Mono vs Poly

Arkansasoffgrid

Is there a "real world" advantage to Mono panels in the heat? Metal roof & 3 months of around 100+ temps in Arkansas.

Cariboocoot

Re: Mono vs Poly

No.

Mono panels lose Voltage in heat the same as poly panels. Look at the temperature coefficient on any given panel: there are some differences between brands but not what you'd call a major division between mono and poly.

The main advantage of monocrystaline panels is the Watts per square area. That can be a serious advantage if 'PV real estate' is limited.

DMJ72

Re: Mono vs Poly

Is there any truth to the saying that Poly panels gather more scattered light?

Cariboocoot

Re: Mono vs Poly

DMJ72 wrote: »

Is there any truth to the saying that Poly panels gather more scattered light?

In the lab, yes. In practical terms no.

A comparison between amorphous, poly, and mono panels under controlled conditions would show the amorphous panels having a more consistent output over time from diffused light than either poly or mono panels, poly coming in second place. But out on the roof over a year's time what you'll see is the efficiency difference per square area with the amorphous panels running a poor third at about 7%, the poly panels running 14-16% and the mono panels 18-20%. It has to do with the way light is 'gathered' by the three different types.

Think of them as having 'receptors' for photons. The amorphous ones are scattered and point in all different directions, the poly ones are aligned in 'rows', and the mono ones in a 'single row'. So as the light angle changes through the day each type picks up a different amount of 'direct sun'. The mono panels having their 'receptors' aimed more directly at the sun pick up more light and thus produce more power from the same amount of irradiation. The down side is that when the sun is not directly aligned with these receptors they pick up less. So if the sun light is diffused or scattered it is never intensely aligned with the receptors resulting in a drop in output. The practical side is that the 'bell curve' of production is lessened and flattened for mono and poly panels more so than for amorphous whose output remains more consistent through the day; less of a bell curve (under any lighting). But since the amorphous panels are so inefficient to begin with there's no practical advantage to this.

(This analogy is not 100% correct; it's just to give an idea of the difference in function. As it is someone will probably feel the need to argue about it.)

DMJ72

Re: Mono vs Poly

Thanks .. interesting info.