You need to lift a 10KG weight about 2 kilometres to get a teaspoon of kerosene's energy, so it's not a great replacement on that front, and having 10KG weights dangling around at variable points between ceiling and floor sounds if anything even more of a liability than a lamp with a naked flame, which does at least stay where its put. Sorry to be negative but it's difficult to conceive of a realistic scenario where decent battery plus solar doesn't knock this into a cocked hat.
> You need to lift a 10KG weight about 2 kilometres to get a teaspoon of kerosene's energy, so it's not a great replacement on that front
This says nothing of light output. If you want light, and most of kerosene's output is heat, your energy calculation is not helpful.
> and having 10KG weights dangling around at variable points between ceiling and floor sounds if anything even more of a liability than a lamp with a naked flame
This seems like an incredibly contrived "problem". What's the liability? Somebody may bump into a somewhat heavy object that is moving downwards at a barely perceptible clip? Somebody may tweak their back lifting the weight? That seems lower risk than my housing burning down with me in it.
Okay, okay, you are right of course, the light efficiency is very different, although the heat may not be an altogether unwanted by-product in many cases. There are also more efficient ways of getting light from petroleum than sticking a wick in it. But if you do want the benefits of LEDs, there are better ways of getting the energy than lifting sacks to the ceiling. It's still 180 meters for a pair of AA rechargeables.
I genuinely don't think the hazards are at all contrived, and range from the grave if unlikely to the mild but virtually certain. You are surely going to knock your head on this massive hovering, albeit reasonably well lit, object on a regular basis, and it might not be as soft and rounded as the illustration. On the floor, in dark mode, you'll be tripping over it, which doesn't always end comically. Reasonable precautions not withstanding it's not impossible that it could crush or smother something beneath it even at its snail's pace, but more likely it could come down hard through overloading, wear or misuse. It's really not something I'd want in a family home.
It is a nice idea and obviously of the very best intentions but I'm afraid it's simply misguided and efforts would be far better directed towards battery plus solar. Sorry.
I would say the hazards of this device sure beat the hazards of kerosene lamps (fire, mostly). [1] lists a series of accidents with kerosene lamps in a three year period in a small town. I think a horse kicking over a kerosene lantern started one of the big Chicago fires. There's even a possibility that a kerosene lamp caused a deadly fire in modern USA [2]. And I'm guessing that fire would be a serious problem in small, dense areas such as the slums (not intended pejoratively) in the third world nations that are likely to have the most use for this.
Solar plus battery might be better than this, but this looks like a whole lot better than a kerosene lamp.
The amount of energy is not directly comparable if the efficiency of its use is very different. A kerosene lamp is multiple orders of magnitude less efficient than decent LEDs, so while you might have to lift 2KM to get the same energy, you'd have to lift much, much less to get the same amount of lumen-hours.
A kerosene lamp has an efficiency of 0.1-1 lumens/watt, while a white LED has anything around 80-100 lumens/watt.
> weights dangling around at variable points between ceiling and floor sounds if anything even more of a liability than a lamp with a naked flame, which does at least stay where its put.
Fire stays where it's put? No. The problems with flames involve toxic gasses poisoning people and the occasional building on fire. That's really not consistent with the idea that "flame stays where its put"
Can't you suspend a bed wired to one of these to the ceiling? At night before you go to sleep climb the stairs and get into the potential energy elevated bed. Then in the morning, after the bed descends, you have enough reading light energy stored for the next night.
Regarding the energy of lifting a 10KG weight 2 KM high is not a 1:1 comparison with the tech here. It's using an LED which much more efficient than a Kerosene powered flame, since most of the energy in the flame is spent in infrared.
