Electronics Cooling Laboratory

CFD image of heat sink

Numerical simulation of ducted pin fin heat sink © 2006 Melanie Beauchemin

The electronics cooling laboratory at SJSU has two primary goals:

       - serving the engineering community by performing applied research 
fostering students' understanding of the thermal management of electronics.

The joint directors of this lab are Dr. Nicole Okamoto and Dr. Jinny Rhee. 
Please contact either of them if you would like to discuss sponsorship of a project.
Recent project partners include Hewlett Packard, Cisco Systems, Apple Computer
Therma, Inc., Lockheed Martin, Space Systems Loral, and the National Science Foundation.

SEM image of copper-diamond interface

Scanning electron microscopy of a lead-free, fluxless solder joint from copper to metallization for syntheti
diamond (Kam, P, et al. © 2008 ASME) 

Our current expertise includes

  • numerical modeling of electronic systems requiring thermal management
  • experimental testing of electronic components and systems cooled using single-phase convection (both air and liquid)
  • cooling of high heat density electronics
  • cooling at high elevations
  • design and testing of advanced thermal interface materials
  • micro heat pipe analysis
  • heat pipe fabrication and testing
  • microchannel heat transfer
  • modeling of thermal management of data centers
  • experimental testing of components used in data center cooling
  • heat exchanger design and testing


Experimental Facilities

  • Approximately 1200 square foot laboratory

  • High altitude thermal testing chamber, capable of simulating altitudes of up to 80,000 ft and temperatures from ambient to 160ºC, from Thermal Product Solutions
  • AMCA 210-99 Airflow Test Chamber from Airflow Measurement Systems; used to measure chassis impedance, generate specified flow rates, and determine fan performance (shown below) 
  • Small airflow test chamber for analyzing component-level performance, such as heat sinks.
  • Low-speed (0-2 m/s), low-turbulence intensity wind tunnel
  • National Instruments and Agilent automated data acquisition systems with a site license for LabView.
  • Infrared camera
  • Thermal interface material tester
  • Ultra-high precision electronic scale
  • 3-D printer
  • A wide variety of standard laboratory equipment such as handheld thermocouple readers, a high-precision electronic manometer (Microtector), and pressure transducers

 Computational Resources

  • Academic site license for the suite of Ansys programs, including Fluent and IcePack 
  • Academic site license for solid modelling software such as Pro-E
  • Academic site license for Engineering Equation Solver (EES), a simultaneous equation solver with thermophysical properties built in that is good for thermal system analysis. 


impedance wind tunnel     low speed wind tunnel

      AMCA 210-99 Airflow Test Chamber                             Low-Speed Wind Tunnel


airflow test chamber for component-level testing                                         high altitude chamber   

  Air-Flow Test Chamber for Component Testing                  High Altitude Chamber


    Publications Related to Thermal Management of Electronics and Data Center Cooling

image of flow visualization through fins
Flow visualization of offset-strip fin array © 1997 Nicole Okamoto

Yu, R., Sommers, A., and Okamoto, N., 2013, “Effect of a Micro-Grooved Surface Design on Air-Side Thermal-Hydraulic Performance of Plain-Fin-and-Tube Heat Exchangers,” International Journal of Refrigeration, Vol. 36, No. 3, pp 1078-1089.

Sommers, A., Yu, R., Okamoto, N., and Upadhyalula, K., 2012, “Condensate Drainage Performance of a Plain-Fin-and-Tube Heat Exchanger Constructed from Anisotropic Micro-Grooved Fins,” International Journal of Refrigeration, Vol. 35, No. 6, pp 1766-1778.

Yu, R., Sommers, A., Okamoto, N., and Upadhyalula, K., 2011, “Impact of an Anistotripic Fin Surface Design on the Thermal-Hydraulic Performance of a Plain-Fin-and-Tube Heat Exchanger”, Proceedings of the ASME International Mechanical Engineering Conference and Exposition, Denver, CO.

Yu, R., Sommers, A., Okamoto, N., and Upadhyalula, K., 2011, “Anisotropic Heat Exchanger Fin Surface Design for Improved Condensate Management,” International Conference on Air Conditioning and Refrigeration, Gangwon-Do, Korea.

Nagendrappa, N., Okamoto, N.C., and Barez, F., 2010 "Thermal Characterization of Fan-in Package-on-Packages," accepted for Semi-Therm 26, Santa Clara, CA.

Meakins, M., Okamoto, N.C., and Bash, C., 2009, "An Energy and Exergy Analysis of Economizer-Based Data Centers, " Proceedings of the ASME International Energy Sustainability Conference, San Francisco, CA.

