What's the first step to “green” my data center?
What improvements yield the biggest savings?
Can there be a negative impact to my data center?

If you can’t measure it, you can’t manage it.

The first step of any greening activity is creating a baseline. To quantify savings and improvement you have to know where you are starting. This can be somewhat overwhelming, and there is a prevailing mentality that great detail and special monitoring must be in place because only a granular baseline is of any value. This is entirely untrue. While it is preferable to examine a system as closely as possible, don’t let it hold you back from moving forward. For example, PUE measurements can be based on a comparison between UPS and PDU draws. The bottom line is work with what you got to get the best comparable data you can. This allows you to move forward with greening projects and measure their impact on your energy consumption.

It isn’t easy being this cool.

It is universally accepted that the largest area energy is being inefficiently used is in the cooling systems of data centers. Despite what your server intake temperatures might be, most rooms have cooling systems that are oversized, set points that are too low, and overall are plagued by poor airflow management. Typically, data centers are “held hostage” by one or two hot spots that force the above-mentioned problems. Often, simple changes and the installation of passive products can decrease cooling energy by 25%-50%.

Start with the basics:

• Balance subfloor pressure
• Place perforated tiles only in front of equipment that needs it
• Cover all unmanaged openings of the raised floor (cable cutouts, PDU’s)
• Use Blanking Panels

After the basics are covered, more aggressive airflow management can be considered. Containment is sweeping the industry as one of the easiest ways to realize huge power savings. Whether it is hot or cold aisle containment, the separation of supply and exhaust air has a profound effect on the data center environment.

The efficiency improvements can be exponential:

• Raised CRAC/CRAH set points
• Raised chiller set points
• Longer economizer cycles
• Reduced fan speeds
• Reduced pump speeds

Aggressive airflow management practices have allowed many data centers to operate in a “free cooling” mode for 70%-90% of the year, even in hot climates. Talk to a SubZero Engineer today to discuss your site’s potential energy savings!

Waiting for the shoe to drop?

With the variety of ways to skin the proverbial cat, myths become circulated to scare consumers towards or away from different products. There are legitimate concerns that need to be accounted for when developing your airflow management, others are no more than marketing for a particular product masquerading as scientific fact. Here are a few common concerns with airflow management - particularly containment:

Will my fire suppression system be compromised?

This is the most commonly asked question regarding containment. Frankly the answer depends on how you go about containing the aisle. Here are the questions to ask when considering containment.

If you are considering a curtain based containment solution:

Is the system attached with fusible links?

Fire suppression systems are designed for the whole room. When you begin to do containment, you essentially create rooms within the room. For the fire suppression system to work properly, particularly water systems, the containment walls need to drop off of the ceiling so that spray pattern is not affected. Gaseous systems are more forgiving, but local compliance with fire codes will likely dictate the use of approved fusible links.

Will the system allow for smoke to travel uninhibited across the ceiling?

Data center fire detection systems are designed in such away that multiple sensors must register a fault before a suppression sequence is initiated. With curtain systems hanging from the ceiling, a gap must be in place so that smoke has the opportunity to move around and trigger the sensors. If there is no gap, either the smoke can be contained or an unnecessary delay can occur while the smoke has to travel further it to trigger another sensor.

If you are considering a roof or ceiling based containment
solution that sits on the racks:

How does the roof get out of the way of the fire suppression system?

There are basically two options in this scenario: (1) Bring nozzles and/or water into the containment, or (2) Have a system that opens in some fashion. Obviously, option (1) would bring considerable expense to the containment installation requiring major re-piping of both water and gaseous systems. Option (2) is more affordable but can come with some serious concerns. Nearly all products on the market have rigid panels that are held up by fusible links that allow the panels to drop in the event of a fire. While this satisfies the issue of fire suppression, it creates huge risks to personnel in the data center. The panels become a fall hazard as well as a tripping hazard. Many local authorities will not allow them based on these facts and customers are forced back to scenario (1). SubZero Engineering is the only containment provider that has been able to come up with a third option, the Polar Cap. The system is a one-piece vinyl roof that retracts into a cassette if a fire occurs by using a fusible link or an electronic fusible link. This allows the existing fire suppression system to be used and poses no risk to personnel in the room.

Outside of containment, things like cable cutout covers, properly sizing and placing perforated tiles, installing blanking panels, and using air deflectors on the back of the racks are much more straight forward. These should cause no interruption to uptime and can easily be installed in a running site.