One of the most daunting tasks that companies face today is figuring out how to wring greater energy efficiency out of their datacenters. Certainly, many vendors are ready to step up and demonstrate where their respective products fit into the power-saving puzzle. But there's something to be said for a vendor-neutral blueprint to plan the overall task.
That all is a wordy lead-in to pointing you to a new report -- available as a free download -- released today by Emerson Network Power. It's titled "Energy Logic: Reducing Data Center Energy Consumption by Creating Savings that Cascade Across Systems," and it's an impressive piece of work, outlining ten interrelated technology strategies that comprise a holistic approach to improving datacenter energy efficiency by as much as 50 percent, according to the company. And as I noted, it's free.
For a little background, Emerson has coined the term "Energy Logic" in this report, a strategy which, according to the company, "centers on 'the cascade effect' by which one watt saved at the processor level can save an average total of 2.84 watts in energy consumption."
The report starts at the server component level, outlining the benefits of low-power processors. "Independent research studies show these lower-power processors deliver the same performance as higher power models," the report says. "In the 5,000-square-foot datacenter modeled for this paper, low-power processors create a 10 percent reduction in overall datacenter power consumption."
Next up: power supplies. The report notes that most power supplies found in servers are working at around 72 percent effiency -- yet "best-in-class power supplies are available today that deliver efficiency of 90 percent. Use of these power supplies reduces power draw within the data center by 124 kW or 11 percent of the 1127 kW total," the report says.
From there, the report suggests that datacenter operators look at power-management software. Despite the fact that processors have built-in power-management features, they end up disabled for fear of crippling response time. Yet "in idle mode, most servers consume between 70 and 85 percent of full operational power."
The Emerson Energy Logic report suggests that admins reconsider how they use power-management features. In the 5,000 square foot datacenter model, the report says that using power-management features can reduce peak power draw from 80 percent to 45 percent, saving "an additional 86 kW or eight percent of the unoptimized datacenter load."
Blade servers have a role to play in the energy-efficient datacenter, according to the Emerson report. "Blade servers consume about 10 percent less power than equivalent rack-mount servers because multiple servers share common power supplies, cooling fans and other components. ... More importantly, blades facilitate the move to a high-density data center architecture, which can significantly reduce energy consumption."
Moving on, Emerson's Energy Logic strategy highlights server virtualization. In the 5,000 square foot model, "assuming 25 percent of servers are virtualized with eight non-virtualized physical servers being replaced by one virtualized physical server, ... virtualization provides an incremental eight percent reduction in total datacenter power," according to the report.
No. 6 on Emerson's energy-efficiency menu for datacenters: best cooling practices. That includes "sealing gaps in floors, using blanking panels in open spaces in racks, and avoiding mixing of hot and cold air." This is low-hanging fruit that requires no additional technology investment but can result in a five percent efficiency boost, based, again, on the 5,000 square foot datacenter model.
415V AC power distribution is the next strategy component in Emerson's Energy Logic scheme. The short of it is, most UPS systems are rather inefficient, as they convert incoming power to DC and then back to AC within the UPS. "In most datacenters, the UPS provides power at 480V, which is then stepped down via a transformer, with accompanying losses, to 208V in the power distribution system," according to the report. "These stepdown losses can be eliminated by converting UPS output power to 415V." The result: "an incremental two percent reduction in facility energy use" in the 5,000 square foot model.
Cooling reappears in the report next, specifically variable capacity cooling. "Typically, CRAC [computer room air conditioners] fans run at a constant speed and deliver a constant volume of air flow. Converting these fans to variable frequency drive fans allows fan speed and power draw to be reduced as load decreases," the report says. Emerson specifically cites digital scroll compressors here, which "allow the capacity of room air conditioners to be matched exactly to room conditions without turning compressors on and off."
The payoff: "A 20 percent reduction in fan speed provides almost 50 percent savings in fan-power consumption."
Ninth in the Emerson Energy Logic lineup is, lo, another cooling strategy: high-density supplemental cooling. Datacenter operators are cramming more machines into their facility, and CRAC systems alone can't handle the extra heat. "Supplemental cooling units are mounted above or alongside equipment racks, and pull hot air directly from the hot aisle and deliver cold air to the cold aisle," the report explains. These units can reduce cooling costs by 30 percent, Emerson reports.
Last but not least, there's monitoring and optimization. With varying types of hardware spread out around the datacenter, cooling can prove inefficient. "Cooling control systems can monitor conditions across the datacenter and coordinate the activities of multiple units to prevent conflicts and increase teamwork," the report says. "In the model, an incremental saving of one percent is achieved as a result of system-level monitoring and control."
There's plenty more information to be gleaned from Emerson's 21-page Energy Logic report, along with helpful charts and diagrams to help datacenter operators as they venture toward a greener, more sustainable facility.
Did I mention the report is available as a free download? Get it right here.