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New Solar Power Material Converts 90 Percent of Captured Light into Heat
- jcr 12y agophys.org is often just regurgitation of press from original sources, typically university press sites. Here's a better source URL: http://www.jacobsschool.ucsd.edu/news/news_releases/release.sfe?id=1589 http://www.jacobsschool.ucsd.edu/news/news_releases/release....
- richmarr 12y agoThanks. It's nice to be able to read the article without the "37 People With The Worst Eyebrows You'll Ever See".
- marcosdumay 12y agoWhat's as useless as the pointed article. I tought the university PR would care to add such things as absorption rate of infrared, and why should I care about this instead of looking at traditional black nickel. Any random black paint absorbs more than 90% of the light, and lots of black coatings survive 700°C.
- VLM 12y agothats why the story itself (which is a couple weeks old) and most discussion isn't catching the "real story". You can find materials and substances that'll survive years at 700C although its non-trivial (not home depot, but no challenge for real engineering). And you can find materials and substances with ridiculous awesome IR profiles that are unfortunately incredible fragile or at least not "engineering useful" tough. But both characteristics in the same material is where the real story is. Its pretty cool. There is another aspect of industrial scale use, not discussed in the weeks since the story came out, where for example, nickel oxide powder has some serious issues for lungs, and no one seems to know the toxicology of this new stuff. I donno where this stuff fits on the continuum of health, if its better or worse that your example of nickel oxides. It would suck if everything downwind turned into a superfund site, then again maybe its harmless as a charcoal bbq. I guess a bad computing analogy would be its not very hard to find a low power computing device. Think of TI and microchip pic series of picowatt or nanoamp things. I've fooled around with the 10F220 series for no reason, "just because". And its not hard to find a computing device that does stuff really fast, any ole COTS desktop CPU or high end video card has interesting specs. But finding a processor that simultaneously uses nanowatts of power while making gigaflops of calculations, in 2014 anyway, would be pretty impressive. And getting a good ratio of flops/watt while being engineering-worthless isn't that impressive, but getting a good ratio of flops/watt while being engineering useful and deployable is really cool.
- sctb 12y agoThanks, we updated the URL.
- andy_ppp 12y agoDoes this mean that we are closer to replacing fossil fuels? It seems as though for energy we could do it now if we wanted, yet we still obsess about fracking and to a lesser extent middle eastern oil? The cost difference is certainly not the reason we don't dive in and make these changes. Those in charge still seem to be of a 'secure the oil and the heroin' and you rule the world. Oh dear -> https://www.youtube.com/watch?v=xW3XeT7qavo https://www.youtube.com/watch?v=xW3XeT7qavo
- stouset 12y agoReplacing fossil fuels is not as simple as having high-efficiency solar panels (which these may not be when converting sunlight to electricity instead of heat). Fossil fuels also have the advantage of having extremely high energy density. They can be transported cheaply and efficiently and they store well. Electricity suffers large losses when being transported long distances directly, and batteries are significantly heavier per kWh. Batteries also degrade over time, are expensive to replace, and often require substances that can be as (or more) destructive to mine than oil is to burn.
- andy_ppp 12y agoI think Tesla kind of prove that all of these problems can be overcome in cars. To address your point on storing intermittent energy: http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity It's about 80% efficient and would probably get more so. So you can solve the storage and intermittency problems of non fossil fuel storage pretty simply.
- hueving 12y agoTesla has not proved that at all. You are completely ignoring the fact that they have no cheap solution to the batteries going bad. That's why there is no pricing available on battery replacements and why they have to have the depreciation matching program with gas cars.
- afarrell 12y ago
- jsilence 12y agoConverting light into heat is by far not as difficult as turning it into electricity. So don't mix this up with the 20-24% efficiency that are achievable in photovoltaics.
- lucidstack 12y ago40%, since some days. :) http://www.livescience.com/49133-super-efficient-solar-energy-system.html http://www.livescience.com/49133-super-efficient-solar-energ...
