Raised Floor and Dropped Ceiling Leakage Update

[jvangilder]

The Room menu now shows airflow leakage details for the raised floor and dropped ceiling.

We haven’t changed any calculations, but here is some additional background information. The airflow leakage velocity 𝑉 at any location is related to the pressure drop Δ𝑃 across the raised floor or dropped ceiling by:

Δ𝑃=𝑓(1/2)𝜌𝑉²

where 𝜌 is the density of air (we assume 1.2 kg/m3 at seal level) and 𝑓 is the dimensionless loss coefficient. We compute 𝑓 as a function of open area 𝛽 for all resistances in EcoStruxure IT Advisor CFD from [1]:

𝑓=(1/𝛽^2.3)(1−𝛽)

Note that 𝛽 in the above equation is a decimal value, not a percentage. For example, 0.01 instead of 1%. Finally, % open area values selected for the various raised floor and dropped ceiling leakage options are based on [2] and [3].

1. VanGilder, J., Seymour, M., Hu, B., Tian, W., Pang, M., and Lin, C., 2022 “Flow Resistance Characteristics for Data Center CFD”, ASHRAE Transactions 2022, Volume 128, Part 2.
2. VanGilder, J., and Zhang, X., 2015, “Development of a Raised-Floor Plenum Design Tool”, Proceedings of InterPACK, July 6-9, San Francisco, California.
3. VanGilder, J. And Zhang, X. 2014, “Cooling Performance of Ceiling-Plenum-Ducted Containment Systems in Data Centers”, Proceedings of the Intersociety Conference on Thermomechanical Phenomena in Electronic Systems (ITHERM 2014), May 27–30, Orlando, Florida.