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SandAndAlum t1_je4p5k6 wrote

Reply to comment by pickingnamesishard69 in German manufacturer achieves 80% overall efficiency with new PVT solar module by galileofan

Roof space hasn't really been limited until recently (price now makes it kinda viable). Separate solar thermal and PV have been a thing for a while now.

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pickingnamesishard69 t1_je4ukgn wrote

The thing with seperate thermal and PV is that you still have thermal energy on the PV that is getting wasted. On top of that, PV panels lose efficiency and degrade faster the hotter they get. Using that extra heat therefore makes double sense, provided (like someone else mentioned) that the extra maintenance is not too costly.

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SandAndAlum t1_je4v4xi wrote

All true. The general principle is neat and becomes more relevant as PV gets cheaper. Combine with a thermal store, feed the AC waste heat in too, and suddenly you've gotten rid of seasonal variability in temperate zones.

Couple things in the article make it sound a little sketchy though. If the PV module remains at 30C then how hot is the working fluid? Do they take out the below-bandgap energy before it hits the silicon or is the module hotter than the fluid?

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pickingnamesishard69 t1_je6kko2 wrote

Tbh i started talking before i read the article, so no clue about the working temperature. There are multiple concepts floating around afaik - using air/gas is neat because it wont freeze, some liquids might be more efficient but require more maintenance and have higher leaking risks... The one i saw a vid on was working with very cold gas that would get heated to maybe 30-50, would then be cooled via heatpump and repeat. Guess it makes sense to both send the medium cold so it doesnt heat too much, and have pipes that can handle heat (they would need to manage max heat if at any moment the system cant pump)

But: dunno, still didnt read on this one. The concept itself is 100% sound and worthwhile imo, but the question of HOW will have to be solved by engineers.

Most likely multiple paths that work in different conditions.

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