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Rice University researchers propose a way to boost solar efficiency

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Re: Rice University researchers propose a way to boost solar efficiency

#61

Post by apo »

The title is misleading. The full title is:

> Researchers at Rice University developed a method to convert heat into light that could boost solar efficiency from 22% to 80%

The conditional tense signals that the researchers didn't actually do so, but that the study might enable it. The article re-iterates that this is speculation:

> The implications of their discovery are significant. Research from Chloe Doiron, a Rice graduate student, revealed that 20% of industrial energy consumption is wasted through heat. It could also mean an increase in the efficiency of solar cells, which are currently only 22% efficient at their peak. Recycling the thermal energy from solar cells using carbon nanotube technology could increase the efficiency to 80% according to the researchers. ...

Re: Rice University researchers propose a way to boost solar efficiency

#62

Post by kazinator »

amluto wrote: post #32

As far as I can tell, this is functionally just a coating with low emittance in the IR outside a narrow band. A matched PV device that is kept cool can, in principle, approach the Carnot efficiency for the temperature difference between the emitter and the PV junction. If the emitter is the sun, then the source temperature is very high and the Carnot efficiency isn’t a major limit. If the source is a solar panel, I’m…

For solar, it somehow has to integrate with the solar panel, so that the same square meter is used both for direct photovoltaic generation of electricity, and for this IR capture, so energy is obtained from a wider band.

I understand your point that it can't just be driven by a secondary IR emission from a warmed-up solar panel; that's not hot enough to be that useful.

In a more detailed article, there is talk about the carbon nanotube device being useful because it can withstand high temperatures:

https://news.rice.edu/2019/07/12/rice-device-channels-heat-i...

They of course understand that they need a big temperature differential.

Re: Rice University researchers propose a way to boost solar efficiency

#64

Post by rocqua »

mruts wrote: post #55
mikepurvis wrote: post #38

Earlier quoted context omitted.

Interesting to contemplate what could be done to shift those incentives around. Obviously there are certifications (LEED), and there's straight-up regulation, but would there be a way to mandate that a builder or landlord is responsible for a portion of future HVAC expenses such that they are motivated to get this right upfront?

The market should (and has in the past) figured this out. Energy costs money, tenants want to spend less money. Tenants will pay more money up front to save themselves money down the line. Therefore landlords should have an incentive to build energy efficient structures even if they aren’t paying for the energy. The problem is when an energy source with an high externality (climate related or otherwise) isn’t priced…

Part of the reason is that it is hard to gauge what the energy bill of an apartment will be before you start renting. That is where certification should come in.

Re: Rice University researchers propose a way to boost solar efficiency

#66

Post by p1esk »

DoofusOfDeath wrote: post #56
Terr_ wrote: post #42

Earlier quoted context omitted.

I am especially infuriated by how it repeats a common misconception of infrared light as the epitome of "heat", as if it was some kind of separate particle.

I'm not infuriated , but having teachers and other adults conflate IR with heat certainly added to my confusion about the physical world when I was a child.

Sorry for a potentially stupid question: why do they need to convert heat into visible light? Why can't we convert heat directly into electricity at the same time as we convert visible light into electricity?

Re: Rice University researchers propose a way to boost solar efficiency

#67

Post by marshray »

dreamcompiler wrote: post #65

"This light can then be used as electricity." No. One cannot use light as electricity. One can use light to make electricity. This is not just a minor typo; it's flat-out wrong.

If you want to get pedantic, you can't "make electricity" either because 'electricity' isn't a defined concept. Usually when people use words such as "make electricity", they actually mean to refer to energy or power transferred using electromagnetic fields interacting with a conductor. But a purely chemical reaction that charges a battery could be said to "make electricity" without even involving that.

More info: http://amasci.com/miscon/elect.html

Re: Rice University researchers propose a way to boost solar efficiency

#68

Post by godelski »

On topic of the HN title, there is research being done into carbon nanotube rectennas. Theoretical efficiency is in the upper 90's%. Problem is that they have very narrow bandwidth. Also as far as I'm aware, no one has even built lab samples that do decently.

Re: Rice University researchers propose a way to boost solar efficiency

#69

Post by clouddrover »

sovnade wrote: post #51

For anyone curious: Carbon Nanotubes, so this will likely not see the outside of a lab any time soon.

Why not? Nawa's ultracapacitors are based on carbon nanotubes and they're going in to production:

https://newatlas.com/nawa-nanotube-ultracapacitor-production...

Vantablack is based on carbon nanotubes and you can buy it now:

https://www.surreynanosystems.com/vantablack/science-of-vant...

Re: Rice University researchers propose a way to boost solar efficiency

#70

Post by philipkglass »

ThomPete wrote: post #50
philipkglass wrote: post #40

Earlier quoted context omitted.

Fuel cells have been commercially available since the 1960s, though they were mostly confined to space program applications then. Automobile manufacturers have produced small numbers of fuel cell vehicles since the turn of the millennium: https://en.wikipedia.org/wiki/Fuel_cell_vehicle#List_of_mode... I'm not making claims about the actual merits of fuel cells, mind you. But claiming they're further out than fusion i…

There are many types of fuel cells. I am talking about the kind of fuel cells which can be used by wind and solar to store energy and distributed economically feasible. We are not even close to that. If you know of anything, by all means, please let me know as the group I am part of would invest in it in a heart beat.

I am talking about the kind of fuel cells which can be used by wind and solar to store energy and distributed economically feasible.

I don't know of anything like that either. Small fuel cells rely on expensive precious metal catalysts and large ones have too much capacity to be a good match for the distributed generation sector.

A technology that is commercially available but too expensive at present for large scale adoption, like fuel cells, is more mature than a technology that hasn't been demonstrated even in a cost-is-no-object context. That's why it's strange to hear fuel cells described as even further out than fusion power.

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