4 ms·

Just to clarify where the original numbers came from... The claim you are responding to: 1 liter of oil ~ 3 days of human energy output. Energy in a liter of

Just to clarify where the original numbers came from... The claim you are responding to: 1 liter of oil ~ 3 days of human energy output. Energy in a liter of oil: about 30 megajoules. Human base metabolic rate: below 100 watt. Let's say 100 watt. 1 watt = 1 joule/second. 30 MJ / 100 joules/second = 300000 seconds = about 3.5 days. So the original claim is correct in that sense edit: Now, this doesn't mean you can get the same benefit from a human laboring for 3 days non-stop as you could get from 1 liter of oil. This is just the energy required by the human body to stay alive. Any additional useful energy output would be on top of that, and humans can only sustain a small amount of additional power for long. That's why your references seem to disagree. Though you will really get that 100 watt from a human in the form of heat, which is why that number needs to be used when designing airco systems.

opwieurposiu 4y ago
I came to understand how much power is in oil through digging a big hole. I had to do some excavation for a mountain cabin I am building. After digging by hand for a while, we bought a 1-ton micro-excavator. One bucket from the excavator is equivalent to about 10 shovels. The avg time per scoop is similar, and it burns half a tank per day, so it works out such that it does the work of about 10 men on around 10 l/day of diesel. Thus I discovered that 1 liter of diesel can do about 1 man-days worth of dirt moving. This liter costs about $1 right now. A day laborer would cost around $160-$250. After digging hard ground by hand where you have to fight for each shovel full, seeing the tiny excavator rip 100lbs of earth like a toddler playing in the sandbox makes you appreciate what a gift oil is. Bigger excavators with better operators are more efficient. I would not be surprised if a big one approaches the 9man-days / liter theoretical limit you calculated above.
- nullc 4y ago
  If you want a really big multiple, use the liter of fuel to run a generator to run epyc cpus performing calculations and compare it to humans performing calculations.

opwieurposiu 4y ago

I came to understand how much power is in oil through digging a big hole. I had to do some excavation for a mountain cabin I am building. After digging by hand for a while, we bought a 1-ton micro-excavator. One bucket from the excavator is equivalent to about 10 shovels. The avg time per scoop is similar, and it burns half a tank per day, so it works out such that it does the work of about 10 men on around 10 l/day of diesel. Thus I discovered that 1 liter of diesel can do about 1 man-days worth of dirt moving. This liter costs about $1 right now. A day laborer would cost around $160-$250. After digging hard ground by hand where you have to fight for each shovel full, seeing the tiny excavator rip 100lbs of earth like a toddler playing in the sandbox makes you appreciate what a gift oil is. Bigger excavators with better operators are more efficient. I would not be surprised if a big one approaches the 9man-days / liter theoretical limit you calculated above.

nullc 4y ago
If you want a really big multiple, use the liter of fuel to run a generator to run epyc cpus performing calculations and compare it to humans performing calculations.