Selecting The Right Economizer

by Emerson Network Power on 12/9/15 2:19 PM

Written By: David Klusas, Emerson Network Power

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You can say what you want about mink farms, but one thing is certain: They stink!

That can be a problem if you’re operating a data center near one and trying to use airside economizers to bring in fresh outside air for free cooling.

There are many efficiency benefits to utilizing outside air for economization, but not every situation is right for bringing outside air into a data center. Each type of economizer has its own advantages and challenges, depending on data center goals, site requirements, geography and climate.

I recently visited four data centers, from Canada to Utah, including the one next to the mink farm, and found multiple occasions where airside economization was not the ideal solution, despite its energy savings.

One data center in Canada was near a heavily forested area, and the company was concerned about smoke from forest fires entering the facility. A data center in Washington was next to an apple orchard, which creates a lot of dust during harvest. Another is using 100% outside air for economization, but has an 8MW chiller plant for backup, in case they ever need to close the outside air dampers and recirculate the indoor air. That’s a HUGE initial investment for only a backup system.

Data centers have made cutting energy consumption a priority to save money and meet government regulations. Cooling accounts for almost 40 percent of data center energy usage, so it’s a main focal point for driving energy savings. More recently, water conservation has become a priority in the selection of cooling systems and economization strategies. At the same time, relative cost and the payback periods remain key factors in selecting these large, expensive systems.

All economizer systems use either outside air and/or water to reduce or eliminate mechanical cooling in data center cooling units. These economizer systems generate significant energy savings of up to 50 percent, compared to legacy systems. The first decision most data center managers make in selecting an economization strategy is the type of data center environment they want to operate, which naturally then leads to a decision on whether or not to bring outside air into the data center. As a result, there are two primary economizer designs typically deployed in data centers: direct and indirect.

While direct and indirect economizers operate in different ways, the ultimate goal of both systems is to provide free cooling to a room or facility, thus reducing the overall energy consumption of the facility. However, fundamental differences between the methods in which direct and indirect systems economize greatly impact the temperature and humidity environment that can be efficiently maintained within the data center.

Direct economization brings outside air into the data center using a system of ductwork, dampers, and sensors. These systems usually have lower capital costs than other forms of economization and work well in moderate climates. In the right climate, direct outside air economizers can be very efficient and an effective economization strategy, but do introduce the risk for contaminants and wide humidity swings into the data center. For maximum annual savings, a wide acceptable supply air temperature and humidity window needs to be implemented in the data center. For highly critical data centers, the risk of outdoor contaminants and wide temperature and humidity swings is sometimes too significant for comfort.

In contrast, indirect economizers can offer significant energy savings while limiting the prior concerns. Indirect economizers do not bring outside air into the data center, but instead use an indirect method to transfer heat from the data center to outside the building. There are primarily three types of indirect economizer technologies:
• Air-to-air heat exchangers, or heat wheels, in a wet or dry state
• Pumped refrigerant economizers, such as the Liebert® DSE™ system economizer
• Cooling towers for chilled water systems

Sensible air-to-air plate frame heat exchangers transfer heat between two air streams, but maintain a complete separation, thus eliminating the opportunity for contamination and transfer of humidity into the data center space. These units can be operated in a dry state, or can be sprayed with water to increase their effectiveness and hours of economization. Heat wheels offer similar qualities to air-to-air plate frame heat exchangers, but can have higher air leakage rates and require additional maintenance to maintain their performance.
The Liebert DSE system is a direct-expansion (DX) system that utilizes an integrated pumped refrigerant economizer to maximize annual energy savings and provide superior availability without the need for separate economization coils. When outdoor ambient temperatures are low enough, the integrated refrigerant pump is used to circulate the refrigerant in lieu of the compressor to maintain the desired supply air temperature. The refrigerant pump uses a faction of the energy used by the compressor. As the outdoor ambient temperatures rise, the Liebert DSE system automatically transitions on compressors to maintain the desired supply air temperature. Its integrated Liebert iCOM™ thermal controls work to automatically optimize the entire system to provide more free-cooling throughout the year.

Because of its efficiency advantages, the Liebert DSE system was recently approved for use in California data centers under Title 24. Its economizer was shown to reduce time dependent valuation (TDV) by 8-10 percent and, since it uses no water, save around 4 million gallons of water annually in a 1MW data center, compared to water economizers.

Initial installation costs for any of these economizer options can be affected by how well the technology under consideration fits into the overall design of the existing facility. The amount of indoor, outdoor or rooftop space required for situating the units will affect the selection decision. Chilled water systems with cooling towers tend to be the most costly, because of the high system first cost, use of water and a higher maintenance burden relating to their complexity.

Emerson Network Power offers options for all of these economizer technologies. There is no single economizer technology that fits every situation. Each has its own strengths based on location and application, and each has its challenges.   Fortunately, there’s an economization option for virtually every location – even next to a mink farm.

