1. COMP 4923 A2 Data Center Cooling Danny Silver JSOCS, Acadia University

2. References Chapter 8 of The Greening of IT, by John Lamb, IBM Press, 2009. Calculating Requirements for Data Centers, by Neil Rasmussen, White Paper #25, American Power Conversion (APC), 2003.White Paper #25

3. Chilly Facts Breakdown of typical electrical power use in a data centre Power, cooling and lights = 50% of total data center energy use Cooling alone accounts for 37% of energy use Second largest energy cost for data centers – 3 MW IT data center, requires 6 MW power – $5.25M a $0.10 / KWH – 10% reduction in IT load = $260,000 savings – 30% reduction in cooling = $580,000 savings

4. Background All electrical equipment produces heat Must be removed to prevent failure/fatigue Air cooling is most common approach Heat is energy and is commonly expressed in Joules, BTU, Tons, or Calories Common measures of heat output (power): – BTU per hour – Tons per day – Joules per second = Watts

5. Background In North America, specifications for power and cooling capability often provided in the legacy BTU and Tons terms Always confusing … world is moving to Watts Conversion to Watts of power (energy / time):

6. Background The bad news: – Very little energy actually used to communicate bits – Most just produces the by-product of heat The good news: – This means that the thermal output of your data center (BTU per hour) = the AC electrical power consumed (Watts)

7. So What Creates the Heat? IT Equipment UPS – Uninterrupted Power Supply Power distribution system Lighting People

8. Simple Data Centre Worksheet Excel version of above tableExcel version of above table.

9. Question Dalhousie has a 2500 sq. ft data center with a 100KW power supply. There are 400 servers in the data center that use about 150 watts max each. A maximum of 10 people work in the data center. Assume that on average the data center is working at 35% capacity. What is the thermal output of the data center (ie. how many Watts of cooling are needed)?

10. Thermal Output of a Typical Data Center

11. Video http://www.youtube.com/watch?v=B- f8WqyQPus http://www.youtube.com/watch?v=B- f8WqyQPus

12. Strategies for Increasing Data Centre Cooling Meter your data center energy use (IT, cooling) – You can reduce if you do not measure Bring cooler closer to heat source Properly seal data center Optimizing air flow Use variable capacity cooling systems to increase efficiency Place lights on motion detector switches Turn off chillers in the winter, use outside air

13. Strategies for Increasing Data Centre Cooling Properly seal data center – Keep all doors closed at all times to maintian cool air and low humidity (should be 40-55%) – Seal all cable openings – Major reason for container approach Optimizing air flow – Goal is to move max air away from equipment – Optimize rack configuration, air conditioner placement, cable management – Use hot and cold aisles

14. Strategies for Increasing Data Centre Cooling Use economizer and variable capacity cooling systems to increase efficiency – Use outside air in winter months (direct use of cool air, or use of cool air to chill A/C) – Variable number of refrigeration compressors – Digital Scroll compressor technology best

15. Future Solutions Fuel cells – replacing backup diesel generators (Fujistu, 2008, California) - Hydrogen-powered fuel cells Multicore processors -can reduce heat by 40% Embedded cooling – Liebert XD rack-level method - removes heat before it leaves the rack Chip-level cooling – chips manufactured with cooling systems embedded

16. Solutions http://www.youtube.com/watch?v=seW6qXL B0YA http://www.youtube.com/watch?v=seW6qXL B0YA http://www.42u.com/42u-rack-cooling.htm http://www.youtube.com/watch?v=9uJ93V12 S1o http://www.youtube.com/watch?v=9uJ93V12 S1o Google Data Center Tour – http://www.youtube.com/watch?v=zRwPSFpLX8I http://www.youtube.com/watch?v=zRwPSFpLX8I

17. Futures IBM'S Zero Emissions Data Center Project – http://www.youtube.com/watch?v=1J7KpgozpRs http://www.youtube.com/watch?v=1J7KpgozpRs