Recapture Capacity for Existing. and Airflow Optimization

Transcription

1 Recapture Capacity for Existing Data Centers Through Cooling and Airflow Optimization

2 Introduction Challenges and Trends Agenda Cooling & Airflow Optimization Takeaways

3 Learning Objectives Recognize opportunities that can optimize an existing facility s operational performance and PUE. Identify fundamental improvements that can be implemented within a legacy facility s equipment limitations. d d d d h i di Better understand advanced techniques and improvements that can provide greater insights into a facility s operational characteristics.

4 Introduction Many existing data centers have inefficiencies that can be reduced through cooling and airflow optimization. The result of this optimization is not only a data center that operates in a MORE EFFICIENT manner, but one that may RECAPTURE previously unusable or lost capacity. We will review the challenges present in typical existing data centers and how they can be addressed in a manner that can improve operational performance.

5 How is Capacity Defined? Data center CAPACITY is the total amount of IT equipment (in terms of power) that the facility can FULLY support. It is dependent on several factors, including: Physical Space Network Bandwidth Available Power Cooling Capacity

6 Data Center Challenges What are the industry drivers & challenges? Compaction and increasing power density of IT equipment Virtualization and consolidation higher & steadier loads Increased networking requirements More energy efficient operation / lower PUE How can we meet these challenges in an existing data center? What were the design power densities? Have the ITE deployments been optimal? Is the available space, power, cooling, and network capacity all of equal concern?

7 Increasing Power Density of ITE 2X Density

8 Virtualization and Consolidation In legacy data centers, servers would be DEDICATED to a specific service. Their level of utilization would be proportional to the real- time demand on the hosted service. Design of today s IT equipment combined with RADICAL changes in software are DOUBLING or even TRIPLING the IT equipment demand / utilization. Very, very possible to experience demands of 50% to 75%. Demand Demand Previous Experience Virtualization ti / Technology

9 Power Usage Effectiveness Power Usage Effectiveness (PUE) is defined as the measurement of how efficiently a data center operates. PUE Rating Ideal 1.2 Very Efficient 1.5 Efficient 2.0 Average 2.5 Inefficient Alternatively, l consider PUE as: Very Inefficient i

10 Recent Greenfield Data Center PUE s PUEs continue to trend downward for Greenfield datacenters - a low PUE for a Greenfield is easier to achieve than in a retrofit situation. E PU Facebook: Google: Google: Microsoft: Yahoo: Avg. Data Center Oregon Belgium Fleet Chicago New York (Uptime Institute)

11 Design vs. actual ITE deployment Power (KW) Design Distribution Homogeneous Load 0 Actual Deployment Mixed Load

12 Inefficiencies Reduce Available Capacity Due to a lack of available cooling ONLY 10% of the data center capacity remains this will result in stranded power capacity. 100% Capa acity Used 80% 60% 40% 20% 0% Current Used Capacity Predicted Max. Cap. Based On Cooling Constraints Ideal Capacity

13 Overcooling, Yet Still Hot Spots? Due to the complexity of a data center environment, a space can be overcooled, yet hot spots still form. ASHRAE Temp ( F) T > < T < < T < < T < 64.4 T<59 Hot Spots Still Present Hot Spots 4 CRAC Units 7 CRAC Units

14 Overcooling, Yet Still Hot Spots? Total IT Load: 906 kw Total Cooling Capacity: 1160 kw (28% Excess Cooling) Racks range from 5.2 to 10 kw ASHRAE Temp ( F) Hot Spots T > < T < < T < < T < 64.4 T < 59

15 Cooling & Airflow Optimization

16 Maximize Available Cooling Available cooling is often a limiting factor in data center capacity. How can we maximize available cooling? Optimize Airflow Measure current performance & rebalance Eliminate mal-distributed air & separate hot / cold airstreams Increase Efficiency & Operational Performance Change control setpoints Increase operational temperatures & delta Ts Maintain i Improved dcooling Continued monitoring of data center conditions Use CFD to simulate cooling requirements prior to future IT equipment deployments

17 Air Measurement Points ASHRAE TC 9.9 recommended measurement points at the IT equipment inlet for installation verification and troubleshooting. 17

18 Airflow Optimization Various techniques are available to ensure cooling is getting to where it should be and at the proper conditions: Blanking Panels Hot / Cold Aisle Containment Floor Tile Balancing Increasing Underfloor Static Pressure CRAC Fan Speed Optimization Underfloor Baffles Plenum and Floor Sealing An invaluable tool in the optimization process is CFD MODELING. It allows you to test potential cooling solutions virtually, before committing to a final design.

