h a l f b a k e r yRIFHMAO
(Rolling in flour, halfbaking my ass off)
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It’s time for us to take another design idea from our ancient ancestors and bring it into the present – namely rubbing two things together to get heat.
The heat generator that does not require electricity, a flame or flammable fuel.
This gadget would be roughly the size and shape of a single
electric hot plate. It would be larger and heavier than a electric hot plate because it would be housing a high energy spring – sorta like the old Victrola record player spring only of new alloy and much higher energy - gear work, a flywheel and two friction surfaces, all of these units would be stacked inside sorta like pancakes. I envision it having a suitcase type handle on one edge so one can easily grab it and go.
One would first wind up the spring, then crank the flywheel up to speed. Once flywheel is at speed, a lever would be thrown to link the potential energy in the spring to the spinning flywheel through gearing. The two friction surfaces would create enough BTU's to cook pans of food, boil water and/or heat a room.
The friction heat generator could be useful in situations where standard space heaters can't or won’t work.
I'm sure there must be an energy/friction/heat formula that could give us a good idea as to how much mechanical and/or potential (spring) energy would be required for the needed amount of thermal units to cook or heat a room. Can one human put enough energy into a spring and flywheel to frictionally (or any other way for that matter) generate enough heat to boil water or heat a room?
Obviously, research needs to be done in the area of friction plates, the loss of energy in transmission from potential to torsional to thermal, etc.
The windmill powered friction oven is cool. What I have in mind is absolutely portable.
Wikipedia: Energy density Extended Reference Table
https://en.wikipedi...ded_Reference_Table
Mentioned in my anno [notexactly, Apr 28 2019]
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It would be wonderful if this could be made affordably enough where people in natural disasters could have it handy. |
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The name field in the idea - the one
that now says "Other,Energy,Thermal" -
is for the name of the idea. For
example, "friction hot plate" or
something like that. |
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You can fix that by changing the title in
the text field you see when you're
logged in and looking at your own idea,
then clicking on "OK". |
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This thing would be very weird to move about when the flywheel was turning because of the resistance to changes in the axis of spin. When I do my supervigorous workout the room does heat up, no doubt because of my efforts. I am wondering if friction is the best way to generate this heat. I can almost smell a burning brake pad smell emanating from your strange, warm, vibrating suitcase. |
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"...cook pans of food, boil water..."
That's one hell of a spring. |
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What is the rate at which a person can put out energy? I remember reading somewhere that it was around 35 Watts. |
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Most hotplates require at least 1000 watts. |
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[needlan] therefore to acheive a cooking time of say 10 minutes at 1000W the human would have to input (1000/35)*10 = 286 mins or approx 4.8 hours of spring-winding. I doubt that the nutritional value of the food would compensate for that amount of effort. |
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Is this not gonna wear itself out really fast? |
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(Rods tiger)A wheel is easy, but our ancient ancestors
didn´t have it. That way of thinking will lead you to
inaction, because our ancient ancestors should have done everything before.
(gorath) You need to exercise a lot to produce enough heat. Your standard person can produce some 500 watts, using all available muscles. A radiating heater of 1000 watts is usually employed to heat a single room. (bungston) Of course a supervigorous workout heats a room without any mechanical contraption
needed. Human body is a machine, after all.
And how are your bones doing?.
Anyway since the idea of a warm, noisy, vibrating, smelling and sproooing suitcase lifts my hearth,
bun for you. |
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This sort of thing has been used for friction welding pipes. One section is spun up, then pressed against a stationary section. Heat is generated, and voila, the pipes are joined. |
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Energy is always conserved, but this process destroys great gobs of exergy. If you want work in and heat out, better to use a more-reversible process - in this case, a heat pump. |
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My thanks for the responses on this gadget.
Some of you seem to have missed the concept that this gadget is using friction heat, not generated electricity.
Ancient man didn't try this because he didn't have the metalurgy sufficient for the spring. A gadget like this in the 1800's would have been massive.
The friction pads would be of a special design specifically suited to temperatures around 400 degrees. Designed with heat creation in mind.
We're talking about something that would get up to 400 degrees F almost instantly and maintain that temperature for 10-15 minutes per winding. It doesn't sound that far fetched to me.
I encourage any/eveyone to try making one. We need such a device. |
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The Tour de France champion can produce about 300 watts of power, or about 1000 BTU/hr of heat. The burner on your gas stove can produce 8000 to 10,000 BTU/hr. |
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So the average person is going to be able to produce about as much useful heat as a candle. |
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I like how people admit they don't understand the physics of their idea, yet are willing to come out with numbers such as "up to 400 degrees F almost instantly and maintain that temperature for 10-15 minutes per winding" without actually knowing what it is they are talking about. No wait, I DON'T like it at all. |
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The above isn't even an equivocal statement of capacity. The output temperature will, of course depend on what it is the device is heating, for a given time period and capacity. |
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Simple physics mate: energy in equals energy out. If you can efficiently convert it, energy is the same, be it thermal, kinetic, potential, radiative, etc. So for a given thermal output, you'll need to "charge up" the device with the same or more potential energy. So to warm up a single cup of water from 20 to 80 degrees celcius, you'll need to input some 45 kJ of energy. That's the same energy as to lift a 1 tonne car 4.5 metres into the air. Or accelerate that car to say 35km/hr (ish). These are horribly rough numbers, but you get the idea ( I hope). People simply don't realise how much energy goes into heating things. |
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I can't bun this I'm afraid. |
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Energy density of 360–500 J/g according to Wikipedia [link]. For the example immediately above, heating 1 cup of water from 20 to 80 °C by adding 45 kJ, you'll need a flywheel of 90 to 125 g, which isn't too bad. |
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// spring (not the idea, but suggested in the annotations) // |
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Energy density of 300 J/kg (note different units). This is an order of magnitude worse. You'll need a 150 kg spring to do the same job. |
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// The name field in the idea - the one that now says "Other,Energy,Thermal" - is for the name of the idea. For example, "friction hot plate" or something like that. // |
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But it could be a good category to have. (Probably not.) I put the idea I just posted in this here category (science: energy: thermal) because, while it's more of an engineering idea than a science idea, it's general enough that any of the other thermal categories would be too narrow. |
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// I can almost smell a burning brake pad smell emanating from your strange, warm, vibrating suitcase. // |
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That image alone makes this worth a bun despite (because of?) the impracticality. |
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// What is the rate at which a person can put out energy? I remember reading somewhere that it was around 35 Watts. // |
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The human body idles at around 100 W. I think that's what's called the basal metabolic rate. A good athlete can do about 400 W mechanical on a stationary bicycle, I think. Muscles are, IIRC, about 25% efficient, so they'll output about 1200 W thermal, which you might want to try capturing, but it'll be low-grade heat, so not very useful. |
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// Is this not gonna wear itself out really fast? // |
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Car brakes seem to last long enough. |
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// 3.41 BTU/watt. The Tour de France champion can produce about 300 watts of power, or about 1000 BTU/hr of heat. The burner on your gas stove can produce 8000 to 10,000 BTU/hr. // |
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The dimensions don't make sense there. Is BTU a unit of energy or of power? I have always been confused about that. |
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// People simply don't realise how much energy goes into heating things. // |
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