Designing for Density: Dynamic Cooling Strategies for High-Density Environments


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This presentation from Emerson Network Power's Business Innovators webcast series explores new and evolving strategies - such as cold-aisle containment - for designing a scalable, energy-efficient cooling infrastructure capable of meeting the high-density cooling challenges of today while preparing for the extreme densities of tomorrow. You will also learn how Sun designed and maintains a sophisticated, energy-efficient cooling infrastructure to support mission-critical applications.

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  • Thom: Hello, everyone. I’d like to welcome you to our Business Innovators Series Webcast– “Designing for Density: Dynamic Cooling Strategies for High-Density Environments” I’m Thom Gall, and I’ll be your host. As you know, our Webcast program is certified by the International Association for Continuing Education and Training. So attending a 1-hour Web cast qualifies you to earn one-tenth of a CEU training credit. Just check the box in your survey following the Webcast, and you’ll receive your certificate by mail within 2-3 weeks. Today, we’ll look the latest thinking in high-density data center cooling design to maximize efficiency and promote continuous availability . This presentation deck will be available to download after the Web cast – check the link in your thank-you e-mail. I’ll give a brief introduction of Emerson Network Power and its Liebert products and services, then we will move on to our presenters.
  • Thom: Before I introduce our speakers for today’s program, I’d like to remind you that you can ask questions through the console throughout the Webcast, and we’ll select several to be answered by our speakers during our closing Q&A. To ask a question, click the questions tab on the bottom of your screen. Type your question in the box along with your company name and submit it. In case we run out of time during our Web cast, we will follow up on your question via e-mail. Now, on to our presenters. Joining us today is Bob Blough, Director of Product Marketing for the Liebert Precision Cooling business of Emerson Network Power. Bob is responsible for providing leadership and direction for precision cooling product development including room, rack and supplemental cooling solutions. Welcome Bob. Bob B: Thanks Thom, I’m looking forward to sharing the latest high-density cooling strategies with our audience today. (ad lib)… Thom: Also joining us is Anthony Cataliotti, Consulting Manager for the Data Center Efficiency Practice for Sun Microsystems in the Americas. Thanks for joining us to discuss how Sun is managing escalating heat densities, Anthony. Tony: Thanks for having me Thom. (ad lib)… Thom: Well then, let’s get started. Bob, tell us about the latest strategies for taming rising heat densities in today’s data centers. Bob B: Sure Thom…
  • …but before we get into that, Let’s recognize that while high densities can be a challenge for cooling, higher density IT architectures offer considerable benefits that make it a very attractive design strategies. With high density IT architectures, you are consolidating more IT compute capabilities into a smaller area which allows for either more compute capability in an existing data center or the opportunity to significantly lower capital costs by designing smaller data centers with less physical infrastructure. With this in mind, let’s explore cooling strategies that enable you to get more IT into your existing data centers or enable architecture designs for future data centers that can dramatically lower physical infrastructure costs.
  • So let’s take a look at some of the challenges that data center managers are facing today.
  • This past years business environment has greatly focused us on the importance of efficiency. Both in terms of providing the right amount of initial equipment as well as the importance of getting the most performance out of that equipment with the least amount of energy. The rapid pace of continuous improvement in server capabilities continues. The US Department of Energy and the Environmental Protection Agency are both focused on data center energy consumption. And the growth and business criticality of IT applications continues to expand at very high rates. What does all of this mean to us for data center cooling strategies? It means that our designs are no longer a straight-forward match of IT load and cooling capacity with even heat load distribution throughout the data center. To illustrate these points, the next few slides with share recent survey results from the Data Centers Users Group.
  • The Data Centers Users Group is an international group of more than 2,000 data center managers that meet twice a year to discuss best practices and share ideas. Part of these events is very comprehensive survey of current topics, concerns, and operational information that enables these data center managers to learn from other companies dealing with similar data center challenges. This table shows that high heat density has consistently been the #1 concern identified in the survey since 2005 . Energy efficiency was not identified as a concern as recently as four years ago, but has dramatically jumped to be the #2 concern. Each respondent identifies their top 3 concerns so the percentages will exceed 100 for each survey column; the results in the table reflect the trends of the importance of each of these common concerns.
