Options For Energy Reduction In Data Centres.

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Options for data centre optimisation and energy reduction

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Options For Energy Reduction In Data Centres.

  1. 1. BYRNE DIXON HAS BRIGHT IDEAS Controlling the energy use in IT server rooms
  2. 2. BYRNE DIXON ASSOCIATES How to reduce energy usage in the Server Room. 1 Define Data Centre Efficiency. Energy Efficiency Metrics 2 Analysis of our current environment. Data Centre power usage in Europe Guidelines for future power reduction. 3 Server Room Efficiency Strategy. Cooling System Overview IT Server Efficiency Server Room Efficiency Mechanical Plant Efficiency Free Cooling Electrical Distribution 4 10+ Easy Steps Measures which can easily be implemented without effecting business continuity.
  3. 3. BYRNE DIXON ASSOCIATES 1 Define Data Centre Energy Efficiency The Green Grid, an industry based consortium dedicated to developing and promoting efficiency for data centres and information services, has adapted the terms power usage effectiveness (PUE) and data centre efficiency (DCE). PUE (power usage effectiveness) = Total Facility Power (Green Grid 2007) IT Equipment Power The reciprocal of the PUE is the term data centre efficiency (DCE) which takes the following form: DCE ( data centre efficiency) = IT Equipment Power (Green Grid 2007) Total Facility Power
  4. 4. BYRNE DIXON ASSOCIATES 2 Analysis of our current environment At the time of the Efficient Servers survey (2006). Data Centre power usage in Europe (EU15 + Switzerland) was 39.6TWh. Server power usage was at 14.7TWh for 6.77 million installed servers. This number increased by 37% between 2003 and 2006. (See www.efficient-server.eu) Current PUE is = Total Facility Power = 39.6TWh = 2.69 IT Equipment Power 14.7TWh For every 1Kw of IT equipment we require 1.6Kw of electrical power to facilitate it.
  5. 5. BYRNE DIXON ASSOCIATES 2 Analysis of our current environment In Practice: In 2000 the average electrical load was 1kw per rack, by 2004 it had risen to 3kw and in 2008 it has risen to 6kw per rack with an average design load of 10-12kw. We predict that this trend will continue. By 2010 the average rack load shall rise to 8kw and the average design load to 16kw.
  6. 6. BYRNE DIXON ASSOCIATES 2 Analysis of our current environment The two most significant areas are HVAC and the UPS and these are the areas which we shall consider.
  7. 7. BYRNE DIXON ASSOCIATES 3 Data Centre Efficiency Strategy. 3.1 Cooling System Overview 3.4 Mechanical Plant Efficiency Data centre cooling process CRAH Vs CRAC units. Target areas for increased efficiency CRAH system efficiency Chiller efficiency (COP) 3.2 IT Server Efficiency CRAC system efficiency Technology refresh Electronic expansion valves Utilisation/Virtualisation. 3.3 Server Room Efficiency 3.5 Free Cooling Temperature and humidity CRAH System CRAH coefficient of performance COP Evaporative pre-cooling Effective air distribution CRAC system CRAH electrical efficiency Additional CRAC free cooling options Kyoto Cooling 3.6 Electrical Distribution UPS Systems
  8. 8. BYRNE DIXON ASSOCIATES 3.1 Cooling system overview.
  9. 9. BYRNE DIXON ASSOCIATES 3.1 Cooling system overview.
  10. 10. BYRNE DIXON ASSOCIATES 3.2 IT Server Efficiency Technology Refresh The latest energy efficient servers have reduced power consumption and improved performance. Upgrade of a server can reduce energy consumption by 15% Utilisation/Virtualisation The industry average for server utilisation is 20% (LBNI). Through the implementation of the latest virtualisation techniques the utilisation factor can rise to 80%.
