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A lightning bolt would be worth only about a nickel (2015)

engineering.mit.edu

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Re: A lightning bolt would be worth only about a nickel (2015)

#111

Post by trelane »

andrewla wrote: post #105
johnwalkr wrote: post #100

Earlier quoted context omitted.

Hours are usually more convenient to work with than seconds when talking about energy use (even in this case when you are comparing to other things. Plus it's the de facto standard unit more people are familiar with. Power bills, electric car capacity, and energy efficiency are all normally described in kWh.

This is true, but it is exactly what I am railing against. It's just tradition -- energy in houses is kWh, so let's use that for other things too. Instead, let's just use Joules everywhere. Easy peasy. Why are my batteries rated in Ah -- it's not like they're providing a variable voltage source; just give me Joules. I know this is a ridiculous hill to die on, but I will die on it!

> it's not like they're providing a variable voltage source; just give me Joules.

They are, technically. https://www.batterypowertips.com/how-to-read-battery-dischar...

Probably doesn't matter though. :)

Re: A lightning bolt would be worth only about a nickel (2015)

#112

Post by trelane »

AnotherGoodName wrote: post #91
csdvrx wrote: post #77

Earlier quoted context omitted.

> The typical house has 240 volt service in the US (two legs of 120v). Can we wire that in a way to would allow installing .uk or .de Schuko Type-F plugs? It would be funny (and weird!) to have 220V available on a european socket for say a desktop equipped with a 1.5kW PSU for the upcoming Nvidia 4090 :)

You probably have a few such sockets around. Not the UK or eu form factor but 240v at least. Look at how your dryer or AC plugs into the wall and you'll see something different to the usual plugs.

These are all standardized and have meaning. https://www.electronicshub.org/electrical-outlet-types/

There are definitely 240V for higher power usage (because they will need half the current for the same power with double voltage, and current (current density, technically) is what causes joule heating and melts wires/ starts fires.

The sockets will be incompatible with Euro or UK sockets. You could change the socket to a euro socket, bit the frequencies will be wrong for euro or uk devices (60Hz in the us, 50 in europe & UK.) This may or may not be important depending on what you're hooking up to it (understand that impedance and other electrical things are a function of frequency). The safest option would be to get something to convert the power (there seen to be products to do that) and put _that_ behind the Euro or UK outlets.

Re: A lightning bolt would be worth only about a nickel (2015)

#113

Post by trelane »

anon_123g987 wrote: post #29
WJW wrote: post #15

Earlier quoted context omitted.

500W is an extremely high number as well. Pro cyclists can reach up to 400 Watt in short bursts, untrained people typically can't maintain more than 100-150W for long. We really use quite a lot of energy when measured in how many humans it would take to provide that much energy "manually".

While it's true that the power of a human is not much (certainly not enough to power a house), but we have a lot of energy . Most of us carries at least 1 kg (~2 lbs) fat, which contains ~37 MJ of energy. For comparison, a stick of dynamite has ~1 MJ of energy. https://en.wikipedia.org/wiki/Fat#Biological_importance https://en.wikipedia.org/wiki/Dynamite#Form

Why stop there? The matter itself is energy, so combine a human with an anti-human....

Re: A lightning bolt would be worth only about a nickel (2015)

#114

Post by trelane »

martin_a wrote: post #58
praptak wrote: post #34

Earlier quoted context omitted.

If you really mean gigawatts (unit of power), then you have to multiply it by the time period when this peak power is reached to get the energy output. Lightning bolts have very short durations, tens of microseconds. Let's be generous and give it 1 millisecond. 1 millisecond times 1 gigawatt is 1 million joules, which is the estimate that the article gives.

> Lightning bolts have very short durations That is why you have to hit the cable at a very specific time. It's not that hard.

martin_a, or marty_m? Hmmmm....

Re: A lightning bolt would be worth only about a nickel (2015)

#115

Post by trelane »

whoomp12342 wrote: post #82

if so little power, how does it fry a tree?

