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Comment by bruce511 | Hacker News Reader

So for those not in the know, fun fact, solar panels work better when they don't get hot. So things like airflow for passive cooling do matter.

I'm aware of several large-scale solar situated in hot regions with no active cooling, so I guess my answer to your question is no, high effeciency panels in hot environments do not need active cooling.

Roof tiles are a different question. There's no airflow underneath them. So they probably get hot. Hot enough to matter? That's hard to say. Do they have the same thermal properties as a regular tile? What is the impact on building temperature? These would be factors to consider during construction. More insulation, better airflow, and do on.

Incidentally since they are not flat (at least not in the picture) that likely accounts for the lower effeciency).

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According to some testing, it matters:

https://youtu.be/Mt9qLRN7JvA

FWIW, the way roofs are designed these days (at least over here in Belgium) there is supposed to be a little bit of airflow underneath your roof, which is achieved by letting the ridge and hip tiles hover over the roof (instead of cementing them like they used to do) and putting a perforated grate at the bottom just above the gutters instead of boarding it up.

Would one be able to extract energy out of the hot tiles as electricity? With a heat exchanger?

Where would you put the cold side?

Fun fact: resistance sucks and makes your electrons bump into protons and crash causing waste heat. Super conductors are usually supercooled and have 0 resistance and every electronic works more efficiently cooler.

> resistance sucks and makes your electrons bump into protons

This is a myth with little bearing to reality. Protons (and the atomic nucleus) are insignificantly tiny when compared to the size of an atom. The major contributor to electrical resistance are defects to the crytal lattice of metals and grain boundaries.

The temperature coefficient of resistance is real, though, and could do with an explanation that isn't too quantum.

Of course it is! And the explanation isn't even too quantum. Heat induces atoms to vibrate, these vibrations mess up with the perfectly periodic potential that you would have at 0 K and induces electron scattering which leads to more electrical resistance.

Don't you need the defects to have semi conductors? I seen some really cool experiments with superconductors and every computer works better cold. Isn't that why Google's quantum computer is supercooled?

> Don't you need the defects to have semi conductors?

No. However, most of the time you want doped semiconductors and doing that introduces defects. The defects are bad for resistive losses but that's life.

> every computer works better cold

No. Conventional electronics based on doped semiconductors don't work below a certain temperature because the impurities are "frozen". There is a sweet spot of temperatures that works best. The purpose of cooling on a computer is to keep the temperature as close to the sweet spot as possible.

> Isn't that why Google's quantum computer is supercooled?

Quantum computers like Google's rely on superconducting materials (most of) those require sub-Kelvin temperatures to work, both to reach the superconducting regime and to reduce phonon induced decoherence. Superconductivity works in quite a different way to conventional materials to conductivity in semiconductors and metals too.

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