# Exergy Analysis of Data Center Thermal Management Systems

## Abstract

Data center thermal management systems exist to maintain the computer equipment within acceptable operating temperatures. As power densities have increased in data centers, however, the energy used by the cooling infrastructure has become a matter of growing concern. Most existing data center thermal management metrics provide information about either the energy efficiency or the thermal state of the data center. There is a gap around a metric that fuses information about each of these goals into a single measure. This chapter addresses this limitation through an exergy analysis of the data center thermal management system. The approach recognizes that the mixing of hot and cold streams in the data center airspace, which is often a primary driver of thermal inefficiency in the data center, is an irreversible process and must therefore lead to the destruction of exergy. Experimental validation in a test data center confirms that such an exergy-based characterization in the cold aisle reflects the same recirculation trends as suggested by traditional temperature-based metrics. Further, by extending the exergy-based model to include irreversibilities from other components of the thermal architecture, it becomes possible to quantify the amount of available energy supplied to the cooling system which is being utilized for thermal management purposes. The energy efficiency of the entire data center cooling system can then be collapsed into the single metric of net exergy consumption. When evaluated against a ground state of the external ambience, this metric enables an estimate of how much of the energy emitted into the environment could potentially be harnessed in the form of useful work. The insights availed from the above analysis include a wide range of considerations, such as the viability of workload placement within the data center; the appropriateness of airside economization as well as containment; the potential benefits of reusing waste heat from the data center; as well as the potential to install additional compute capacity without needing to increase the data center cooling capacity. In addition, the analysis provides insight about how local thermal management inefficiencies in the data center can be mitigated. The chapter concludes by suggesting that the proposed exergy-based approach can provide a foundation upon which the data center cooling system can be simultaneously evaluated for thermal manageability and energy efficiency.

## Keywords

Data Center Heat Engine Exergy Analysis Exergy Loss Exergy Destruction## Nomenclature

- \( A \)
Availability or available energy (exergy) [J]

- \( \bar{A} \)
Area [m

^{2}]- \( C \)
Coefficient matrix (9.67)

- \( {C_{\rm{p}}} \)
Specific heat at constant pressure [J/kg K]

- \( {\hbox{CFD}} \)
Computational fluid dynamics

- \( {\hbox{cfm}} \)
Cubic feet per minute

- \( {\hbox{const}} \)
Arbitrary constant value

- \( {\hbox{COP}} \)
Coefficient of performance defined as the heat removed by a cooling system normalized to the work input to the cooling system for removal of heat

- \( {\hbox{CRAC}} \)
Computer room air conditioning unit

- \( E \)
Energy stored in system [J]

- \( e \)
Energy transported per unit massflow [J/kg]

- \( f \)
Function

- \( F \)
Matrix defining flow conditions at boundaries (9.67)

- \( g \)
Acceleration due to gravity [m/s

^{2}]- \( H \)
Enthalpy of a system [J]

- HVAC
Heating, Ventilation, and Air-Conditioning system

- \( h \)
Specific enthalpy (enthalpy per unit mass) [J/kg]

- \( \bar{h} \)
Convection coefficient [W/m

^{2}K]- \( i \)
Counter in summation

- \( J \)
Joule unit of energy

- \( {\hbox{KE}} \)
Kinetic energy [J]

- \( M \)
Mass stored in system [kg]

- \( {\hbox{Ma}} \)
Mach number

- \( m \)
Mass flow [kg]

- \( N \)
Number especially as a limit for the counter in summation

- \( n \)
Number especially as a limit for the counter in summation

- \( \hat{n} \)
Normal (unit) vector in a direction perpendicular to the plane of consideration

- \( P \)
Pressure [Pa or N/m

^{2}]- \( {\hbox{PE}} \)
Potential energy [J]

- \( Q \)
Amount of heat transferred [J]

- \( q \)
Heat dissipation [J]

- \( R \)
Universal gas constant [J/kg-K]

- \( {\hbox{RHI}} \)
Return heat index (9.49) non-dimensional measure of recirculation

- \( S \)
Entropy in system [J/K]

- \( s \)
Specific entropy (entropy per unit mass) [J/kg K]

- \( {\hbox{SHI}} \)
Supply heat index (9.48) non-dimensional measure of recirculation

- \( {\hbox{SOR}} \)
Successive over relaxation

- \( T \)
Absolute temperature [K]

- \( t \)
Time [s]

- \( U \)
Internal energy [J]

- \( u \)
Component of velocity nominally in the direction of

*x*-axis [m/s]- \( \rlap-{V} \)
Volume [m

^{3}]- \( V \)
Velocity [m/s]

- \( v \)
Component of velocity nominally in the direction of

*y*-axis [m/s]- \( W \)
Amount of work transferred [J] nominally in the form of electricity or mechanical work

- \( w \)
Component of velocity nominally in the direction of

*z*-axis [m/s]- \( x \)
Distance in the direction of

*x*-axis [m]- \( y \)
Distance in the direction of

*y*-axis [m]- \( z \)
Height or distance in the direction of

*z*-axis [m]- \( \alpha \)
Thermal diffusivity defined as the ratio of thermal conductivity to the volumetric thermal capacity (\( \rho {C_{\rm{p}}} \))

- \( \beta \)
Nondimensional measure of recirculation (9.50) at the rack inlet

- \( \Delta \)
Change in value or state

- \( \delta \)
Incremental (infinitesimally small) change

- \( \Phi \)
Exergy of a closed system [J]

- \( \varphi \)
Potential flow function (9.60, 9.61)