Singh, S., and Okamoto, N.C., 2009, "Optimal Micro Heat Pipe Configuration for High Performance Heat Spreaders, " IMAPS Workshop on Thermal Management, Palo Alto, CA.

Okamoto, N.C., Hsu, T-R, and Bash, C., 2009, "A Thermal Management of Electronics Course and Laboratory for Undergraduates," Advances in Engineering Education, Vol. 1, No. 3.

Kam, P.C., Coppage, A.G., Kam, C.C., Shafian, S., Chun, B., and Rhee, J., 2008, "Lead-free, Fluxless Solder Joints to Synthetic Diamond," Proceedings of the 2008 ASME International Mechanical Engineering Congress and Exposition, Oct. 31-Nov.6, Boston, MA

Rogacs, A., and Rhee, J., 2007, "Performance – Cost Optimization of a Diamond Heat Spreader,” Proceedings of 2007 IEEE CPMT Division, Advanced Packaging Materials Conference, San Jose, CA, Oct. 3-5.

Bhave, N., and Okamoto, N.C., 2007, "Modeling Noncoplanarity Effects on Thermal Performance of Computer Chips," Proceedings of the IEEE Advanced Packaging Materials Symposium, San Jose, CA, Oct. 3-5.   

Rhee, J., and Bhatt, A., 2007, “Spatial and Temporal Resolution of Conjugate Conduction-Convection Thermal Resistance,” IEEE Transactions on Components and Packaging Technologies, Vol. 30, No. 4, pp. 673-682

Rhee, J., and Hernandez, S.I., 2006, “Thermal Management of Electronics in Telecommunications Products: Designing for the Network Equipment Building System (NEBS) Standards,”  ASME J. Electronics Packaging, Vol. 128, No. 4, pp. 484-493.

Rhee, J., and Moffat, R.J., 2006, "Experimental Estimate of the Continuous One-Dimensional Kernel Function in a Rectangular Duct With Forced Convection, Journal Heat Transfer, Vol. 128, No. 8, pp. 811-818.

Beauchemin, M., and Rhee, J., 2006, “Investigation of Cylindrical Pin Fin Heat Sinks at High Altitude,” Proceedings of the ASME Congress and Exposition, Chicago, IL, Nov. 5-10.

Seidel, R., and Rhee, J., 2006, “Parametric Analysis of Heat Sink Performance at High Altitudes with Air Impingement Cooling,” Proceedings of the ASME Congress and Exposition, Chicago, IL, Nov. 5-10.

Rhee, J., 2006, "The Role of Temperature Superposition in Thermal Management," Proceedings of the 11th IEEE CPMT Advanced Packaging Materials Conference, Atlanta, GA 

Bhatt, A., and Rhee, J., 2006, "Thermal Spreading Resistance for Square and Rectangular Entities," Proceedings of the 11th IEEE CPMT Advanced Packaging Materials Conference, Atlanta, GA

Heresztyn, A.J.H., and DeJong Okamoto, N.C., 2005, "Thermal Design of Microchannel Heat Sinks for Low-Orbit Micro-Satellites," Proceedings of the 3rd International Conference on Microchannels and Minichannels, American Society of Mechanical Engineers, Toronto.

Rhee, J., and Wong, G., 2004,  "Characterization of Airflow Impedance in Two Types of Telecommunications Chassis," Proceedings of the 20th Semi-Therm International Conference, San Jose, CA. 

DeJong Okamoto, N.C., and Hsu, T-R, 2004, "Development of a Laboratory Curriculum Devoted to the Thermal Management of Electronics," Proceedings of the ASEE Annual Conference, Salt Lake City. Invited Presentation.

DeJong, N.C., and A.M. Jacobi, 2003, “Heat Transfer and Pressure Drop for Flow through Bounded Louvered-Fin Arrays,” Experimental Thermal and Fluid Science, Vol. 27, pp. 237-250.

DeJong, N.C., and A.M. Jacobi, 2003, “Localized Flow and Heat Transfer Interactions in Louvered-Fin Arrays,” International Journal of Heat and Mass Transfer, Vol. 46, pp. 443-455.

Rhee, J., and Azar, K., 1999, “Adjusting Temperature Data for High Altitude” Electronics Cooling Magazine, September, Vol. 5, No. 3. 

DeJong, N.C., and A.M. Jacobi, 1999, “Local Flow Structures and Heat Transfer in Convex-Louver Fin Arrays,” Journal of Heat Transfer, Vol. 121, pp. 136-141.

