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Heat transfer for a oven coil.

by zzinfinity
Tags: heat transfer, oven, thermodynamics
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zzinfinity
#1
Nov30-12, 06:46 PM
P: 47
I'm curious how heat transfers between the heating element in my electric oven and the air in the oven. Say when I first turn on my oven the air is at room temperature (say 70F) and the surface temperature of the heating coil is at say 500F. After some time passes, the air in the oven rises to 350F. Does the surface of the heating coil remain at 500F or does it change with the ambient conditions?

And a related question. Is the maximum temperature an oven can reach determined by the heating coil, or the insulation of the exterior. Suppose I was able to insulate my oven so well that no heat could escape to the outside air (hypothetically) . Would the heating coil continue to raise the air temperature until it melted? Or would something else limit the heating.

Any thoughts would be appreciated! Thanks!
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russ_watters
#2
Nov30-12, 07:15 PM
Mentor
P: 22,313
Quote Quote by zzinfinity View Post
I'm curious how heat transfers between the heating element in my electric oven and the air in the oven.
Conduction, convection and radiation -- though the radiation is mostly between the coil and the sides of the oven (and whatever you are cooking), which then turns to convection and conduction as well.
Say when I first turn on my oven the air is at room temperature (say 70F) and the surface temperature of the heating coil is at say 500F. After some time passes, the air in the oven rises to 350F. Does the surface of the heating coil remain at 500F or does it change with the ambient conditions?
The heating coil will heat up as the air in the oven and the surfaces of the oven heat up.
And a related question. Is the maximum temperature an oven can reach determined by the heating coil, or the insulation of the exterior. Suppose I was able to insulate my oven so well that no heat could escape to the outside air (hypothetically) . Would the heating coil continue to raise the air temperature until it melted? Or would something else limit the heating.
Its both/either. You can raise the temperature capability by adding insulation or adding more heat.
zzinfinity
#3
Dec1-12, 01:26 AM
P: 47
Thanks for your response! Do you have an idea by how much the coil surface temperature rises? If the air temperature increases by 300 F does the surface temperature of the coil also increase by 300 F or is it a different proportion?

When you say you can raise the temperature by adding more heat, what exactly do you mean by that? Bigger coil, bigger current? And if I insulate my over perfectly such that no heat escapes, is the temperature the coil can bring the air to bounded?

Thanks!


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