Sustainable design, global warming, depleting fuel reserves, energy use, and operating cost are becoming increasingly more important. The intent of this publication, as part of the ongoing ASHRAE Datacom Series, is to provide the reader with detailed information on the design of datacom facilities that will aid in minimizing the life-cycle cost to the client, and to maximize energy efficiency in a facility to align with ASHRAE’s stated direction (from the 2006 Strategic Plan) to ‘lead the advancement of sustainable building design and operations.’ This book covers many aspects of datacom facility energy efficiency, and includes chapters on the topics of environmental criteria, mechanical equipment and systems, economizer cycles, airflow distribution, HVAC controls and energy management, electrical distribution equipment, datacom equipment efficiency, liquid cooling, total cost of ownership, and emerging technologies. There are also appendices on such topics as facility commissioning, operations and maintenance, and the telecom facility experiences.

PDF Catalog

PDF Pages	PDF Title
14	1.1 Purpose 1.2 Background 1.2.1 Historical Perspective and Trends
15	Figure 1.1 Historical data center with mainframe computer and tape storage. Figure 1.2 Sample motherboard of a modern server.
17	Figure 1.3 ASHRAE power trend chart (ASHRAE 2005c).
18	Figure 1.4 Average power allocation for 12 benchmarked data centers (LBNL 2007a).
19	Figure 1.5 Comparative forecast of annual server power and cooling expenditures to new server expenditures, through 2010. 1.2.2 Energy Efficiency and TCO Definitions Efficiency
21	Total Cost of Ownership (TCO)
22	1.2.3 Overview of ASHRAE 1.2.4 Overview of ASHRAE Technical Committee (TC) 9.9
23	1.2.5 Overview of ASHRAE TC 9.9 Datacom Book Series 1.2.6 Primary Users for This Book
24	1.3 Best Practices and Chapter Summaries 1.3.1 Best Practices Table 1.1 Best Practices
27	1.3.2 Overview of Chapters
30	2.1 Introduction Figure 2.1 Energy consumption impact of environmental criteria (LBNL average of 12 data centers.
31	2.2 Overview of Environmental Classes 2.3 Environmental Criteria
32	Table 2.1 Class 1, Class 2, and NEBS Design Conditions
33	Figure 2.2a Recommended data center Class 1, Class 2, and NEBS operating conditions. Refer to Appendix F for an equivalent figure with SI units. 2.3.1 Temperature
34	Figure 2.2b Allowable data center Class 1, Class 2, and NEBS operating conditions. Refer to Appendix F for an equivalent figure with SI units.
36	2.3.2 Humidity
37	2.3.3 Filtration and Contamination
39	2.3.4 Ventilation 2.3.5 Envelope Considerations
40	2.4 Energy-Efficiency Recommendations/Best Practices
42	3.1 Introduction Figure 3.1 Energy consumption impact of mechanical equipment and systems (LBNL average of 12 data centers).
43	3.2 Cooling Distribution Equipment 3.2.1 Fans
44	Figure 3.2a Datacom facility HVAC schematic using CRAH units, with list of alternatives.
45	Figure 3.2b Datacom facility HVAC schematic using CRAC units with air-cooled condenser for heat rejection.
46	3.2.2 Chilled-Water Pumps 3.2.3 Cooling Coils
47	Figure 3.3 Representative cooling coil air pressure drop as a function of approach temperature between entering chilled-water temperature and leaving air temperature. 3.2.4 Humidification Equipment
48	3.2.5 Dehumidification and Reheat Coils
49	3.2.6 CRAH/CRAC Unit Energy Considerations
50	Figure 3.4 Comparison of CRAH and CRAC units.
51	3.3 Mechanical Cooling Equipment 3.3.1 Types and Sizes of Chillers
52	3.3.2 Chilled-Water Supply Temperature 3.3.3 Chilled-Water Differential Temperature
53	Figure 3.5a Sample chiller efficiency as a function of leaving chilled-water temperature, units of kW/ton (with all other parameters held essentially constant). 3.3.4 Condenser-Water Differential Temperature
