Variable-Speed Compressor Enabled Energy Efficient Cooling of Blade Servers.
Chan, George.
2011
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Abstract: Largely due to the power consumption of their thermal management
systems, data centers, consume over 2% of the electricity produced in the United States.
Therefore a fundamental understanding of data center energy management is both
environmentally and economically important. In previous work, models were developed to
explore the energy consumption of the thermal management. Both con... read moreventional air-cooling and
hybrid cooling, where microprocessors are liquid cooled and other components are air
cooled, were considered. These models were based on chillers which are not optimal for
demonstrating energy savings as the compressor is not variable speed and thus consumes
essentially the same amount of energy irrespective of its set point. In addition, the
analytical models include several oversimplifications especially with respect to the
chiller sub-models (e.g., compressor work computation and heat transfer characteristics of
the condenser, etc.). The analytical model developed in this thesis was based on the
physical properties and operating characteristics of real world components, which were
validated and integrated based on thermo-fluid principles. As a result of exercising the
model between the air-cooled and hybrid cooled systems it was found that the refrigerant
mass flow rate can be reduced by 40-50% or an energy savings of up to 420 W. This
relationship is similar to the previous work conducted by Hwang, however the amount of
savings is different due to modeling real world components. Additionally the model
demonstrates the sensitivity to ambient air temperature, as temperature was increased from
20 ºC to 40 ºC, through a 58% reduction in system performance or an increase in compressor
work from 224 W to 525 W. The model also revealed various relationships between the system
performance as related to the system pressure rise and the refrigerant mass flow rate. The
integrated analytical model shows there are opportunities for energy reduction in the
thermal management systems for data centers. Additionally this thesis demonstrates the
importance of component sizing, and the impact ambient air temperature has on system
performance. Finally this model found that the system performance was a function of both
the pressure rise over the compressor and the refrigerant mass flow rate.
Thesis (M.S.)--Tufts University, 2011.
Submitted to the Dept. of Mechanical Engineering.
Advisors: Marc Hodes, and Vincent Manno.
Committee: Alan Lyons.
Keywords: Mechanical Engineering, and Energy.read less - ID:
- cj82kk80z
- Component ID:
- tufts:20770
- To Cite:
- DCA Citation Guide EndNote
