1 Google’s Green Data CentersNetwork POP Case Study; By Google.

2 Introduction Every year Google saves millions of dollars and avoids emitting tens of thousands of CO2 thanks to their Data Center Sustainability efforts. According to Google their facility use half the energy of a typical data center Google runs many large propriety data centers but also maintain several smaller networking rooms called POPs or “Points of Presence”. These case study will focus on these smaller room, describing best practices and simple changes one can make to save lots of dollars each year.

3 Little Investment yields bigger profitsGoogle spent $25,000 to optimize their room’s air flow and reduce air conditioner use. These $25,000 little investments in plastic curtains, air return extensions, and a new air conditioner controller returned to a savings of $67,000/year. The most important thing to notice is that, all this things implemented without any operational downtime.

4 Best Practice #1 – Measuring PerformanceIT Equipment Energy Facility Overhead Energy 𝑃𝑈𝐸= 𝐼𝑇 𝐸𝑞𝑢𝑖𝑝𝑚𝑒𝑛𝑡 𝐸𝑛𝑒𝑟𝑔𝑦+𝐹𝑎𝑐𝑖𝑙𝑖𝑡𝑦 𝑂𝑣𝑒𝑟ℎ𝑒𝑎𝑑 𝐸𝑛𝑒𝑟𝑔𝑦 𝐼𝑇 𝐸𝑞𝑢𝑖𝑝𝑚𝑒𝑛𝑡 𝐸𝑛𝑒𝑟𝑔𝑦

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6 Best Practice #2 – Optimizing air flowCooling is the largest contributor to facility overhead energy. The most important step in optimizing air flow is preventing hot and cold air mixing. There is no single right way to do this. Localized hot spots are problematic for machines and trigger CRACs to turn on unnecessarily. Proper placement of temperature monitors and using computer modeling helps to quickly identify and eliminate hot spots.

7 Best Practice #3 – Turning up the thermostatIt has long been believed that IT equipment needs to run at low temperatures – between 15°C/60°F and 21°C/70°F. Most IT equipment manufacturers spec machines at 32°C/90°F or higher, so there is plenty of margin. In addition, most CRACs are set to dehumidify the air down to 40% relative humidity and to reheat air if the return air is too cold. Simply rising the temperature from 22°C/72°F to 27°C/81°F in a single 200kW networking room could save thousands of dollars annually in energy cost.

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9 Immediate improvementsIn addition to PUE they needed to measure cooling, hoping to improve cooling at point where they can shut off some CRACs After installing temperature monitors and examining airflow, they created thermal models using computational fluid dynamics (CFD) to run air flow simulations.

10 Immediate improvements stepsStep 1: Established critical monitoring points (CMPs) Step 2: Optimize air vent tiles Step 3: Increased temperature and relative humidity settings Step 4: Contained UPS(uninterrupted power supply) Step 5: improved CRAC unit controller

11 Cold aisle containmentAfter sealing off the cold aisle, saw another 0.2 drop in PUE to 2.0

12 CRAC air return extensionInstalled motion sensors to turn off the overhead lights when the room was unoccupied, which further reduced the electrical power. With these changes in place, the PUE dropped from 2.0 to 1.7.

13 Final Outcome Using computer modeling to analyze the airflow for our final setup, we can see a fairly efficient network room with far more air flowing through machines instead of bypassing them. Having made changes to one POP, they applied the same changes to others, recording improvements each step of the way. PUE was checked using data collected every second over an 18 month period, and each PUE value contains an average of 86,400 data points. The results are consistent for every POP in which google implemented these efciency improvements.

14 Final Outcome Cont. Data center energy efficiency retrofits are a good example of where smart business and environmental stewardship coexist. In the POP in our case study, a capital investment of $25,000 led to a yearly energy savings of over 670MWh, saving $67,000 in yearly energy expenses. In addition, each improvement paid for itself in less than a year and will save hundreds of thousands of dollars throughout the lifetime of the equipment.

15 Some POPs data after improvementsThe best practices described in this case study form the key elements of Google’s power optimization strategies.

16 Thank You