Heating with solar panels instead of infrared radiants...

[AntronX]

Come back and tell me how much voltage was required.

42V * 10A for NE Solar 370W panel (34Vmp).

 

[AntronX]

This could make use of old degraded EVA sheet panels that are no longer economical to keep mounted on solar rack. At 35°C panel backsheet temp it did noticeably radiate warmth when standing 5 feet away in 22°C ambient.

 

[rin67630]

This could make use of old degraded EVA sheet panels that are no longer economical to keep mounted on solar rack. At 35°C panel backsheet temp it did noticeably radiate warmth when standing 5 feet away in 22°C ambient.

Thank you for that information !
Thermal radiants need more than ten times that temperature to achieve that.

 

[AntronX]

Thermal radiants need more than ten times that temperature to achieve that.

I am not sure if this warmth was from IR or just thermal. Panels radiate at 1200nm silicon emission peak. The backsheet would have to be transparent to that wavelength or it would just absorb and radiate as thermal. Warmth was barely noticeable but I guess with 10 panels all around the room it could warm up nicely at 4.2 kW total. Same effect can probably be achieved with heating wire embedded into drywall.

 

[AntronX]

Also placing my forearm 1 foot in front of glass side did not produce increase in warmth sensation. I wonder what IR emission efficiency solar cells have. It's probably not very high.

 

[rin67630]

Also placing my forearm 1 foot in front of glass side did not produce increase in warmth sensation. I wonder what IR emission efficiency solar cells have. It's probably not very high.

There we would need some calibrated IR Thermocam. I don't have that in my tinkering budget.
I imagine that a plain surface at just 35°C will not radiate much to give a warm feeling at 22°C ambiant.
But thank you for sharing your experience anyway.

 

[Hedges]

42V * 10A for NE Solar 370W panel (34Vmp).

Strange.
Your measurements support rin's theory, and mine before it ran into experience.
I connected 2s panels in the sun to backfeed one in the dark, 41V which is > Voc of one panel, to get 2A which is less than half of Imp. (all degraded panels, which could explain such low voltage when sourcing 2A.)

Measuring PV panel performance

I suppose I could buy a solar panel tester like Will reviewed, but that doesn't feel DIY enough to me. Besides, I'm a cheapskate, and I try to do things in the most difficult (and expensive if the equipment wasn't on hand) way. I'm presently working on an underperforming string of Sharp 165W...

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