Thank goodness for that!
"Sadly, our vision of Terminator-style urine-powered killbots menacing humanity or hanging around toilets begging for a drink never came to fruition."
Boffins in Bristol have the perfect solution to the two most common late-night problems: finding somewhere to urinate and keeping your phone charged. Liquid lab techs at the Bristol Robotics Laboratory have figured out a way to take power from your pee, using an array of cylinders containing electro-active micro-organisms to …
Take a dumb phone to a festival - battery will last ages, SMS and calls sufficient for finding mates, no tears if you lose it.
That said, last festival I went to had an oversubscribed cell, so SMS messages took 5 minutes to send.
I lost my smartphone several times, but always found it the next day in a dance tent (honest people), and being on a lighting crew, I had access to 13 A sockets around the site. Having two 5000 mAH power banks (one left on charge, one in use) works well.
Top tip: a 12 V solar panel of the type used to trickle-charge car batteries, and a couple of computer cooling fans - when the sun comes up the fans kick in and delay your tent becoming an oven for an hour or so, giving you more time to sleep off the hangover.
That's not the way you're supposed to enjoy a festival these days.
If you can't live stream the concert to your followers, blocking your neighbours' view for 2 hours by holding your phone above your head, post useless comments on antisocial networks instead of, I don't know, JUST WATCH THE F***ING SHOW!!, you might as well stay at home.
... this is nonsense. Max solids in healthy urine 40g per litre, maybe 60g per day. Max calorific value of those solids is 2000kcal per kg. If you can get them all out ofsolution for free (you can't) and you can oxidise them 100 percent efficiently (ditto) you are looking at am absolute max of 5W per person.
You'd probably be better off with a nice clean baseball hat with a solar panel in the peak than messing about with stinky sticky solids and unreliable bioactive films.
Watts is indeed power but what matters for charging batteries is energy, and your number is picked out of empty air anyway.
40g at about 8MJ/kg is about 300kJ. A phone battery holds around 36kJ. It's feasible, even at an efficiency of conversion of around 12-15%.
Intuitively, the quantity of urea in a day's production of urine is much larger than the amount of lithium in a phone battery.
Voyna, I took it for granted that we all know the relationship between energy and power.
You are right, of course, that with my max. 5W and your entirely reasonable 10% efficiency, you could power a moderately busy smartphone all day. But I still think that unless you are processing vast quantities of urine a day, you are going to struggle to get enough energy out to do more than manage the material handling and bioculture maintenaince.
There's better, and less sticky and smelly, ways of getting a few kJ of energy when you are off grid.
BTW, according to this urine solids are about 1700 kcal/kg so the 2000 max I "picked from empty air" doesn't look too shabby.
I presume the idea is to power the toilet, rather than phones. I know that one of the Gates Foundation's things is to try and get better toilets, as an easy way to improve drinking water supplies, by keeping the human waste out of them.
So I'm guessing they're looking at enough power to operate pumps or filters. Though I'd have thought solar (with batteries for night time obviously) was just going to be cheaper and easier.
Of all the bad puns on display from El Reg and the commentards, I'd like to give particular praise to whiz kids. I think that's my number one. After that, I'm sure the writer was flushed with success.
It's no good stating a wattage without the period. If you had said "continuous" then I wouldn't have quibbled. But in any case 5W continuous is 430kJ/day, which is more than average pee power at 100% efficiency.
Even if only 10% efficiency can be achieved from a fiddly bacterial process, it might have applications in remote Third World villages where the sun doesn't shine and the wind doesn't blow - a communal latrine for 100 people at 10% could provide around 40W continuous power, and that's a useful amount.
Exactly. I had this same problem recently when describing how much power the brain consumes. 20 watt hours is the average. Somebody said "Did you really mean that?" and got four upvotes too. If we could do a full hour of thinking in just one nanosecond it would be 72,000,000,000,000 watts per hour. That is very similar to fusion power, period.
oh, microbes are pretty good at evolving ... and once you have a mutation with a small reproductive advantage (usually because they've found a way to reduce production of the product (including electrical energy) you're interested in, a tiny advantage of <1% will result in the less productive strain overwhelming your bioreactor within days (at the outside) and you'll have to flush the lot, resterilise, and start again.
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