It's not so little power, it's so little _energy_ (power over some period of time). It's a crap-tonne of power, just over a _very_ short period of time.

And yes, power is what fries the tree: https://en.wikipedia.org/wiki/Joule_heating

Re: A lightning bolt would be worth only about a nickel (2015)

#116

Post by ThePowerOfFuet »

jeramey wrote: post #90
csdvrx wrote: post #77

Earlier quoted context omitted.

> The typical house has 240 volt service in the US (two legs of 120v). Can we wire that in a way to would allow installing .uk or .de Schuko Type-F plugs? It would be funny (and weird!) to have 220V available on a european socket for say a desktop equipped with a 1.5kW PSU for the upcoming Nvidia 4090 :)

You’d probably need to do this with an AC-DC-AC transformer to also get the circuit converted to the 50hz cycle European power systems use, but it’d just be a waste because of the power losses involved (not to mention the expense of the transformers). Also, a typical 15A circuit in a home will handle ~1.8kw of sustained load, so as long as you can dedicate a circuit to such a rig, you’d be fine.

Computer power supplies don't give a shit about frequency. They will happily accept 120/50 or 240/60.

Re: A lightning bolt would be worth only about a nickel (2015)

#117

Post by yourapostasy »

themitigating wrote: post #63
andrewla wrote: post #60

> The average lightning strike contains about 1 million joules, enough energy to fry the founding father in his boots. “The typical house in the U.S. has 100 amp service or about 28 horsepower,” says Kirtley. Boy do I get frustrated when using compatible units without conversion. The unit that I hate more than any other unit in the universe is the KwH, which is dimensionally equivalent to the Joule, so I don't unders…

The typical house has 240 volt service in the US (two legs of 120v). I would also say a decent number of homes have 200amp as well

A surprising (but still tiny) number of US houses also can have three-phase brought out to them by the electric utility. Some utilities will charge you upfront for stringing it up and lighting up the wires, but another surprising number of utilities will just amortize it from the monthly cost of service.

It's still rare enough you have to ask ahead of time if you want it for any building you get into, but in some major metro areas it has gone from "you have got to be joking" to "sure, let me check on that".

Now if only I can find a reliable, durable three-phase solar inverter...

Re: A lightning bolt would be worth only about a nickel (2015)

#118

Post by [deleted] »

andrewla wrote: post #60

> The average lightning strike contains about 1 million joules, enough energy to fry the founding father in his boots. “The typical house in the U.S. has 100 amp service or about 28 horsepower,” says Kirtley. Boy do I get frustrated when using compatible units without conversion. The unit that I hate more than any other unit in the universe is the KwH, which is dimensionally equivalent to the Joule, so I don't unders…

[deleted]

Re: A lightning bolt would be worth only about a nickel (2015)

#119

Post by BizarroLand »

iasay wrote: post #10
omnicognate wrote: post #7

Earlier quoted context omitted.

Olympic track cycling medallist powers toasting a slice of bread, which takes everything he's got and leaves him exhausted: https://youtu.be/S4O5voOCqAQ

That reminds me of a thread I saw on an Internet forum a few years ago about some guy suggesting powering his fridge with a bicycle during a power outage. Turns out this is an extremely complicated problem which is probably best solved by ignoring it.

I bet you would get better results directly spinning the compressor via a flywheel rather than trying to generate the electricity to run the refrigerator.

Re: A lightning bolt would be worth only about a nickel (2015)

#120

Post by BizarroLand »

trelane wrote: post #113
anon_123g987 wrote: post #29

Earlier quoted context omitted.

While it's true that the power of a human is not much (certainly not enough to power a house), but we have a lot of energy . Most of us carries at least 1 kg (~2 lbs) fat, which contains ~37 MJ of energy. For comparison, a stick of dynamite has ~1 MJ of energy. https://en.wikipedia.org/wiki/Fat#Biological_importance https://en.wikipedia.org/wiki/Dynamite#Form

Why stop there? The matter itself is energy, so combine a human with an anti-human....

Sweet oblivion looks just like me
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