4 ms·
> I'm sure that 20W the whole panel generates every few days for an hour or two will offset the cost You can—and it's usually safe to, in the translation from
by JadeNB 3y ago
> I'm sure that 20W the whole panel generates every few days for an hour or two will offset the cost
You can—and it's usually safe to, in the translation from actual researchers to PR departments—ceertainly doubt the viability of this claim, but the whole article is devoted to at least explicitly claiming that they're aware of the obvious problems, and can overcome them:
> … the efforts to collect energy from falling raindrops have faced a technical hurdle that has made the concept inefficient and impractical. … as one might expect, the amount of power per raindrop is incredibly small. …
> Now, a team of researchers says they have found a design and configuration that greatly reduces the coupling capacitance issue and one they claim could make energy-harvesting rain panels a practical reality.
One key seems to be that, although you're obviously meant to think of rooftop panels, it seems more to be about large-scale installations:
> “The peak power output of the bridge array generators is nearly 5 times higher than that of the conventional large-area raindrop energy with the same size, reaching 200 watts per square meter,” Li explained, “which fully shows its advantages in large-area raindrop energy harvesting.”
(I do notice on re-reading that it says "… may lead to the development of rooftop, power-generating rain panels", but (1) one can freely claim that anything may lead to something else, and (2) one can claim that anything may lead to anything else, so I prefer to go by quotes from the researchers themselves.)
- Retric 3y agoRaindrops fall at 10m/s or less. The absolutely rainiest place on earth revives 12 meters of rain per year. A 1x1x12 meter block of water weighs 12,000kg going 10m/s it has KE = 1/2 M * V^2 = 6 * 10 ^ 5j. 200 watts per meter is 200j/second… So your hypothetical 200 watts per square meter at 100% efficiency assuming spherical cow types of ideal conditions could possibly provide that power for 50 minutes per year under ideal circumstances or average 0.02w/m2 over a year. And average roughly 0.002w/m2 in extremely rainy though not world record setting locations. Now, you ignore the kinetic energy in rainfall and try and harvest the potential energy when it lands at a high altitude, allowing a large collection area and large differences in altitude. But we call those things dams.
- ilyt 3y agoRight, so why they are bothering ? The technical limit is known and it is making it barely acceptable if it was free (because you still need to have dedicated inverter channel for the power conversion as characteristics are much different than what solar panels generate). And if it wasn't free or near-free it's competing with putting one more panel or adding one more battery to the system. Or... just big, cheap funnel that is feeding water generator Sure you lose some of the velocity but it is so much simpler system Like, generating energy from tiny movements have its niches (like sensors powered by piezoelectrics from vibrations of machine they monitor), but using it for raindrops just feels like a waste of time, most areas don't even get enough rain for that to matter. Now if they figured out to do it to airflow with few moving parts, that would be more interesting.
- feoren 3y agoPeak output doesn't matter: you cannot get more energy out of rain than rain has. You could build a turbine that can theoretically generate 10MW at its max speed, but if it's being pushed by ants, who cares what its max theoretical output is? Look at the top comment of this thread. Even at 100% efficiency, there is nowhere near 200 W/m^2 of energy to possibly extract from rain. Four orders of magnitude less.