54	3.3.5 Variable-Speed Compressor Drives Figure 3.5b Sample chiller efficiency as a function of leaving chilled-water temperature, units of COP (with all other parameters held essentially constant). 3.4 Heat Rejection Devices
55	3.4.1 Open Cooling Towers Figure 3.6 Sample chiller efficiency as a function of evaporator differential temperature (with other parameters held essentially constant).
56	Figure 3.7 Sample chiller efficiency as a function of condenser-water differential temperature (with other parameters held essentially constant).
57	Figure 3.8 Sample part-load centrifugal chiller efficiency with and without VFD. 3.4.2 Dry Coolers
58	Figure 3.9 Open cooling tower schematic.
59	Figure 3.10 Sample chiller efficiency as a function of cooling tower approach temperature (with all other parameters held essentially constant). 3.4.3 Hybrid and Other Systems
60	Figure 3.11 Dry cooler schematic.
61	Figure 3.12 CRAC unit schematic with economizer precooling coil.
62	3.4.4 Condenser-Water Pumps 3.4.5 Heat Exchangers 3.4.6 Refrigerant Condensers
63	3.5 System and Equipment Design for Efficient Part-Load Operation 3.6 Energy-Efficiency Recommendations/Best Practices
64	Figure 3.13 CRAC unit schematic with air-cooled condenser for heat rejection.
66	4.1 Introduction 4.2 Economizer Code Considerations
67	Figure 4.1 Energy consumption impact of economizers (LBNL average of 12 data centers). 4.3 Air-side economizers
68	Figure 4.2a Air-handling system with air-side economizer (see Figures 4.3a and 4.3b for process).
69	Figure 4.2b Configuration of a CRAC with air-side economizer.
70	Figure 4.3a Sample economizer cycle conditions for Regions I and II (see Figure 4.3b for regions).
71	Figure 4.3b Air-side economizer environmental regions.
73	4.4 Adiabatic-cooled air-side economizers
74	Figure 4.4 Air-handling system with air-side economizer and evaporative cooling (see Figures 4.5a and 4.5b for process).
75	Figure 4.5a Sample evaporative economizer conditions for Regions I and III (see Figure 4.5b for regions).
76	Figure 4.5b Direct evaporative economizer air-side economizer environmental regions.
77	4.5 Water-side Economizers Figure 4.6 Direct water-side economizer.
78	Figure 4.7 Indirect water-side economizer.
79	Figure 4.8 Water-side economizer when integrated into a CRAC unit.
80	4.6 Climatic Advantages of Various Economizers Table 4.1 Air-Side Economizers—Utilization Potential for Selected Cities for Supply and Return Conditions Shown in Figure 4.3a
81	Table 4.2 Adiabatic-Cooled Air-Side Economizer— Utilization Potential for Selected Cities for Supply and Return Conditions Shown in Figure 4.5a
82	Table 4.3 Relative Availability of Water-Side and Air-Side Economizer Hours for Selected US Cities as a Function of Supply Air Temperature
84	4.7 Energy-Efficiency Recommendations/Best Practices
86	5.1 Introduction Figure 5.1 Energy consumption impact of airflow distribution (LBNL average of 12 data centers.
88	5.2 Airflow management at the data center level 5.2.1 Vertical Underfloor (VUF)
89	Figure 5.2 Example data center with VUF cooling architecture.
90	5.2.2 Vertical Overhead (VOH) Figure 5.3 Example data center with VOH cooling architecture.
91	5.2.3 Local Cooling 5.2.4 Supplementary Cooling
92	5.3 Air Handler/CRAH/CRAC Unit Selection 5.3.1 Operating Pressure 5.3.2 Fan Selection 5.3.3 Variable-Speed Fans
93	5.4 Coil Selection/Supply Air Temperature 5.4.1 Selection of Supply Air Temperature 5.4.2 Chiller Efficiency/Pumping Power
94	5.4.3 Use of Economizers 5.4.4 Humidity Control 5.5 Airflow Management Adjacent to and within the Datacom Equipment Rack 5.5.1 Rack Airflow Configurations
95	5.5.2 Blanking Panels 5.5.3 Raised Floor Cable Cut-Out Sealing Grommet 5.6 Airflow Optimization
97	5.7 Energy-Efficiency Recommendations/Best Practices
98	6.1 Introduction Figure 6.1 Energy consumption impact of HVAC controls and energy management (LBNL average of 12 data centers).
