Transcript Session Number & Title

PAC 3.6: Airflow and Pressure Behavior:
A Practical vs Theoretical Examination
Peter Matte Sealco
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Data Center World – Certified Vendor Neutral
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Airflow and Pressure Behavior: A Practical vs
Theoretical Examination
If it works on paper, why are the results different in
my data center? This session is a real world
exploration of airflow and pressure behavior.
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Topics
• Static Pressure/CFM correlation (case study)
• Accurate airflow reading and why you can question current practices
• Airflow impact using perforated panels and high output grates
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Does the math support the claim?
• Cooling unit efficiencies. How much air am I delivering?
• True high impact cooling efficiency gains (case study)
• DCIM, I can define it. Ok, maybe not, but lets examine
• Examining containment (Pulling the curtain back, pun intended)
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Is the correlation between static pressure and CFM always textbook?
Before
After
Before
After
Before
After
Row #
Location
CFM
CFM
Temp.
Temp.
St. Press.
St. Press.
1
EMC 9900
274
348
70
68
0.045
0.033
2
SUN3263
279
339
67
68
0.043
0.040
2
RITAL 0772
255
302
68
67
0.045
0.048
2
NET 9968
261
400
69
60
0.042
0.046
4
DELL 3413
260
310
68
64
0.041
0.054
4
DELL 4839
261
415
67
65
0.042
0.055
4
APC 4919
261
280
66
64
0.043
0.058
5
HP 0541
261
345
65
57
0.035
0.059
5
EMC 9951
294
337
65
64
0.035
0.061
6
EMC 9901
296
332
65
64
0.032
0.062
6
DELL 1618
281
324
65
63
0.033
0.062
6
RITAL 0502
361
437
64
62
0.035
0.066
8
DELL 1361
278
332
65
62
0.040
0.066
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IBM 0625
274
328
64
62
0.040
0.067
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RITAL 0797
270
418
65
61
0.037
0.068
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HITACHI 0843
254
289
64
61
0.037
0.073
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SUN 0356
254
370
63
63
0.038
0.073
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SUN 1092
257
306
64
68
0.041
0.075
16
SUN 1289
361
446
71
68
0.055
0.077
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NETEZZA 0009
365
424
71
70
0.049
0.078
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HP 9914
282
355
71
68
0.056
0.079
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APC 4848
266
320
70
68
0.056
0.079
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HP 1249
388
498
67
68
0.054
0.079
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CPI 0443
389
550
65
66
0.058
0.086
Total Average
291
367
66.6
64.6
0.043
0.064
Some factors to consider
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•
•
•
How much time lapsed between
readings?
What tools are you using? Are they
calibrated?
Are BMS pressure nodes accurate?
What other environmental changes
occurred at this time?
• Different cooling units running
• Variable speed drives
• Eddy and/or Venturi effect
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How much air can I deliver? What are the true requirements and deliverables
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Volume of Air per CFM
3.124 (BTU’s per watt) X KW = BTU
BTU X 1,000 (watts) = _____
____ Divided by Delta T at the server= CFM needed
CFM Needed minus 10 -15% (factor due to racks not always at the maximum KW)
Example
3.124 X 2KW = 6.2Btuh
6.2 X 1,000(watts) = 6,200Btuh
6,200 Btuh divided by 20 (delta) = 310cfm
310 cfm – 15% = 264
Averages out to around 132 cfm per KW @ 20 degree delta
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Cooling Unit Efficiencies
30 Ton Unit
“As you can see, the full capacity of the sample CRAC unit (149kW) is
achieved when 80°F return air is returned to the CRAC unit. However, if
that return air temperature is reduced by 5°F, the output of the CRAC unit
decreases by 15 percent. If the return air temperature is decreased by 8°F,
the capacity of the CRAC unit decreases by 24 percent.”
Todd Boucher, Data Center Knowledge
Strategies for Evaluating Data Center Aisle Containment
by Industry Perspectives on March 16, 2015
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Cooling Unit Efficiencies
Standard Centrifugal Fans
Thinking Outside the Box
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•
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Can I reduce the amount of Tons to
increase airflow?
Can I install an EF Fan on a DX unit
without freezing the coil?
What are the benefits of an EC Fan?
EC Motor with Plug Fans
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Where are the biggest ROI’s Really?
Sealco’s AirSeal team implemented a Plenum Integrity Service in an 85,000 square foot enterprise data
center focusing on the following services:





Bench line airflow readings were taken of subfloor CFM, Static Pressure, Supply Air Temperature
to Servers, and Return Air Temperatures to cooling Units.
Brush grommets were installed sealing 1,222 floor penetrations totaling 466 square feet of open
space on the raised floor.
6,700 blanking plates were installed in empty cabinets
A sub-floor barrier system was installed, reducing down on facility white space by 25%.
A final, secondary set of Airflow readings were taken to both measure results and map out
excess airflow target areas on the raised floor.
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Where are the biggest ROI’s Really?
Results







Sub-floor Static Pressure: Increased 93%
Sub-floor CFM: Increased 49%
Sub-floor Temperature: Decreased 2.7 degrees CRAC Unit Return Temperature: Increased 3.2
degrees
Decreased the square footage of the cooled environment by 25%
Total Cooling Units Turned off: 29 out of 69
kWh/yr. saved: 1.599M
Return on Investment: 4 months
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Environmental Monitoring, where are the savings?
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Examining Containment
Full Containment
Hybrid/Partial Containment
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Examining Containment
Full Containment
Hybrid/Partial Containment
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Examining Containment
Full Containment
Hybrid/Partial Containment
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Examining Containment
Common comments/questions
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•
•
•
•
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Containment saves you 30%. Sure it does, go ahead and explain
Full Containment is the only method of containment
Partial Containment is the only method of containment (80/20 theory)
Hot or cold aisle containment, which is best
Cold aisle containment would make the entire room too hot to work in (one of my favorites)
Does the AHJ care? (enter sarcasm here)
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Containment Data Center Math
Bypass Air Formula = (X) x T1 + (1-X) x T2 = T3
Sample Numbers
T1 = Hot Aisle Temp =
94 degrees
T2 = Supply Temp =
68 degrees
T3 = Return Temp @ CRAC =
76 degrees
SO THEREFORE
94X + 68 (1-X) = 76
94X + 68 – 68X = 76
94X - 68x = 76 – 68
26x = 8
X = 8/26 OR 31% Lost Bypass Air Flow
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Containment Data Center Math
1 rack
= 10 kw and growing
10 kw x 8760 hrs a year
= 87,600 kwh
87,600 kwh x $0.10 / kwh
= $8,760
(104racks)
104 racks x $8,760
= $911,040 annual IT energy
costs
$900K IT energy costs x 2.32 (est. PUE) =
$2.08M
Total data center energy costs
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Containment Data Center Math
CONCLUSION:
Total Data Center Energy Costs - $2,088,000
$2,088,000 – $911,040 (IT Load) = $1,176,960 (Mech. Load)
Est. 85% of total mechanical load goes toward supporting IT load - $1,000,416
$1,000,416 x 31% Lost Bypass Airflow = $310,129.00
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3 Key Things You Have Learned During this Session
1. Not everything you read about can or should be
applied to your facility
2. Each row in your room should be looked at
individually
3. Most products do not directly save you $$, what
you do with those products does
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Thank you
Peter Matte
Vice President, Sealco
Cell: 214.457.7863
Office: 972.234.5567
[email protected]
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