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Agenda Fundamentals and the Operation of the Pumped
Refrigerant Economizer System
Design Considerations and Optimization
Data From the Field
The Title 24 Approval Process, Method and Documentation
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3
Liebert DSE Indoor Unit
Next generation data
center cooling system
Liebert EconoPhase
First ever pumped
refrigerant economizer Liebert MC
Intelligent, high
efficiency condensers
iCOM Thermal System
Manager
System Overview
Fix
ed
Dig
ital
Fix
ed
Dig
ital
Digital scroll compressors match cooling to IT load
Staged evaporator coil reduces compressor power and optimizes economizer performance
Electronic expansion valve for part-load and low ambient efficiency
EC plug fans match airflow to server needs
Reduced compressor power
through iCOM optimization
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System Components
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Variable
speed fans Fin/Tube Liebert MC +/-
Efficiency (COP)
31 47 + 52%
Sound Power (dBA)
77.3 73 - 4.3 dBA
Refrigerant Charge (lb)
22 6 - 73%
Footprint (ft2)
39.8 33.6 - 15%
Weight (lb)
670 400 - 40%
Liebert iCOM Control CAN bus communication with
indoor unit to maximize efficiency
High-Efficiency Air-Cooled Condensers
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Liebert DSE Indoor Unit
Liebert MC Condensers
Liebert EconoPhase Module
EconoPhase module is installed in series with the compressor circuit, with no need for additional coils or heat exchangers.
EconoPhase Pumped Refrigerant Economizer
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DX Operation Mode
Cooling
Mode
Outdoor
Temp
Cooling
PUE
Full
Compressor 95 1.28
Compressor Evaporator
Electronic
expansion valve
Refrigerant
Pump Condenser
Evaporator: 3.2 kW
Condenser: 3.9 kW
Pump 1: 0 kW Pump 2: 0 kW
Compressor 2: 8.5 kW Compressor 1: 8.5 kW
Compressor 2: 8.5 kW 8
Full and Partial Economization
Cooling
Mode
Outdoor
Temp
Cooling
PUE
Full
Compressor 95 1.28
Partial
EconoPhase 65 1.17
Compressor Evaporator
Electronic
expansion valve
Refrigerant
Pump Condenser
Evaporator: 3.2 kW
Condenser: 3.9 kW
Compressor 1: 0 kW
Pump 2: 0 kW Pump 1: 0.6 kW
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Full and Partial Economization
Cooling
Mode
Outdoor
Temp
Cooling
PUE
Full
Compressor 95 1.28
Partial
EconoPhase 65 1.17
Full
EconoPhase 45 1.09
Compressor Evaporator
Electronic
expansion valve
Refrigerant
Pump Condenser
Evaporator: 3.2 kW
Condenser: 3.9 kW
PUE as low as 1.05 Full Economizer Mode
Compressor 2: 0 kW Compressor 1: 0 kW
Pump 1: 0.6 kW Pump 2: 0.6 kW
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Annual free-cooling hours increase at higher return air conditions and lower unit loads:
At 70% load and 85°F, full
economization is
available at 50°F outdoor
EconoPhase 100% Free-Cooling Capability
Percentage of Annual Hours with 100% Free-Cooling Available
Location 85°F Return Air 95°F Return Air
San Francisco, CA 42% 70%
Chicago, IL 55% 62%
Charlotte, NC 36% 45%
Economization Hours in San Francisco DSE 125 at 90ºF RAT, 70% Unit Load
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Liebert DSE Indoor Unit
Liebert MC Condenser
Liebert EconoPhase
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Liebert
iCOM
Liebert DSE with iCOM Benefits:
– Maximizes free-cooling hours
through automatic
economizer transition control
– Minimizes power
consumption by optimizing
component operation for
lowest total system power
– Provides built-in diagnostics
to ensure proper system
operation
– Provides interface to Liebert
data center management
systems
End-to-End Thermal Management Solution
Pump
Speed
Refrigerant
Temperature
Pump
Head
EconoPhase
Unit Status
Condenser
Fan Speed
Ambient
Temperature Head
Pressure
Liebert MC
Unit Status
Unit
Capacity
Room
Temperature
Evaporator
Fan Speed
Room
Humidity
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Integrated economizer control with automatic diagnostics
– iCOM monitoring of pump operation
– Automatic changeover on loss of free cooling
– Pump unit serviceable without loss of mechanical cooling
EconoPhase Automatic Diagnostics
MC Condenser and PRE Skid
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Liebert DSE Models Technical Data
Model
DA080 (1) DA085 (1) DA125 DA150 DA165
95°F DB, 52.3 DP
Total Capacity kW (net) 88 100 146 170 181
Sensible Capacity kW (net) 84 94 146 170 181
Full-load SCOP @ 95°F ambient 3.2 3.1 3.8 3.2 3.1
SCOP @ 35°F ambient (kW/kW)* 10.5 10.1 17.5 13.0 12.8
85°F DB, 52.3 DP
Total Capacity kW (net) 85 92 130 153 163
Sensible Capacity kW (net) 77 83 130 153 163
Full-load SCOP @ 95°F ambient 3.0 2.7 3.4 2.9 2.8
SCOP @ 35°F ambient (kW/kW)* 9.1 8.7 12.2 12.0 11.7
*Economizer mode operating at 100% DX capacity
Note: Capacity data is rated and factory-certified per ASHRAE 127-2012 with a 5% tolerance
(1) Available in UPFLOW units as well as downflow
Basic Dimensions - Downflow Units
Model Length (A) Width (B) Height (C)
DA080 100" 35" 76"
DA085 100" 35" 76"
DA125 144" 47" 76"
DA150 144" 47" 76"
DA165 144" 47" 76"
*Add minimum 18" height for separate filter plenum, plus floorstand height
FIELD SUPPLIED DATA
Real World Data Compared to Predicted
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Partial Economization Begins at 70°F
0
100
200
300
400
500
600
700
800
Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct
DSE Economizer Monthly Run Hours 2012-2013
Unit #1 Econ Hrs
Unit #2 Econ Hrs
2012 Temperatures
5,354Hrs
Liebert DSE Beta Test Upstate NY
2013 Temperatures
4,018Hrs
Liebert DSE Cooled Data Center Performance
1.00
1.05
1.10
1.15
1.20
1.25
1.30
1.35
1.40
0
50
100
150
200
250
300
350
400
29-Aug-12 18-Oct-12 7-Dec-12 26-Jan-13 17-Mar-13 6-May-13 25-Jun-13 14-Aug-13 3-Oct-13 22-Nov-13 11-Jan-14
C
oo
lin
g P
UE
K
W
Power History
Data Center Total Avg. KW
UPS Total Avg. KW
Actual Avg. Cooling KW
Avg O/A Temp
Cooling PUE
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Driver – Improved PUE
Initial Interest - ASHRAE Allowable Conditions (20% RH to 62.6° F. Dew Point)
Reality - Most Customers prefer ASHRAE Recommended Conditions (41.9° F. Dew Point to 60% RH)
DSE is an indirect system and not sensitive to tight inside humidity tolerances.
