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Solar panels disguised as terracotta tiles in Pompeii

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Re: Solar panels disguised as terracotta tiles in Pompeii

#111

Post by pjc50 »

isoprophlex wrote: post #12
xg15 wrote: post #4

Earlier quoted context omitted.

> Inside the module there are incorporated standard monocrystalline silicon cells. The surface, that is opaque at the sight but translucent to sun rays, allows the light to enter and feed the cells. When they talk about "sun rays", do they mean the UV portion of sunlight? Because if the material were transparent to visible light, it would be, well, transparent, wouldn't it?

Monocrystalline Si has a 1.2 eV band gap iirc, meaning it absorbs everything smaller (more energetic) than ~ 1100 nm. Our eyes see, what, 200-600 nm? Removing the 200-600 nm bit leaves you with approx 50% of the energy left between 600 and 1100 nm, glancing at [1] This is all VERY back of the envelope... but I think these lose around half of the energy you'd get out of conventional panels. [1] https://www.researchgat…

Nice maths.

For the benefit of the audience: if you imagine picking a point on that curve and drawing a square under and to the left of it, a solar panel captures only that energy from the orange region. Photons with longer wavelengths aren't captured: not enough energy to push an electron up the bandgap. Photons with shorter wavelengths have more and more energy to push an electron up, but can only capture 1.9226e-19 joules per photon of that energy at 1.2eV.

Re: Solar panels disguised as terracotta tiles in Pompeii

#112

Post by pjc50 »

cmarschner wrote: post #84
bruce511 wrote: post #72

Earlier quoted context omitted.

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.…

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?

Re: Solar panels disguised as terracotta tiles in Pompeii

#113

Post by taopai »

sundvor wrote: post #79

This tech would be amazing for anyone slapped with a random heritage listing do not modify ban on installing PV, as has happened here in Melbourne, VIC. E.g. https://www.pv-magazine-australia.com/2022/06/08/melbourne-h...

Agree. In Spain, most councils do not allow solar panels to be installed on houses in the old town. My uncle has to take them out...

Re: Solar panels disguised as terracotta tiles in Pompeii

#114

Post by jaclaz »

drusenko wrote: post #50
xoa wrote: post #29

Earlier quoted context omitted.

Yes, the Tesla Solar Roof tiles, and they did get some tiny number (thousands or something like that?) installed. I actually had ordered one and was in line to get it installed last year. But the company cancelled it, and then Tesla started cancelling all of them apparently. The reason the installer gave was that the v1/v2 were too labor intensive to be worth it, and they were waiting for the v3, but from reports I r…

Did you ever end up finding any other company making any tiles that resembled slate, out of curiosity?

There is a reference here (for UK):

https://news.ycombinator.com/item?id=34286801

Re: Solar panels disguised as terracotta tiles in Pompeii

#115

Post by pjc50 »

graphe wrote: post #102
hgomersall wrote: post #90

Earlier quoted context omitted.

A properly designed house with solar can be energy neutral over the year in the UK (not notable for its sunny climate).

What does energy neutral mean? What does properly designed mean? And at what cost to comfort or the property? You could turn off all your electricity and heat yourself with kerosene and have used no electricity for the year.

Usually means "passivehaus", and "energy neutral" would mean "generates an equal quantity of electricity to that consumed, when summed over the year".

> heat yourself with kerosene

That's not energy neutral, is it now, unless you have a kerosene well on the property.

Re: Solar panels disguised as terracotta tiles in Pompeii

#116

Post by jaclaz »

NL807 wrote: post #60
zbrozek wrote: post #40

Artisanal production - nope nope nope nope nope Give me a lights-out factory without a single human being churning out a gazillion units per day with 100% test coverage please. Anything else will have all kinds of quality control and reliability problems when trying to produce a bunch of nominally-identical widgets.

It's a niche product for a very specific environment.

Actually it is a very small scale experiment for a very niche product.

