Data center containment is the practice of splitting the aisles of a data center into segregated hot and cold sections, depending on how each aisle is set up. For example, some data centers might have the front of their servers on the inside of the aisle, with fans blowing the exhaust outside the aisle. Others might have the front of their servers on the outside of the aisle, and vent heat inside the aisle.
Containment keeps the hot air exiting servers from mixing with the cold air coming in from the Computer Room Air Conditioning (CRAC), dramatically improving energy efficiency and also maintaining a more consistent temperature, which reduces the overall load on both air conditioning units and the servers themselves.
Green House Data uses full containment in our Cheyenne and East Coast data centers, but only recently implemented it in our Seattle, WA facility. This case study demonstrates how even a simple containment system can lead to significant energy efficiency improvements. We expect the system to pay for itself within the year, in part thanks to generous rebates from Seattle Public Utilities.
For this facility, we chose to contain the cold aisle, where air comes into the server racks from the CRACs. Read more about types of containment, how many facilities are using it, and how it can improve efficiency in this blog post.
The initial deployment includes only curtain-type containment, but solid doors will be added throughout Suite 1919 in the Westin Building Exchange. Even the comparatively simple curtain method is not inexpensive — the project cost was over $10,000 for a relatively small square footage footprint. However, curtains are still less expensive than full containment, as featured in our Cheyenne facility.
It is also much faster and easier to add to an existing data center aisle, resulting in immedate energy cost savings and more efficient cooling loads. Green House Data Data Center Operations staff were able to install the cold aisle containment curtains in just one day.
The above image shows curtain-type containment (left) vs. the fully contained pods with doors that we have installed in our Cheyenne data center.
After installing curtains to separate the cold aisle from the hot aisle, the Seattle 19th floor suite saw deltas in hot aisle temperature ranging from 1 degree Fahrenheit to 7 degrees, with an associated increase in humidity of up to 7%. Cold aisles saw a more dramatic improvement, with an average decrease in temperature of 9 1/3 degrees Fahrenheit — a 12.5% improvement in cooling efficiency.
Average mid-summer energy bills for these suites reach approximately $15,000. With cooling estimated at 40% of energy spend, that's $6,000 a month going to cooling during the hottest months. We'll save $750 a month on cooling based on these projections.
At that rate, it would take us a little over a year for a positive ROI — which isn't unreasonable, but it also isn't what will happen. Because cooling loads are lower in winter, it may be closer to two years. However, we will recoup our overall CapEx in short time thanks to another factor: local incentives.
Just like adding efficiency improvements to your home, business energy efficiency projects often qualify for government rebates from power providers and other organizations. In this case, Seattle Public Utilities offers rebates and incentives for green business practices, and was able to refund 70% of the containment project costs. Thanks to this rebate, our overall break-even point has likely already been reached, as it would occur within 4 months assuming they are the hottest and most expensive of the year for energy consumption. The project took place in early 2017, so we've had the entire summer to recoup energy savings.
Of course, we also had to verify those savings before and after by providing consumption data and temperature measurement to Seattle City Light. Green House Data is grateful to the utility for providing a program that encourages green business practices and equipment, and also for helping us to improve our own efficiency and reduce costs within our Seattle facility.
When embarking on an efficiency project of this scale, be sure to check with relevant organizations in case you can save some capital expenses. Document everything you can in order to offer supporting documentation if required.