DeJong, N.C., L.W. Zhang, A.M. Jacobi, S. Balachandar, and D.K. Tafti, 1998, “A Complementary Experimental and Numerical Study of the Flow and Heat Transfer in Offset Strip-Fin Heat Exchangers,” Journal of Heat Transfer, Vol. 120, pp. 690-698.

DeJong, N.C., and A.M. Jacobi, 1997, “An Experimental Study of Flow and Heat Transfer in Parallel-Plate Arrays: Local, Row-by-Row and Surface Average Behavior,” International Journal of Heat and Mass Transfer, Vol. 40, pp.1365-1378.

DeJong, N.C., M.C. Gentry, and A.M. Jacobi, 1997, “An Entropy-Based, Air-Side Heat Exchanger Performance Evaluation Method: Application to a Condenser,” International Journal of HVAC&R Research, Vol. 3(3), pp. 185-195.

Rhee, J., Danek, C.J., and Moffat, R.J., 1993 “The Adiabatic Heat Transfer Coefficient on the Faces of a Cube in an Electronics Cooling Situation,” Proceedings of the 1993 International Electronics Packaging Conference, Binghampton, NY.

  Recent Projects

CFD image  through computerTop and side view of board level packaging © 2002 Sergio Hernandez


Thermal characterization of a new generation of PoP Packages


Optimal micro heat pipe configuration on high performance heat spreaders


Conjugate Conduction-Convection Thermal Management of LEDs


Energy and Exergy Analysis of Data Center Economizer Systems


Cooling Optimization of High Density Raised Floor Data Centers.


Eliminating the Raised Floor Configuration in a Data Center by Implementing a Single Cooling Coil.


Thermal Stress Analysis of a Heat Spreader and High Heat Flux Source


Modeling Noncoplanarity Effects on Thermal Performance of Computer Chips


Test Fixture for Heat Sink Performance Evaluation


Experimental Investigation of Thermal Interface Materials


Airflow Impedance and Fan Configuration in PC Cooling (senior design project)


Thermal Control of a Low-Earth Orbit Three-Axis Stabilized Micro-Satellite using Microchannel Heat Sink


Application of Microchannel Heat Transfer Enhancement


Characterization of Airflow Impedance for Two Types of Telecommunications Chassis


Determination of Heat Transfer Coefficient using Liquid Crystal Thermography


Preliminary Investigation of Forced Cooling at High Altitudes


Using CFD to Analyze the Effect of Fluid Properties on Micro-Channel Heat Exchanger Behavior



 class project for ME 146

Cooling of high-heat flux electronics using liquid: Student design project from ME 146

In addition to basic courses in thermodynamics, heat transfer, and fluid dynamics, the Mechanical Engineering Department offers the electives "Thermal Management of Electronics" and "Electronics Packaging". ME 145 Electronics Packaging is taught by Dr. Fred Barez. ME 145 provides an introduction to the fundamental principles of electronic packaging, materials, thermal management, shock and vibrations, EMI/RFI/ESD, fatique, reliability, and standardized test procedures. Simple design to insure product rules and guidelines are presented.

ME 146 Thermal Management of Electronics

The National Science Foundation has sponsored the development of this elective and associated lab relating to the thermal management of electronics. The website for this course includes handouts for lab experiments as well as Powerpoint lectures, which anyone may use. For additional information about any experiment, please contact Dr. Okamoto. If you teach a course on this topic, we would love to post a link to your course webpage.

Class topics include:

Sources of heat generation in electronics Thermal resistance method
Pressure drop calculations Fans and heat sinks
Constriction and spreading resistance Thermal interface materials
Thermal stress analysis Air cooling of electronics
Liquid cooling of electronics Computational fluid dynamics
Jedec Standards Cooling of data centers
Heat Pipes Thermo-electric cooling
Vapor compression systems RoHS (restriction of hazardous substances)
Nano-scale heat transfer Temperature measurement methods


For more information, contact

Nicole Okamoto
voice: 408-924-4054
fax: 408-924-3995
email: Nicole.Okamoto@sjsu.edu
web: http://www.sjsu.edu/people/nicole.okamoto/

Department of Mechanical Engineering
San José State University
One Washington Square
San José, California 95192-0087

Development of this laboratory has been sponsored by the Department of Mechanical and Aerospace Engineering at San Jose State University and the National Science Foundation (through Grant Number 0311713).Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

This website is maintained by Nicole Okamoto.