- \( \eta \)
Efficiency

- \( \rho \)
Density [kg/m

^{3}]- \( \omega \)
Relaxation factor for Gauss–Seidel iteration (9.70)

- \( \Psi \)
Stream exergy for flow through an open system [J]

- \( \psi \)
Specific stream exergy (stream exergy per unit mass) [J/kg]

## Subscripts

- 0
Ground state

- 1
State of a system (nominally initial state) or arbitrary index value (e.g., in summation)

- 2
State of a system (nominally final state) or arbitrary index value (e.g., in summation)

- II
Related to second law (such as second-law efficiency)

- a
Ambient

- airspace
related to the airspace within a data center

- b
At the boundary of a control volume nominally the boundary of a cell in a finite volume mesh

- C
Carnot

- CRAC
Related to the CRAC units in a data center

- cv
Control volume

- cycle
Integrated over an entire cycle i.e., final and initial states are identical

- d
Destroyed or irreversibly consumed

- f
Related to the faces (surfaces) of a cell within a finite volume mesh

- gen
Generated

- H
Related to high-temperature reservoir (source)

- i
Inlet or counter in summation, often for variables relating to the

*x*-direction- in
Inlet or flowing into a given control volume

- j
Counter in summation often for variables relating to the

*y*-direction- k
Counter in summation often for variables relating to the

*z*-direction- KE
Related to the transfer of kinetic energy

- L
Related to low-temperature reservoir (sink)

- max
(Theoretical) maximum value

- o
Outlet

- out
Outlet or flowing out of a given control volume

- P
Related to the processor within a computer system

- PE
Related to the transfer of potential energy

- Q
Related to the transport of heat

- sup
Supply state

- rack
Related to the computer racks in a data center

- rec
Recoverable

- ret
Return state

- rev
Reversible

- t, th
thermal

- W
Related to work

## Superscripts

- .
Rate (i.e., per unit time)