  11. 11. BYRNE DIXON ASSOCIATES 3.3 Server Room Efficiency Efficiency Basics – Coefficiency of performance 3.3.1 3.3.2 Temperature and Humidity Requirements 3.3.3 Effective Air Distribution Under-floor Air Balancing and Direction Rack Air Distribution Room Air Distribution 3.3.4 CRAH/CRAC Electrical Efficiency 3.3.5 EMBS vs Punker 3.3.6 EC Motors 3.3.7 N+1 Redundancy Operation
  12. 12. BYRNE DIXON ASSOCIATES 3.3.1 Efficiency Basics - Coefficient of Performance Coefficient of Performance (COP) = Cooling Output = Qi Work input Wnet Increase COP = Reduce area Wnet = Decrease Condensing temp and increasing evaporator temp.
  13. 13. BYRNE DIXON ASSOCIATES 3.3.2 Temperature and Humidity Requirements ASHRAE Recommendation Temperature 20 – 25 degC Humidity 40 – 50%Rh
  14. 14. BYRNE DIXON ASSOCIATES 3.3.2 Temperature and Humidity Requirement ASHRAE Recommendation Temperature 20 – 25 degC Humidity 40 – 50%Rh To raise the air output of a 60kw CRAC unit from 30% to 40% RH requires 7.5kw (Approx €1k/Kw/yr) Dry Bulb = 26 deg C Dry Bulb = 20 deg C RH = 30% To reduce the air output of a RH = 40% 60kw CRAC unit from 45% to DP = 6 deg C DP = 6 deg C 40% RH 11.5 kw W = 5.8g/kG W = 5.8g/kG (Approx €1k/Kw/yr) Same level of moisture – different RH
  15. 15. BYRNE DIXON ASSOCIATES 3.3.2 Temperature and Humidity Requirement ASHRAE Recommendations 20-25ºC room temperature. Ignore room temperature because its misleading. Think cold aisle air temperature and return air temperature Supply enough segregated cold air at the right temperature and return temperature will be high. Increase CRAH COP = Increase Return Air temperature = Effective Air Management 100kw of cooling at 26degC requires 19.6kw of electricity 100kw of cooling at 21degC requires 28.5kw of electricity 8.9kw represents a 31% reduction in CRAC unit power consumption. 8.9kw shall cost us € 9,356.00 over the year. COP (Coefficient or performance) = Cooling output Kw Electrical Power Input
  16. 16. BYRNE DIXON ASSOCIATES 3.3.3 Effective Air Management = Step 1 Balance under-floor air pressure Through CFD analysis we can analyse the layout of a room to ensure airflow balance. Eddy Currents and Rivers below floor Creates hotspots above floor
  17. 17. BYRNE DIXON ASSOCIATES More balanced pressure and airflow. Sub floor partitioning can divert the airflow and also reduce the velocity therby balancing the pressure.
  18. 18. BYRNE DIXON ASSOCIATES 3.3.3 Effective Air Management = Step 2 Rack airflow management Blanking Plates Side Panels Koldlok Airguard Perforated Doors
  19. 19. BYRNE DIXON ASSOCIATES 3.3.3 Effective Air Management = Step 2 Rack airflow management WWW.BYRNEDIXON .COM WWW.BYRNEDIXON .COM With Blanking Plates Without Blanking Plates
  20. 20. BYRNE DIXON ASSOCIATES 3.3.3 Effective Air Management = Step 3 Room airflow management Cold Aisle Containment Hot Aisle Containment WWW.BYRNEDIXON .COM
  21. 21. BYRNE DIXON ASSOCIATES 3.3.3 Effective Air Management = Step 3 Room airflow management Cold Aisle Containment WWW.BYRNEDIXON .COM WWW.BYRNEDIXON .COM
  22. 22. BYRNE DIXON ASSOCIATES 3.3.3 Effective Air Management = Step 3 Room airflow management Hot Aisle Containment WWW.BYRNEDIXON .COM WWW.BYRNEDIXON .COM
  23. 23. BYRNE DIXON ASSOCIATES Hot Aisle Containment WWW.BYRNEDIXON .COM WWW.BYRNEDIXON .COM Cold Aisle Containment
  24. 24. BYRNE DIXON ASSOCIATES Project : Reinsurance Company Location : Bermuda Before Optimisation WWW.BYRNEDIXON .COM WWW.BYRNEDIXON .COM
