Keep cool: Fred Stack from Emerson addresses data center cooling challenges

By Fred Stack

Emerson’s Fred Stack talks to Business Management about keeping temperatures down for IT infrastructure while maintaining efficiency.

For large technology companies, running a wide-spread IT infrastructure can raise challenges. How can businesses ensure maximum efficiency in the face of the challenges posed by having such demanding technology infrastructure?

Fred Stack. Businesses can ensure maximum efficiency by reducing energy consumption at the IT equipment level. This approach has the greatest impact on overall efficiency because the energy savings cascade across all supporting systems.

In 2008, Emerson Network Power unveiled a roadmap for optimizing data center energy efficiency called Energy Logic, which explores how IT equipment and supporting power and cooling infrastructure can deliver a 50 percent or greater reduction in data center energy consumption without compromising performance or availability.

At the core of the Energy Logic approach is the Cascade Effect, which illustrates how the IT load is directly correlated with the data center's UPS and cooling requirements, driving energy consumption on the infrastructure side as a result. By focusing on saving energy at the initial server component level rather than at the power and cooling level, energy consumption savings will cascade down through all facets of the data center. For instance, 1 Watt of energy saved at the server component level creates a reduction in total facility energy consumption of approximately 2.84 watts. 

Energy efficiency has become a hot topic across all industries. What are the main challenges technology companies are faced with when trying to implement energy efficiency?

FS. Rising energy costs and an increased focus on environmental responsibility have pushed many companies to look at energy efficiency as a way to cut costs. At the same time, new applications have emerged, making the business world increasingly dependent on the IT infrastructure that supports those applications.

The challenge for data center managers now is to maintain or improve availability while simultaneously reducing costs and increasing efficiency. A rash of well-publicized data center outages in 2008 and 2009 led to speculation that cost cutting was resulting in increased downtime. In the wake of those outages, respondents to Emerson Network Power's fall 2009 Data Center Users' Group survey showed a renewed emphasis on availability. It jumped from the fourth-most important concern just six months earlier to the No. 1 concern of data center and IT managers participating in the study.

How can businesses today maintain energy efficient practices without compromising on productivity?

FS. There are various tactics, specific to cooling, that can help businesses maintain efficiency without compromising availability. The first, which has a significant impact on all other actions recommended, is a proper isolation of the hot and cold air. This is achieved through hot aisle/cold aisle arrangement of the IT racks, blanking panels in and between the racks (and between the rack and the floor); sealing cable entry cut-outs; and plenum air return tactics. These tactics enable the increase of the cold aisle and CRAC return air temperatures, which increases both efficiency and cooling capacity. 

To allow for future IT expansion, data centers are designed with excess cooling capacity. Using variable capacity cooling tactics - including variable capacity compressors such as digital scrolls, variable airflow on CRAC or CRAH fans or variable speed components within the chiller plant - to match the actual load will reduce energy consumption. Some of these tactics can be retrofitted in existing data centers. For instance, upgrading a blower system to variable speed and reducing fan speed by 20 percent will result in a 50 percent reduction in fan power consumption. Using high-density cooling tactics to bring cooling closer to the heat source can reduce cooling power consumption by as much as 65 percent compared to traditional, room-only designs.

Cold aisle containment is another tactic that can minimize hot spots and lead to a significant reduction in carbon footprint, with energy savings of 50 percent compared to conventional perimeter cooling when intelligent controls are utilized. Economizers, which use outside air to reduce work required by the cooling system, can be an effective approach to lowering energy consumption if they are properly applied and maintained, thus mitigating the availability risks caused by issues such as gaseous contamination and transitions to and from free-cooling.

Can you outline some of Emerson Network Power's solutions for these issues?

FS. One critical feature in all of Emerson Network Power's Liebert cooling units is the implementation of the Liebert iCOM® controls, which enables independent control of each unit's cooling capacity and air flow management. This optimizes the variable capacity features and allows for a variety of intelligent control algorithms depending upon a user's room architecture and operational practices. The most advanced implementations utilize sensors located at the server racks to control the temperature and the air flow to precisely meet the needs of the servers.   

Other solutions include high-density, row-based cooling options like the Liebert CRV™, which brings cooling closer to the heat source and continually adjusts to changing operating conditions based on real-time temperature and humidity readings. The Liebert SmartAisle™ solution utilizes cold aisle containment to increase cooling efficiency and rack capacity. This option can deliver greater than 30 percent energy savings and a 40 percent cooling capacity increase without compromising availability.

Another option, the Liebert Air Economizer System, utilizes advanced enthalpy control to deliver average annual energy savings of 30 to 60 percent depending on geographic location. It is compatible with downflow configurations of the Liebert DS™ and Liebert CW™ precision cooling systems. An example of rack cooling that eliminates the need for cooling system fans is the recently released Liebert XDR™, which results in savings of over 90% percent compared to perimeter cooling.

How do you assess which of your solutions would be the most effective for each particular customer?

FS. All companies have unique needs, so cooling options need to be assessed accordingly. Our sales representatives utilize a consultative approach that focuses on listening to and observing the user's needs, enabling the representative to properly advise the customer on various approaches. Additionally, we offer a full suite of assessment services that includes a detailed CFD analysis of a site's infrastructure, which can identify efficiency solutions without implementing additional cooling hardware. 

Data centers are most effective when they are accessible by the most staff members. How can businesses ensure they fully optimize their data center's potential? 

FS. The best practice is to minimize physical access while maximizing virtual access.  Gaining control of the infrastructure environment, through centralized monitoring and visibility, leads to an optimized data center that improves availability and energy efficiency. Centralized monitoring systems-such as Liebert SiteScan® or Liebert Nform®- provide not only a window into equipment and facility performance, but also point out trends and prevent problems wherever they may be located. 

What do you predict will be key influences on energy efficiency in this industry over the coming years?

FS. In 2005, an EPA study determined that the IT industry accounted for 1.5 percent of all energy consumed within the U.S. Since that time, the demand for IT applications and productive output continues to rise exponentially, but the actual energy consumed is flat to down. Innovations in hardware and application approaches have reduced energy consumption reductions despite increases in work output. Examples of this include the elimination of the CRT display for LCD technology, and the adoption of virtualization techniques that increases the server utilization from 10 percent to 80 percent.

The next step in the evolution of data center cooling is to eliminate the need for any fans (which typically account for 10 percent of the IT server energy load) in the cooling system or the servers. A fluid cooling approach - no water, but a two-phase refrigerant - results in the energy consumed by the entire cooling system being less than the energy consumed by the server fans alone. This challenges the math on how to claim a percentage of efficiency improvement.  We prefer to call it energy consumption elimination. 

Because of the perceived trends from the 2005 EPA study, government regulators are poised to implement regulations that stifle these new innovative approaches. Without interference, technology will continue to develop to meet rising user demand. Data center managers will continue to seek out ways to cut energy consumption while preserving uptime, and precision cooling is just one of the areas that will be impacted.

Biography

Fred Stack is the Vice President of Marketing of Liebert Precision Cooling at Emerson Network Power. He is responsible for developing new precision cooling product development roadmaops that reflect evolving market needs and incorporate new technology. These roadmaps are the foundation for his team's development of new products and application engineering tools to fill gaps in data center infrastructure.