THE ROAD TO TITLE 24 APPROVAL
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Executive Summary CEC Submission Report
At the time the Energy Code was written, the refrigerant economization method was just being released into the market place to meet high efficiency needs
Since 2012, over 1500 of the Liebert DSE systems have been installed throughout North America, South America, Europe and Australia
52 systems are installed in California data centers.
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CEC Economization Requirements
The Energy Code requires all Data Centers to meet the efficiency requirement of either one of two prescriptive economization methods (outside air economization or water economization). This now includes pumped refrigerant economization.
Or demonstrate through the Exceptional Design Compliance method the proposed solution meets or exceeds the energy efficiency of the prescriptive methods.
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Title 24 – Section 140.9 (a)– Prescriptive Requirements for Computer Rooms
Economizers
– (A) air-side with full capacity at 55F DB outdoor temp
– (B) water-side with full capacity at 40F DB outdoor temp
– Exceptions
• Room under 5 tons
• 50 tons of new equipment in an existing room in existing bldg
• 20 tons of new equipment in a new room in existing bldg
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Title 24 Time Dependant Valuation
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“…TDV is quite simple. It holds the total cost of energy constant at forecasted retail price levels but gives more weight to on‐peak hours and less weight to off‐peak hours. This means that energy efficiency measures that perform better on‐peak will be valued more highly than measures that do not.”
Source:
http://www.energy.ca.gov/title24/2013standards/prerulemaking/document
s/general_cec_documents/Title24_2013_TDV_Methodology_Report_23F
eb2011.pdf
The Path To Approval
Baseline energy budget created using the Energy Commission’s public domain software CBECC-Com (Build 717).
The proposed Liebert DSE model was created using the CBECC-Com software, by extracting the IDF model (IDF is a format used by EnergyPlus) and then adding custom curves for the Liebert DSE equipment.
The custom curves were developed from a regression analysis of Liebert pumped refrigerant system data, following the AHRI 1360 standard used for determining the efficiency rating.
We then simulated the proposed model. Once both models were created and simulated, the results were extracted to the Exceptional Design Compliance - End-Use Summary Comparison spreadsheet.
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End-Use Summary – TDV Margins
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Source:
http://www.energy.ca.gov/title24/2008standards/special_case_appliance/ref
rigerant_economizer/2015-06-
09_Emerson_Proposal_to_Include_Refrigerant_Economizers_in_T24.pdf
Pumped Refrigerant Approved in 14 of 16 Climate Zones
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Energy and Water Savings
A cooling system with a water economizer uses an average of 4.2 million gallons of water per year for a data center with an IT load of 1.2 MW.
The Liebert DSE pump refrigerant economization system utilizes less energy based on the TDV calculation methods for 14 of these 16 climate zones
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Water Reduction in All Climate Zones
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Project Approval Process
The CEC approved the inclusion of the Liebert EconoPhase pumped refrigerant economizer as a prescriptive option on September 9, 2015, as shown in the CEC’s Blueprint newsletter, Issue 111.
“The approval to use pumped refrigerant economizers is an alternative to the use of water-side economizers per Section 140.9(a)1B, and is specific to pumped refrigerant economizers installed in climate zones 1-9, 11-14, and 16.”
The Liebert EconoPhase economizer system is not yet accounted for in the CEC’s performance software, so engineers and others wanting to use the Liebert DSE with Econophase pumped refrigerant economizer in California should follow this guideline:
– If the project is complying using the performance approach, then the cooling system serving the computer room should be specified as a basic, efficient chilled water plant, with an integrated water economizer. The compliance documents can be used to show local government jurisdictions that the efficiency of the Liebert DSE is equivalent or better than the chilled water system and acceptable as a prescriptive alternative.
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Source: http://www.energy.ca.gov/2015publications/CEC-400-
2015-031/CEC-400-2015-031.pdf
Refrigerant Economizers Approved as Alt. Comp. Pkg. for Title 24
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Source: http://docketpublic.energy.ca.gov/PublicDocuments/15-MISC-
03/TN206117_20150916T095116_Resolution_of_the_Energy_Commi
ssion_re_Refrigerant_Economizers.pdf
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Questions?
