ASHRAE Journal - February 2013 - 64

emerging technologies
($/kWh)

Annual Energy
Savings

Percent
Energy Savings

Project Cost

240

$0.121

$21,206

40%

$178,787
(Design Through Installation)

8.4

Newport/
New Chiller

$0.115

$26,192

65%

$100,783
(Design Through Installation)

3.8

Jacksonville/
Compressor Retrofit

120

$0.054

$15,358

41%

$107,592 (Installation, Including
Compressor)

7.0

Project/Type

Tons

San Diego/
Third Compressor Added

Utility Rate

Payback
(Years)

Table 1: Summary results from Navy Technology Validation Program, oil-free magnetic bearing technology.6

Market Potential
Small centrifugal compressors are now commercially available from multiple sources and are expected to replace reciprocating and screw compressors for chilled-water systems in
the 25 to 80 ton (88 to 281 kW) range.8 Comparatively high
first cost can be, and has been, substantially offset by improved
energy efficiency.
Mechanical contractors serving the school construction
market report that magnetic bearing chillers are among the new
technologies of interest to this market.9 With overall school
construction demand down by 50% from prerecession levels,
the major drivers for selection of building products and technologies in this market have been life-cycle costs and return on
investment, rather than LEED or sustainability.

In New England, with electric rates hovering around $0.15/
kWh, data storage centers with water-cooled chillers are realizing
reduced power consumption as well as lower maintenance costs
and high reliability from use of oil-free, magnetic bearing compressors.10 Both data center users and data center service providers
are concerned about shutdown risks. Many data center users have
migrated from leases based on cost/ft2 to leases based on “service
levels agreements” (SLAs), which compensate data center users
for time periods in which they cannot access critical data.
Cooling system reliability affects shutdown risk. Given 80%
of chiller field problems have been attributed to failures in
compressor-oil return, oil-free compressors are an attractive
option for data center service providers.10 Also, data center applications benefit from the low inrush current required to start
a magnetic bearing compressor, which permits downsizing of
standby generator equipment.

References
1. Dieckmann, J., K. Roth, J. Brodrick. 2003. “Emerging Technologies: Small Centrifugal Compressors.” ASHRAE Journal 45(10).
2. Brondum, D.C., et al. 1998. “High-speed, direct-drive centrifugal
compressors for commercial HVAC systems.” Proceedings of the 1998
International Compressor Engineering Conference.
3. U.S. Department of Energy, Federal Energy Management Program. 2012. “Selecting and Evaluating New and Underused Energy
Technologies.” Transcript, April 5. http://tinyurl.com/cz3d2sh.
4. U.S. Department of Energy, Federal Energy Management Program. 2012. “Selecting and Evaluating New and Underused Energy
Technologies.” Presentation, April 5. http://tinyurl.com/ccckzyz.
5. U.S. Department of Energy, Federal Energy Management Program. 2010. “Evaluation of a Variable-speed Centrifugal Compressor
with Magnetic Bearings.” http://tinyurl.com/ae2dx5h.
6. Kistler, P. 2009. “Magnetic Bearing Chiller Compressor.” Naval
Facilities Engineering Service Center. http://tinyurl.com/bjjcnlk.
7. GovEnergy. 2006. “Oil Free Magnetic Bearing Chiller Compressors.” http://tinyurl.com/cwm2s3x.
8. Navigant Consulting. 2011. “Energy Savings Potential and RD&D
Opportunities for Commercial Building HVAC Systems.” September
30. http://tinyurl.com/cgf6m3j.
9. ACHR News. 2012. “Contractors Give K-12 Schools Failing
Grade.” July 30. http://tinyurl.com/cwcbb69.
10. BuyMass.org. 2012. “Five Things to Know About Cooling Data
Centers.” Nov. 28. http://tinyurl.com/d8ee6hl.

www.info.hotims.com/44629-45

ASHRAE Journal

Mildred Hastbacka is a director and emerging technologies
scout for TIAX LLC and John Dieckmann is a director in the
Mechanical Systems Group of TIAX LLC, Lexington, Mass.
Antonio Bouza is a technical manager with the U.S. Department
of Energy, Washington, D.C.
February 2013

ASHRAE Journal - February 2013

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