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heat transfer module in a building
Posted 2011/02/01 11:41 GMT-5 Heat Transfer & Phase Change 1 Reply
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Hi, I have to simulate a heat transfer in a simply and empty room. The heat source is Radiant floor eating system.
I drew my 3D geometry in a heat transfer module. Is it right?
I have difficulties with boundary and subdomain settings because the results are not realistic. Temperature grows only up to 1m (total is 3). I have inserted external and initial internal temperatures, coefficients of conductivity of walls. Other things? Have I consider convection and conduction?
At this moment, I have used only basic equations.
In my room there is only air (and I took values from library)
Have you got advice for me?
I drew my 3D geometry in a heat transfer module. Is it right?
I have difficulties with boundary and subdomain settings because the results are not realistic. Temperature grows only up to 1m (total is 3). I have inserted external and initial internal temperatures, coefficients of conductivity of walls. Other things? Have I consider convection and conduction?
At this moment, I have used only basic equations.
In my room there is only air (and I took values from library)
Have you got advice for me?
1 Reply Last Post 2011/02/01 13:16 GMT-5
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Posted:
1 decade ago
Hi
It seems that you are starting simple, which is always the best way, indeed you should check one physics by one physics, i.e. conduction of air, then convection, the latter is more tricky as it also gravity an temperature driven, there are a few examples I belive ready now in 4.1 too about the different effects (one by one). Finally you have radiation, probably negligible if you are talking about small temperature differences such as in a room used by living persons, except of you have an IR owen. Finally start to mix them.
then thermal effects are mostly slow, you should be able to estimate roughly the time constant for a square or rectangular room with a constant temperaturegradient from bottom to top, with a heat source at the bottom and cooling bove. then compare this time constant to the time of your transient analysis, just to be sure you wait long enough.
Difficult to say much more like that
--
Good luck
Ivar
It seems that you are starting simple, which is always the best way, indeed you should check one physics by one physics, i.e. conduction of air, then convection, the latter is more tricky as it also gravity an temperature driven, there are a few examples I belive ready now in 4.1 too about the different effects (one by one). Finally you have radiation, probably negligible if you are talking about small temperature differences such as in a room used by living persons, except of you have an IR owen. Finally start to mix them.
then thermal effects are mostly slow, you should be able to estimate roughly the time constant for a square or rectangular room with a constant temperaturegradient from bottom to top, with a heat source at the bottom and cooling bove. then compare this time constant to the time of your transient analysis, just to be sure you wait long enough.
Difficult to say much more like that
--
Good luck
Ivar