Energy efficiency continues to be a major concern for data centers with raised floor systems. In the past, energy cost was simply a given, on par with the costof hardware and labor. As hardware has become more efficient and automated procedures have taken over labor, the cost of energy has continued to climb and it now represents around 25% of total operating costs for most data centers. In most data centers, one of the biggest uses of energy involves the strategic cooling of equipment in conjunction with the raised floor system.
The typical data center uses nearly twice as much electricity as it needs for actual computing, with the remainder going toward cooling, lighting and systems that maintain the data center. One measure of this ratio of use is PUE, or power usage effectiveness, and a PUE of 1.0 is considered ideal. This means all of the power brought to the data center is used for computing, although this is not exactly an achievable goal.
The price of energy is such a large concern for data centers, they have gone to great lengths to optimize their PUE. The largest operators of data centers, Google and Facebook, have not only worked to make their data centers energy efficient. they have come close to this ideal PUE. Along the way, they have learned some valuable lessons to save energy. Their work has been amazing and shows the possibilities in new construction. However, it challenges the vast majority of older data centers with raised access floor. For data centers built 10 to 40 years ago, all hope is not lost. There are a number of ways to follow this trend without spending a fortune to take advantage of the lessons learned in energy efficiency.
Energy Efficiency for Legacy Data Centers
Legacy data centers may use a number of cost-effective techniques to boost the energy efficiency of their facility and improve the performance of their raised floor systems.
Energy Efficient Grommets
One option is sealing existing cutouts in raised floor systems for a fast and effective energy facelift. Energy efficient grommets are an effective way to prevent bypass air from escaping the underfloor to improve the efficiency and cooling capacity of the entire system. According to Uptime Institute, Inc., electricity consumed by a data center’s IT equipment is the largest infrastructure cost, and up to 80% of conditioned air never reaches the air intake of equipment due to unsealed cable openings.
Bypass air creates hot spots, which causes not only inefficiency but increased costs. Sealing cable and hose openings is one of the most cost-effective ways to update an existing raised floor system, and energy efficient grommets will not only increase the cooling capacity of existing units but also reduce the need to buy additional cooling units.
Perforated Raised Floor Tiles
Another option is the strategic installation of perforated raised floor tiles or high velocity grates. A major study conducted by the Uptime Institution of 19 large computer rooms determined that most facilities have problems with hot spots. Many data centers simply throw more AC at the problem, which most often fails. These perforated data center floor tiles must be installed with a plan in mind, however, and not simply because an area feels warm.
When cable openings are sealed, the airflow of perforated floor tiles is increased by 66%. Airflow modeling will allow for the strategic placement and quantity needed of perforated floor tiles or high velocity grates.
Rack System Layout
Finally, it’s possible to improve the cooling and power efficiency of legacy raised floor systems by re-examining the current rack layout. More data centers today use in-row solutions, which maximizes efficiency. Cabinets should be joined in a series of rows resting on the raised floor tiles. The fronts of the racks facing each other become cold aisles. Cold aisles are then positioned around the perimeter of the room, or at the end of hot aisles, and this pushes cold air under the raised floor system and through the cold aisle. Perforated raised floor tiles are then placed only in the cold aisles to concentrate the cool air in front of the racks to make sure adequate air reaches the server intake. As air moves through the servers, it’s heated and dissipated into hot aisles.
Implementing a strategic energy plan can make any data center more efficient, whether new or old.