Authors: William Tschudi, Lawrence Berkeley National Lab Stephen Fok, Pacific Gas and Electric Company Stephen Fok, Pacific Gas and Electric Company Presented at ASHRAE Winter Meeting in Dallas, Texas January 31, 2007 BEST PRACTICES for ENERGY EFFICIENT DATA CENTERS INDENTIFIED THROUGH CASE STUDIES and DEMONSTRATION PROJECTS

 Northern California service territory including the Silicon Valley  Estimated MW of Data Center electricity load in our service territory  Partnering with LBNL in addressing Data Center Energy Efficiency Opportunities & Emerging Technologies  In 2006, major utility EE Program Implementation produced 132 MW and 677 GWh in Electricity Savings BEST PRACTICES for ENERGY EFFICIENT DATA CENTERS INDENTIFIED THROUGH CASE STUDIES and DEMONSTRATION PROJECTS

OVERVIEW:  LBNL Data Center Benchmarking - Roadmap  Best Practices and Design Guidelines Sourcebook  Air Management Demonstration  Air Economizer Demonstration  Centralized Air Handling Case Study  Free Cooling using Water-Side Economizer Case Study  Efficient Uninterruptible Power Supplies Case Study  Q&A

A “research roadmap” was developed for the California Energy Commission and outlined key areas for energy efficiency research, development, and demonstration LBNL Data Center Benchmarking

23 Data Center Case Studies -  Banks/financial institutions  Web hosting  Internet service provider  Scientific Computing  Recovery center  Tax processing  Storage and router manufacturers

LBNL Data Center Benchmarking - IT equipment load density

Benchmarking energy end use

Overall power use in Data Centers Courtesy of Intel Corporation

Data Center performance differences

HVAC system effectiveness We observed a wide variation in HVAC performance

Best Practices topics identified through Benchmarking

CA utility Design Guidelines Sourcebook Guides available through Energy Design Resources Website

Air Management Demonstration Goal: Demonstrate better cooling and energy savings through improvements in air distribution in a typical and a high density environment.

Air Management Demonstration – High Density Data Center The as-found conditions were monitored The as-found conditions were monitored –Temperatures –Fan energy –IT energy An area containing two high-intensity rows and three computer room air conditioning units was physically isolated from rest of the center – approximately 175 W/sf An area containing two high-intensity rows and three computer room air conditioning units was physically isolated from rest of the center – approximately 175 W/sf

Air Mgmt Demo, High Density Data Center - (First alternate) Cold Aisle Isolation

Air Mgmt Demo, High Density Data Center - (Second Alternate): Hot Aisle Isolation

Air Mgmt Demo, High Density Data Center - Procedure Once test area was isolated, air conditioner fan speed was reduced using existing VFD’s Once test area was isolated, air conditioner fan speed was reduced using existing VFD’s Temperatures at the servers were monitored Temperatures at the servers were monitored IT equipment and fan energy were monitored IT equipment and fan energy were monitored Chilled water temperatures were monitored Chilled water temperatures were monitored Hot aisle return air temperatures were monitored – ΔT was determined Hot aisle return air temperatures were monitored – ΔT was determined

Air Mgmt Demo, High Density Data Center - Fan energy savings : 75% Since there was no mixing of cold supply air with hot return air - fan speed could be reduced

Air Mgmt Demo, High Density Data Center - Better temp control would allow raising the temp in the entire data center ASHRAE Recommended Range Ranges during demonstration

Air Mgmt Demo, High Density Data Center Since air is not mixing, the overall air supply temperature could be raised (typically centers are below ASHRAE recommended minimums because of mixing) Since air is not mixing, the overall air supply temperature could be raised (typically centers are below ASHRAE recommended minimums because of mixing) Hotter air is returned to the computer room air conditioners - Larger temperature difference (ΔT) allows air conditioning unit to have more capacity Hotter air is returned to the computer room air conditioners - Larger temperature difference (ΔT) allows air conditioning unit to have more capacity

Air Economizer Demonstration Goal: encourage use of outside air economizers where climate is appropriate Goal: encourage use of outside air economizers where climate is appropriate Strategy: Strategy: –address data center professional’s biggest concerns: contamination and humidity control –quantify energy savings at one center

Air Economizer Demonstration Total of EIGHT data centers were studied. Snapshot/monitoring over several days Total of EIGHT data centers were studied. Snapshot/monitoring over several days Continuous monitoring equipment in place at one center. Data collection over several months Continuous monitoring equipment in place at one center. Data collection over several months Before and after capability at TWO centers Before and after capability at TWO centers Energy savings estimate based on utility billing records. Energy savings estimate based on utility billing records.

Air Economizer Demonstration Water soluble salts in combination with high humidity can cause failures Water soluble salts in combination with high humidity can cause failures Static electricity can occur with very low humidity Static electricity can occur with very low humidity Humidity control for make-up air (or no controls) is usually sufficient Humidity control for make-up air (or no controls) is usually sufficient Particle concentrations with normal filtration are orders of magnitude lower than recommended Particle concentrations with normal filtration are orders of magnitude lower than recommended Site No. 8 energy savings was estimated to be about 1% of total energy depending on economizer set point.

Air Economizer Demo - Contamination is orders of magnitude less at servers

Air Economizer Demo - Particle Concentrations by Size

Centralized Air Handling Case Study Utilize larger & more efficient fans and motors vs CRAC Utilize larger & more efficient fans and motors vs CRAC Use of variable frequency drives Use of variable frequency drives Located outside of the data center enhances space allocation and maintenance of IT equipment Located outside of the data center enhances space allocation and maintenance of IT equipment

Free Cooling using Water-Side Economizer Case Study Best suited for climates with wet bulb temp 3000 hrs per year Best suited for climates with wet bulb temp 3000 hrs per year Very effective for chilled water systems designed for >50 deg F Very effective for chilled water systems designed for >50 deg F Possible chilled water plant energy savings of up to 75% Possible chilled water plant energy savings of up to 75%

(1) At the same level of redundancy, approx 5% efficiency gains is possible from operating the UPS at 33% vs 25% of full load (2) Additional HVAC savings improves life cycle costing Efficient Uninterruptible Power Supplies Case Study

William Tschudi, P.E.: Stephen Fok, P.E.: – Best Practices for Energy Efficient Data Centers Identified through Case Studies and Demonstration Projects - Q & A