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Stefan Elbel
Stefan Elbel
Research Assistant Professor
(217) 244-1531
2121 Mechanical Engineering Lab

Education

  • Ph.D. in Mechanical Engineering, University of Illinois at Urbana-Champaign, 2007
  • M.Sc. in Mechanical Engineering, University of Illinois at Urbana-Champaign, 2003
  • Diplom-Ingenieur (FH) in Automotive Engineering/Mechatronics, Esslingen University of Applied Sciences (Germany), 2000

Academic Positions

  • Research Assistant Professor, University of Illinois at Urbana-Champaign, Department of Mechanical Science and Engineering, 2018 - date

Short Courses

  • Contributions to two short courses on "Ejector Design for Vapor Compression Systems" and on "Update on Flammable Refrigerants" to be held at Purdue, University, West Lafayette, IN, USA, May 2021 (in preparation, delayed to 2021 due to COVID)
  • Flame-free fittings for flammable refrigerants, Short course at Purdue University, West Lafayette, IN, USA, July 8, 2018
  • Training course on transcritical CO2 technology, Short course for practicing engineers organized by Creative Thermal Solutions, Inc., Urbana, IL September 20-21, 2016
  • Training course on economical design of efficient bottle coolers utilizing carbon dioxide, Short course for practicing engineers organized by Creative Thermal Solutions, Inc., Urbana, IL September 22-25, 2015
  • Latest technology trends in low-charge hydrocarbon refrigeration, Short course for practicing engineers organized by Creative Thermal Solutions, Inc., Urbana, IL January 22-23, 2015
  • Training course on economical design of efficient bottle coolers utilizing carbon dioxide, Short course for practicing engineers organized by Creative Thermal Solutions, Inc., Urbana, IL June 24-27, 2014
  • Economical design of efficient bottle coolers utilizing CO2, Short course for practicing engineers organized by Creative Thermal Solutions, Inc., Urbana, IL June 11-14, 2013
  • CO2 as the refrigerant in bottle coolers, Short course for practicing engineers organized by Creative Thermal Solutions, Inc., Urbana, IL July 6-12, 2012
  • Experience with transcritical CO2 systems and their efficiency improvements, Short Course in Supermarket Refrigeration organized by Creative Thermal Solutions, Inc. and the Air Conditioning and Refrigeration Center at the University of Illinois at Urbana-Champaign, Urbana, IL, USA, February 23-24, 2010
  • Update on natural refrigerants: military environmental control units, Short course (together with J.A. Manzione/US. Army) at Purdue University, West Lafayette, IN, USA, July 12-13, 2008

Other Undergraduate Advising Activities

  • Advisor of winning 2007 University of Illinois Solar Decathlon Thermal Comfort Team

Research Statement

Dr. Elbel is interested in experimental and numerical research in the areas of thermodynamics, fluid mechanics, and heat transfer. His focus is on energy conversion systems with specialization in vapor compression technology using synthetic and natural refrigerants. He conducts both fundamental and applied research on components and systems used in mobile, residential, commercial, and industrial heating and cooling applications.

Dr. Elbel has been researching transcritical carbon dioxide cooling and heating cycles for a large variety of applications for more than 15 years. He has worked extensively on designing and improving refrigerant ejector systems to increase the energy efficiency of vapor compression cycles. His interest in expansion work recovery has been extended to vortex tubes that offer attractive improvement potentials at very low cost. He is also working on waste heat recovery systems that allow the efficient generation of waste heat driven cooling as a promising alternative to absorption cooling systems.

Research Interests

  • Fundamental and applied research on components and systems used in mobile, residential, commercial, and industrial heating and cooling applications
  • Energy conversion systems with specialization in vapor compression technology using synthetic and natural refrigerants
  • Experimental and numerical research in thermodynamics, fluid mechanics, and heat transfer

