1. Energy Efficient Data Centre Design
Presenter: Tony de Francesco B.Eng Mech (Hons. Class 1)
Systems Engineer
ENERGY EFFICIENT DATA CENTRE DESIGN

2. Meet STULZ Worldwide
Since its founding in 1947, STULZ has specialised in areas requiring technological expertise and entrepreneurial flexibility.
ENERGY EFFICIENT DATA CENTRE DESIGN

3. STULZ Australia - Business Areas
As an air conditioning specialist STULZ offers a wide range of customer solutions for the high-tech areas of IT, telecommunications and automation.
In conjunction with an extensive range of precision air conditioning units, STULZ also manufacture a range of internal and external chillers for precision and comfort applications.
Precision Air Condition Units
Humidification Systems
Standalone Steam Humidification
Ultrasonic Humidification
For Close Control Areas, such as
Museums,
Archives,
Art Galleries,
Storage Rooms,
Testing Laboratories, and
Process Areas.
STULZ provides 24/7/365 days a
Year service and support through our
factory trained service technicians,
local spare parts and a range of
Comprehensive Service
Agreements.
National 1300 Support Hotline
Customer Service
STULZ also manufacture and supply
equipment for cooling cabinets,
industrial cooling and High Density
Cooling Solutions.
High Density Cooling Solutions
ENERGY EFFICIENT DATA CENTRE DESIGN

4. Topics Room Design CRAC Unit Design 3. CHW System Design
ENERGY EFFICIENT DATA CENTRE DESIGN

5. 1. Room Design
ENERGY EFFICIENT DATA CENTRE DESIGN

6. Source: ASHRAE - Thermal Guidelines for data Processing Environments, pg 10
ENERGY EFFICIENT DATA CENTRE DESIGN

7. Rack Cooling Basics
Source: HP
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8. Typical Computer Room Air Distribution
50%RH
Average, say 57%RH
23%RH
88%RH
ENERGY EFFICIENT DATA CENTRE DESIGN

9. Required Air Flow Rate: V = 100,000 / (1.21 x 15)
Rack Cooling Example ΔT
20 5 kW/rack = 100 kW
Therefore if, Q = 100,000 W
DT = (35 – 20) = 15K
Let ρA x cPA = 1.21 kJ/m³K Q V
Required Air Flow Rate: V = 100,000 / (1.21 x 15)
=> 5,500 l/s total or 275 l/s per rack
ENERGY EFFICIENT DATA CENTRE DESIGN

10. Typical Raised Floor Air Distribution Design°C °C °C
3750 l/s
@ 13°C °C
@ 35°C °C
5500 l/s
@ 20°C
4.67 7°C
12.5°C
20 racks
x 5kW ea
Q = 100kW
Power In: Pa ESP
Power In:
34 COP = 3.16
Total Power In = Fan Power + Chiller Power =
= 41.2 kW for 100 kW of rack load => η = 2.43
ENERGY EFFICIENT DATA CENTRE DESIGN

11. Direct Rack Air Cooling Total Power In = Fan Power + Chiller Power°C °C
Smaller Chiller! °C
5500 l/s
@ 20°C
Smaller CRAC! °C
17.5°C
20 racks
x 5kW ea
Q = 100kW
Power In: Pa ESP
Power In: 27 COP = 3.77
30% Power Reduction!
Total Power In = Fan Power + Chiller Power =
= 28.8 kW for 100 kW of rack load => η = 3.47
ENERGY EFFICIENT DATA CENTRE DESIGN

12. Underfloor Supply Air Distribution
Source: ASHRAE - Datacom Equipment Power Trends and Cooling Applications, Page 34
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13. Ducted Return Air Distribution
Source: ASHRAE - Datacom Equipment Power Trends and Cooling Applications, Page 35
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14. Ducted Supply & Return Air Distribution
Source: ASHRAE - Datacom Equipment Power Trends and Cooling Applications, Page 35
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15. Example: Stulz Rack Air Removal Unit
How Does It Work?
Fan assisted system that draws air through rack from either the raised floor or from the cold isle and discharges the air out of the top of the door
Features
Airflow of 830l/s delivers ~15kW of cooling
Returns air back to room at high temp, say 35°C
ENERGY EFFICIENT DATA CENTRE DESIGN