- imaginenore 12y ago44.7% actually http://upload.wikimedia.org/wikipedia/commons/a/a5/PVeff%28rev141208%29.jpg http://upload.wikimedia.org/wikipedia/commons/a/a5/PVeff%28r... http://en.wikipedia.org/wiki/Solar_cell_efficiency http://en.wikipedia.org/wiki/Solar_cell_efficiency
- jsilence 12y agoAh, nice graph! Thanks for posting! I was unaware about the steady progress. Still far away from the 90+% thermal efficiency that is possible with solar heating. My hopes on photovoltaics are on the relatively new contender Perovskite. Really nice to see the steep progress in efficiency there.
- imaginenore 12y agoThe theoretical limit for solar cells is much lower than 100%: http://en.wikipedia.org/wiki/Shockley%E2%80%93Queisser_limit http://en.wikipedia.org/wiki/Shockley%E2%80%93Queisser_limit
- jsilence 12y agoAh, nice graph! Thanks for posting! I was unaware about the steady progress. Still far away from the 90+% thermal efficiency that is possible with solar heating. My hopes on photovoltaics are on the relatively new contender Perovskite. Really nice to see the steep progress in efficiency there.
- Wissmania 12y agoWhat was the previous best conversion rate? This doesn't get us all the way to electricity, so its not really interesting info without a point of reference.
- imaginenore 12y agoThe previous one was 99.965% efficient. http://www.iflscience.com/technology/new-super-black-material-absorbs-99965-light http://www.iflscience.com/technology/new-super-black-materia... So yeah, this article is bull.
- jacquesm 12y agoSolar power is a bit of a misnomer here because most people reading that will assume it implies eventual conversion into electricity or motive power. Electricity is like steak, heat energy is more like hamburger. It's useful but not nearly as useful as electricity, so you're going to need another conversion step (steam turbines are best at this right now) to get to a more usable form of power and that conversion step will have losses (radiation losses, mechanical losses, electrical losses). So 'overall' efficiency is the key, not the efficiency of a single step in the process (they should at a minimum then list their current efficiency next to the previously achieved maximum for that step and how cost effective this new method is).
- binarymax 12y agoTrue, but I can picture many uses for the heat as is - such as off-grid heating water for homes/hotels/factories, which would normally burn natural gas or use electricity from the grid.
- lotsofmangos 12y agoyou're going to need another conversion step Lonnie Johnson's JTEC is an interesting looking approach for that bit - http://en.wikipedia.org/wiki/Johnson_thermoelectric_energy_converter http://en.wikipedia.org/wiki/Johnson_thermoelectric_energy_c...
- Dirlewanger 12y agoHeat to generate steam, in turn generating AC potentially?
- venomsnake 12y agoWhile what you say is totally true, huge part of the energy budget of humanity is heating stuff. If we remove heating for cooking, heating homes and water ... we will reduce drastically our footprint. Also my inner steampunk geek will love the sight of huge sterling engines moving around ...
- vmarsy 12y agoTrue, also a lot of industries requires heating things as well so if it's efficient for them to paint their warehouse it's a good thing! And if you have a nice source of heat, it could provide a nice A/C without requiring electricity (http://en.wikipedia.org/wiki/Einstein_refrigerator http://en.wikipedia.org/wiki/Einstein_refrigerator)
- minthd 12y agoWe already have materials that can achieve 75% efficiency [1] and probably more(it's just a rough search), so the 90% figure is much less impressive . But they also claim low cost and low maintenance over other methods, which are highly valuable. [1]http://www.mit.edu/~soljacic/cermet_solar-thermal_OE.pdf http://www.mit.edu/~soljacic/cermet_solar-thermal_OE.pdf
- fche 12y ago... or, on the residential scale, a black rubber membrane sandwich known as a solar pool heater.