Research Areas

  • Fluid Mechanics

Selected Articles in Journals

  • Haider M., Elbel S., 2021, "Development of ejector performance map for predicting fixed-geometry two-phase ejector performance for wide range of operating conditions," Int. J. Refrig., 128:232-241
  • Che M., Elbel S., 2021, "Experimental study of local air-side heat transfer coefficient on real-scale heat exchanger fins by employing an absorption-based mass transfer method," Appl. Therm. Eng., 189:116718
  • Mahvi A.J., Boyina K., Musser A., Elbel S., Miljkovic N., 2021, "Superhydrophobic heat exchangers delay frost formation and enhance efficiency of electric vehicle heat pumps," Int. J. Heat Mass Tran., 172:121162
  • King W.P., Amos J., Azer M., Baker D., Bashir R., Best C., Bethke E., Boppart S.A., Bralts E., Dietkus R., Durack G., Elbel S., Elliott G., Fava J., Goldenfeld N., Goldstein M.H., Hayes C., Herndon N., Jamison S., Johnson B., Johnson H., Johnson M., Kolaczynski J., Lee T., Maslov S., McGregor D., Milner D., Moller R., Mosley J., Musser A., Newberger M., O’Bryan L., O’Leary J., Pagano A., Philpott M., Pianfetti B., Pille A., Pizzuto L., Rubessa M., Rylowicz S., Shipley C., Stewart B., Switzky R., Tawfick S., Wheeler M., White K., Wood E., Wood C., Wooldridge A.R., 2020, "Emergency ventilator for COVID-19," PLoS One, 15(12): e0244963
  • Zhang Y., Elbel S., 2020, "Visualization study of the relationship between the orientation of tube and the flow regimes near the expansion valve," SAE Int. J. Adv. & Curr. Prac. in Mobility, Technical Paper 2020-01-1256
  • Gullo P., Kærn M.R., Haida M., Smolka J., Elbel S., 2020, "A review on current status of capacity control techniques for two-phase ejectors," Int. J. Refrig., 119:64-79
  • Lawrence N., Elbel S., 2020, "Servicing and installing equipment using flammable refrigerants: assessment of field-made mechanical joints (ASHRAE RP-1808)," Science and Technology for the Built Environment, 26(5):621-630
  • Zhu J., Elbel S., 2020, "Experimental investigation of the influence of vortex control on transcritical R744 ejector and cycle performance," Appl. Therm. Eng., 164:114418
  • Zhu Z., Elbel S., 2020, "CFD simulation of vortex flashing R134a flow expanded through convergent-divergent nozzles," Int. J. Refrig., 112:56-68
  • Zhu J., Elbel S., 2019, "Measurement of static pressure profiles of vortex flashing R134a flow expanded through convergent-divergent nozzles," Int. J. Refrig., 108:258-270
  • Che M., Elbel S., 2019, "An experimental method to quantify local air-side heat transfer coefficient through mass transfer measurements utilizing color change coatings," Int. J. Heat Mass Tran., 114:118624
  • Lawrence N., Elbel S., 2019, "Experimental investigation on control methods and strategies for off-design operation of the transcritical R744 two-phase ejector cycle," Int. J. Refrig., 106:570-582
  • Lawrence N., Elbel S., 2018, "Numerical investigation of the effect of microchannel evaporator design and operation on the improvement potential of ejector refrigeration cycles," Energy, 164:21-34
  • Zhu J., Botticella F., Elbel S., 2018, "Experimental investigation and theoretical analysis of oil circulation rates in ejector cooling cycles," Energy, 157:718-733
  • Zhu J., Elbel S., 2018, "Experimental investigation of a novel expansion device control mechanism: vortex control of initially subcooled flashing R134a flow expanded through convergent-divergent nozzles," Int. J. Refrig., 85:167-183
  • Zhu J. and S. Elbel, 2017, "Influence of geometric parameters on two-phase flow vortex control," SAE Int. J. Passeng. Cars - Mech. Syst. 10(1):121-127.
  • Zhu, J. and S. Elbel, 2016, "A new control mechanism for two-phase ejector in vapor compression cycles for automotive applications using adjustable motive nozzle inlet swirl," SAE Int. J. Passeng. Cars - Mech. Syst. 9(1):44-51.
  • Lawrence, N. and S. Elbel, 2016, "Experimental investigation on the effect of evaporator design and application of work recovery on the performance of two-phase ejector liquid recirculation cycles with R410A," Appl. Therm. Eng., 100:398-411.
  • Elbel, S. and N. Lawrence, 2016, "Review of recent developments in advanced ejector technology," Int. J. Refrig., 62:1-18.
  • Lawrence, N. and S. Elbel, 2015, "Mathematical modeling and thermodynamic investigation of the use of two-phase ejectors for work recovery and liquid recirculation in refrigeration cycles," Int. J. Refrig., 58:41-52.
  • Lawrence, N. and S. Elbel, 2015, "Analysis of two-phase ejector performance metrics and comparison of R134a and CO2 ejector performance," Science and Technology for the Built Environment (formerly HVAC&R Res.), 21:515-525.
  • Brown I.P., G. Sizov, M. Critchley, J. Yin, S. Memory, S. Elbel, C. Bowers, M. Petersen, and P. Hrnjak, 2014, "Design and evaluation of interior permanent magnet compressor motors for commercial transcritical CO2 (R-744) heat pump water heaters," IEEE T. Ind. Appl., 51(1):576-586.
  • Bowers, C.D., D. Wrocklage, S. Elbel, and P. Hrnjak, 2014, "Evaluation of seasonal performance improvements in a 3-Ton air-conditioning heat pump system using a novel design of integrated electronic expansion valves and distributors," ASHRAE Tran., 120(1):1-8.
  • Lawrence N. and S. Elbel, 2014, "Experimental investigation of an alternate two-phase ejector cycle with low-pressure refrigerants R134a and R1234yf," Int. J. Refrig., 38(2): 310-322.
  • Petersen, M., C. Bowers, S. Elbel, and P. Hrnjak, 2013, "Development of high efficiency carbon dioxide commercial heat pump water heater," HVAC&R Res., 19(7): 823-835.
  • Wang, X.F., P.S. Hrnjak, S. Elbel, A.M. Jacobi, and M.G. He, 2013, "Heat transfer performance for a falling-film on horizontal flat tubes," J. Heat Transf., 135(7): 072901.
  • Zhao H., S. Elbel, P. Hrnjak, 2013, "Controlled atmosphere brazing of aluminum heat exchangers," Weld J., 92(2): 44-46.
  • Lawrence, N. and S. Elbel, 2013, "Theoretical and practical comparison of two-phase ejector refrigeration cycles including first and second law analysis," Int. J. Refrig., 36(4): 1220-1232.
  • Wang, X.F., P.S. Hrnjak, S. Elbel, A.M. Jacobi, and M. He, 2012, "Flow modes and mode transitions for falling films on flat tubes," J. Heat Transf., 134(2): 021801.
  • Elbel, S., 2011, "Historical and present developments of ejector refrigeration systems with emphasis on transcritical carbon dioxide air-conditioning applications," Int. J. Refrig., 34(7): 1545-1561.
  • Elbel, S. and P. Hrnjak, 2008, "Experimental validation of a prototype ejector designed to reduce throttling losses encountered in transcritical R744 system operation," Int. J. Refrig., 31(3): 411-422.
  • Elbel, S. and P. Hrnjak, 2004, "Flash gas bypass for improving the performance of transcritical R744 systems that use microchannel evaporators," Int. J. Refrig., 27(7): 724-735.

