Understanding the Stack Effect

 

1. Understanding the Stack Effect - Water tank



2. understanding the stack effect - chimneys





3. Understanding the Stack Effect - Architecture

- Hydrodynamic building = a structure consisting of several round balloons and long balloons connected to their neighbors by large and small gaps. 

- Factors of the stack effect: 1. 2 compartments connected by gaps, having a height, and aligned in parallel, 2. Density difference (air and waㄱter at the same temperature, air at a different temperature) 

-Eliminate the stack effect: eliminate the gaps or eliminate the height or eliminate the density difference



4. Definitions of Bouyancy and Stack Effect

Definition of Bouyancy

- The force by which a fluid overcomes the gravitational pull of an object immersed in that fluid and pushes the object upward. 

- Buoyancy = the force caused by the pressure difference on the top surface of an object - the object's gravity 

- Pressure difference acting on the top surface of the object = proportional to the difference in density between two adjacent compartments


Definition of Stack Effect 

- It is a phenomenon in which air moves in and out of a building through leakage gaps due to the buoyancy of air caused by the difference in density between indoor and outdoor air due to differences in temperature and humidity.

- In general, in a vertically long compartment, the inflow and outflow of gas occurs between the upper and lower openings of a compartment or building due to the pressure difference [(ρ_o - ρ_i)gh1≠(ρ_o - ρ_i)gh2] caused by the density difference due to the temperature difference between inside and outside and the height difference between the upper and lower openings.



5. Related video

https://youtu.be/4WI4f_EK22E




* Back to Main Procedures : General COMTAM Simulation Procedure for Pressure differential system(Mainly High-rise building) (contamsmulationlab.blogspot.com)

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