16. Liquid Cooled Racks
Source: ASHRAE - Datacom Equipment Power Trends and Cooling Applications, Page 38
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17. Stulz Liquid Cooled Rack Solutions
CyberChill
Integrated Rack Cooling Solution
RAW Rear Door Air/Water Heat Exchanger
Racks designed for 10-22kW of heat load
ENERGY EFFICIENT DATA CENTRE DESIGN

18. CyberChill: Basic Function
cooling water connection
ENERGY EFFICIENT DATA CENTRE DESIGN

19. RAW Module: Basic Function – Closed Loop
RAW Module mounts to the rear door of the rack of your choice
cooling water connection
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20. RAW Module: Basic Function – Open Loop
RAW Module mounts to the rear door of the rack of your choice
cooling water connection
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21. Stulz Liquid Cooling Intrastructure
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22. 2. CRAC Unit Design
ENERGY EFFICIENT DATA CENTRE DESIGN

23. Cooling Capacity: What does total & net sensible mean?
Input
Conditions
Function
Return Air
24° C; 45 % r. H.
8.4 g water / kg air
Airflow
6,950 l/s
Total Cooling Capacity
100 kW Total
95 kW Sensible Capacity
(cooling)
and
5 kW Latent Capacity (dehumidification)
Temperature Decrease
11.4° C
Humidity Decrease
0.3 g / kg
Cooling Air
12.6° C; 89 % r. H.
8.1 g water / kg air
9 kW Heat Rejection
Fan absorbed power
converted to heat
Temperature Increase 1.1° C
Cooling Air
13.7° C; 83 % r. H.
8.1 g water / kg air
86 kW Net Sensible
Cooling Capacity
ENERGY EFFICIENT DATA CENTRE DESIGN

24. Effect of Supply Fan Efficiency
Traditional belt driven fan technologies can reduce the available cooling capacity by as much as 10%!
Up to 30% reduction in fan power can be achieved by using highest efficiency direct driven fan technologies in lieu of typical belt driven fans.
A reduction in fan power of only 1kW would result in an energy cost saving of over $1000 p.a. and reduction of tonnes CO2/yr $0.10//kWhr and COP = 4)
ENERGY EFFICIENT DATA CENTRE DESIGN

25. High Efficiency Direct Driven EC Fans
Electronically commutated (EC) permanent magnet DC motor
Variable Speed Driven
Rotary motion of the motor is achieved via electronically switching device (electronic commutator) and not via mechanical carbon brushes and therefore wear-free requiring no maintenance
Efficiencies of up to 92%
An EC motor is simply a DC motor without mechanical brushes and commutator rings.
EC Technology began almost 30 years ago in computer and telecom applications.
ENERGY EFFICIENT DATA CENTRE DESIGN

26. Benefits of EC Fan Technology
Reduced fan power provides increased real (net) cooling capacity and reduces load on refrigeration plant
Variable airflow rate capability allows rates to be set at commissioning for optimum levels (rather than nominal levels)
Non-Maintenable item: no v-belts or pulleys – Reduction of life cycle costs
Inbuilt Softstart operation eliminating high inrush current. Particularly helpful in diesel generator mode.
ENERGY EFFICIENT DATA CENTRE DESIGN

27. Benefits if EC Fan Technology (DX Operation)
Data
A.C Belt Driven Fan
EC Direct Driven Fan
Airflow per Unit
l/s
20Pa
Cooling Capacity (Total) per Unit kW
101.5
Cooling Capacity (Sensible) per Unit
94.6
Compressor Power Consumption per Unit
22.0
Evaporator Fan Power Consumption per Unit
9.2
5.9
Condenser Fan Power Consumption per Unit
3.1
COP
4.6
EER
2.7
Operating Hours per Year per unit
hrs
8,760
Energy Pricing
$/kWhr
$0.10
Average Annual Compressor Operation
100%
96%
Total Energy Consumption
kWhrs/yr
300,293
263,256
Comparative Energy Costs
$/yr
$30,029
$26,326
Comparative Savings in Energy Costs
$3,704
Comparative Savings in CO2
tonnes/yr
40.0
Return Air Setpoint: 45%RH
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28. Dual Fluid System
Each individual CRAC unit has two independent cooling systems
Possible cooling combinations include:
CHW / CHW
Water Cooled DX / CHW
Air Cooled DX / CHW
Cooling mode can be optimised to provide most efficient method of cooling
Dual fluid system also provide increased levels of redundancy
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29. Benefits of Dual Fluid System
Reduced energy consumption by sourcing chilled water from more efficient central plant whilst providing high operational safety/system availability
Example Operating Logic:
B/H Mode
A/H Mode
Emer.
Operation
Peak Load Operation
Office A/C On
Off
Chiller
CHW Circuit
DX Circuit
Compressor
Condenser
Office A/C
Precision A/C
Office A/C
Office A/C
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30. 3. CHW System Design
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31. Typical Data Centre Configuration
CRAC 1
CRAC 2
CRAC 3
CRAC 4
5,000 l/s
5,000 l/s
5,000 l/s
0 l/s
TOTAL: 35,000 l/s
5,000 l/s
5,000 l/s
5,000 l/s
5,000 l/s
CRAC 5
CRAC 6
CRAC 7
CRAC 8
Duty / Standby Operation (N+1)
ENERGY EFFICIENT DATA CENTRE DESIGN