Articles in Conference Proceedings

  • Elbel S., Zheng J., 2021, "Evaluation of various refrigerant leak detector technologies for use with low-GWP A2L refrigerants (AHRTI #9014)," 2nd IIR Conference on HFOs and Low GWP Blends (HFO2021), Osaka, Japan, June 16-18, Paper 1026 (online participation)
  • Kang M., Elbel S., 2021, "Improving performance of solid-state cooling cycles using two-phase zeotropic heat transfer fluids," 9th IIR International Conference on Caloric Cooling and Applications of Caloric Materials (THERMAG IX), University of Maryland, College Park, MD, USA, June 7-11, Paper 103 (online participation)
  • Kang M., Elbel S., 2021, "Optimization of regenerator design with respect to geometric and operational parameters for solid-state caloric cooling using 1-D transient system model," 9th IIR International Conference on Caloric Cooling and Applications of Caloric Materials (THERMAG IX), University of Maryland, College Park, MD, USA, June 7-11, Paper 102 (online participation)
  • Zhang Y., Elbel S., 2021, "Simulation-based study on predicting the flow-induced noise near the expansion device," 18th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, May 23-28, Paper 210039 (online participation)
  • Kang M., Elbel S., 2021, "Applying two-phase zeotropic heat transfer fluids to solid-state cooling cycle and comparison with baseline using single phase water," 18th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, May 23-28, Paper 210036 (online participation)
  • Kang M., Elbel S., 2021, "Comprehensive study of heat transfer and pressure drop in regenerator and optimization of solid-state caloric cooling cycles using realistic hydraulic diameter of regenerator," 18th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, May 23-28, Paper 210035 (online participation)
  • Yoshida T., Elbel S., 2021, "Numerical analysis for performance comparison between hybrid ejector and conventional refrigeration systems," 18th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, May 23-28, Paper 210032 (online participation)
  • Gao Y., Silsbee D., Tang K., Elbel S., "An updated quantification method for liquid refrigerant distribution in microchannel evaporators using infrared thermography," 18th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette IN, USA, May 23-28, Paper 210022 (online participation)
  • Zhao H., Elbel S., Hrnjak P., 2021, "Low melting temperature brazing materials for aluminum heat exchanger fabrication," 18th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, May 23-28, Paper 2568 (online participation)
  • Haider M., Elbel S., 2021, "System designing of transcritical CO¬2 air conditioning systems using ejector performance maps," 18th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, May 23-28, Paper 2528 (online participation)
  • Zheng J., Elbel S., 2021, "Evaluation of leak detectors for flammable refrigerants (AHRTI #9014)," 18th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, May 23-28, Paper 2506 (online participation)
  • Zhang Y., Elbel S., 2021, "Experimental observation of flow regimes and flow-induced noise near the expansion device with different installation orientations," 18th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, May 23-28, Paper 2240 (online participation)
  • Yoshida T., Matsubara T., Masaaki A., Masamichi I., Elbel S., 2021, "Numerical analysis for heat driven ejector refrigeration systems for various refrigerants," 18th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, May 23-28, Paper 2233 (online participation)
  • Che M., Elbel S., 2021, "Application of a color change coating to evaluate flow velocity distribution and wall shear stress of fan blade," 18th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, May 23-28, Paper 2177 (online participation)
  • Che M., Elbel S., 2021, "Experimental evaluation of local air-side heat transfer coefficient on single fins," 18th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, May 23-28, Paper 2176 (online participation)
  • Inampudi S.T., Botticella F., Elbel S., 2021, "Experimental comparison of seasonal performance in R410A chiller using single speed and two stage compressor," 18th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, May 23-28, Paper 1484 (online participation)
  • Elbel S., 2021, "Refrigerant charge reduction to mitigate risks associated with flammable refrigerants," Presentation at ASHRAE 2021 Virtual Winter Conference, Feb 9-11, Seminar 24
  • Lawrence N., Elbel S., Zheng J., Wenzel M., Hrnjak P., 2020, "Ammonia chiller performance enhancement by implementation of ejector overfeed cycle with brazed plate evaporator," 14th IIR Gustav Lorentzen Conference on Natural Refrigerants, Kyoto, Japan, December 7-9, Paper 1013 (online participation)
  • Lawrence N., Elbel S., Hrnjak P., 2020, "Advanced R744 technology applied to a multi-temperature refrigerated container," 14th IIR Gustav Lorentzen Conference on Natural Refrigerants, Kyoto, Japan, December 7-9, Paper 1012 (online participation)
