free cooling in data centres · “electricity used in global data centers in 2010 likely accounted...
TRANSCRIPT
Free Cooling in Data Centres
– Is it Feasible in Perth?
Rob Brooks MIEAust CDCDP
Stulz WA/SA Regional Manager
“Electricity used in global data
centers in 2010 likely accounted for
between 1.1% and 1.5% of total
electricity use, respectively. For the
US that number was between 1.7 and
2.2%. “
Source: Jonathan Koomey. 2011. Growth in Data center electricity use 2005 to 2010.
Data Centre Power Consumption
BCA Section J mandates outside air economy cycle systems under
certain conditions.
So why can’t we apply economy cycles
to Data Centres?
Free Cooling in Comfort Air-Conditioning
ADVANTAGES:
- High efficiency
DISADVANTAGES
- Room humidity and air quality are dependent on
outside air conditions (Bushfires/Pollution)
- Structural changes to the building (Security!)
- Can be high capital cost
- Not feasible for many commercial sites, particularly
high rise buildings.
- Difficult to retrofit to existing facilities (i.e. most
suited to ‘green-field’ developments).
A/C UNIT
IT RACKIT RACK
Direct Free Cooling:
HOT AISLE
Supply Air °C ≡ Outside Air °C + 3
Hot Air
Exhausted
To provide cooling without the
use of a refrigeration process
A method of using low external
air temperatures for economical
cooling
Back to Basics: What is “Free Cooling”actually?
INDIRECT FREE COOLING METHODS
1. Indirect Free Cooling: Air / Air Heat Exchangers
7
ADVANTAGES:
- Room humidity and air quality are independent of
outside air conditions
DISADVANTAGES
- Large footprint requirement for HX
- HX must in close proximity to or in data centre
space
- Relatively high capital cost
- Not feasible for many commercial sites, particularly
high rise buildings.
- Difficult to retrofit to existing facilities (i.e. most
suited to ‘green-field’ developments).A/C UNIT
IT RACKIT RACK
Indirect Free Cooling: Air / Air Heat Exchangers
Rotary Heat Exchanger Plate Heat Exchanger
HOT AISLE
Supply Air °C ≡ Outside Air °C + 3
Hot Air
Cooled by HX
Cool Air Drawn
through HX
INDIRECT FREE COOLING METHODS
1. Indirect Free Cooling: Air / Air Heat Exchangers
2. Indirect Free Cooling: Air / Water Heat Exchangers
Cool Air Drawn
Through HX
Hot Air Cooled by
CRAC Unit
ADVANTAGES:
- Room humidity and air quality are
independent of outside air conditions
- Small equipment footprint. Normal cooling
and free cooling systems combined.
- Flexible and scalable
- Relatively low capital cost
- Suitable for most commercial sites, including
high rise buildings
- Easily retrofitted to existing facilities
- Suited for small and large capacity systems
DISADVANTAGES
- Slightly lower effectiveness
A/C UNIT
IT RACKIT RACK
HOT AISLE
Supply Air °C ≡ Outside Air °C + 5
Indirect Free Cooling: Air / Water Heat Exchangers
What factors are important in
the design of a Free Cooling
Solution?
1. Annual Ambient Conditions
Perth
ASHRAE Environmental Guidelines
Allowable Class 1
Operating
Environment
New Recommended Class 1
& 2 Operating Environment
Traditional
Recommended Class 1 &
2 Operating Environment
Environmental
conditions at the
inlet of the IT
equipment
2. Permissible IT Air-On Conditions
What factors are important in the design
of a Free Cooling Solution?
“Traditional” Design
Open hot aisle/cold aisle rack arrangement
Fixed capacity compressors
Return air temperature control (24oC / 45 % RH)
Fixed CRAC fan speeds Comparison – “Traditional”
Air-Cooled Free Cooling
Air Temp 24°C 24°C
Control Return Air Return Air
Compressor Fixed Speed Fixed Speed
Containment No No
Fan Speed
Control
No No
Traditional
Allowable Class 1
Operating
Environment
New Recommended Class 1
& 2 Operating Environment
Old Recommended Class 1 &
2 Operating Environment
Environmental
conditions at the inlet
of the IT equipment
24 C / 45 %
Return Air
14 C / 85 %
Supply Air
“Traditional Design”Total Cost ofOwnershipComparison
Perth
110 kW Room Load
Air-cooled vs Indirect Free CoolingFixed Speed CompressorsReturn Air Control24oC / 45 % RH
Comparison Results – “Traditional”
Air-Cooled Free Cooling
Air Temp 24°C 24°C
Control Return Air Return Air
Compressor Fixed Speed Fixed Speed
Power Base - 4.7%
TCO Base + 7.3%
pPUEcooling 1.32 1.29
EERns 3.09 3.46
Is Free Cooling Feasible in Perth?
NO!
Can we change that using State-of-the-Art Technology?
“State-of-the-art” Design
Hot or cold air containmentEliminate mixing of hot and cold air Enables higher CRAC supply air temperature/efficiency
Variable speed/variable capacity EC compressorsAllows supply air control rather than return airHigher efficiency at part load than scroll unloading
Supply air temperature controlControl the server inlet temperature rather than CRAC return air temperature (ASHRAE!)
CRAC fan speeds vary with loadReduce CRAC fan speed at part load for higher efficiencyvia raised floor pressure management or delta T control
R410A
6.23
5.86
4.92
4.26
4.794.67
4.35 4.41
3.28
3.944.06 4.11
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
5 10 15 20 25 30 35 40 45
EE
R
Cooling Capacity (kW)
Compressors tested in ASD411A CRAC unit in certified test lab at 35°C / 30% RH return air.
Compressor Technology Comparison
EC
Fixed
Digital
State-of-the-art
Allowable Class 1
Operating
Environment
New Recommended Class 1
& 2 Operating Environment
Old Recommended Class 1 &
2 Operating Environment
Environmental
conditions at the inlet
of the IT equipment New
Traditional
Free Cooling In Perth?
» In Perth there are 8064 hours p.a. below
27°C in accordance to AIRAH
8,064 annual hours
92% Trad.New
Cost Comparison
Air-Cooled Free Cooling
Air Temp 24°C 23°C
Control Return Air Supply Air
Compressor Fixed Speed Variable Speed
Containment No Yes
Fan Speed
Control
No Yes
State-of-the-art
Total Cost ofOwnershipComparison
Perth
110 kW Room Load
Air-cooled vs Indirect Free Cooling
62% Energy Savings
33% Saving on TCO
Payback 3.3 Years
Partial PUE 1.12
EERns 8.44
Operating Modes:
• Summer/DX
Compressor Only
• Mix Mode
Compressor + Free Cooling
• Extended Free Cooling
No Compressor Operation
• Free Cooling
No Compressor Operation +
Fan Speed Reduction
Stulz Dynamic Free Cooling
Free Cooling – Is it Feasible in Perth?
YES!
thank you for your
attention!