Energy Efficiency Opportunities in Federal High Performance Computing Data Centers (FEMP case study, September 2013)

Overview

This document is a September 2013 case study prepared by Lawrence Berkeley National Laboratory (LBNL) for the US Department of Energy's Federal Energy Management Program (FEMP); the author is Rod Mahdavi. It is based on energy assessments at DoD high-performance computing data centres, jointly funded by the DoD and FEMP.

The method is to group the recommended measures into packages: air management, cooling retrofit, generator block-heater modification, lighting and chilled-water plant. For each package, a typical cost per kW of IT load and a simple payback are given. This presentation lets a facility pick the package closest to its own situation and quickly estimate the size and return of the investment.

The results are striking: estimated total savings exceeded 8,000 MWh per year with about 7,500 tons per year of greenhouse gas reduction, and measures averaged under two years payback. The air management adjustment package typically costs about $100 per kW of IT and pays back in about a year. Other packages range from $10 to $400 per kW of IT with 2.5-3 year paybacks, including a generator block-heater modification. For context, rack power at the sites averaged up to 10-25 kW, and sites commonly used 480 V power without intervening transformation. The findings are therefore most meaningful for high-density computing environments; when applied to enterprise facilities or other regions, costs should be updated, since the figures reflect 2013 US conditions.

Key points

1. Estimated total savings exceeded 8,000 MWh/yr with about 7,500 tons/yr GHG reduction.
2. Measures averaged under two years payback.
3. Rack power averaged up to 10-25 kW; sites commonly used 480 V power without intervening transformation.
4. Air management adjustment package: about $100/kW of IT, about 1 year payback.
5. Other packages range from $10/kW to $400/kW of IT with 2.5-3 year paybacks.
6. A generator block-heater modification is one of the packages.
7. Packages: air management, cooling retrofit, block heater, lighting, chilled-water plant.

Using it in design

• Use the package cost/kW and payback ranges as defaults in the retrofit measure library (air management, generator block heater controls, chilled-water plant).
• Show generator block-heater energy as a standby load in the electrical model.
• Rank air management as the shortest-payback step ahead of larger cooling investments.
• When using the costs, note in the report that the source is 2013 US data.

Who should read it

Engineers and facility managers prioritising energy-efficiency retrofits in existing data centers.

Publication details

Authors

Rod Mahdavi

Publisher

U.S. DOE Federal Energy Management Program / Lawrence Berkeley National Laboratory

Year

2013

Document language

English

Source type

Government / public

Access

Free to read

Licence

Copyright retained; citation only — the publisher’s terms apply to the original document

Citation