  • Lawrence N., Elbel S., Hrnjak P., 2020, "Transcritical R744 multi-temperature refrigerated container system designed for high ambient temperature operation," 6th IIR International Conference on Sustainability and the Cold Chain (Online), https://iccc2020.sciencesconf.org, August 26-28, Paper 292575
  • Botticella F., Liu Z., Elbel S., 2020, "Performance measurements of transcritical R744 system using low-complexity ejector," 6th IIR International Conference on Sustainability and the Cold Chain (Online), https://iccc2020.sciencesconf.org, August 26-28, Paper 292574
  • Haider M., Elbel S., 2020, "Ejector selection made easy: a new way of mapping performance of two-phase ejectors," IIR Rankine 2020 Conference on Advances in Cooling, Heating and Power Generation (Online), https://ior.org.uk, July 27-31, Paper 1134
  • Elbel S., Hrnjak P., 2020, "Improvement of capacity and COP through use of two-stage compressor in transcritical R744 systems," IIR Rankine 2020 Conference on Advances in Cooling, Heating and Power Generation (Online), https://ior.org.uk, July 27-31, Paper 1133
  • Elbel S., 2020, "Energy savings in commercial air conditioning by use of a low-charge ammonia chiller," Presentation at online conference on natural refrigerants: The Future of Air Conditioning organized by Danish Technological Institute and ATMOsphere, https://atmo.org, June 23-24
  • Zhang Y., Elbel S., 2020, "Sound evaluation of flow-induced noise with simultaneous measurement of flow regimes at TXV inlet of automotive evaporators," SAE World Congress (event cancelled due to COVID, but paper published), Detroit, MI, USA, April 21-23, Paper 2020-01-1255
  • Haider M., Elbel S., 2020, "Development of a new ejector performance map for design of an automotive air conditioning system," SAE World Congress (event cancelled due to COVID, but paper published), Detroit, MI, USA, April 21-23, Paper 2020-01-1244
  • Elbel S., 2020, "Two-phase ejectors to improve efficiency of applications using low-GWP refrigerants," Presentation at ASHRAE 2020 Winter Conference, Orlando, FL, USA, Feb 1-5, AHR Expo Session 6
  • Botticella F., Liu Z., Elbel S., 2019, "Impact of low-cost ejector design on transcritical R744 system performance," Deutsche Kälte‐ und Klimatagung, Ulm, Germany, November 18-20, Paper II.2.11
  • Elbel S., Hrnjak P., 2019, Performance optimization of two-stage compressor system using transcritical R744, 11th International Conference on Compressors and their Systems, London, UK, September 9-11, Paper 184
  • Che M., Elbel S., 2019, Application of a new method to quantify local air-side heat transfer coefficient on fundamental geometries, 25th IIR International Congress of Refrigeration, Montreal, Canada, August 24-30, Paper 1543
  • Che M., Elbel S., 2019, Development of a new optical method to quantify local air-side heat transfer coefficient, 25th IIR International Congress of Refrigeration, Montreal, Canada, August 24-30, Paper 1541
  • Zhang Y., Elbel S., 2019, Simultaneous measurements of flow-induced noise and two-phase flow regime in expansion valves, 25th IIR International Congress of Refrigeration, Montreal, Canada, August 24-30, Paper 445
  • Lawrence N., Elbel S., 2019, Design and operation of a thermal harshness test facility for electric motors in hermetic environments, 25th IIR International Congress of Refrigeration, Montreal, Canada, August 24-30, Paper 353
  • Lawrence N., Elbel S., Hrnjak P., Design and performance evaluation of an R744 multi-temperature refrigerated container, 25th IIR International Congress of Refrigeration, Montreal, Canada, August 24-30, Paper 352
  • Che M., Elbel S., 2019, Quantification of local air-side heat transfer coefficient using color-change coatings, 14th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics - HEFAT 2019, Wicklow, Ireland, July 22-24, Paper 151
  • Che M., Elbel S., 2019, Measurement of local air-side heat transfer coefficient through absorption-based optical method, 9th International Conference on Compressors and Refrigeration, Xi’an, China, July 10-12, Paper 1122
  • Zhang Y., Elbel S., 2019, Simultaneous measurement of flow-induced noise and two-phase flow regimes in expansion devices, 9th International Conference on Compressors and Refrigeration, Xi’an, China, July 10-12, Paper 1121
  • Elbel S., 2019, Quantification of local air-side heat transfer through an absorption-based color change coating, Presentation at ASHRAE 2019 Annual Conference, Kansas City, MO, USA, June 22-26, Seminar 60
  • Elbel S., 2019, Why and when expansion work recovery makes sense, Presentation at the HighEFF Annual Consortium Meeting, Trondheim, Norway, May 8-9
  • Botticella F., Liu Z., Elbel S., 2019, Trade-offs between design complexity and performance impacts for transcritical R744 ejectors, 8th IIR Conference on Ammonia and CO2 Refrigeration Technologies, Ohrid, North Macedonia, April 11-13, IIR Proc. Refrigeration Science and Technology, vol. 2019-April, p. 227-234 8 p
  • Zhu J., Elbel S., 2018, Vortex flow control for transcritical R744 ejector systems, Deutsche Kälte‐ und Klimatagung, Aachen, Germany, November 21-23, Paper II.2.13
