EcoStruxure IT Design CFD release notes 2023

[JLehr]

Angled walls

December 2023

We've just released a feature that we've had in development for a while, support for angled walls.

This allows you to model almost any data center shape. In addition to the rectangle cutouts that are already present, there are now triangle cutouts you can use to model your data center room.

Check out the built-in Reference Project > Complex Room Shape to see what is possible.

 

 

Raised Floor and Dropped Ceiling Leakage details

May 2023

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.

 

Default IT Equipment Airflow/Power

February 2023

We changed the default IT Equipment airflow assumption from 125 cfm/kW (212 m^3/hr/kW) to 100 cfm/kW (170 m^3/hr/kW).

Though seemingly a minor tweak, this can have a large impact on your designs. With 20% less IT airflow, fewer coolers may be required and those remaining coolers may be operated at lower airflow rates - while still ensuring good cooling performance.

It is important to keep in mind that we are simply estimating airflow as a function of power; good airflow data is hard to find while power is typically known.

Actual server airflow varies from model to model and even between different configurations of the same model. Servers may also automatically increase their airflow above an inlet-temperature threshold, e.g., 27 C (80.6 F).

Over the years, IT airflow has trended downward as data-center best practices have improved (e.g., hot/cold aisle, containment) and IT vendors reduce IT fan power. As the IT airflow goes down, the temperature rise across the IT equipment goes up. However, maximum exhaust temperatures are limited by inlet temperature thresholds and maximum safe "touch" temperatures.

As a result of these constraints, IT airflow per power has become more consistent in recent years. The best overall source of IT airflow data that we have found is IT Equipment Design Impact on Data Center Solutions by ASHRAE.

Below is a plot from that reference. Looking at the plot, we see that the average airflow per power is actually closer to 75 cfm/kW (125 m^3/hr).

The default value in EcoStruxure IT Advisor CFD is a bit larger to give us some conservative margin and account for non-server IT equipment like storage products and networking gear which typically has more airflow on a per-power basis.

 

Cloud GPU upgrade

February 2023

We've just upgraded the cloud GPU hardware to give you an even faster, better experience.

Thank you for your continued use of EcoStruxure IT Design CFD and designing data centers grounded in good science!

[JLehr]

We've just released a feature that we've had in development for a while, support for angled walls.

This allows you to model almost any data center shape. In addition to the rectangle cutouts that are already present, there are now triangle cutouts you can use to model your data center room.

Check out the built-in Reference Project > Complex Room Shape to see what is possible.

[JLehr]

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.

[JLehr]

We changed the default IT Equipment airflow assumption from 125 cfm/kW (212 m^3/hr/kW) to 100 cfm/kW (170 m^3/hr/kW).

Though seemingly a minor tweak, this can have a large impact on your designs. With 20% less IT airflow, fewer coolers may be required and those remaining coolers may be operated at lower airflow rates - while still ensuring good cooling performance.

It is important to keep in mind that we are simply estimating airflow as a function of power; good airflow data is hard to find while power is typically known.

Actual server airflow varies from model to model and even between different configurations of the same model. Servers may also automatically increase their airflow above an inlet-temperature threshold, e.g., 27 C (80.6 F).

Over the years, IT airflow has trended downward as data-center best practices have improved (e.g., hot/cold aisle, containment) and IT vendors reduce IT fan power. As the IT airflow goes down, the temperature rise across the IT equipment goes up. However, maximum exhaust temperatures are limited by inlet temperature thresholds and maximum safe "touch" temperatures.

As a result of these constraints, IT airflow per power has become more consistent in recent years. The best overall source of IT airflow data that we have found is IT Equipment Design Impact on Data Center Solutions by ASHRAE.

Below is a plot from that reference. Looking at the plot, we see that the average airflow per power is actually closer to 75 cfm/kW (125 m^3/hr).

The default value in EcoStruxure IT Advisor CFD is a bit larger to give us some conservative margin and account for non-server IT equipment like storage products and networking gear which typically has more airflow on a per-power basis.

[JLehr]

We've just upgraded the cloud GPU hardware to give you an even faster, better experience.

Thank you for your continued use of EcoStruxure IT Design CFD and designing data centers grounded in good science!