Solar PV Vertically Mounted - Help Needed

[elektronix]

Hi,

I need to place panels vertically on a wall. I was told of a losss

of 15 %, but I see more that 30 %, with bare cells pointing a midday

sky vs. placed vertically.

Is there a method to increase intake of the sun light when

cells/panels are vertical?

Is there any kind of Fresnel lens applied onto a vertical solar

panel to increase power?

How a plastic cover changes power intake on vertically mounted

cells, versus no cover?

Any hints are appreciated.

********

Here are my observations.

I started playing with solar cells I just got from eBay.  

(I broke already two (2 x $2.50)).

I measured at 18:45 o'clock, in the direct late afternoon sun, having:

• 0.51 V open circuit voltage
  
• 0.40 A short circuit current.
  
  

Next day, medium cloudy, at 13:30 (almost noon, with summer time),

I measured:

• 0.48 V open circuit voltage
  
• 0.10 A short circuit current.
  
  

I noticed, that pointing cells just straight up into the

milky sky gave me higher current than trying to point where the

sun was behind clouds.

Then I placed my cells vertically and noticed a loss at least 30 % on

short circuit current.   Bare cells test, no plastic/glass cover.

Thanks,

Elektronix

[Ungrounded Lightning Rod]

I need to place panels vertically on a wall. I was told of a losss  of 15 %, but I see more that 30 %, with bare cells pointing a midday  sky vs. placed vertically.

Sounds about right.  Assume a latitude of roughly 45 degrees.  Vertical mounting will degrade you by a factor of cosine (90-45 = 45 degrees), which is about .707, or about 30% loss.

Is there a method to increase intake of the sun light when cells/panels are vertical?

Tilt them right.  B-)

Mirrors.

A big prisim sticking out even farther than the panels would have if they had been mounted normal to the noon sun.

Is there any kind of Fresnel lens applied onto a vertical solar panel to increase power?

Not unless you tilt it out like the panel should have been.  Then you could use a fresnel prisim, or even a concentrator (although that is NOT recommended, because you can cook the cells with too much light and infrared).

The problem is that, with the panel at an angle, you're not intercepting as wide a swath of sunlight as you would have if it was pointed at the sun.  You have to do something to get some more sunlight to hit the panel.

A horizontal mirror will do it, doubling up your insolation.  But it will also get dirty.  And I assume you mounted them vertically because you didn't want anything sticking out where it could be bumped - let alone stepped on.

How a plastic cover changes power intake on vertically mounted cells, versus no cover?

About the same way it does with tilted cells.  Depends entirely on the plastic and the angle of the sun.  But it will reduce it a bit, both by absorbing some of the light and bouncing some off - the latter moreso when the sun is hitting it at a larger angle.

[Ungrounded Lightning Rod]

I noticed, that pointing cells just straight up into the milky sky gave me higher current than trying to point where the  sun was behind clouds.

With the sky cloudy enough that the light is evenly distributed, more light will hit a horizontal panel (which is exposed to the entire sky) than one pointed at the sun's location (which is exposed to only part of the sky.)

But unless your area is cloudy virtually all the time you'll be ahead to tilt it to match the noonday sun's direction.  (Or track the sun - but that usually costs as much as extra panels for the same total power.  And it's moving parts to break.)  Just adjust the tilt every couple months during the spring and fall and you'll be fine.

[Opera House]

Check out the rear view mirror in your car.  It has a lever for night driving.  This tilts the mirror so the reflection that you see is not from the reflective mirror surface but the surface of the glass.   You are always reflecting some sunlight off any transparent cover.  That loss is the price you pay for protection from the environment.