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Re:Major breakthrough on nuclear fusion energy by advisedwang on Wednesday February 09, 2022 @01:12PM (#30275982)
Water has a specific heat capacity of 4184J/kg/C. Lets say to get to the boil you need to go from 20C to 100C and that a kettle holds 1.75L.

59MJ / (80C * 4184J/kg/C) = 176kg ~= 176L ~= 100 kettles.

Water has a latent heat of vaporization of 2260 kJ/kg. So to boil it dry:

59MJ / (80C * 4184J/kg/C + 2260 kJ/kg) = 22kg ~= 22L ~= 12 kettles.

I have no idea what the journalist calculated.

Re:Major breakthrough on nuclear fusion energy by zucker42 on Wednesday February 09, 2022 @02:39PM (#30277368)
I suppose it's possible that the "standard" kettle size is ~3L. They don't seem too uncommon on Amazon.
Re:Major breakthrough on nuclear fusion energy by ketozhang on Wednesday February 09, 2022 @06:35PM (#30280350)
I think the journalist is calculating load capacity. A 1500A @120V kettle requires 0.18 MW. Rounding up, 60 kettles requires 12 MW. It's not how much water you can boil, it's how many kettles you can run at the same time.
Re:Major breakthrough on nuclear fusion energy by advisedwang on Wednesday February 09, 2022 @08:39PM (#30281430)
59MJ over 5 seconds would be 11GW, so if it was load, that would be 6000 2kw kettles!

Although obviously those kettles wouldn't achieve much in those 5 seconds!

Re:Major breakthrough on nuclear fusion energy by ketozhang on Wednesday February 09, 2022 @09:57PM (#30281921)
I'm way off. I meant 15A. Now I've no clue what the journalist is calculating.
Re:Major breakthrough on nuclear fusion energy by advisedwang on Thursday February 10, 2022 @02:02PM (#30290887)
They should start selling 1500A kettles though. Bring a pot of water to the boil instantly.
Re:Major breakthrough on nuclear fusion energy by ComputerGuru on Wednesday February 09, 2022 @07:47PM (#30281008)
But they’re UK, so it wouldn’t be 110V. Nice try, though!
Re:Major breakthrough on nuclear fusion energy by qquark on Wednesday February 09, 2022 @08:36PM (#30281395)
A 180kW kettle ?! Great Scott !
Re:Major breakthrough on nuclear fusion energy by moron4hire on Wednesday February 09, 2022 @01:38PM (#30276480)
Did you factor in the inefficiencies of the power distribution grid and the heating element of the kettle? I'd say the journalists are just repeating what they've been told by the scientists, and the scientists factored inefficiency in on a calculation similar to your first.
Re:Major breakthrough on nuclear fusion energy by 34679 on Wednesday February 09, 2022 @02:21PM (#30277139)
There may exist inefficiencies in the transfer of heat from the element to the water, but there is no such thing as an inefficient heating element. All of the power it uses will be converted to heat. Take a light bulb for example. When used to light a space, the inefficient part would be the energy that is lost to heat. The rest is converted to light, but as soon as that light hits an object, it's converted to heat. So even a light bulb is a perfectly efficient heating element.

With this in mind, you aren't saving any money on your electric bill by turning off lights when your furnace is on.

Re:Major breakthrough on nuclear fusion energy by Retric on Wednesday February 09, 2022 @02:45PM (#30277448)
The internal heating element isn’t strictly speaking 100% efficient on AC as it’s producing a changing electric field etc. It’s just generally ignorable in practical terms.
Re:Major breakthrough on nuclear fusion energy by whimsicalism on Wednesday February 09, 2022 @02:37PM (#30277344)
Presumably heat dispersing into the air rather than into the water would be an example of an inefficient heating element.
Re:Major breakthrough on nuclear fusion energy by VBprogrammer on Wednesday February 09, 2022 @02:34PM (#30277317)
The kettle is also losing a lot of heat to the air in the room.
Re:Major breakthrough on nuclear fusion energy by advisedwang on Wednesday February 09, 2022 @01:40PM (#30276517)
Nope, I didn't factor in anything like that. Also kettle's don't actually heat every ml to 100C so there's some fudge in the other direction. I mostly was just getting nerdsniped.
Re:Major breakthrough on nuclear fusion energy by fartcannon on Wednesday February 09, 2022 @02:10PM (#30276998)
Thermodynamics is very good at sniping nerds. The first law is basically a universe builder. The second law is maybe a universe destroyer? :)