This document discusses how improving airflow management (AFM) in computer rooms can increase cooling efficiency and save on operating costs. It introduces the Cooling Capacity Factor (CCF) metric to measure cooling output relative to IT load. Research found average data centers have 48% bypass airflow, 20% hot spots, and a CCF of 3.9, indicating overprovisioned cooling. Case studies show how optimizing AFM through techniques like closing unused cooling units can significantly reduce energy costs and cooling infrastructure needs.

1. Utilization of Computer Room Cooling
Infrastructure: Measurement Reveals
Opportunity (OPEX, CAPEX, Density)
LARS STRONG, P.E.

2. Agenda
 The State of Computer Room Airflow Management
 Understanding Your Cooling Utilization with the Cooling
Capacity Factor
 Research & Case Studies

3. The State of Airflow Management
2002 Uptime Institute Research
Bypass Airflow* 60%
Hot Spots 10%
Cooling Capacity 2.6x
2012 Upsite Technologies
Research
Bypass Airflow* 48%
Hot Spots 20%
Cooling Capacity 3.9x
*More accurately, “Raised Floor Bypass Open Area” in today’s terminology.

4. But Why?
 Cooling capacity is difficult to quantify
 It’s hard to justify initiatives, determine ROI
 Conflict of interest,
vendor influence
 No ‘one-size-fits-all’ solution
 People paying the electric bill
detached from the data center
 Few organizations have objectives clearly stated that
can be supported by cooling optimization

5. Bypass Airflow Clarified
Typical existing conditions

6. Bypass Airflow Clarified
After AFM improvements

7. Bypass Airflow Clarified
Optimized

8. High Awareness, Low Implementation
• Open holes in the floor
• Blanking panels often
missing
• Misplaced perforated tiles
• Gaps between racks

9. AFM Problems Are An Opportunity
•Money
•OpEx Savings
•CapEx Savings
•Capacity
•Cooling Capacity
•Room for IT Equipment
•IT Reliability
•Green Initiatives
•CO2 Reduction
“…an average data center could reduce its operating
expense by $32,000 annually, simply by improving
airflow management.”
- Upsite CCF White Paper

10. The Cooling Capacity Factor (CCF)
 A metric Upsite Technologies developed to determine
the cooling effectiveness of a data center. CCF
measures the cooling output relative to the IT load,
providing an accurate picture of cooling infrastructure
efficiency.

11. CCF: How It’s Calculated
 Convert the total rated (stated) cooling capacity to kW,
divide by 110% of the IT critical load (kW)
 Total rated cooling capacity (210 tons x 3.52) = 739 kW
 110% of the IT critical load = 259 kW
 CCF = 2.8 (739/259)
 Rated capacity is 280% of the load

12. The Research
Raised
floor
area (sq
ft)
# of
running
cooling
units
Raised
floor
bypass
open area
(%)
Hot spots
(% of
cabinets)
Cold spots
(% of
cabinets)
(Data from
6 sites)
Proper
perforated
tile
placement
(%)
Cooling
Capacity
Factor
(CCF)
Averages 7,527 8 48% 20% 35% 77% 3.9
Minimum 720 2 13% 0% 0% 7% 1.2
Maximum 37,000 40 93% 86% 86% 100% 32.0
Recommended n/a n/a <10% 0% 0% 100% 1.2
Conclusion: Inefficient cooling configuration / airflow management is the
problem; capacity is not the problem.

13. Case Studies
#1 - Large Financial
 Cooling unit capacity 65kW
 Total number of cooling units running 34
 Total rated cooling capacity 2,210 kW (34 x 65 = 2,210 kW)
 UPS output load 642kW
 Estimated heat load 706 kW (642 kw x 1.1 = 706 kW)
 CCF 3.1 (2,210 / 706 = 3.1)

14. Case Studies
#1 - Large Financial
 34 cooling units running
 11 units at full capacity required to support load
 Conservatively adding 5 for redundancy 16 needed
 18 cooling units could be turned off (34 – 16 = 18)
 18 units, 7.5hp fan motors = 122kW reduction
 At $0.10/kWhr, = $8,901/mo, $106,813/yr savings
 At $2,000/unit/yr maintenance $36,000/yr savings
 Total savings $142,000/yr

15. Case Studies
#2 – small (2,000 sqft) hardware manufacturer
Before conditions
 Total rated cooling capacity 645 kW
 Estimated heat load 300 kW
 CCF 2.2 (645 / 300 = 2.2)
After conditions
 Total rated cooling capacity 560 kW (after turning 2 off)
 Estimated heat load 310 kW
 CCF 1.8 (560 / 310 = 1.8)
 Reported annual savings $21,000
 8 month ROI on air flow management improvements

16. Remember
Tons x 3.517 = kWc
Cooling unit capacity
 Rated capacity at standard conditions (75 deg F, 45%Rh)
 Capacity goes up with increase in return temperature
 Capacity goes down with decrease in return temperature
 ASHRAE Guidelines
•Temperature range: 64°F to 80.6°F (18°C to 27°C)
•Dew Point range: 42°F to 60°F (5.5°C to 15°C)

17. Important Metrics
 PUE
 CCF
 Bypass open area
 Hot Spots - % of cabinets containing a hot spot
 Cold Spots - % of cabinets containing a cold spot
 Perforated tile placement - % of perforated tiles properly placed
 Ratio of supply air volume to IT equipment airflow volume

18. Questions?
Lars Strong, P.E.
Senior Engineer, Upsite Technologies
lstrong@upsite.com
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