- ′″
Per unit volume

- →
Vector

## References

- 1.Çengel YA, Boles MA (2001) Thermodynamics: an engineering approach, 4th edn. McGraw-Hill, Hightstown, NJGoogle Scholar
- 2.Moran MJ, Shapiro HN (2004) Fundamentals of engineering thermodynamics, 5th edn. Wiley, New York, NYGoogle Scholar
- 3.Bejan A (1997) Advanced engineering thermodynamics, 2nd edn. Wiley, New York, NYGoogle Scholar
- 4.Sonntag RE, Borgnakke C (2000) Introduction to engineering thermodynamics, 2nd edn. Wiley, New York, NYGoogle Scholar
- 5.Reynolds WC (1977) Engineering thermodynamics. McGraw-Hill, Hightstown, NJGoogle Scholar
- 6.Turns SR (2006) Thermodynamics: concepts and applications. Cambridge University Press, Cambridge, UKMATHGoogle Scholar
- 7.Tester JW, Modell M (1996) Thermodynamics and its applications. Prentice-Hall, Englewood Cliffs, NJGoogle Scholar
- 8.Jones JB, Dugan RE (1995) Engineering thermodynamics. Prentice-Hall, Englewood Cliffs, NJGoogle Scholar
- 9.Moran MJ (1982) Availability analysis: a guide to efficient energy Use. Prentice-Hall, Englewood Cliffs, NJGoogle Scholar
- 10.Bejan AD (1982) Entropy generation through heat and fluid flow. Wiley, New YorkGoogle Scholar
- 11.Bejan A, Tsatsaronis G, Moran M (1996) Thermal design and optimization. Wiley, New York, NYMATHGoogle Scholar
- 12.Gyftopoulos EP, Beretta GP (2005) Thermodynamics: foundations and applications. Dover, Mineola, NYGoogle Scholar
- 13.Keenan JH (1951) Availability and irreversibility in thermodynamics. Br J Appl Phys 2:183–192Google Scholar
- 14.Kotas TJ (1995) The exergy analysis of thermal plant analysis. Krieger, Malabar, FLGoogle Scholar
- 15.Verkhivker GP, Kosoy BV (2001) On the exergy analysis of power plants. Energy Convers Manag 42(18):2053–2059Google Scholar
- 16.Rosen MA (2001) Energy- and exergy-based comparison of coal-fired and nuclear steam power plants. Exergy 1(3):180–192Google Scholar
- 17.Koroneos C, Haritakis I, Michaloglou K, Moussipolos N (2004) Exergy analysis for power plant alternative designs—parts I and II. Energy Sources 26:1277–1295Google Scholar
- 18.Ameri M, Ahmadi P, Khanmohammadi S (2008) Exergy analysis of a 420 MW combined cycle power plant. Int J Energy Res 32(2):175–183Google Scholar
- 19.Sengupta S, Datta A, Duttagupta S (2007) Exergy analysis of a coal-based 210 MW thermal power plant. Int J Energy Res 31(1):14–28Google Scholar
- 20.Tsatsaronis G, Park M-H (2002) On avoidable and unavoidable exergy destructions and investment costs in thermal systems. Energy Convers Manag 43(9–12):1259–1270Google Scholar
- 21.Bejan A, Mamut E (1999) Thermodynamic optimization of complex energy systems. Springer, New York, NYGoogle Scholar
- 22.Hepbasli A, Akdemir O (2004) Energy and exergy analysis of a ground source (geothermal) heat pump system. Energy Convers Manag 45(5):737–753Google Scholar
- 23.Balli O, Aras H, Hepbasli A (2008) Exergoeconomic analysis of a combined heat and power system. Int J Energy Res 32(4):273–289Google Scholar
- 24.Taniguchi H, Mouri K, Nakahara T, Arai N (2005) Exergy analysis on combustion and energy conversion processes. Energy 3(2–4):111–117Google Scholar
- 25.Rosen MA, Dincer I (2003) Exergy methods for assessing and comparing thermal storage systems. Int J Energy Res 27(4):415–430Google Scholar
- 26.Wright SE, Rosen MA (2004) Exergetic efficiencies and the exergy content of terrestrial solar radiation. J Sol Energ Eng 126(1):673–676Google Scholar
- 27.Caton JA (2000) On the destruction of availability (exergy) due to combustion processes—with specific application to internal combustion engines. Energy 25(11):1097–1117Google Scholar
- 28.Rosen MA (1995) Energy and exergy analyses of electrolytic hydrogen production. Int J Hydrogen Energ 20(7):547–553Google Scholar
- 29.Hotz N, Senn SM, Poulikakos D (2006) Exergy analysis of a solid oxide fuel cell micropowerplant. Proceedings of the 13th international heat transfer conference (IHTC-13), Sydney, AustraliaGoogle Scholar
- 30.Chan SH, Low CF, Ding OL (2002) Energy and exergy analysis of simple solid-oxide fuel-cell power systems. J Power Sources 103(2):188–200Google Scholar
- 31.Hussain MM, Baschuk JJ, Li X, Dincer I (2005) Thermodynamic analysis of a PEM fuel cell power system. Int J Thermal Sci 44(9):903–911Google Scholar
- 32.Bavarsad PG (2007) Energy and exergy analysis of internal reforming solid oxide fuel cell-Gas turbine hybrid system. Int J Hydrogen Energ 32(17):4591–4599Google Scholar
- 33.Szargut J, Morris DR, Steward FR (1988) Exergy analysis of thermal, chemical and metallurgical processes. Hemisphere, New York, NYGoogle Scholar
- 34.Wall G (1988) Exergy flows in industrial processes. Energy 13(2):197–208Google Scholar
- 35.Brodyansky VM, Le Goff P, Sorin MV (1994) The efficiency of industrial processes: exergy analysis and optimization. Elsevier, Amsterdam (The Netherlands)Google Scholar
- 36.Creyts JC, Carey VP (1997) Use of extended exergy analysis as a tool for assessment of the environmental impact of industrial processes. Proceedings of the international mechanical engineering conference and exposition, Dallas, TX, AES-37, pp. 129–137Google Scholar
- 37.Creyts JC, Carey VP (1999) Use of extended exergy analysis to evaluate the environmental performance of machining processes. Proceedings of the institution of mechanical engineers, vol. 213(4), Part E: Journal of Process Mechanical Engineering, pp 247–264, doi: 10.1243/0954408991529861Google Scholar
- 38.Sato N (2004) Chemical energy and exergy: an introduction to chemical thermodynamics for engineers. Elsevier, San Diego, CAGoogle Scholar
- 39.Morris D, Steward F, Szargut J (1994) Technological assessment of chemical metallurgical processes. Can Metall Q 33(4):289–295Google Scholar
