Stack effect on small scale

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In summary: Maybe you could talk a little more about how you're thinking about balancing the airflow and pressure?I was hoping I could avoid having to increase the size or add cooling ribs to the outside. I might get some added cooling by hollowing out the vertical parts of the frame, but I don't know how much of an effect an airflow 4.0E-6 m3/s gives me.If you're wanting to use passive cooling in an electronics enclosure, this is what you'll have to use.
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mhjerde
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Does it make sense to try to use the chimney effect/stack effect to increase heat dissipation for a smallish electronic enclosure?

I'm thinking that if I hollow out the two vertical ends of the enclosure, I can get a 100mm high 5x5mm "chimney" on each side. On paper I get about 0.09 Pa pressure difference and a airflow of about 4.0E-6 m3/s. That does not look like much, but I have very little experience with this topic.
Does it matter if the chimney is straight or conical? Is there an ideal shape?
The enclosure is made from 6061 aluminium, dyed and anodized.

I'm hoping someone could offer an opinion on this. Is it worth pursuing?
 
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So you're basically trying to take advantage of natural convection for cooling? Are you familiar with natural convection calcuations?
 
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I can't say I'm too familiar with natural convection calculations. I managed a rough estimate of the surface area needed to dissipate heat for the prototype in an upright position, without really understanding all the intricacies of natural convection. It also turned out to be a bit on the low side for real world use.

I was hoping I could avoid having to increase the size or add cooling ribs to the outside. I might get some added cooling by hollowing out the vertical parts of the frame, but I don't know how much of an effect an airflow 4.0E-6 m3/s gives me.
 
  • #4
mhjerde said:
I can't say I'm too familiar with natural convection calculations.

If you're wanting to use passive cooling in an electronics enclosure, this is what you'll have to use.

mhjerde said:
I managed a rough estimate of the surface area needed to dissipate heat for the prototype in an upright position, without really understanding all the intricacies of natural convection. It also turned out to be a bit on the low side for real world use.

What calculations did you use to determine this?

mhjerde said:
I was hoping I could avoid having to increase the size or add cooling ribs to the outside. I might get some added cooling by hollowing out the vertical parts of the frame, but I don't know how much of an effect an airflow 4.0E-6 m3/s gives me.

You also mention that you plan to use 100mm tall vertical tubes to create a 0.09Pa pressure difference (which I'm assuming you calculated using the standard atmospheric model) but the pressure difference in a vertical tube is balanced by gravity- it doesn't just start flowing air by itself.
 

1. What is the stack effect on small scale?

The stack effect on small scale refers to the natural phenomenon where warm air rises and cool air sinks, creating a flow of air within a small space such as a building or room.

2. How does the stack effect impact indoor air quality?

The stack effect can greatly impact indoor air quality by causing air pollutants and contaminants to be pushed upwards and circulated throughout the building. This can lead to poor air quality and potential health hazards.

3. What factors contribute to the stack effect?

The stack effect is influenced by a variety of factors, including temperature differences between indoor and outdoor air, height and design of the building, and wind conditions. These factors can all affect the strength and direction of the air flow.

4. Can the stack effect be controlled?

Yes, the stack effect can be controlled through proper ventilation and insulation techniques. By sealing air leaks and using mechanical ventilation systems, the stack effect can be reduced and indoor air quality can be improved.

5. What are some potential consequences of the stack effect on small scale?

The stack effect can lead to uneven temperatures throughout a building, discomfort for occupants, and increased energy costs due to the constant flow of air. It can also contribute to the spread of airborne illnesses and decrease the overall air quality in the building.

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