Stratification of air in a closed system vs the stack effect

In summary, temperature stratification of air is dependent on a dynamic system with a heat source. As the system reaches equilibrium, the temperature stratification will decrease. The stack effect, also known as the chimney effect, is a term relevant to open systems where there is a difference in density between two spaces. In a closed system, temperature stratification tends to be static after a period of time as the system reaches equilibrium. This is supported by the concept of thermal destratification and the stack effect.
  • #1
Elquery
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TL;DR Summary
Would air, given a truly closed system, stratify by temperature? Is the stack effect relevant to closed systems, or is it specific to outside reference?
In thinking about temperature stratification of air: I assume that in a truly closed system with no heat inputs, air would NOT stratify by temperature.

On the other hand, a heat source introduced in a closed container would generate stratification while it was generating heat (and following for a time). It would then trend towards equilibrium (diffusion, entropy, etc.)

So temperature stratification is dependent on a dynamic system, and the trend is towards equilibrium: remove the source of heat, and stratification will actually REDUCDE not increase.
Yes?

Therefore, the more isolated a system is, the less temperature stratification we will observe. Yes?
Therefore, the 'stack effect' is a term most relevant to open systems. Indeed it is sometimes referred to as chimney effect, which implies a communication between two... steady states?
 
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  • #2
Stratification of air inside a closed place tends to be a more or less static phenomenum.
Stack effect is dynamic, as a vertical movement is stablished due to difference of densities between two spaces.

Please, see:
https://en.m.wikipedia.org/wiki/Thermal_destratification

https://en.m.wikipedia.org/wiki/Stack_effect

I believe that you are correct about absence of stratification in an ideal closed system after certain period of time for equlibrium of temperature within the mass of gas or air to be reached.
 
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1. What is the difference between stratification of air in a closed system and the stack effect?

The stratification of air in a closed system refers to the natural process of air settling into layers based on temperature differences. The stack effect, on the other hand, is the movement of air within a building caused by the difference in air pressure between the top and bottom of the building.

2. How does stratification of air affect indoor air quality?

Stratification of air can have a significant impact on indoor air quality. In a closed system, warm air rises and creates a layer of stagnant, low-quality air near the ceiling. This can result in poor ventilation and the accumulation of pollutants, leading to potential health hazards.

3. Can the stack effect be controlled in a building?

Yes, the stack effect can be controlled through proper building design and ventilation systems. For example, using mechanical ventilation systems can help to equalize air pressure and prevent the stack effect from occurring.

4. How does the stack effect impact energy efficiency in a building?

The stack effect can have a significant impact on energy efficiency in a building. In the winter, warm air rises and escapes through leaks in the building's upper levels, causing the heating system to work harder to maintain a consistent temperature. In the summer, the opposite occurs, with cool air escaping through leaks and the air conditioning system working harder. This can result in higher energy bills.

5. Are there any ways to mitigate the effects of stratification and the stack effect in a building?

Yes, there are several ways to mitigate the effects of stratification and the stack effect in a building. These include proper insulation to prevent air leaks, using mechanical ventilation systems, and implementing air circulation strategies such as ceiling fans. Additionally, regular maintenance and sealing of air leaks can help to improve indoor air quality and energy efficiency.

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