- 40.Dincer I, Hussain MM, Al-Zaharnah I (2003) Energy and exergy use in industrial sector of Saudi Arabia. Proceedings of the institution of mechanical engineers, vol. 217(5), Part A: Journal of Power and Energy, pp 481–492, doi: 10.1243/095765003322407539Google Scholar
- 41.Szargut J, Morris DR (1990) Cumulative exergy losses associated with the production of lead metal. Int J Energy Res 14(6):605–616Google Scholar
- 42.Gong M (2004) Exergy analysis of a pulp and paper mill. Int J Energy Res 29(1):79–83Google Scholar
- 43.Dewulf J, Van Langenhove H (2004) Thermodynamic optimization of the life cycle of plastics by exergy analysis. Int J Energy Res 28(11):969–976Google Scholar
- 44.Uche J, Serra L, Valero A (2008) Exergy costs and inefficiency diagnosis of a dual-purpose power and desalination plant. J Energ Resource Technol 128(3):186–193Google Scholar
- 45.Gutowski T, Dahmus J, Thiriez A, Branham M, Jones A (2007) A thermodynamic characterization of manufacturing processes. Proceedings of the IEEE international symposium on electronics and the environment, Orlando, FLGoogle Scholar
- 46.Chengqin R, Nianping L, Guanga T (2002) Principles of exergy analysis in HVAC and evaluation of evaporative cooling schemes. Build Environ 37(11):1045–1055Google Scholar
- 47.Dikic A, Akbulut A (2008) Exergetic performance evaluation of heat pump systems having various heat sources. Int J Energy Res 32(14):1279–1926Google Scholar
- 48.Paoletti S, Rispoli F, Sciubba E (1989) Calculation of exergetic losses in compact heat exchanger passages. Proc ASME Adv Energ Syst 10–2:21–29Google Scholar
- 49.Yumruta R, Kunduz M, Kanolu M (2002) Exergy analysis of vapor compression refrigeration systems. Exergy 2(4):266–272Google Scholar
- 50.Bejan A, Ledezma G (1996) Thermodynamic optimization of cooling techniques for electronic packages. Int J Heat Mass Transf 39(6):1213–1221Google Scholar
- 51.Bejan A, Morega AM, Lee SW, Kim SJ (1993) The cooling of a heat generating board inside a parallel plate channel. Int J Heat Mass Transf 14:170–176Google Scholar
- 52.Bejan A (1997) Constructal-theory network of conducting paths for cooling a heat generating volume. Int J Heat Mass Transf 40(4):799–811MATHGoogle Scholar
- 53.Ogiso K (2001) Assessment of overall cooling performance in thermal design of electronics based on thermodynamics. J Heat Transfer 123(5):999–1005Google Scholar
- 54.Ndao S, Peles Y, Jensen MK (2009) Multi-objective thermal design optimization and comparative analysis of electronics cooling technologies. Int J Heat Mass Transf 52:4317–4326MATHGoogle Scholar
- 55.Culham JR, Muzychka YS (2001) Optimization of plate Fin heat sinks using entropy generation minimization. IEEE Trans Compon Packag Technol 24(2):159–165Google Scholar
- 56.Shuja SZ (2002) Optimal Fin geometry based on exergoeconomic analysis for a Pin-Fin array with application to electronics cooling. Exergy 2(4):248–258Google Scholar
- 57.Shih CJ, Liu GC (2004) Optimal design methodology of plate-fin heat sinks for electronic cooling using entropy generation strategy. IEEE Trans Compon Packag Technol 27(3): 551–559Google Scholar
- 58.Zhou J-H, Yang C-X, Zhang L-N (2008) Minimizing the entropy generation rate of the plate-finned heat sinks using computational fluid dynamics and combined optimization. Appl Therm Eng 29(8–9):1872–1879Google Scholar
- 59.Bar-Cohen A, Iyengar M, Kraus AD (2003) Design of optimum plate-Fin natural convective heat sinks. ASME J Electron Packag 125(2):208–216Google Scholar
- 60.Iyengar M, Bar-Cohen A (2001) Design for manufacturability of SISE parallel plate forced convection heat sinks. IEEE Trans Compon Packag Technol 24(2):150–158Google Scholar
- 61.Khan WA, Culham JR, Yovanovich MM (2004) Optimization of pin-fin heat sinks using entropy generation minimization. Proceedings of the 9th inter society conference on thermal and thermomechanical phenomena (ITHERM), pp 259–267, doi: 10.1109/ITHERM.2004.1319183Google Scholar
- 62.Khan WA, Culham JR, Yovanovich MM (2008) Optimization of pin-fin heat sinks in bypass flow using entropy generation minimization. J Electron Packag 130(3), Article 031010, doi: 10.1115/1.2965209Google Scholar
- 63.Bejan AD (1996) Entropy generation minimization. Wiley, New York, NY, pp 104–109MATHGoogle Scholar
- 64.Kern DQ, Kraus AD (1972) Extended surface heat transfer. McGraw-Hill, New York, NYGoogle Scholar
- 65.Kraus AD, Aziz A, Welty J (2001) Extended surface heat transfer. Wiley, New York, NYGoogle Scholar
- 66.Khan WA, Culham JR, Yovanovich MM (2009) Optimization of microchannel heat sinks using entropy generation minimization methods. IEEE Trans Compon Packag Technol 32(2): 243–251Google Scholar
- 67.Bar-Cohen A, Iyengar M (2002) Design and optimization of Air-cooled heat sinks for sustainable development. IEEE Trans Compon Packag Technol 25(4):584–591Google Scholar
- 68.Carey VP, Shah AJ (2006) The exergy cost of information processing: a comparison of computer-based technologies and biological systems. J Electron Packag 128(4):346–352Google Scholar
- 69.Shah AJ, Carey VP, Bash CE, Patel CD (2003) Exergy analysis of data center thermal management systems. Paper IMECE2003-42527. Proceedings of the ASME international mechanical engineering congress and exposition, Washington, DCGoogle Scholar
- 70.Shah AJ, Carey VP, Bash CE, Patel CD (2004) An exergy-based control strategy for computer room air-conditioning units in data center. Paper IMECE2004-61384, Proceedings of the 2004 international mechanical engineering congress and exposition, Anaheim, CAGoogle Scholar