  • Elbel S., 2018, Evaluation of field-made mechanical joints for systems with flammable refrigerants (ASHRAE RP-1808), AHRTI Flammable Refrigerants Research & Planning Conference held at Underwriters Laboratories (UL), Northbrook, IL, October 8-9
  • Lawrence N., Raj S., Elbel S., 2018, Assessment of leakage rate and durability of field-made mechanical joints for systems using low-GWP flammable refrigerants (ASHRAE RP-1808), 1st IIR International Conference on the Application of HFO Refrigerants, Birmingham, UK, September 2-5, Paper 1115
  • Zhao H., Elbel S., Hrnjak P., 2018, Compatibility of filler and base metals in heat exchanger manufacturing process, 17th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 9-12, Paper 2551
  • Zhu J., Elbel S., 2018, Measurement of pressure profile of vortex flashing flows in convergent-divergent nozzles, 17th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 9-12, Paper 2414
  • Lawrence N., Elbel S., Hrnjak P., 2018, Design and investigation of a transcritical R744 refrigerated container for military applications, 17th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 9-12, Paper 2387
  • Lawrence N., Elbel S., Raj S., LaGrotta T., Duggan M., 2018, Leakage rate measurement and durability testing of field-made mechanical joints for systems with flammable refrigerants (ASHRAE RP-1808), 17th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 9-12, Paper 2379
  • Elbel S., Lawrence N., Raj S., 2018, Leakage rate measurement and durability testing of field-made mechanical joints for systems with flammable refrigerants (ASHRAE RP-1808), 17th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 9-12, Paper 2375
  • Che M., Elbel S., 2018, Novel visualization method to quantify local air-side heat transfer coefficient, 17th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 9-12, Paper 2176
  • Zhang Y., Elbel S., 2018, Modeling of acoustics based geometry optimization of orifice tube design, 17th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 9-12, Paper 2158
  • Zhang Y., Elbel S., 2018, Experimental analysis to mitigate flow induced noise in expansion devices, 17th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 9-12, Paper 2157
  • Kang M., Elbel S., 2018, Performance analysis of active magnetic regenerative refrigeration cycle using transient modeling, 17th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 9-12, Paper 2156
  • Zhu J., Elbel S., 2018, CFD simulation of vortex flashing flows in convergent-divergent nozzles, 17th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 9-12, Paper 2147
  • Elbel S., 2018, Quantification of local air-side heat transfer through a novel optical method, Presentation at ASHRAE 2018 Annual Conference, Houston, TX, USA, June 23-27
  • Lawrence N., Elbel S., Hrnjak P., 2018, Design and validation of a transcritical CO2 mobile refrigerated container system for military applications, 13th IIR Gustav Lorentzen Conference on Natural Refrigerants, Valencia, Spain, June 18-20, Paper 1301
  • Zhu J., Elbel S., 2018, Vortex control for motive flow rate modulation of transcritical R744 ejector systems, 13th IIR Gustav Lorentzen Conference on Natural Refrigerants, Valencia, Spain, June 18-20, Paper 1143
  • Elbel S., Lawrence N., Raj S., LaGrotta T., Duggan M., 2018, Experimental evaluation of flame-free refrigerant fittings according to test criteria specific to R744, 13th IIR Gustav Lorentzen Conference on Natural Refrigerants, Valencia, Spain, June 18-20, Paper 1142
  • Zhu J., Botticella F., Elbel S., 2018, Measurement of oil in circulation in transcritical R744 systems using two-phase ejector, 13th IIR Gustav Lorentzen Conference on Natural Refrigerants, Valencia, Spain, June 18-20, Paper 1141
  • Zhao H., Elbel S., Hrnjak P., 2018, Joining of aluminum and stainless steel for heat exchanger applications, 7th International Brazing and Soldering Conference, New Orleans, LA, USA, April 15-18
  • Zhu J., Elbel S., 2018, Implementation of reinforcement learning on air source heat pump defrost control for full electric vehicles, SAE World Congress, Detroit, MI, USA, April 10-12, Paper 2018-01-1193
  • Zhu J., Botticella F., Elbel S., 2018, Oil circulation rate in ejector cooling cycles, SAE World Congress, Detroit, MI, USA, April 10-12, Paper 2018-01-0077
  • Zhu J., Elbel S., 2018, Application of vortex control to an automotive transcritical R744 ejector cycle, SAE World Congress, Detroit, MI, USA, April 10-12, Paper 2018-01-0060
  • Zhu J., Elbel S., Botticella F., 2018, Measurement of oil in circulation in transcritical R744 systems using two-phase ejector, 6th International on Cryogenics and Refrigeration, Shanghai, China, April 12-14
  • Zhu J., Elbel S., 2018, Application of vortex control to a transcritical R744 ejector cycle, 6th International on Cryogenics and Refrigeration, Shanghai, China, April 12-14, Paper PB-R-135
  • Zhu J., Botticella F., Elbel S., 2018, Oil circulation rate in ejector cooling cycles, 5th IIR Conference on Sustainability and the Cold Chain, Beijing, China, April 6-8, Paper 004
  • Zhu J., Elbel S., 2018, Application of vortex control to a transcritical R744 ejector cycle, 5th IIR Conference on Sustainability and the Cold Chain, Beijing, China, April 6-8, Paper 003
