The muscular power (in Watts) of the man

[Grelinette]

Thank you for your answers that restore wrong ideas about human power ... and I am very disappointed to learn that my calves probably do not reach the 300 watts I was hoping

To return to the study of an elliptical trainer with wheels, or more exactly of a wheelchair that can accommodate a static elliptical trainer, despite a lower performance than the conventional bike, I think it's still a interesting concept because it distributes better the physical effort (high + low of the body), thus more balanced sporting.
Perhaps by modifying some mechanical details one can improve the efficiency, like to bring the point of support of the feet of the axis of the pedal. Interesting and to see ...

(At worst, adding a small electric motor, directly on the center inertial wheel of the elliptical bike, can bring a little extra motivation to the cyclist-walker )

[dede2002]

...
And did you know that the muscle yield was, also, of the order of 20%? That is, if 100W is provided muscularly, the body must be cooled by 500W ... this is called sweating ...

I also say because it is the efficiency of the engines ...

400W, not 500W ...

I just learned something, I thought that the muscles had a better performance than a gas engine, because the energy does not go through high temperatures.

So, by supplying 100W for 1 hour, we “heat” 400 Wh, which corresponds to the evaporation of 0.6 liters of water.

[Christophe]

Yes 400W sorry ...

Yes it must be that for evaporation, it seems coherent, attention there is also a part of IR radiation and "air cooling" (= breathing)

At rest (but awake) a human being "radiates" between 60 and 120W depending on his body size ... On average we retain 70W

As it is biology there are a lot of differences from one person to another ... We are not clones!

[PVresistif]

to estimate the power of a human, a method seems to me to be mountain biking
let's take the example of a climber from 75 Kg who makes 20 km / h on a slope at 5% (good climber from my point of view), so this good sportsman develops a power of:
speeds: 20 km / h = 5.55 m / s; climb to 5% either climb 0.05 x 5.55 = 0.275 m / s
d or power: 75 kg * 9.81 N / kg * .275 m / 1s = 202 Watt if yield 100%
if we admit without wind a good yield of 90% we are at 220 W; personally I think that you must already be a good athlete to do such power over several hours (without EPO anyway)
at 150 W during 2 hours (good exercise every day) that makes 0.30 kwh, enough to heat 10 liters of water from 10 to 35 ° C !!! long live the nuclear and oil, think 99% of the population

[sen-no-sen]

(...) to 150 W during 2 hours (good exercise every day) that makes 0.30 kwh, enough to heat 10 liters of water from 10 to 35 ° C !!! long live nuclear and oil, let's think 99% Population

You are not far from the truth, I would say between 3 and 5% of the population is able to hold such a pace for two hours!
As I mentioned earlier, it would take at least 40 million cyclists to replace a medium power nuclear power plant (4000MW)!

[Grelinette]

* That is 40 million cyclists to produce the power of an average nuclear power plant! Taking into account the load factor (fatigue, sleep meal, RTT, illness), it would be necessary to pedal the whole EU to replace four reactors!

I like comparisons reminiscent of orders of magnitude and size!

That said, if a large part of cyclists who go for road trips and indoor athletes who pedal in a vacuum "at a loss" (in terms of energy consumed without production for the community) came to pedal within a power station to turn a large wheel like old agricultural machines, we could certainly reduce the use of a nuclear power station a little!

Wheel_agricole_chevaux.jpg (66.57 Kio) Viewed 5819 times

We can also imagine that all static bikes put into service, in France or even in Europe, are equipped with a dynamo and a cable to connect to the nearest electrical outlet to inject the energy produced in the network! ...

[sen-no-sen]

We can also imagine that all static bikes put into service, in France or even in Europe, are equipped with a dynamo and a cable to connect to the nearest electrical outlet to inject the energy produced in the network! ...

Alas the load factor of a human being is lamentable ... all the more so in a contemporary society.
Indeed pedaling at a moderate pace, a cyclist of good physical condition will be able to produce around 100 Watts on a maximum of 3 hours.
And already 3 hours of bikes is not nothing, we can easily evacuate 95% of the French population to achieve such a sporting act!
Because between the sedentariness, the less than 12 years, the most 60 years, the disabled / wounded or sick there are not many people left to be able to pedal effectively.

But let's admit (!!!) that this is possible and that all the inhabitants of our beautiful country are athletes.
Well even in such a case, based on 3 hours of pedaling / 24 hours, it would 8 relay teams to be able to produce electricity permanently.
Given that 40 would be roughly X million 3 hours, 8 times more than 320 hours would be needed to ensure our energy-hungry thirst, which would give us nearly XNUMX million cyclists to replace us. an nuclear power station * ... by means of RTT, holidays, diseases, it would be necessary to count on not far from 450 millions of cyclists which is close to the population of the EU (511 millions of hab)

Conclusions: our energy consumption is not human!
Ex: a vacuum cleaner 1500 Watts is 15 cyclists, good in view of the time we spend aspiring is at least 8 high intensity cyclists!

* And there are 19 central France! We must therefore rely on all developing countries to ensure the operation of our nuclear power plant! And I'm not talking about replacing oil !!!
We can easily understand that the end of slavery was consecutive to the advent of the steam engine ... we can imagine what could possibly happen in case of lack of energy!

[PVresistif]

I would like to make a general remark about human power.
I remind you that almost the majority of "hard" jobs are filled by immigrant workers: see for example construction sites; so let's face it the "modern" man is more and more fen and therefore will always consume more oil and electricity.
Unless of course to advocate a return to the Middle Ages and its lot of nuggets like tuberculosis or plague.

[Did67]

Yes, that raises a few small questions ... The least of which is not that of ethics consisting in "burning", in the space of 3 or 4 generations, the stock of fossil energies ... Or that of endless growth of populations and their energy "needs" in a finite world (fossil fuels are available in finite quantities; the flow of solar energy reaching the earth is also limited; remains, for optimists, E = mc² and fission ...).

[dede2002]

... the "modern" man is more and more fenant and therefore will consume more and more oil and electricity.
Unless of course to advocate a return to the Middle Ages and its lot of nuggets like tuberculosis or plague.

Hello ,

Showers, drinking water supplies, soap, septic tanks, etc. existed well before the use of oil and electricity ...
And now in the 21st century, the "whatnot" you quote still exist, in "growing" cities, full of traffic jams where you can admire the latest 4x4 v8 models ...

Amha, the decrease will be inevitable, but "happy or not" it will depend on the adaptation time, among other things ...

ps: human power-energy question, "modern man" pays to spend it on fitness or in all kinds of sports, he is not that lazy