- 71.Shah AJ, Carey VP, Bash CE, Patel CD (2005) Exergy-based optimization strategies for multi-component data center thermal management: part I, analysis. Paper IPACK2005-73137. Proceedings of the pacific rim/ASME international electronic packaging technical conference and exhibition (InterPACK), San Francisco, CAGoogle Scholar
- 72.Shah AJ, Carey VP, Bash CE, Patel CD (2005) Exergy-based optimization strategies for multi-component data center thermal management: part II, application and validation. Paper IPACK2005-73138. Proceedings of the pacific rim/ASME international electronic packaging technical conference and exhibition (InterPACK), San Francisco, CAGoogle Scholar
- 73.Shah A, Carey V, Patel C, Bash C (2008) Exergy analysis of data center thermal management systems. J Heat Transfer 130(2), Article No. 021401, doi: 10.1115/1.2787024Google Scholar
- 74.Shah AJ, Carey VP, Bash CE, Patel CD (2008) An exergy-based figure-of-merit for electronic packages. J Electron Packag 128(4):360–369Google Scholar
- 75.Sciubba E (2005) Exergo-economics: thermodynamic foundation for a more rational resource use. Int J Energy Res 29(7):613–636Google Scholar
- 76.Sciubba E (2001) Beyond thermoeconomics? The concept of extended exergy accounting and its application to the analysis and design of thermal systems. Exergy 1(2):68–84Google Scholar
- 77.Sayed-El YM (2003) The thermoeconomics of energy conversions. Pergamon, Oxford, UKGoogle Scholar
- 78.Tsatsaronis G (2002) Application of thermoeconomics to the design and synthesis of energy plants. In: Grangopoulos CA (ed) Exergy, energy system analysis, and optimization, encyclopaedia of life support systems. EOLSS Publishers, UK (website: www.eolss.net) pp 160–172, ISBN 978-1-84826-614-8
- 79.Valero A (1995) Thermoeconomics: the meeting point of thermodynamics, economics and ecology. In: Sciubba E, Moran M (eds) Second law analysis of energy systems: towards the 21st century. Circus, Rome, pp 293–305Google Scholar
- 80.Ayres RU, Ayres LW, Warr B (2002) Exergy, power and work in the US economy, 1900–1998. Energy 28(3):219–273Google Scholar
- 81.Dincer I, Rosen M (2007) Exergy: energy environment and sustainable development. Elsevier, Elsevier, NYGoogle Scholar
- 82.Rosen MA, Dincer I (1997) On exergy and environmental impact. Int J Energy Res 21(7): 643–654Google Scholar
- 83.Zvolinschi A et al (2007) Exergy sustainability indicators as a tool in industrial ecology. J Ind Ecol 11(4):85–98Google Scholar
- 84.Hammond GP (2004) Engineering sustainability: thermodynamics, energy systems, and the environment. Int J Energy Res 28(7):613–639Google Scholar
- 85.Zevenhoven R, Kavaliauskaite I (2004) Mineral carbonation for long-term CO
_{2}storage: an exergy analysis. Int J Thermodyn 7(1):23–31Google Scholar - 86.Cornelissen RL (1997) Thermodynamics and sustainable development: the use of exergy analysis and the reduction of irreversibility. PhD Dissertation, University of Twente, The NetherlandsGoogle Scholar
- 87.Connelly L, Koshland CP (2001) Exergy and industrial ecology—part I: an exergy-based definition of consumption and a thermodynamic interpretation of ecosystem evolution. Exergy 1(3):146–165Google Scholar
- 88.Connelly L, Koshland CP (2001) Exergy and industrial ecology—part II: a non-dimensional analysis of means to reduce resource depletion. Exergy 1(4):234–255Google Scholar
- 89.Gong M, Wall G (2001) On exergy and sustainable development—part I: conditions and concepts. Exergy 1(3):128–145Google Scholar
- 90.Gong M, Wall G (2001) On exergy and sustainable development—part II: indicators and methods. Exergy 1(4):217–233Google Scholar
- 91.Balocco C et al (2004) Using exergy to analyze the sustainability of an urban area. Ecol Econ 48(2):231–244Google Scholar
- 92.Hannemann C, et al. (2008) Lifetime exergy consumption of an enterprise server. Proceedings of the IEEE international symposium on electronics and the environment, San Francisco, CAGoogle Scholar
- 93.Haseli Y, Dincer I, Naterer GF (2008) Unified approach to exergy efficiency environmental impact and sustainable development for standard thermodynamic cycles. Int J Green Energ 5:105–119Google Scholar
- 94.Sullivan RF (2003) Alternating cold and hot aisles provides more reliable cooling for server farms. White Paper by The Uptime Institute, Santa Fe, NMGoogle Scholar
- 95.APC (2003) Avoidable mistakes that compromise cooling performance in data centers and network rooms. White Paper # 49 by American Power Conversion, Washington, DCGoogle Scholar
- 96.ASHRAE (2004) Thermal guidelines for data processing environments. Atlanta, GAGoogle Scholar
- 97.Shrivastava S, Sammakia B, Schmidt R, Iyengar M (2005) Comparative analysis of different data center airflow management configurations. Proceedings of the ASME international electronic packaging technical conference and exhibition (InterPACK), San Francisco, CAGoogle Scholar
- 98.Iyengar M, Schmidt R, Sharma A, McVicker G, Shrivastava S, Sri-Jayantha S, Amemiya Y, Dang H, Chainer T, Sammakia B (2005) Thermal characterization of non-raised floor air cooled data centers using numerical modeling. Proceedings of the pacific rim/ASME international electronic packaging technical conference and exhibition (InterPACK), San Francisco, CAGoogle Scholar
- 99.Patel CD (2000) Enabling pumped liquid loop cooling: justification and the key technology and cost barriers. International Conference on High-Density Interconnect and Systems Packaging, Denver, COGoogle Scholar
- 100.Bash CE, Patel C, Sharma RK (2003) Efficient thermal management of data centers—immediate and long-term research needs. Int J HVAC&R Res 9(2):137–152Google Scholar
