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-   -   Heat sinking to Aluminum block and dissipation (http://www.physicsforums.com/showthread.php?t=666110)

 fastline Jan22-13 04:38 PM

heat sinking to Aluminum block and dissipation

I am curious if someone can help be estimate heat sinking and dissipation in an Aluminum structure? What I am trying to do is is cool a hot liquid by just allowing it to heat the structure it is in since there is a reasonable amount of mass. Though the Aluminum structure is not designed specifically to dissipate, this becomes just a function of dT and surface area mostly.

power in is about 1000w max, structure is estimated at about 30 ci, and 352in2 of area. There is not active fan but that can be added really needed. Ambient temp not to exceed 110F and structure temp just should not "burn you". Vague, I know...

I am just trying to figure out the energy required to heat the structure, and it's ability to dissipate the heat.

 NascentOxygen Jan23-13 05:45 AM

Re: heat sinking to Aluminum block and dissipation

As a start, you'll need to look up tables of specific heat, to find the value for aluminum.

You can figure out how much heat energy is contained in the hot liquid by multiplying its temperature by its specific heat by its mass.

 fastline Jan23-13 08:53 AM

Re: heat sinking to Aluminum block and dissipation

Thanks for that. From the calcs I have run, this structure of Al will not hold much energy as heat.

However, more importantly, the dissipation. I determined the U value as 36 (btu/ft2 F)but I cannot remember if I would use the dT above ambient? IE Ambient is 100F structure is 110F, surface area is 2.5ft2 so heat loss is 900btu?

Determining forced air U values seems much more complex so I am just trying to roughly estimate that.

 CWatters Jan24-13 08:57 AM

Re: heat sinking to Aluminum block and dissipation

Power = UValue * Area * ΔT

where ΔT is the temperature gradient between the same two points used to calculate the UValue.

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