99	6.2 Control System Architecture 6.2.1 Background 6.2.2 Mechanical and Control System Reliability
101	6.3 Energy-Efficiency Measures 6.3.1 Part-Load Operation 6.3.2 Outdoor Air Control
102	6.3.3 Demand Based Resets Chilled-Water Reset Supply Air Pressure/Use of Variable-Speed Drives (VSDs) to Maintain Underfloor Pressure for CRAC Units
104	6.3.4 Air-Side Economizer Sequences Standard Air-Side Economizer Control Strategy Wet-Bulb Economizer Control Strategy
105	6.3.5 Water-Side Economizer Sequences Integrated Economizers Parallel Economizers
106	Combined Water- and Air-Side Economizers 6.3.6 Thermal Storage Chilled-Water TSS
107	Ice Storage TSS Phase-Change Storage TSS 6.3.7 Humidity Control
108	6.4 Energy-Efficiency Recommendations/Best Practices
110	7.1 Introduction Figure 7.1 Electricity distribution.
111	Figure 7.2 Energy consumption impact of electrical distribution equipment (LBNL average of 12 data centers). 7.2 Distribution Techniques
112	7.3 Energy-Efficiency Considerations Figure 7.3 One-line diagram of the electrical distribution to the data center. 7.3.1 Electrical Power Distribution Components
113	Figure 7.4 Power path with typical efficiencies. Figure 7.5 Equivalent AC circuit of a cable with one conductor.
114	7.3.2 Component Junction Points 7.3.3 Infrastructure Equipment
115	Figure 7.6 UPS semiconductor technology trend (Source: European Committee of Manufacturers of Electrical Machines and Power Electronics).
116	Figure 7.7 UPS efficiency as a function of equipment type and load (Source: Lawrence Berkeley National Laboratory).
118	7.4 Improving Energy Efficiency Figure 7.8 Simple electrical distribution to a data center.
119	Figure 7.9 Simple electrical distribution to a data center with a lower resistance.
120	7.5 Energy-Efficiency Recommendations/Best Practices
122	8.1 Introduction Figure 8.1 Energy consumption impact of servers (LBNL average of 12 data centers.)
124	8.2 Powering datacom equipment 8.2.1 Load Requirements
125	8.2.2 Power Delivery Network Design Table 8.1 Example—Voltages Required on Server Platform (Intel 2006)
127	Figure 8.2 Power delivery to loads. 8.3 Power-conditioning equipment 8.3.1 Linear Regulators
128	Figure 8.3 Power delivery network (PDN) implementations. 8.3.2 Voltage Regulators/Point-of-Load Converters
129	Figure 8.4 Linear regulator. Figure 8.5 Switch-mode voltage regulator based on a buck converter topology.
130	Figure 8.6 VR efficiency from 12 V input to 1.2 V output.
131	Figure 8.7 VR efficiency as a function of load at different input and output voltages. 8.3.3 DC/DC Converters
132	8.3.4 Power Supply Units Figure 8.8 Efficiency of a 48 to 1.5 V VR as a function of load and input voltage (ã2005 Artesyn Technologies). Figure 8.9 Efficiency of bus converters as a function of load and input voltage (ã2006 Artesyn Technologies).
133	Figure 8.10 AC input PSU.
134	Figure 8.11 AC input PSU efficiency as a function of load (LBNL Interim Report 2005).
135	Figure 8.12 Effect of input voltage on PSU efficiency (Intel 2007). Figure 8.13 –48 V DC input PSU. 8.4 Other factors affecting energy efficiency
136	8.4.1 Air-Moving Devices 8.4.2 Equipment Rating 8.4.3 Power Management
137	8.4.4 Redundancy 8.4.5 Reliability 8.4.6 Device Technologies
138	Figure 8.14 Example of redundant AC input power supplies and a redundant VR. 8.4.7 Virtualization/Consolidation
139	8.5 Estimating energy efficiency of datacom equipment
140	Figure 8.15 Breakdown of power dissipation within a server system at maximum load and at light load. Figure 8.16 Example datacom power delivery example used to illustrate energy-efficiency calculations.
141	Table 8.2 Calculated Energy Efficiency for Example System in Figure 8.16
142	8.6 Energy-Efficiency Recommendations/Best Practices
144	9.1 Introduction
