1. COMP 4923 A2Data 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.

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 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

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=seW6qXLB0YA • http://www.42u.com/42u-rack-cooling.htm • http://www.youtube.com/watch?v=9uJ93V12S1o • Google Data Center Tour • http://www.youtube.com/watch?v=zRwPSFpLX8I

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