Hi I wanted to know if there are any effective device out there that can be used for heating a room for example by friction. I was thinking about something like a bicycle that uses friction to create heat. Maybe connected to a water reservoir to warm up the water. Does anything similar already exist?
Thanks for any help. If there is a better subreddit for this question please tell me too.
Posted Jan 25, 2022, 5:56 PM UTC
Even if you could convert 100% of a person's physical output to heat, you won't be doing very much heating. For example elite cyclists can only output 400watts for ~1hour. Your average person is probably 1/4 of that. FYI
Ok thank you, that already helps a lot! So I won't expect too much. But I still am curious for a friction device. If its 200watts as heat its already quite something.
200 W... thats nothing...? How would that be relevant?
1 calorie heats 1 gram of water one degree celcius. 1 calore is 4.18 Joules.
If you want to heat one liter of water from room temperature to boiling it is roughly 80 degrees celcius and 1000 grams. That means you need 80C*1000g*4.18 j/(g*C)=334400 joules.
Watts is j/s, so it will take an elite cyclist 334400/400=836s=~14minutes to heat one liter of water to close to boiling (Hitting the boiling point takes even more energy).
So in the hour described above an elite cyclist can heat ~4 liters of water to close to boiling. Try heating four liters of water and leave it in a cold room.
It will not do much.
You can't heat your house with muscle power.
Unless you keep livestock on the ground floor and live upstairs. (Was done for centuries).
Thanks, thats another god point. I was thinking about a single room in case of a blackout.
Any exercise bike will convert the users energy into heat. Where else would it go?
Thanks good point, i thought maybe sound/vibration