145	Figure 9.1 Energy consumption impact of liquid cooling (LBNL average of 12 data centers). Table 9.1 A Comparison of Open versus Closed Architecture for Liquid Cooling
146	9.2 Comparison of Key Liquid Coolant Properties
147	Table 9.2a Comparison of Key Coolant Properties (I-P Units)
148	Table 9.2b Comparison of Key Coolant Properties (SI Units)
149	9.3 Energy Optimization with Selected Liquid Coolants 9.3.1 Water-Based Liquid Cooling Systems Pumping Power
150	Table 9.3 Ratios of Key Coolant Properties to a Baseline of Water
152	Fan Energy Chilled-Water Production
153	Figure 9.2 Heat rejection pathway for a common datacom facility. Heat Rejection Efficiency
154	9.3.2 Pumped Refrigerant Cooling Systems
155	9.3.3 Dielectric-Based Liquid Cooling Systems
156	Figure 9.3 Diagram of waste heat rejection bypassing mechanical cooling. 9.4 Liquid-Cooled Enclosures
157	9.4.1 Open-Cooling Architecture 9.4.2 Closed-Cooling Architecture
159	9.5 TCO Aspects of Liquid Cooling
161	9.6 A sample comparison: pumping power
162	Table 9.4 Sample Comparison of Transport COP for Air, Water, and Phase-Change Refrigerant Heat Rejection
163	9.7 Energy-Efficiency Recommendations/Best Practices
166	10.1 Introduction
167	10.2 TCO Methodology 10.2.1 Background 10.2.2 Time Value of Money (The Discount Rate)
169	10.2.3 Life Time Questions
170	10.2.4 Simplified TCO Modeling Methodology
171	10.2.5 ROI as an Alternate Methodology 10.2.6 Uncertainty and Risk
173	10.3 TCO Analysis as Applied to Energy Costs and Energy-Efficiency Metrics 10.3.1 Calculation of Annual Energy Costs 10.3.2 Energy-Efficiency Metrics (On an Annualized Basis)
174	10.4 TCO Analysis as Applied to Non-energy Costs
175	10.5 Summary
176	11.1 Introduction 11.2 DC Power
177	Figure 11.1 Schematic representation of a typical AC power distribution system for a datacom facility. 11.3 Fuel Cells, Distributed Generation, and CHP
178	Figure 11.2 Comparison of AC and DC power distribution system efficiencies (LBNL 2007d). 11.4 Future Research
179	11.5 Conclusions
180	Bibliography
184	References
191	Selected Web Links
216	Table C.1 Comparison between Class 1 & 2 Data Centers and NEBS
227	Table 2.1 Class 1, Class 2, and NEBS Design Conditions
228	Figure 2.2a Recommended data center Class 1, Class2, and NEBS operating conditions (SI units).
229	Figure 2.2b Allowable data center Class 1, Class 2 and NEBS operating conditions (SI units).
231	Figure 3.3 Representative cooling coil air pressure drop as a function of approach temperature between entering chilled-water temperature and leaving air temperature.
232	Figure 3.6 Sample chiller efficiency as a function of evaporator differential temperature (with other parameters held essentially constant).
233	Figure 3.7 Sample chiller efficiency as a function of condenser-water differential temperature (with other parameters held essentially constant).
234	Figure 3.8 Sample part-load centrifugal chiller efficiency with and without variable frequency drive.
235	Figure 3.10 Sample chiller efficiency as a function of cooling tower approach temperature (with other parameters held essentially constant).
236	Table 9.4 Sample Comparison of Transport COP for Air, Water, and Phase-Change Refrigerant Heat Rejection
239	Table G.1 Comparison of 2004 and 2008 Recommended Environmental Envelope Data
241	Figure G.1 2008 recommended environmental envelope (new Class 1 and 2).
242	Figure G.2 Inlet and component temperatures with fixed fan speed.
243	Figure G.3 Inlet and component temperatures with variable fan speed.

Published By	Publication Date	Number of Pages
ASHRAE	2009	256


PDF Format	Searchable	Printable	Preview Now

Standard Title	Best Practices for Datacom Facility Energy Efficiency, Second Edition
Published Code	ASHRAE
Publication Date	2009
Pages Count	256

ASHRAE BestPracticesforDatacomFacilityEnergyEfficiency 09 2009

PDF Catalog