19 Mal-Distributed Air Mal-distributed air is not reaching its intended destination, both wasting energy and limiting the amount of cooling available to the IT equipment. Mal-distribution of air is caused by: Leakage through ducts / raised flooring (often ranges from 5% to 15% of the total cooling airflow) Unsealed raised floor cutouts such as cable openings Consider using brush seals, grommets, etc. Incorrectly located air outlets / perforated floor tiles Air outlets should ONLY be in cold aisles near active IT equipment

20 Blanking Panels Blanking panels are an affordable solution for maximizing supply air effectiveness. Panels Missing Recirculated Air Without Blanking Panels 50% of Racks Above ASHRAE Recommended Without Side Panels With Blanking Panels & Side Fillers 0% of Racks Above ASHRAE Recommended

21 Blanking Panels Blanking panels are an affordable solution for maximizing supply air effectiveness. Side SdePanels esmissing Recirculated Air Without Blanking Panels 50% of Racks Above ASHRAE Recommended Without Side Panels With Blanking Panels & Side Fillers 0% of Racks Above ASHRAE Recommended

22 Floor Tile Balancing The tile layout must be designed to match the IT equipment in both location and amount of airflow. ITE Thermal Report (condensed) Description Heat Release Airflow (CFM) (Watts) Typical Max Minimum Full Typical Adjust floor damper settings to minimize BYPASS AIR (air that does not enter the server is WASTED CAPACITY) Bypass Air

23 Increasing Underfloor Static Pressure The UNDERFLOOR STATIC PRESSURE is important in maintaining proper airflow throughout the data center. Typical readings range from 0.01 to approximately 0.20 in. W.G. Advantages of higher static pressure: More resiliency in case of lost CRAC unit Higher flow rates through grilles More consistent flow rates How to overcome low static pressure: Increase fan speed Reduce leakage Adjust damper positions

24 Increasing Underfloor Static Pressure Example 1: Dampers Set to 50% Open Static Pressure: to in. W.G. Min Airflow: 46 CFM Max Airflow: 990 CFM Standard Deviation: 240 CFM

25 Increasing Underfloor Static Pressure Example 2: Dampers Set to 20% Open Static Pressure: to in. W.G. Min Airflow: 418 CFM Max Airflow: 700 CFM Standard Deviation: 61 CFM

26 Containment Panels Extend Up to Ceiling End Cap End Cap Only Full Hot Aisle Partial Hot Aisle Ceiling Panel End Cap End Cap Only Full Cold Aisle Partial Cold Aisle

27 Containment Example Data Center Overview Supply Air Temperature = 55 F 10,000 ft 2 ; Slab to Deck Height: 25 ft 138 ITE cabinets totaling 1080 kw (range from 5.2 to 16 kw) 24,000 CFM of Cooling Supply Air

28 Containment Example Full Hot Aisle Containment Supply Air Temperature = 74 F Scenario Name Supply Air Rack Max Inlet Containment Temp ( F) Failures Temp ( F) Base Model (No Containment) 55 None Full Hot Aisle Containment 74 Full

29 Increase Efficiency & Performance ASHRAE TC9.9 Green Tips contains good PRACTICAL advice for improving efficiency and performance in existing datacenters. Some considerations: Change control setpoints & increase deadbands Increase operational temperatures Reduce fan speeds More efficient humidification

30 ASHRAE TC 9.9 Thermal Envelope 2008 Criteria 2008 Low Temp 64.4 F High Temp 80.6 F Low Moisture 41.9 F DP High Moisture 60% RH & 59 F DP Legacy Data Centers 64.4 F 80.6 F We are no longer confined to such a small set of operating conditions 30

31 Precision Cooling? 2008 ASHRAE Thermal Guidelines Recommended Envelope Many Operating Points (290) Dry % Relative Humidity Bulb = = = = = = = = = = = = = = = =9 =13 =14 =15 =16 =16 =16 =16 =16 =16 =15 =15 =14 =14 =13 =13 =13 =12 =12 =11 =10 =10 =290

32 ASHRAE TC 9.9 Thermal Envelope 2011 ALLOWABLE The allowable envelope is where the IT manufacturers test their equipment in order to verify that the equipment will function within those environmental boundaries. 32

33 Reduce Fan Speeds Fan affinity laws tell us that fan power (P) is proportional to the cube of the fan speed (N), while airflow (Q) is directly proportional. This can translate into SIGNIFICANT energy savings for a fairly small reduction in fan speed. Fan Speed / Airflow (%) Fan Power (HP) Power Savings (%) Consider at total of 5 CRACs arranged at N+1 running at 100% What if they run at 80% speed?

34 Advantages of Raised Temperatures Depending on the configuration of the cooling system, raising the supply air temperature in a data center provides an opportunity for significant ADVANTAGES: Increased chiller capacity Increased chiller energy efficiency Ability to take advantage of more economizer hours In ANY data center, improved separation of fh hot & cold airstreams and airflow management can INCREASE the ΔT (return temp supply temp). Increased CRAC / CRAH capacity Potentially INCREASED capacity of piping distribution systems Increased chiller efficiency

35 Available Economizer Hours Air temperatures for Toronto (air mixing to maintain 59 F min. temp)

36 Takeaways Performance can be improved and CAPACITY can be REGAINED through optimizing airflow and cooling. For a given Total Facility load, more IT power capacity can be made available by implementing a more efficient cooling system. Modify control RANGES to ELIMINATE fighting. ASHRAE guidelines show elevated temperature ranges are possible without sacrificing reliability. CFD analysis is an invaluable tool in evaluating current & FUTURE cooling requirements. Continued Measurement & monitoring is vital for efficient i toperation.