  • Elbel S. and N. Lawrence, 2017, "Optimization of microchannel evaporator design in HVAC&R applications using two-phase ejectors," 8th International Conference on Compressors and Refrigeration (ICCR), Xi’an, China, Paper F17
  • Elbel S., N. Lawrence, and, J. Zhu, 2017, "Comparison of various motive flow control methods to implement capacity modulation in HVAC&R systems using two-phase ejectors," 8th International Conference on Compressors and Refrigeration (ICCR), Xi’an, China, Paper F16
  • Elbel S., 2017, "Opportunities for utilizing two-phase ejectors to increase efficiency of commercial refrigeration systems using natural refrigerants," Presentation at ASHRAE 2017 Annual Conference, Long Beach, CA, USA, June 24-28
  • Elbel S., 2017, "Modeling, design and efficiency of two-phase ejectors to increase COP of transport refrigeration systems," Presentation at ASHRAE 2017 Annual Conference, Long Beach, CA, USA, June 24-28
  • Zhao, H., S. Elbel, and P. Hrnjak, 2017, "Joining dissimilar materials in heat exchanger manufacturing process," 5th International Congress and Exhibition on Aluminum Heat Exchanger Technologies for HVAC&R, Düsseldorf, Germany, May 16-17
  • Elbel, S. and P. Hrnjak, 2016, "Natural refrigerants for light commercial applications: a fair comparison of the pros & cons of CO2 and propane," 12th IIR Gustav Lorentzen Conference on Natural Refrigerants, Edinburgh, UK, August 21-24, Paper 1099.
  • Lawrence, N. and S. Elbel, 2016, "Experimental comparison of the performance of a CO2 ejector cycle for transcritical and subcritical operation," 12th IIR Gustav Lorentzen Conference on Natural Refrigerants, Edinburgh, UK, August 21-24, Paper 1085.
  • Lawrence, N. and S. Elbel, 2016, "Numerical modeling of the off-design performance of a transcritical CO2 two-phase ejector cycle," 12th IIR Gustav Lorentzen Conference on Natural Refrigerants, Edinburgh, UK, August 21-24, Paper 1084.
  • Lawrence, N. and S. Elbel, 2016, "Experimental study on control methods for transcritical CO2 two-phase ejector systems at off-design conditions," 12th IIR Gustav Lorentzen Conference on Natural Refrigerants, Edinburgh, UK, August 21-24, Paper 1083.
  • Lawrence, N. and S. Elbel, 2016, "Implementation of a two-phase ejector cycle for R744 glass door merchandisers," 12th IIR Gustav Lorentzen Conference on Natural Refrigerants, Edinburgh, UK, August 21-24, Paper 1082.
  • Visek, M., S. Elbel, P. Hrnjak, B. Hoaglan, C. Tang, and D. Smith, 2016, "Conversion of platelet incubator refrigeration system to R600a and performance optimization," 16th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, Paper 2615.
  • Wujek, S.S., W.L. Staats, Elbel S.W., J.P. Koplow, H.A. Kariya, and P.S. Hrnjak, 2016, "Method for determining air side convective heat transfer coefficient using infrared thermography," 16th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, Paper 2587.
  • Wenzel, M., S. Elbel, and P. Hrnjak, 2016, "Design, build-up, and commissioning of 350 kW refrigeration test facility for experimental investigation of large cold chain equipment," 16th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, Paper 2580.
  • Visek, M., S. Elbel, and P. Hrnjak, 2016, "Conversion of cold beverage dispenser’s refrigeration system to R744 refrigerant," 16th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, Paper 2556.
  • Zhao, H., S. Raghunandanan, S. Elbel S., and P. Hrnjak, 2016, "A study of microchannel heat exchanger performance associated with the manufacturing process," 16th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, Paper 2545.
  • Musser, A., P. Hrnjak, and S. Elbel, 2016, "Internal heat exchanger performance quantification and comparison testing methods including exploration of the effects of location of measurements and oil in circulation," 16th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, Paper 2453.
  • Elbel, S., M. Duggan, T. LaGrotta, S. Raj, and P. Hrnjak, 2016, "Accelerated fatigue testing of aluminum refrigeration press fittings for HVAC & R applications," 16th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, Paper 2438.
  • Elbel, S., M. Visek, and P. Hrnjak, 2016, "A fair comparison of CO2 and propane used in light commercial applications featuring natural refrigerants," 16th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, Paper 2429.
  • Zhu, J. and S. Elbel, 2016, "Modeling of initially subcooled flashing vortex flow in the nozzle for possible applications in the control of ejector cooling cycles," 16th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, Paper 2368.
  • Lawrence, N. and S. Elbel, 2016, "Numerical study on the design of microchannel evaporators for ejector refrigeration cycles," 16th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, Paper 2092.
  • Zhu, J. and S. Elbel, 2016, "A new control mechanism for two-phase ejector in vapor compression cycles using adjustable motive nozzle inlet vortex," 16th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, Paper 2076.
