putting solar panels under glass ?

[Thunderchild]

is putting solar panels under glass going to improve on the amount of power produced ? or is it just to keep then safe ? what if the panels do get wet ?

 

[Nigel Goodwin]

is putting solar panels under glass going to improve on the amount of power produced ?

No, if anything it will reduce it!.

or is it just to keep then safe ? what if the panels do get wet ?

Just to keep them safe, getting wet depends on how the panels are designed, if they are designed to get wet then there's no problem.

 

[Sceadwian]

Glass will always reduce power to a solar cell, some glasses more than others, and you can't trust your eyes because the frequencies solar cells are sensative to are not in the human sight range so if you use something like plastic you have to be careful about what type as it may absorb a lot of power that you can't see (mostly in the IR range I think) Depends on the solar cells spectral profile and the shielding materials profile.

 

[Thunderchild]

ok well they are old cells and as it is covered in glue/silicone I suppose that don't help does it ? perhaps I'd better try to peal it off, it looks like a strip of circuit board with the elements (8) stuck to it and they are connected in series to make up 4 volts

 

[Sceadwian]

I would hope that the manufacture wouldn't put a plastic that obviously reduced power over the top of a cell, but seeing as how the plastic is visibly opaque it wouldn't hurt to rip it off and try a sheet of glass over the top instead. You're only going to add a few percent to the efficiency of the cells though, it might not be worth it, especially if your glass doesn't adequately protect the cells.

 

[Thunderchild]

well on top of that glue there was a plastic cover I have already removed but it had gone yellowy (20 odd years old) and was knoking out 30 % of efficienzy.
I'm considering dismantling them and perhaps rearranging them, how delicate are those elements ?

 

[Sceadwian]

Don't flex them. Bending or twisting them will break them easily. They're resistant to shock and pressure so long as it's not enough to crush the basic materials.

 

[justDIY]

how did you compute 30% efficiency?

 

[Aloefundi]

how did you compute 30% efficiency?

Thats a bit of a difficult one to work out.

A number of factors will need to be taken into account. Such as...

Rated Output of PV panel
Current Longitude of installation
Mounting angle vs Season

Going through them, here's my take.

Rated Output - PV is rated at 50 W. Actual output under 'ideal circumstances' is 49 W this would be a 98% effeciency

Current Longitude - Differing Longitudes will have different 'ideal' mounting angles, It's no good having the PV horizontal when a 23 deg inclination is required for maximum exposure to sunlight. this would also affect effeciency, working it out however is not that easy.

Mounting angle vs Season - This is a nice one ;-) Depending on the time of year, the sun is at a different angle in the sky, this affects the 'ideal' mounting angle of your PV, based on the time of year (Unless you are lucky enough to live at or near the equator) What most people do is work out the Upper and Lower angle and use the mean between the two, make a fixed bracket at this angle and live with the difference in efficency.

There should be others but this is what springs to mind.

regards

Aloe

 

[Sceadwian]

I think he just mean that it'd lost 30% of it's output due to the plastic yellowing.

 

[Thunderchild]

I think he just mean that it'd lost 30% of it's output due to the plastic yellowing.

precisely on removing the old plastic it went from 60-70 mA to 100-110 mA