by Jose Ruiz
Note: This is the first installment of a regular series providing you with economical options for improving your data center cooling performance.
Passive data center cooling performance is defined by the gains in data center cooling efficiency through the application of effective cooling techniques that do not require additional cooling infrastructure, major equipment restructuring and most importantly, the consumption of additional power. This series will discuss concepts that are not new to the data center industry that are often not implemented, resulting in the detriment of site performance that can extend into your bottom line. This series will introduce simple and cost-effective techniques that will improve your facility’s performance and save you money.
Flood cooling is not effective cooling.
Flood cooling is a traditional approach used in a number of data centers. It gets the job done, but at what expense? In practice, flood cooling is when air is “dumped” into the computing environment either overhead or under floor. Unfortunately, flood cooling alone is not effective cooling.
Effective cooling is a supplemental technique of flood cooling that directly increases and maximizes the efficiency of the cooling you are providing the IT equipment. How? The concept is straightforward: put the cold air where it will work to your benefit, the inflow vent of the IT equipment – the face of the rack.
For example, in a traditional hot aisle/cold aisle configuration, you have a four-foot cold aisle with two perforated tiles separating the front of the cabinets.
Figure 1. Four-foot cold aisle
If you apply data center best practices, then you start installing equipment in your cabinets or racks from the bottom up. The lowest equipment will receive the most effective cold air via the perforated tile because they are the first ones to demand the air. As air travels up, the majority of the air is unused or bypassed. (See Figure 2.) This phenomenon will affect the equipment installed higher in the rack since they will receive the warmer, mixed air.
The cost-effective fix
By replacing standard, perforated tile with a directional airflow panel, such as the Tate Directional Perf, the effectiveness of the supplied air increases by 70%. Tate calls this: Total Air Capture and states that directional airflow achieves 93% of total air capture. That’s pretty impressive. From a density perspective, a 25% directional perf can cool a 7.8 kW rack.
Figure 2. FF 6Sigma CFD simulation. Cold air not being used and being bypassed.
The key benefits provided by effective cooling include:
- Improved air flow through the IT equipment
- Increasing the life of your mechanical equipment
- Reducing your PUE
- Increasing your supply air temperature set point
- Saving on energy costs
- Increasing the overall facilities’ efficiency
- Maximizing the compute capacity of your data center
Sometimes it’s the little things that have the biggest impact. Rather than taking drastic and expensive measures to improve performance, significant gains can sometimes be achieved for the price of a few floor tiles.