  • Elbel S., 2016, "Natural, low-GWP refrigerants for light commercial refrigeration: examples of successfully converted applications using R290, R600a and R744," Presentation at ASHRAE 2016 Annual Conference, St. Louis, MO, USA, June 26-29.
  • Elbel, S. and C. Tang, 2016, "Conversion of platelet incubator to hydrocarbon refrigerant," ATMOsphere America, Chicago, IL, USA, June 16-17.
  • Zhao, H., S. Elbel, and P. Hrnjak, 2016, "Influence of surface morphology on wetting behaviors of Zn-Al filler metal on aluminum matrix composite," LÖT 2016 - 11th International Conference on Brazing, High Temperature Brazing and Diffusion Bonding, Aachen, Germany, June 7-9.
  • Zhu, J. and S. Elbel, 2016, "Vortex tube heat booster to improve performance of heat driven cooling cycles for automotive applications," SAE World Congress, Detroit, MI, USA, April 12-14, Paper 2016-01-0245.
  • Lawrence, N. and S. Elbel, 2016, "Performance improvements of R744 glass door merchandiser using low-cost two-phase ejector," 4th IIR Conference on Sustainability and the Cold Chain, Auckland, New Zealand, April 7-9.
  • Lawrence, N. and S. Elbel, 2016, "Experimental investigation of control strategies for off-design operation of a transcritical CO2 two-phase ejector refrigeration system for the cold chain," 4th IIR Conference on Sustainability and the Cold Chain, Auckland, New Zealand, April 7-9.
  • Zhu, J. and S. Elbel, 2015, "Fresh look at vortex tubes and their potential use as expansion device in automotive vapor compression systems," SAE 2015 Thermal Management Systems Symposium, Troy, MI, USA, September 29 - October 1.
  • Padilla Fuentes, Y., P. Hrnjak, and S. Elbel, 2015, "High-efficiency, low-cost glass door merchandisers using transcritical carbon dioxide," 24th IIR International Congress of Refrigeration, Yokohama, Japan, August 16-22, Paper 305.
  • Padilla Fuentes, Y., P. Hrnjak, and S. Elbel, 2015, "Low-charge propane refrigeration system technology for single and multi-door bottle coolers," 24th IIR International Congress of Refrigeration, Yokohama, Japan, August 16-22, Paper 303.
  • Zhu, J. and S. Elbel, 2015, "Vortex tube heat booster to improve performance of heat driven cooling cycles," 24th IIR International Congress of Refrigeration, Yokohama, Japan, August 16-22, Paper 299.
  • Elbel, S., S. Wujek, and P. Hrnjak, 2015, "Waste heat driven cooling by vapor jet ejector," 24th IIR International Congress of Refrigeration, Yokohama, Japan, August 16-22, Paper 297.
  • Lawrence, N. and S. Elbel, 2015, "Study on the use of ejectors for capacity modulation and performance improvement in CO2 commercial refrigeration systems," 24th IIR International Congress of Refrigeration, Yokohama, Japan, August 16-22, Paper 195.
  • Lawrence, N. and S. Elbel, 2015, "Experimental investigation of two-phase ejector liquid recirculation cycles with R410A," 24th IIR International Congress of Refrigeration, Yokohama, Japan, August 16-22, Paper 194.
  • Lawrence, N. and S. Elbel, 2015, "Numerical investigation of evaporator design in the ejector refrigeration cycle with R134a and CO2," 24th IIR International Congress of Refrigeration, Yokohama, Japan, August 16-22, Paper 193.
  • Lawrence, N. and S. Elbel, 2015, "Numerical investigation of the effect of microchannel evaporator design on the performance of two-phase ejector automotive air conditioning cycles," SAE World Congress, Detroit, MI, USA, April 21-23, Paper 2015-01-0362.
  • Zhao H., S. Elbel, and P. Hrnjak, 2015, "An investigation on thermal integrity of brazed heat transfer devices," Proceedings of the 6th International Brazing and Soldering Conference (IBSC), Long Beach, CA, April 19-22.
  • Zhao, H., S. Elbel, and P. Hrnjak, 2015, "Low temperature controlled atmosphere brazing of aluminum matrix composite," Proceedings of the 6th International Brazing and Soldering Conference (IBSC), Long Beach, CA, April 19-22.
  • Padilla Fuentes, Y., S. Elbel, and P. Hrnjak, 2014, "Extremely low refrigerant charge beverage display cooler technology using propane," 11th IIR Gustav Lorentzen Conference on Natural Refrigerants, Hangzhou, China, August 31 - September 2, Paper 98.
  • Lawrence, N. and S. Elbel, 2014, "Review and analysis of the effect of ejector geometry on the performance of two-phase CO2 ejectors," 11th IIR Gustav Lorentzen Conference on Natural Refrigerants, Hangzhou, China, August 31 - September 2, Paper 53.
  • Lawrence, N. and S. Elbel, 2014, "Numerical investigation of two-phase ejector liquid recirculation cycles with natural refrigerants," 11th IIR Gustav Lorentzen Conference on Natural Refrigerants, Hangzhou, China, August 31 - September 2, Paper 52.
  • Elbel, S., Y. Padilla Fuentes, C. Bowers, and P. Hrnjak, 2014, "Successful conversion and validation of glass door merchandisers using transcritical R744," 11th IIR Gustav Lorentzen Conference on Natural Refrigerants, Hangzhou, China, August 31 - September 2, Paper 44.
  • Zhu, J., M. Mohiuddin, and S. Elbel, 2014, "Vortex tubes used as expansion device in vapor compression systems, 11th IIR Gustav Lorentzen Conference on Natural Refrigerants," Hangzhou, China, August 31 - September 2, Paper 43.