  • This year’s survey also fond that the current economic climate has impacted some industries more significantly than others, but as these results show, the impact is widespread with nearly one-third experiencing staff reductions and more than 60% having budgets cut. Reducing energy consumption has shifted to become a higher priority that is requiring action to be taken to become more efficient. This can be a challenge with existing data centers as often energy efficiency was not a high design criteria several years ago when the data center was built. Opportunities do exist to improve the energy efficiency of the cooling equipment in existing data centers and we’ll discuss these in a few slides.
  • An interesting trend the past few years, has been the average heat load for each rack in the data center. It was only a few years ago that average rack densities were 2-3 kiloWatts. Now the survey is reporting average densities above seven with expectations for averages above 10 in the very near future. As important as this average density is, it is typically more important to understand the variation in rack heat densities. It is quite common to see a data center that has an average rack density of 6 or 7 kilowatts have some rack densities of 12 or 15, while others are under two. This variation and diversity throughout the data center requires very careful planning and cooling strategies that are flexible enough to efficiently cool the high density racks without wastefully over-cooling the low density racks.
  • So let’s take a look at some of the factors behind these concerns.
  • The four rack illustrations in the top of this slide show how the heat density of fully populated high performance server racks have changed over the past 10 years. While many people are not deploying 40kW racks today; it is typically not because that lack the desire for this performance. It is quite common that the old “rules of thumb” that used to guide data center design are limiting how the IT equipment is deployed in their data centers today . Rules such as 75 watts per square foot and servers in the bottom third of the rack can significantly limit server deployments. This approach adversely impacts the overall efficiency of the data center by requiring more and more racks to “spread out the server heat load”. These additional partly loaded server racks then often create the impression that a bigger and often new data center is required. I’d like to propose that the more efficient approach is to break the old rules of thumb, and get more out of your data centers through high density cooling strategies.
  • High density architectures are characterized by adding higher and higher density servers, such as blade servers to a single rack. While there are benefits to supporting more computing power in less space, it also comes with its challenges. Server racks with more than 10kW of heat load require a significant amount of air for cooling. With high density architectures, the air distribution strategies become a very critical part of the design. As these two data center floor plans illustrate, the uneven distribution of high density rack densities on the right may require cooling strategies that differ from those deployed on the left. The cooling strategy needs to incorporate not only sufficient total cooling capacity, but also ensure that the correct amount of air is delivered to the desired location and that hot air recirculation and cool air bypass losses are minimized. While all servers vary from each other, and commonly have varying airflow levels as inlet temperatures change, a common average for reference has been 100 cfm of cool air for each kW of IT server load. Understanding the airflow characteristics of your servers is very important as you proceed with higher and higher density architectures because of the challenges of moving sufficient volumes of air throughout the data center efficiently.
  • Earlier, I mentioned the importance of energy efficiency as well as the focus of the US Department of Energy on data center energy consumption. The pie chart in the bottom illustrates why. Typically, about half of the energy consumed by a data center is for the useful work of the IT equipment. The other half is consumed by the supporting infrastructure with cooling representing the majority of this energy consumption. Fortunately, there are many opportunities to save energy through simple steps that can significantly improve the efficiency of your cooling system. The low hanging fruit opportunities that I’ve seen in nearly every data center that I’ve visited are (1) air management – cool air bypassing the servers through cable openings and hot air recirculating back through racks without blanking panels. (2) temperature and humidity setpoints of the CRAC units – typically set lower than necessary as well as conflicting setpoints conditions for multiple units in a room, and (3) excessive number of units operating – networking the units together in a teamwork mode enables more efficient cooling system performance while still ensuring the availability of backup cooling capacity if needed.
  • Now that we understand the challenges associated with high-density infrastructures, let’s dive in on opportunities for resolving them.