- 101.Patel CD, Bash CE, Sharma R, Beitelmal A, Malone CG (2005) Smart chip, system and data center enabled by advanced flexible cooling resources. Proceedings of the IEEE semiconductor thermal management and measurement symposium (SEMITHERM), San Jose, CAGoogle Scholar
- 102.Patel CD, Shah AJ (2005) Cost model for planning, development and operation of a data center. Technical Report HPL-2005-107R1, Hewlett Packard Laboratories, Palo Alto, CAGoogle Scholar
- 103.Koomey J, Brill K, Turner P, Stanley J, Taylor B (2008) A simple model for determining true total cost of ownership for data centers. White Paper No. TUI 3011C Version 2.1, The Uptime Institute, Santa Fe, NM.Google Scholar
- 104.Patel CD, Friedrich R (2002) Towards planetary scale computing—technical challenges for next generation Internet computing. In: Joshi YK, Garimella SV (eds) Thermal challenges in next generation electronic systems. Millpress, Rotterdam, The NetherlandsGoogle Scholar
- 105.Patel CD, Bash CE, Belady C, Stahl L, Sullivan D (2001) Computational fluid dynamics modeling of high compute density data centers to assure system inlet air specifications. Proceedings of the pacific rim/ASME international electronic packaging technical conference and exhibition (InterPACK), Kauai, HIGoogle Scholar
- 106.Schmidt R (2001) Effect of data center characteristics on data processing equipment inlet temperatures. Proceedings of the pacific rim/ASME international electronic packaging technical conference and exhibition (InterPACK), Kauai, HIGoogle Scholar
- 107.Mitchell-Jackson J, Koomey JG, Nordman B, Blazek M (2001) Data center power requirements: measurements from silicon valley. Energy 28(8):837–850Google Scholar
- 108.Mitchell-Jackson JD (2001) Energy needs in an internet economy: a closer look at data centers. M.S. Thesis (Energy and Resources Group), University of California, Berkeley, CAGoogle Scholar
- 109.Patel CD, Bash CE, Sharma R, Beitelmal M, Friedrich R (2003) Smart cooling of data centers. Proceedings of the international electronic packaging technical conference and exhibition (InterPACK’03), Maui, HIGoogle Scholar
- 110.Patel CD (2003) A vision of energy aware computing—from chips to data centers. Proceedings of the international symposium on micromechanical engineering, Tsuchiura, JapanGoogle Scholar
- 111.Tolia N, WangZ, Marwah M, Bash C, Ranganathan P, Zhu X (2009) Zephyr: a unified predictive approach to improve server cooling and power efficiency. Proceedings of the ASME/pacific rim technical conference and exhibition on packaging and the integration of electronic and photonic systems, MEMS, and NEMS (InterPACK), San Francisco, CAGoogle Scholar
- 112.Sharma R, Bash C, Patel C, Friedrich R, Chase J (2005) Balance of power: dynamic thermal management for internet data centers. IEEE Internet Comput 9(1):42–49Google Scholar
- 113.Moore J, Chase J, Ranganathan P, Sharma R (2005) Making scheduling “cool”: temperature-aware workload placement in data centers. Usenix annual technical conference, Anaheim, CAGoogle Scholar
- 114.Moore J, Chase J, Farkas K, Ranganathan P (2005) Data center workload monitoring, analysis, and emulation. Proceedings of the eighth workshop on evaluation using commercial workloads (CAECW-8), San Francisco, CAGoogle Scholar
- 115.Fiorina C (2000) Transforming companies, transforming countries. Keynote address at the Japanese Chamber of Commerce and Industry, New York, NYGoogle Scholar
- 116.Patel C, Sharma R, Bash C, Graupner S (2003) Energy aware grid: global workload placement based on energy efficiency. Proceedings of the ASME international mechanical engineering congress and exposition (IMECE), Washington DC.Google Scholar
- 117.Wang D (2004) A passive solution to a difficult data center problem. Proceedings of the intersociety conference on thermal and thermomechanical phenomena (ITHERM), San Diego, CA, pp 586–592Google Scholar
- 118.Heydari A, Sabounchi P (2004) Refrigeration assisted spot cooling of a high heat density data center. Proceedings of the intersociety conference on thermal and thermomechanical phenomena (ITHERM), San Diego, CA, pp 601–606Google Scholar
- 119.Schmidt R, Chu R, Ellsworth M, Iyengar M, Porter D, Kamath V, Lehmann B (2005) Maintaining datacom rack inlet air temperatures with water cooled heat exchangers. Proceedings of the ASME international electronic packaging technical conference and exhibition (InterPACK), San Francisco, CAGoogle Scholar
- 120.Hewlett Packard (2009) Improving data center efficiency—incorporating air stream containment. White Paper. http://h10134.www1.hp.com/insights/whitepapers/downloads/air_stream_containment.pdf. Accessed 14 Dec 2009
- 121.Gondipalli S, Sammakia B, Bhopte S, Schmidt R, Iyengar MK, Murray B (2009) Optimization of cold aisle isolation designs for a data center with roofs and doors using slits. Proceedings of the ASME international electronic packaging technical conference and exhibition (InterPACK), San Francisco, CAGoogle Scholar
- 122.Marwah M, Sharma R, Patel C, Shih R, Bhatia V, Mekanapurath M, Velayudhan S (2009) Data analysis, visualization and knowledge discovery in sustainable data centers. Proceedings of the ACM compute conference, Bangalore, IndiaGoogle Scholar
- 123.Samadiani E, Joshi Y, Hamann H, Iyengar MK, Kamalsy S, Lacey J (2009) Reduced order thermal modeling of data centers via distributed sensor data. Proceedings of the ASME international electronic packaging technical conference and exhibition (InterPACK), San Francisco, CAGoogle Scholar
- 124.Sharma R, Marwah M, Lugo W (2009) Application of data analytics to heat transfer phenomena for optimal design and operation of complex systems. Proceedings of the ASME summer heat transfer conference, San Francisco, CAGoogle Scholar
