Optimizing Network Performance through PASSIVE AIR FLOW MANAGEMENT IN THE DATA CENTER Lylette Macdonald, RCDD Legrand Ortronics BICSI Baltimore 2011
Agenda: Discuss passive thermal management at the Rack Level Aisle Level Facility Level
What is Layer Zero TM? Solid foundation Best practices in network design Improved network performance, energy efficiency
Physical Infrastructure Is Critical to the Success of the Network Racks, cabinets, cable management and airflow systems address the needs of today s data centers, including: Ai fl M t D it P f & P t ti Airflow Management, Density, Performance & Protection, Flexibility, Scalability, & Energy Efficiency
Thermal Management at the RACK LEVEL
Understanding Thermal Management Thermal management is: Consistent cooling of IT equipment Maximizing rack population Maximizing IT footprint Thermal management is NOT: Not an air conditioning thing Not a facilities issue Not all about energy 50%+ increase in cooling capacity
Changing the Way You Look at Your Network With the right planning, the defining elements of capacity, density, efficiency and scalability can be aligned through h the infrastructure. t One basic best practice: adopt the rack as the basic building block for data center density. Energy Efficient Data Center Solutions and Best Practices, CISCO
Racks & Cabinets Optimized for Cisco Nexus Switches Use racks designed to maximize the benefits for the Nexus 7000 Series switches Passive cooling capabilities for high density server environments Advanced d cable management system reduces cable congestion and protects signal integrity Built with a high weight threshold to support a fully configured switch
Passive Thermal Management Built-in at the rack/cabinet level Baffle system maintains efficient coldaisle/hot-aisle airflow, providing maximum cooling for side-vented equipment Side rails remove the barriers to network equipment airflow Cisco Nexus 7018 in Server Rack
Open Rack Airflow Management Typical EIA relay rack with vertical cable management The same EIA relay rack with the addition of airflow baffles
Thermal Management at the AISLE LEVEL
Containment design lowers energy costs for cooling Data center managers can save 4% in energy costs for every degree of upward change in the ambient temperature. Mark Monroe, Director of Sustainable Computing Sun Microsystems The higher the temperature set-point, the greater the potential savings.
Hot or Cold Aisle Containment? Use the natural properties of airflow Cold air requires containment Hot air naturally rises Both hot and cold air must be managed
Enhance Energy Efficiency Use passive thermal management to: Prevent hot and cold airflow from mixing Isolate, redirect airflow from side-vented equipment Open airflow to network equipment Create cooling without t additional fans
Air Control Components Floor Mid-level Top-of-rack
Thermal Management at the FACILITY LEVEL
Types of CFD s Under Floor Above Floor Rack Facility Tracks the air pressure in the subfloor Tracks the air movement in the ambient room Tracks the air movement through the rack Tracks all of the above as one airflow envelope
Data Intensive Factors to consider: Rack thermal load data, including specific equipment data Obstructions AC characteristics A single, comprehensive CFD can take several hours to run Good data in, good data out
The Power of CFD modeling Visualize Analyze Predict
Visualize Data center airflow is complicated due to the variable of thermal loads created by the IT equipment. The CFD process allows for an engineer to see the invisible. Track a 1 micron particle as it flies through the room. Once we can visualize the airflow we 1 can take the next step to analyze the wherefore and the whys.
Analyze Air temperature and Relative Humidity Airflow direction and volume (CFM) Supply to the thermal load Return path to the AC Actual cooling tonnage based on return air temperature 2
Predict How changes to the airflow will increase cooling capacity How failure of each AC unit will impact the IT equipment cooling Energy savings due to optimized airflow management 3
Living Document Accurate inventory of thermal load producing equipment Regular update new IT inventory and its affect on the cooling solution Plan new installations such as high density servers
Most Data Centers Employ Flood Cooling Associated issues: Lower than necessary temperature set points Higher than required humidity set points Poor airflow requires fans to run more often Cold return air to CRAC intake reduces efficiency Wasted rack space
Most Data Centers Are Too Cold ASHRAE guidelines have just changed recommended operating temperatures es in a data center
Reasons the cooling system may not be efficient Cold air pumped into raised floor not rising through perforated tiles Mixing of hot and cold air through spaces in racks and cabinets CRAC units pulling in cold air instead of hot Too many obstacles for good airflow
CFD Services should address: Subfloor pressure balancing and cable cutout management Elimination of cabinet level l cool air loss Loss of cooling air from cold aisle areas Return air mixing with cooling air Loss of cooling air to Baseline cold aisle and 9000 Sq. Ft. isolated equipment Data Center The air patterns show areas where hot air is mixing with the cold supply air
Thermal Management applied in a DATA CENTER
Baseline CFD Subfloor
Step One CONTROL THE SUPPLY AIRFLOW Two impediments to desired air flow An imbalance of subfloor air pressure Subfloor plenum is leaking cold supply air into the room Goal: Have 140-160 CFM per floor tile in the cold aisle
Optimized p CFD Subfloor
Baseline CFD Ambient Room
Baseline Room Temperature
Step Two PREVENT SUPPLY AIR FROM FLOWING THROUGH THE EQUIPMENT RACKS Blanking Panel Goal: Stop hot exhaust air from recirculating into the equipment intake.
The Results From blocking raised floor openings, disrupting air velocity, and adding blanking panels in unused rack and cabinet space
Step Three PARTITION HOT AND COLD AISLES ABOVE THE RACKS Two cold aisles contained with Air Curtain Vinyl Panels and Air Curtain Vinyl Strip Doors The separation enabled the shut off of one 22T CRAC unit Note: This solution does not limit the use of overhead cable routing which is a common problem when using ducts or chimneys. Curtains Goal: Contain hot or cold air
Baseline Intake Airflow
Step Four DIRECT HOT EXHAUST AIR TO THE AC COIL THROUGH THE DROP CEILING VOID Prevent mixture of hot and cold air by funneling exhaust directly into the drop ceiling void Raise set point 10 F Goal: Increase CRAC unit efficiency CRAC Extension
Optimized CFD Problem Area
The Results Floor Plugs, Air Disrupters, Blanking Panels, Air Containment Curtains and CRAC Extension Before After
Step Five COMPLETE CONTAINMENT Supply air coming from the subfloor bubbles out like a water fountain Air spills in all four directions Three walls are needed to hold, or pool, the supply air so that its only direction is through the IT equipment Air Containment Booth Goal: Direct airflow through IT equipment
Optimized CFD Ambient Room
The Results Passive Air Flow and Thermal Management Floor Plugs, Sub-Floor Disrupters, Blanking Panels, Air Curtains, CRAC Extensions and Air Containment Booth Our model shows that with full containment, including isolated equipment, two CRAC units can be shut off
CRACs: Cooling & Temperatures Rack Statistics: The results of all 5 steps All racks are still between the 70 F and 80 F range Name Airflow Return Temp Supply Temp Cooling (Ton) Cooling (kw) CRAC 1 13,500 73.5 53.9 25.4 89.5 CRAC 1_1 Turned off ----- ----- ----- ----- CRAC 3 10,200 78.0 60.8 16.9 59.5 CRAC 1_2 Turned off ----- ----- ----- ----- CRAC 3_1 10,200 78.0 56.6 21.1 80.4 Two 22 ton CRAC units have been shut off Huge increase in cooling capacity of the three CRAC units
Total Passive Thermal Design Air flow management at racks, cabinets and cable management Aisle containment solutions Complete Thermal Management CFD Analysis Services
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