- davidovitch 12y agoI find it quite annoying that the original papers are not mentioned anywhere in the article. How difficult can it be to include a link/reference/doi to the source? I understand that for many people these scientific articles are too much, and unfortunately most of the times the scientific sources are still behind pay walls, but it is very important if one wants to verify the claims made in the news article. I believe the following articles are the ones on which this story is based: http://dx.doi.org/10.1016/j.nanoen.2014.06.016 http://dx.doi.org/10.1016/j.nanoen.2014.06.016 http://dx.doi.org/10.1016/j.nanoen.2014.10.018 http://dx.doi.org/10.1016/j.nanoen.2014.10.018 (behind a pay-wall unfortunately)
- drdiatom 12y agoAgreed. Fortunately there's a media contact details at the end of the article. I'm sure they'd like that feedback as well. Did you email them in addition to posting this comment on HN? :) I just did, expressing similar sentiments.
- toddkaufmann 12y agoWouldn't it be great if you could just annotate that article and include the link? It seems you can now that hypothes.is has launched[1]. [1] http://hypothes.is/ http://hypothes.is/
- minthd 12y agoHere's a free link to the pdf: http://circuit.ucsd.edu/~zhaowei/Journals/Nano_Energy_Dylan_Bryan_2014.pdf http://circuit.ucsd.edu/~zhaowei/Journals/Nano_Energy_Dylan_...
- samatman 12y agoIt's like, how much more black could this be? and the answer is none. None more black. http://en.wikipedia.org/wiki/Black_body http://en.wikipedia.org/wiki/Black_body
- rndn 12y agoIn other words it's a material which has a very low reflectance across a large range of frequencies (i.e. a black material)?
- diltonm 12y agoChecking out some of the Fresnel videos on Youtube really helps one appreciate the power of the Sun. If the new material can withstand 700 C then point a Fresnel at it and hook up the output to a Stirling engine for conversion to electricity.
- rab_oof 12y agoExactly. Should open source patent this.
- mapt 12y agoSo... black latex paint? Asphalt? Water? http://en.wikipedia.org/wiki/File:Albedo-e_hg.svg http://en.wikipedia.org/wiki/File:Albedo-e_hg.svg The advance is not that they "reached 90%", that's absolutely trivial, and nothing to do with a "Solar Power Material". They seem to be claiming that their advance is a black material they can paint onto thermal pipes that is durable at 1000K for an extended period of time in Earth's atmosphere, made out of blends of nanoparticles. "High temperature black paint created that lasts 5-10 years instead of 1 year, reducing maintenance needs for concentrating solar thermal" would be a more honest title.
- swamp40 12y agoIt's probably the same material they use to make park slides. If the sun's out, they are usually too hot for the kids to slide on...
- nv1729 12y agoAre you sure? From http://en.wikipedia.org/wiki/Solar_cell_efficiency#mediaviewer/File:PVeff(rev141208).jpg http://en.wikipedia.org/wiki/Solar_cell_efficiency#mediaview... it seems theres a cap at 45%
- edmccard 12y ago>it seems theres a cap at 45% That number is for photovoltaic cells converting light to electricity; the 90% in the article is for converting light to heat.
- kragen 12y agoit's actually rather surprising, and important, that they were able to get 90 percent solar absorptivity combined with 30 percent infrared emissivity. this is difficult because absorptivity is the same thing as emissivity, but of course you can have different emissivities at different wavelengths; that's why things are different colors. but the vast majority of opaque solid materials have rather pastel colors, which is to say that their absorptivity (and thus emissivity) varies slowly with wavelength. this is undesirable for concentrating solar power, because it makes it hard to transfer the heat energy from the sunlight to the coolant rather than reradiating it as infrared. all the materials you named with albedos of under .1 are also great absorbers of infrared, which means they're also great emitters of infrared, so they wouldn't work very well for this application. (you also happened to pick three that won't withstand kilokelvin temperatures.) there are a number of 'spectrally selective coatings' already in existence with this unusual combination of emissivities, but they are all very expensive to produce. the longer lifetime is useful too, but not so useful they bothered to mention it in the abstract of their paper. the small particles mentioned are made of a silicon-germanium blend, although they claim you can use different semiconductors for this. they picked that blend because its bandgap is about a volt, so it absorbs photons of more than about an electron volt.