  25. 25. BYRNE DIXON ASSOCIATES Project : Reinsurance Company Location : Bermuda After Optimisation WWW.BYRNEDIXON .COM WWW.BYRNEDIXON .COM
  26. 26. BYRNE DIXON ASSOCIATES Project : Reinsurance Company Location : Bermuda After Optimisation WWW.BYRNEDIXON .COM WWW.BYRNEDIXON .COM
  27. 27. BYRNE DIXON ASSOCIATES 3.3.4 CRAH/CRAC Unit Electrical Efficiency CRAH Unit Electrical Efficiency Centrifugal Fans : Forward Curved Impeller Vs Backward Curved Impeller
  28. 28. BYRNE DIXON ASSOCIATES 3.3.4 CRAH/CRAC Unit Electrical Efficiency Centrifugal Fans : Forward Curved Impeller Vs Backward Curved Impeller Forward Curved Fan Backward Curved Fan Low velocity 6 m/s High velocity 15m/s High pressure Low pressure Efficiency 65-75% Efficiency 50-60%
  29. 29. BYRNE DIXON ASSOCIATES 3.3.4 CRAH/CRAC Unit Electrical Efficiency EC (Electronic Commutation) Fans 80% efficient Vs 40% for Ac fans DC driven, no pf losses Smaller profile, reduced resistance in flow. Combined in CRAH unit can reduce power by 50% Higher efficiency at part load
  30. 30. BYRNE DIXON ASSOCIATES 3.3.4 CRAH/CRAC Unit Electrical Efficiency
  31. 31. BYRNE DIXON ASSOCIATES 3.3.4 CRAH/CRAC Unit Electrical Efficiency EC fan motor profile AC fan motor profile
  32. 32. BYRNE DIXON ASSOCIATES 3.3.4 N+1 Redundency Operation. If we increase the fan speed by 33% we increase the electrical load by 180% (Third fan Law)
  33. 33. BYRNE DIXON ASSOCIATES 3.4 Mechanical Plant Efficiency 3.4.1 CRAH Vs CRAC units. 3.4.2 CRAH System 3.4.3 Chiller efficiency (COP) 3.4.4 CRAC System 3.4.5 Electronic Expansion Valves
  34. 34. BYRNE DIXON ASSOCIATES 3.3.4 CRAH Vs CRAC Units CRAH units CRAC units Water or Glycol cooled by chiller, water tower/dry cooler Refrigerant cooled at external Condenser Generally used in large facilities. Hybrid water precooling Chilled water temp may be raised to increase efficiency Generally Used in smaller facilities (Remove latent cooling) Refrigerant temperature is set. More opportunity for efficiency and free cooling
  35. 35. BYRNE DIXON ASSOCIATES 3.3.4 CRAH Unit operation 1 Chiller 5 Chiller Refrigerant 2 Chilled Water Loop 3 Condenser/Dry Cooler 4 Condenser water loop CRAH Unit operation
  36. 36. BYRNE DIXON ASSOCIATES 3.3.4 Chiller Efficiency Chiller efficiency is governed by the difference in temperature between the chilled water and the condenser water. The lower the differential temperature the higher the efficiency. Lowering the condensor temperature is more difficult that raising the chiller temperature which is easier to implement and predict. Each one degree increase in chilled water temperature increases the efficiency 3-4%. But each 1 degree raised reduces the CRAH capacity by 10% unless the return air temperature is raised as well. By raising the chilled water temperature above the dew point we will eliminate latent cooling.
  37. 37. BYRNE DIXON ASSOCIATES 3.3.4 CRAC Unit operation 1 Evaporator 2 Compressor 3 Expansion valve 4 Refrigerant Loop CRAC Unit operation
  38. 38. BYRNE DIXON ASSOCIATES 3.3.4 Electronic Expansion Valve Electrical consumption is governed by work carried out by the Compressor. The work at the compressor is dependent on the system pressure. A proportional electronic expansion valve can vary the pressure in accordance with the Cooling load required Outside air temperature. By varying the valve position we can minimise the condensing pressure and maximise the evaporation pressure. Hence reduce the amount of work performed and energy used. May be requested as an option from suppliers.