- 125.Marwah M, Sharma R, Lugo W (2009) Autonomous detection of thermal anomalies in data centers. Proceedings of the ASME international electronic packaging technical conference and exhibition (InterPACK), San Francisco, CAGoogle Scholar
- 126.Bash CE, Patel CD, Sharma RK (2006) Dynamic thermal management of an air-cooled data center. Proceedings of the intersociety conference on thermal and thermomechanical phenomena (ITHERM), San Diego, CAGoogle Scholar
- 127.Kang S, Schmidt RR, Kelkar KM, Radmehr A, Patankar SV (2000) A methodology for the design of perforated tiles in a raised floor data center using computational flow analysis. Proceedings of the eighth intersociety conference on thermal and thermomechanical phenomena in electronic systems (ITHERM), Las Vegas, NVGoogle Scholar
- 128.VanGilder JW, Lee T (2003) A hybrid flow network-CFD method for achieving any desired flow partitioning through floor tiles of a raised-floor data center. Proceedings of the international electronic packaging technical conference and exhibition (InterPACK), Maui, HIGoogle Scholar
- 129.Schmidt R, Karki K, Patankar S (2004) Raised-floor data center: perforated tile flow rates for various tile layouts. Proceedings of the ninth intersociety conference on thermal and thermomechanical phenomena in electronic systems (ITHERM), Las Vegas, NVGoogle Scholar
- 130.Karki KC, Radmehr A, Patankar SV (2003) Use of computational fluid dynamics for calculating flow rates through perforated tiles in raised-floor data centers. Int J Heat Ventil Air-Condition Refrig Res 9(2):153–166Google Scholar
- 131.Karki KC, Patankar SV, Radmehr A (2003) Techniques for controlling airflow distribution in raised floor data centers. Proceedings of the pacific rim/ASME international electronic packaging technical conference and exhibition (InterPACK), Maui, HIGoogle Scholar
- 132.VanGilder JW, Schmidt RR (2005) Airflow uniformity through perforated tiles in a raised floor data center. Proceedings of the pacific rim/ASME international electronic packaging technical conference and exhibition (InterPACK), San Francisco, CAGoogle Scholar
- 133.Radmehr A, Schmidt RR, Karki KC, Patankar SV (2005) Distributed leakage flow in raised floor data centers. Proceedings of the pacific rim/ASME international electronic packaging technical conference and exhibition (InterPACK), San Francisco, CAGoogle Scholar
- 134.Rambo JD, Joshi YK (2004) Supply air distribution from a single air handling unit in a raised floor plenum data center. Proceedings of the joint indian society of heat and mass transfer/american society of mechanical engineers heat and mass transfer conference (ISHMT/ASME), Kalpakkam, IndiaGoogle Scholar
- 135.Patel CD, Sharma RK, Bash CE, Beitelmal A (2002) Thermal considerations in cooling large scale high computer density data centers. Proceedings of the eighth intersociety conference on thermal and thermomechanical phenomena in electronic systems (ITHERM), San Diego, CAGoogle Scholar
- 136.Bash C, Forman G (2007) Cool job allocation: measuring the power savings of placing jobs at cooling-efficient locations in the data center. Proceedings of the Usenix annual technical conference, Santa Clara, CAGoogle Scholar
- 137.Bhopte S, Agonafer D, Schmidt R, Sammakia B (2005) Optimization of data center room layout to minimize rack inlet air temperature. Proceedings of the pacific rim/ASME international electronic packaging technical conference and exhibition (InterPACK), San Francisco, CAGoogle Scholar
- 138.Schmidt R, Iyengar M (2005) Effect of data center layout on rack inlet air temperatures. Proceedings of the pacific rim/ASME international electronic packaging technical conference and exhibition (InterPACK), San Francisco, CAGoogle Scholar
- 139.Schmidt R, Cruz E (2002) Raised floor computer data center: effect on rack inlet temperatures of chilled air exiting both the hot and cold aisles. Proceedings of the intersociety conference on thermal and thermomechanical phenomena (ITHERM), San Diego, CA, pp 580–594Google Scholar
- 140.Schmidt R, Cruz E (2002) Raised floor computer data center: effect on rack inlet temperatures when high powered racks are situated amongst lower powered racks. Proceedings of the ASME international mechanical engineering congress and exposition (IMECE), New Orleans, LAGoogle Scholar
- 141.Schmidt R, Cruz E (2003) Cluster of high powered racks within a raised floor computer data center: effect of perforated tile flow distribution on rack inlet air temperatures. Proceedings of the ASME international mechanical engineering congress and exposition (IMECE), Washington, DC, pp 245–262Google Scholar
- 142.Schmidt R, Cruz E (2003) Raised floor computer data center: effect on rack inlet temperatures when adjacent racks are removed. Proceedings of the pacific rim/ASME international electronic packaging technical conference and exhibition (InterPACK), Maui, HIGoogle Scholar
- 143.VanGilder JW, Shrivastava SK (2007) Capture index: an airflow-based rack cooling performance metric. ASHRAE Transact 113(1):126–136Google Scholar
- 144.Herrlin MK (2008) Airflow and cooling performance of data centers: two performance metrics. ASHRAE Transact 114(2):182–187Google Scholar
- 145.Bedekar V, Karajgikar S, Agonafer D, Iyengar M, Schmidt R (2006) Effect of CRAC location on fixed rack layout of a data center. Proceeding of the 9th intersociety conference on thermal and thermomechanical phenomena (ITHERM), San Diego, CAGoogle Scholar
- 146.Sharma RK, Bash CE, Patel CD (2002) Dimensionless parameters for evaluation of thermal design and performance of large-scale data centers. Proceedings of the eighth ASME/AIAA joint thermophysics and heat transfer conference, St. Louis, MOGoogle Scholar