32. Optimal Data Centre Configuration
CRAC 1
CRAC 2
CRAC 3
CRAC 4
4,375 l/s
4,375 l/s
4,375 l/s
4,375 l/s
TOTAL: 35,000 l/s
4,375 l/s
4,375 l/s
4,375 l/s
4,375 l/s
CRAC 5
CRAC 6
CRAC 7
CRAC 8
CHW Fan Management Mode (N+1)
ENERGY EFFICIENT DATA CENTRE DESIGN

33. Chilled Water Fan Management
Airflow:
2 x 8,000 l/s
Fan absorbed power:
2 x 8.0 = 16.0 kW
Combined noise
2 x 65.1dBA = 68.1dBA
Example:
3 x ASD1500CW
R/A = 24°C/45%
CHW = 7/12°C water
Standby
2 x =
212.0 kW net sensible
3 x 70.7 = kW net sensible
Airflow:
3 x 4,850 l/s
Fan absorbed power:
3 x 1.8 = 5.4 kW
Combined noise
3 x 54.5dBA = 59.3dBA
Benefits:
Energy savings
Reduced noise levels
Improved air distribution
Dampers not required
Annual Energy Savings:
Fan Savings: 10.6 kW = $9,286/yr
Est. Chiller Savings: 2.7 kW = $2,321/yr
* Energy cost rate: 0,1 $/kWh & Chiller COP = 4
$11,607 / yr
125 tonnes CO2 / yr
ENERGY EFFICIENT DATA CENTRE DESIGN

34. CASE STUDY: Westpac Data Centre
Existing Units with Belt Drive Centrifugal Fans
EC Fan Technology
(N+2 Operation)
(Energy Saving Mode)
Total No. of Units Installed 9
No of Duty Units 7
Airflow per Unit (l/s)
100 Pa
100 Pa
100 Pa
Total Cooling Capacity (kW) per Unit
65.4
60.7 46
Sensible Cooling Capacity (kW) per Unit
62.8
Fan Power Per Unit (kW)
5.7
3.5
1.6
Net Total Cooling Capacity (kW)
418
400
Net Sensible Cooling Capacity (kW)
Total Airflow (l/s)
31,367
35,385
33,147
Total Fan Power (kW)
39.9
24.5
14.4
Refrigeration Power at system EER=4 (kW)
114.5
106.2
103.5
Total Power (kW)
154.4
130.7
117.9
Hours of Operation (h)
8,760
Total Energy Consumption (kWh)
1,352,106
1,145,151
1,032,804
Unit Energy Cost ($/kWh)
0.10
Annual Energy Cost ($)
$135,211
$114,515
$103,280
Annual Energy Cost Difference ($) -
-$20,696
-$31,930
Annual Reduction in CO2 (tonnes per year)  -
223.5
344.8
ENERGY EFFICIENT DATA CENTRE DESIGN

35. Summary:
Identify user’s needs in order to best select equipment capacities/capabilities
Consider energy impact of design/procurement decisions
Select all system components (including IT Racks) to optimise system efficiency
The design process must include input from, and coordination of, all facets of the design, i.e. mechanical, electrical, comms, IT suppliers, etc.
Ensure design operation is documented and all staff (facilities management & IT) are trained in correct operation of system
ENERGY EFFICIENT DATA CENTRE DESIGN

36. ...thank you
ENERGY EFFICIENT DATA CENTRE DESIGN