61–70 of 75 posts
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Yeah I wish there was more of this happening. BTW what happens when your water is fully hot and the sun is shining - does that panel detect there is no load so doesn't generate?
Presumably over-shooting to some degree in the middle of the day is good, since it provides a cheap form of energy storage. Obviously you'd want a cut off at some temp though, for safety concerns.
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A little on a tangent, but I've been thinking that it might be valuable to keep this offline knowledge infra around for backup, afaik properly stored book has lifespan that is still an order of magnitute longer than any digital storage.
It's a complicated question. On the one hand, barring natural disaster/fire/water leaks/etc., your library book will last a good long time--at least until the library gets rid of it because they need the space and no one's checked it out recently. On the other hand, even with inter-library loan, it's not super-accessible especially if it's in, say, a private university library. And if something does happen to it, it'…
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If it were really that valuable to human progress wouldn't another company or competitor to Clamonds’s Improved Thermopile become extremely profitable and valulable?
Maybe? But sometimes people don’t see “obvious wins” for a very long time. Look at Musk’s electric car story: there were a variety of electric cars that companies killed off (like the EV1) years earlier than the Tesla was released. It’s unclear if anyone who had the capital would have seriously entered the space if Tesla as a company did not exist. Maybe we’d be exactly as far along, but there’s a good chance the lac…
I put some used PV panels on my shed's roof and wired them up to the bottom element of my electric water heater. This cut my household electric use in half. Not connected to the grid so no expensive permits needed.
Sorta related if you don't want to hack that sort of thing yourself - Hybrid Hot Water Heater Saves 69 Percent On Energy Consumption: https://russell.ballestrini.net/hybrid-hot-water-heater-save...
I saw video of a guy installing one in his off grid house. He was mostly stoked with it because it only drew about 300W. But had a problem because it would do a check of the heating elements on startup which would crowbar his inverter. He fixed that by installing lower wattage elements.
It's a cute approach, but perovskite solar cells can probably do much better. Perovskite solar cells can be made at close to room temperature, use relatively common elements, and can be made fairly thin. The current efficiency record for perovskite solar cells is 25.6%[0]. [0] https://www.pv-magazine.com/2021/04/06/unist-epfl-claim-25-6...
The purpose of the article was to explore diy manufacturing of pv cells. I don't think this korean/swiss collaboration on high efficiency perovskite solar cells is within the reach of your backyard fabricator.
The intro motivates the topic by noting that silicon solar cells present a toxic environmental hazard. The author then, apparently with a straight face, posits that cells made from antimony or selenium, of all things, would be a good alternative. For more laughs, the author goes on to suggest that one of advantages of such antimony and selenium cells is that you could build them without a protective covering—-that the semiconductor would be fully exposed to any passerby.
It’s like those renfair cosplayers who reject electric motors for their zombie apocalypse scenarios, and plan to repopulate the earth using hydraulic machinery with “easy to procure from any junkyard” flexible hydraulic hoses.
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There is no thermostat for the PV panels. The summer power output of the panels comes into equilibrium with the heat loss of the tank at 80-85C. I did add a 93C thermal fuse to augment the safety of the PTV value. I have a mixing valve on the output of the water heater to mix with cold down to about 50C. This lets you get around 2x the nameplate capacity of hot water out of the tank so there is enough to bridge a clo…
Sounds neat! I'd like to read a writeup on your build if one exists.
I put some used PV panels on my shed's roof and wired them up to the bottom element of my electric water heater. This cut my household electric use in half. Not connected to the grid so no expensive permits needed.
I was thinking to do this but I had some concern about electrolysis, as electric water tanks are designed for AC, not DC. But I never learned if this was a real concern or not.
It's a cute approach, but perovskite solar cells can probably do much better. Perovskite solar cells can be made at close to room temperature, use relatively common elements, and can be made fairly thin. The current efficiency record for perovskite solar cells is 25.6%[0]. [0] https://www.pv-magazine.com/2021/04/06/unist-epfl-claim-25-6...
https://solar.lowtechmagazine.com/power.html The website is powered entirely by solar and is currently consuming 2.44 watts. With that massive power consumption they are probably mining bitcoin too.
2.4w? My led bulbs use 4w - I doubt you could mine much bitcoin with that low a power?