  • Designing for Density: Dynamic Cooling Strategies for High-Density Environments

    1. 2. <ul><li>Designing for Density: </li></ul><ul><li>Dynamic Cooling Strategies for </li></ul><ul><li>High-Density Environments </li></ul>
    2. 3. Agenda <ul><li>Emerson Network Power overview </li></ul><ul><li>Cooling Design Strategies for High Densities of Today and Extreme Densities of Tomorrow , Bob Blough </li></ul><ul><li>Modular Cooling Design for Energy-Efficient Data Centers , Anthony Cataliotti </li></ul><ul><li>Q&A </li></ul>Anthony Cataliotti Consulting Manager Data Center Efficiency Practice Americas Sun Microsystems Bob Blough Director of Product Marketing Liebert Precision Cooling Emerson Network Power
    3. 4. Cooling Design Strategies for High Densities of Today and Extreme Densities of Tomorrow
    4. 5. Challenges for the Data Center
    5. 6. Trends affecting data center operations <ul><li>Technology needs to keep pace with business demands </li></ul><ul><li>Data centers becoming more complex and supporting higher densities </li></ul><ul><li>Budgets are either frozen or being reduced </li></ul><ul><li>Energy efficiency initiatives are becoming higher priority </li></ul><ul><li>Data center managers being asked to do more with less </li></ul>
    6. 7. Data Center Users’ Group survey: Top facility concerns <ul><li>Heat density still #1 issue. </li></ul><ul><li>Energy efficiency now a top concern. </li></ul>What are your top three (3) facility / network concerns? Spring 2005 Fall 2007 Spring 2008 Spring 2009 Heat density (cooling) 78% 64% 56% 55% Power Density 55% 50% 35% Energy efficiency (energy costs & equipment efficiency) 0% 39% 40% 47% Adequate monitoring / data center management capabilities 18% 27% 43% 46% Availability (uptime) 57% 33% 45% 41% Space constraints / growth 23% 29% 26% 29% Data storage 0% 6% 4% 11% Technology changes / change management 23% 15% 12% 11% Security (physical or virtual) 17% 10% 7% 8% Data center consolidations 13% 10% 13% 7% Other 1% 5% 1% 5% Regulatory compliance 10% 4% 2% 3%
    7. 8. Data Center Users’ Group survey: Current economic condition <ul><li>Budget cuts #1 result. </li></ul><ul><li>Energy efficiency is becoming a high priority. </li></ul>How has the current economic environment affected your organization? (Select all that apply) Spring 2009 Budget cuts 61% Reducing energy usage has become a high priority 44% Data center build / expansion delayed 35% Staff reductions 31% Other 13%
    8. 9. Data Center Users’ Group survey: Increasing densities <ul><li>When budgets permit, more than half of respondents indicated future facilities would be designed to support densities of between 10 kW and 20 kW per rack. </li></ul><ul><li>This is significantly higher than the 7.4 kW average that the survey shows is supported by current facilities. </li></ul>For your next data center build or expansion, which are you more likely to build? Spring 2009 Low density (Average < 4 kW/rack) data center 1% Medium density (Average = 5-9 kW/rack) data center 34% High density (Average = 10-20 kW/rack) data center 52% Extreme density (Average >20 kW/rack) data center 13%
    9. 10. Progressing to High-Density
    10. 11. Managing server density and the progression to high-density Old design strategies limit the number of high-density servers that can be loaded into a single rack.
    11. 12. <ul><li>Getting air out of the racks </li></ul><ul><li>Hot air mixing with the inlet of other racks </li></ul><ul><li>Diversity of loads in the data center </li></ul><ul><li>Not aware that more fans create heat </li></ul><ul><li>Flexibility of “on demand cooling” </li></ul>Challenges associated with high-density architectures The average server replacement cycle is 3 – 4 years.
    12. 13. Source: EYP Mission Critical Facilities Inc., New York Data Center Power Draws Cooling presents an opportunity for energy savings <ul><li>Sources of energy waste </li></ul><ul><ul><li>Fans / blowers running on redundant units </li></ul></ul><ul><ul><li>Lack of air containment (cable openings, room leakage) </li></ul></ul><ul><ul><li>Unnecessary cooling unit cycling on and off </li></ul></ul><ul><ul><li>Lack of humidification control between units </li></ul></ul><ul><ul><li>Mixing of hot and cold air lowering the effectiveness of the cooling unit </li></ul></ul><ul><ul><li>Excess fan energy that turns into heat </li></ul></ul>Cooling About 37%-45%
    13. 14. To view this presentation in its entirety, visit: