, except labour, steel, pipe, concrete...

Ralph

[Joe Blake]

If you are of a "tinkering" nature and don't wish to spend too much, have you considered getting hold of a few of the reflective blankets used by paramedics to keep patients warm? I can buy them from my local camping store for about $3 or so each. Lay the blanket flat on something like a sheet of cardboard, then tape on the back with say duct tape. Put the reflector in front of the PV panel on a frame made of PVC water pipe and this can then change the angle of reflectance. The wrinkled surface of the blankets will disperse the light at varying angles which, according to some theories, is actually better than having all the light coming in at the one angle. (Note: The article I linked to originally is headed with a photograph showing a similar idea.)

The blankets are pretty tough, relatively speaking (although prone to melting with heat), and I've been using these blankets as reflective shields on the ceiling of my living room and bedroom for several years. Makes about a degree difference in the temperature of the ceiling. Further, the blankets are semi-transparent and I've put them on the outside of my windows to stop heat coming in - or even going out - the glass.

Depending on how this experiment works with your PV, you may be able to make a better judgement on using more substantial reflectors.