Re: Solar panels disguised as terracotta tiles in Pompeii

#117

Post by pjc50 »

positr0n wrote: post #69
kristopolous wrote: post #35

Earlier quoted context omitted.

That's fine, they look great. Realizing we've got stuff looking like that that generates freakin' electricity is amazing.

Given the poorer efficiency, wouldn't it be better use of limited money and resources to put regular tiles on houses and normal solar panels somewhere else? (Honest question. I've always wondered why residential rooftop solar, especially since it's usually government subsidized, makes sense anywhere in the world.)

Land tends to be expensive; it would be a real challenge in Europe to find somewhere that isn't being used already for some economic purpose, and also isn't a conservation area and/or physically inacessible or difficult to build on.

Re: Solar panels disguised as terracotta tiles in Pompeii

#118

Post by midoridensha »

yywwbbn wrote: post #109
midoridensha wrote: post #91

Earlier quoted context omitted.

I'm not advocating bulldozing ancient churches or the pyramids, but to build those things (or modern equivalents in terms of resources as a percentage of resources available to the society at large) today would be supremely stupid and wasteful. Arguably, wasting resources on burial mounds might be part of why Ancient Egyptian civilization collapsed, just like the civilization of Rapa Nui (Easter Island) with their st…

We’re still will to dedicate large amounts of resources for building museums, concert halls and other public buildings that fundamentally don’t really have a more practical purpose than medieval churches.

What? This is really dumb. Museums are extremely practical, just like schools: they educate people. Concert halls are for entertainment; they're just as useful as restaurants (after all, you could just eat microwave meals at home). Most public buildings have some kind of valid use that doesn't involve superstitious beliefs. Even medieval churches probably had some non-supernatural uses, I'm guessing, like being used as meeting halls or for public addresses. Egyptian pyramids had none of this: a few pharoahs' dead bodies were sealed away inside them along with lots of treasure, and that was it. Everyone else got dumped in a pit when they died.

Edit: I see your point now, that medieval churches had other functions besides the religious stuff. Still, I see those things as only secondary functions to the buildings; museums and concert halls have those things as their primary functions and are optimized for them. I've been in medieval churches, and there's very little artwork in them, relative to their size, compared to any decent art museum. But I agree, they were a lot more functional for the people of the time than the pyramids.

Re: Solar panels disguised as terracotta tiles in Pompeii

#119

Post by Cthulhu_ »

positr0n wrote: post #69
kristopolous wrote: post #35

Earlier quoted context omitted.

That's fine, they look great. Realizing we've got stuff looking like that that generates freakin' electricity is amazing.

Given the poorer efficiency, wouldn't it be better use of limited money and resources to put regular tiles on houses and normal solar panels somewhere else? (Honest question. I've always wondered why residential rooftop solar, especially since it's usually government subsidized, makes sense anywhere in the world.)

Why not both? SolarCity (now Tesla) had solar panels that looks like roof tiles. There's a lot of roof space in any town, it makes sense to use that instead of use up land (that could be used for housing or agriculture) for solar power generation.

But it can be all of the above, too. More energy produced is not going to go to waste, and there's plenty of unusable areas like deserts where solar electricity can be generated in various ways.

Re: Solar panels disguised as terracotta tiles in Pompeii

#120

Post by Cthulhu_ »

yen223 wrote: post #42

The thought of future archaeologists being thoroughly confused by Roman terracotta tiles that apparently generates electricity amuses me.

In theory they would be able to determine they were a much later addition. Then again, things like ancient Egypt lasted for thousands of years, so perhaps they will consider 2000 years a short amount of time.

That said, it does feel like the past few centuries (since the Industrial Revolution, but even moreso since the late 1800s/early 1900s) have seen incredible avancement in technology, unlike anything seen before. I mean electricity as we know it - the means to reliably generate and use it - have only been around for just over 200 years now.

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