- 147.Sharma RK, Bash CE (2002) Dimensionless parameters for energy-efficient data center design. Proceedings of the IMAPS advanced technology workshop on thermal management (THERM ATW), Palo Alto, CAGoogle Scholar
- 148.Schmidt RR, Cruz EE, Iyengar MK (2005) Challenges of data center thermal management. IBM J Res Dev 49(4/5):709–723Google Scholar
- 149.Schmidt R, Iyengar M, Chu R (2005) Meeting data center temperature requirements. ASHRAE J 47(4):44–49Google Scholar
- 150.Herrlin MK (2005) Rack cooling effectiveness in data centers and telecom central offices: the rack cooling index (RCI). ASHRAE Transact 111(2):725–731Google Scholar
- 151.Aebischer B, Eubank H, Tschudi W (2004) Energy efficiency indicators for data centers. International conference on improving energy efficiency in commercial buildings, Frankfurt, GermanyGoogle Scholar
- 152.Norota M, Hayama H, Enai M, Kishita M (2003) Research on efficiency of air conditioning system for data center. Proceedings of the IEEE international telecommunications energy conference (INTELEC), Yokohama, Japan, pp. 147–151Google Scholar
- 153.The Green Grid (2007) Green grid metrics: describing datacenter power efficiency. Technical Committee White Paper. http://www.thegreengrid.org. Accessed 14 June 2010
- 154.Rolander N, Rambo J, Joshi Y, Mistree Y (2005) Robust design of air cooled server cabinets for thermal efficiency. Proceedings of the ASME international electronic packaging technical conference and exhibition (InterPACK), San Francisco, CAGoogle Scholar
- 155.Rambo J, Joshi Y (2005) Thermal performance metrics for arranging forced Air cooled servers in a data processing cabinet. J Electron Packag 127(4):452–459Google Scholar
- 156.Schmidt RR, Karki KC, Kelkar KM, Radmehr A, Patankar SV (2001) Measurements and predictions of the flow distribution through perforated tiles in raised-floor data centers. Proceedings of the pacific rim/ASME international electronic packaging technical conference and exhibition (InterPACK), Kauai, HIGoogle Scholar
- 157.McAllister S, Carey VP, Shah AJ, Bash CE, Patel CD (2008) Strategies for effective Use of Exergy-based modeling of data center thermal management systems. Microelectron J 39(7): 1023–1029Google Scholar
- 158.Munson BR, Young DF, Okiishi TH (1998) Fundamentals of fluid mechanics, 3rd edn. Wiley, New York, NYGoogle Scholar
- 159.White EM (1987) Fluid mechanics. McGraw-Hill, New York, NYGoogle Scholar
- 160.Batchelor GJ (1967) An introduction to fluid dynamics. Cambridge University Press, Cambridge, UKMATHGoogle Scholar
- 161.Patankar SV (1980) Numerical heat transfer and fluid flow. Taylor & Francis, New York, NYMATHGoogle Scholar
- 162.Versteeg H, Malasekra W (1996) An introduction to computational fluid dynamics: the finite volume method approach. Prentice-Hall, Englewood Cliffs, NJGoogle Scholar
- 163.Tannehill JC, Anderson DA, Pletcher RH (1997) Computational fluid mechanics and heat transfer. Taylor and Francis, Washington, DCGoogle Scholar
- 164.Jaluria Y, Torrance KE (2003) Computational heat transfer (2nd edition). Taylor and Francis, New York, NYGoogle Scholar
- 165.Kotake S, Hijikata K (1993) Numerical simulations of heat transfer and fluid flow on a personal computer. Elsevier Science, Amsterdam (The Netherlands)Google Scholar
- 166.Ketkar SP (1999) Numerical thermal analysis. ASME Press, New York, NYGoogle Scholar
- 167.Cebeci T, Bradshaw P (1988) Physical and computational aspects of convective heat transfer. Springer, New York, NYMATHGoogle Scholar
- 168.Kahan W (1958) Gauss-seidel methods of solving large systems of linear equations. Ph.D. Thesis, University of Toronto, Toronto, CanadaGoogle Scholar
- 169.Varga R (1962) Matrix iterative analysis. Prentice-Hall, Englewood Cliffs, NJGoogle Scholar
- 170.Young D (1971) Iterative solutions of large linear systems. Academic, New York, NYGoogle Scholar
- 171.Hageman L, Young D (1981) Applied iterative methods. Academic, New York, NYMATHGoogle Scholar
- 172.Mentor Graphics (2010) FloVENT: Built Environment HVAC CFD Software. http://www.mentor.com/products/mechanical/products/flovent. Accessed 26 June 2010
- 173.Moffat RJ (1988) Describing the uncertainties in experimental results. Exp Therm Fluid Sci 1:3–7Google Scholar
- 174.Sen A, Srivastava M (1997) Regression analysis: theory, methods and applications. Springer, New York, NYMATHGoogle Scholar
- 175.Pope AJ (1976) The statistics of residuals and the detection of outliers. NOAA Technical Report, Washington, DCGoogle Scholar
- 176.Draper NR, Smith H (1998) Applied regression analysis. Wiley, New York, NYMATHGoogle Scholar
- 177.Box GEP, Hunter WG, Hunter SJ, Hunter WG (1978) Statistics for experimenters: an introduction to design, data analysis and model building. Wiley, New York, NYMATHGoogle Scholar
- 178.Sharma R, Christian T, Arlitt M, Bash C, Patel C (2010) Design of farm waste-driven supply side infrastructure. Proceedings of the 4th ASME international conference on energy sustainability, Phoenix, AZGoogle Scholar
- 179.Shah AJ, Carey VP, Bash CE, Patel CD (2005) Exergy-based optimization strategies for multi-component data center thermal management: part I, analysis. Proceedings of the pacific rim/ASME international electronic packaging technical conference and exhibition (IPACK2005-73138), San Francisco, CAGoogle Scholar
- 180.Shah AJ, Carey VP, Bash CE, Patel CD (2005) Exergy-based optimization strategies for multi-component data center thermal management: part II, application and validation. Proceedings of the pacific rim/ASME international electronic packaging technical conference and exhibition (IPACK2005-73138), San Francisco, CAGoogle Scholar