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Topics: CUE, Emerson Network Power, Data Center, data center energy, efficient data center, DVL, UPS, Thermal Management, DCIM, energy efficiency, preventative maintenance, 7x24, Economizer

Highly reliable data centers using managed PDUs

by Emerson Network Power on 10/8/15 9:09 AM

Ronny Mees | Emerson Network Power

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Today’s most innovative data centers are generally equipped with managed PDUs since their switching capabilities improve reliability. However, simply installing managed PDUs is not enough – an “unmanaged” managed PDU will actually reduce reliability.

So how do managed PDUs work? These advanced units offer a series of configurations which – if properly implemented – improve the availability of important services. The main features are Software Over Temperature Protection (SWOTP) and Software Over Current Protection (SWOCP), which are well described in the blog post “Considerations for a Highly Available Intelligent Rack PDU”.

It is also well-known, that managed PDUs can support commissioning or repairing workflows in data centers. The combination of well designed workflows and managed PDUs pushes the operational reliability to a higher level.

In high performance data centers, using clusters, another important point comes into play: clusters are complex hierarchical structures  of server farms, which are able to run high performance virtual machines and fully automated workflows.

As described here or here, such clusters are managed by centralized software together with server hardware.

Over the last couple of years cluster solutions have been developed following strong and challenging availability goals, in order to avoid any situation, which make physical servers struggle within the cluster. However, there would still be the risk of applications and processes generating  faults and errors and screwing-up the complete cluster, unless there was an automated control process – the good news is: there is.

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The process which controls those worst case scenarios is called fencing. Fencing automatically kicks out of the cluster any not working nodes or services in order to maintain the availability of the others.

Fencing has different levels, which are hopefully wisely managed. In a smooth scenario fencing will stop disturbing services, or re-organize storage access (Fibre channel switch fencing) to let the cluster proceed with its tasks.

Another power fencing option is also called “STONITH” (Shoot The Other Node In The Head) and allows the software to initiate an immediate shutdown (internal power fencing) of a node and/or a hard switch off (external power fencing).

The internal power fencing method uses IPMI and other service processer protocols, while the external power fencing uses any supported network protocol to switch of a PDU outlet.  It is recommended to use secured protocols only, such as SNMPv3. So managed PDUs as MPH2 or MPX do not only support a nice power balance, monitor power consumptions or support datacenter operations workflows – they also allow the fence software to react quickly for higher cluster reliability. So it’s not a secret that cluster solutions manufacturers – e.g. Red Hat with RHEL 6.7 and newer – openly support such managed rack PDUs.

For More Emerson Network Power Blogs, Click Here

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Topics: Data Center, PUE, robust data center, Containment, efficient data center, DVL, electrical distribution, energy, Battery, Thermal Management, energy efficiency, 7x24, PDU

Breaking Down the Cost Implications of a Data Center Outage

by Marissa Donatone on 7/23/14 10:35 AM

Emerson Network Power and the Ponemon Institute worked together to determine the full economic cost of unplanned data center outages. Below is a preview, for the full report CLICK HERE


The 2013 Cost of Data Center Outages is the only benchmark study that attempts to estimate the full costs associated with an unplanned data center outage. According to the study, the cost of a data center outage has increased since 2010.

The cost per square foot of data center outages now ranges from $45 to $95. Or, a minimum cost of $74,223 to a maximum of $1,734,433 per organization in our study. The overall average cost is $627,418 per incident.

This benchmark analysis focuses on representative samples of organizations in the U.S. that experienced at least one complete or partial unplanned data center outage during the past 12 months. The analysis was based on 67 independent data centers located in the United States. Following are the functional leaders within each organization who participated in the study:

  • Facility manager
  • Chief information officer
  • Data center management
  • Chief information security officer
  • IT compliance leader

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Topics: downtime, data center infrastructure, efficient data center, data center outages

The Benefit of Increasing Return Air Temperatures

by Marissa Donatone on 8/20/13 8:44 AM

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Topics: data center infrastructure, Data Center, Data Center, data center design, data center infrastructure management, efficient data center, 7x24 exchange, critical air conditioning

Emerson Network Power- Integrate People, Process and Technology

by Marissa Donatone on 8/14/13 11:20 AM

Emerson Network Power Outlines How Best to Integrate People, Process and Technology to Transform Data Center Operations and Performance 

Columbus, Ohio [August 8, 2013] – With the data center at a critical stage in its evolution, Emerson Network Power, a business of Emerson (NYSE: EMR) and a global leader in maximizing availability, capacity and efficiency of critical infrastructure, today released a white paper that provides IT and data center managers with best practices for moving toward a holistic approach to data center management that rises above organizational, system-level silos while optimizing the interaction of people, process and technology to achieve true operational efficiency.

The white paper, titled “Integrating People, Process and Technology to Transform Data Center Operations and Performance,” takes a closer look at the constraints preventing organizations from optimizing data center performance and efficiency, and it provides a clear path for overcoming them through the better utilization of people, process and technology.

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Topics: Emerson Network Power, data center infrastructure, Data Center, data center energy, efficient data center

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