  39. 39. BYRNE DIXON ASSOCIATES 3.5 Free Cooling 3.5.1 Free Cooling Hours 3.5.2 CRAH System 3.5.3 Evaporative precooling 3.5.4 CRAC System 3.5.5 Additional CRAC free cooling options 3.5.6 Kyoto Cooling
  40. 40. BYRNE DIXON ASSOCIATES 3.5.1 Free Cooling Hours Number of hours below 13 deg C Dublin Airport Shannon Airport Mean (1977 to 2006) Mean (1977 to 2006) Number of hours with Number of hours with temperatures <= 13 year Month temperatures <= 13 deg. C month deg. C 2006 1 741 1 742 2006 2 674 2 674 2006 3 730 3 728 2006 4 679 4 649 2006 5 576 5 506 2006 6 352 6 278 2006 7 170 7 105 2006 8 193 8 122 2006 9 330 9 263 2006 10 577 10 534 2006 11 685 11 675 2006 12 735 12 736 6442 6012
  41. 41. BYRNE DIXON ASSOCIATES 3.5.2 CRAH System Free cooling chiller which combines a DX condensor and a free cooling coil Can provide full and partial free cooling Free cooling available for 75% of the year Available in stages for part load Free Cooling Chiller Indirect Free Cooling
  42. 42. BYRNE DIXON ASSOCIATES 3.5.3 Evaporative Precooling Can be installed to existing chillers Requires additional maintenance Evaporative Cooling Direct Free Cooling
  43. 43. BYRNE DIXON ASSOCIATES 3.5.4 CRAC System CRAC System Hybrid system combining water and refrigerant loops Dry cooler provides cold condenser water to the refrigerant condensor Also precooling the air in the CRAC unit
  44. 44. BYRNE DIXON ASSOCIATES 3.5.5 CRAC System - Additional options for incorporating free cooling to CRAC units
  45. 45. BYRNE DIXON ASSOCIATES 3.5.6 Kyoto Cooling System Kyoto is the use of outside air to provide cooling to the server room. < 21ºC Kyoto cooling only 95% 21-26ºC Kyoto cooling plus compression 5% > 21ºC Compression cooling only < 1%
  46. 46. BYRNE DIXON ASSOCIATES 3.5.6 Kyoto Cooling System
  47. 47. BYRNE DIXON ASSOCIATES 3.5.6 Kyoto Cooling System Contain Cold Aisles Allow cold aisle air to raise from 16ºC up to 22ºC Increase hours of free cooling Return temperature at 28-37ºC No humidity transfer across wheel.
  48. 48. BYRNE DIXON ASSOCIATES 3.6 Electrical Efficiency Specify UPS based on efficiency at full and part load Newer UPS have quoted very high efficiency at 50% load Passive Stand-by Topology High efficiency, low cost Does not condition the mains
  49. 49. BYRNE DIXON ASSOCIATES Data centre power usage before and after optimisation. The two most significant areas are HVAC and the UPS and these are the areas which we shall consider.
  50. 50. BYRNE DIXON ASSOCIATES 4 10 + Easy Steps Measures which can be implemented without effecting business continuity. 1 Implement a hot aisle - cold aisle layout. 2 Reduce air loss 3 Install blanking plates, air guards and, perforated doors. 4 Install sub floor partitioning to balance the airflow and pressure Balance the load in the room – match the load to the airflow 5 6 Check the location of air distributing floor tiles, relocate or provide additional. 7 Replace perforated floor tiles with air grills. 8 Install containment between the hot and cold aisles 9 Widen the temperature and humidity bands 10 Bring all units CRAC units on at lower fan speed. Ensure two free tiles between cabinets in cold aisle – Bring cabinets to edge of floor tiles 11 Maintain filters – Ensure filters with minimum pressure drop are installed. 12 13 Reset chilled water temperature incrementally after return air temperature has risen. Check for and eliminate free cooling – Is there water coming from the condensate drain 14

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