  • Lawrence, N.and S. Elbel, 2014, "Experimental and numerical study on the performance of R410A liquid recirculation cycles with and without ejectors," 15th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 14-17, Paper 2187.
  • Lawrence, N. and S. Elbel, 2014, "Analysis and comparison of two-phase ejector performance metrics for R134a and CO2 ejectors," 15th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 14-17, Paper 2188.
  • Elbel, S., Y. Padilla Fuentes, C. Bowers, and P. Hrnjak, 2014, "Successful design, implementation, and validation of transcritical R744 technology for beverage display coolers," 15th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 14-17, Paper 2192.
  • Mohiuddin, M. and S. Elbel, 2014, "A fresh look at vortex tubes used as expansion device in vapor compression systems," 15th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 14-17, Paper 2193.
  • Bowers, C.D., D. Wrocklage, S. Elbel, and P. Hrnjak, 2014, "Improvements in refrigerant flow distribution using an expansion valve with integrated distributor," 15th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 14-17, Paper 2369.
  • Bowers, C.D., G. Baker, S. Elbel, and P. Hrnjak, 2014, "Accelerated thermal cycling test for heat exchangers used in reversible heat pump," 15th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 14-17, Paper 2363.
  • Padilla, F. Y., S. Elbel, and P. Hrnjak, 2014, "Extremely low refrigerant charge beverage display cooler technology using propane," 15th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 14-17, Paper 2458.
  • Zhao, H., S. Elbel, and P. Hrnjak, 2014, "Influence of surface morphology on wetting behaviors of liquid metal during aluminum heat exchanger fabrication," 15th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 14-17, Paper 2461.
  • Benanti, T.L., E.T. Hessell, R.A. Urrego, S.S. Wujek, C.D. Bowers, and S. Elbel, 2014, "Effects of refrigerant-lubricant combinations on the energy efficiency of a convertible split-system residential air-conditioner," 15th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 14-17, Paper 2499.
  • Wujek, S.S., M.J. McCready, G. Mozurkewich, W.F. Schneider, and S. Elbel, 2014, "Experimental and modeling improvements to a co-fluid cycle utilizing ionic liquids and carbon dioxide," 15th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 14-17, Paper 2501.
  • Zhao, H., S. Elbel, and P. Hrnjak, 2014, "Wetting behaviors of Al based filler metals on aluminum matrix composites," International Conference on Brazing, Soldering and Special Joining Technologies, Beijing, China, June 9-13.
  • Bowers, C., D. Wrocklage, S. Elbel, and P. Hrnjak, 2014, "Evaluation of seasonal performance improvements in a 3-ton residential heat pump system using a novel design of integrated electronic expansion valves and distributors," poster presentation at the 11th IEA Heat Pump Conference, Montreal, Canada, May 12-16.
  • Lawrence, N. and S. Elbel, 2014, "Comparison of CO2 and R134a Two-Phase Ejector Performance for Use in Automotive Air Conditioning Applications," SAE World Congress, Detroit, MI, USA, April 8-10, Paper 2014-01-0689.
  • Bowers, C., M. Petersen, S. Elbel, and P.S. Hrnjak, 2014, "Nueva generación de calentadores de agua comerciales por bomba de calor utilizando dióxido de carbono y diferentes enfoques de mejora," Spanish translation of Bowers C., Petersen M., Elbel S., Hrnjak P., 2012, Next generation commercial heat pump water heater using carbon dioxide using different improvement approaches, 10th IIR Gustav Lorentzen Conference on Natural Working Fluids, Delft, The Netherlands, June 25-27, Paper 181, published in February 2014 issue of Frio-Calor-Aire Acondicionado.
  • Bowers, C., D. Wrocklage, S. Elbel, and P. Hrnjak, 2014, "Evaluation of seasonal performance improvements in a 3-ton residential heat pump system using a novel design of integrated electronic expansion valves and distributors," Presentation at ASHRAE 2014 Winter Conference, New York, NY, USA, January 18-24.
  • Elbel, S., 2013, "Successful Design and Implementation of Transcritical CO2 Technology for Beverage Display Coolers," Presentation at ASHRAE 2013 Annual Conference, Denver, CO, June 23-26
  • Lawrence, N., and S. Elbel, 2013, "Experimental and analytical investigation of two-phase ejector air-conditioning cycles using low-pressure refrigerants R134a and R1234yf, SAE World Congress," Detroit, MI, USA, April 16-18, Paper 2013-01-1495
  • Bowers, C.D., S. Elbel, M. Petersen, and P.S. Hrnjak, 2013, "Mejoras en el rendimiento de los calentadores de agua comerciales de bomba de calor, que utilizan dióxido de carbón," Spanish translation of Bowers, C.D., S. Elbel, M. Petersen, and P.S. Hrnjak, 2011, "Performance improvements in commercial heat pump water heaters using carbon dioxide," 23rd IIR International Congress of Refrigeration, Prague, Czech Republic, August 21-26, Paper 211, published in February 2013 issue of Frio-Calor-Aire Acondicionado
  • Elbel, S. and N. Lawrence, 2012, "Investigation of automotive ejector air-conditioning cycles," Presentation at SAE 2012 Thermal Management Systems Symposium, Scottsdale, AZ, October 31 - November 1
  • Brown, I.P., M.W. Critchley, J. Yin, S.B. Memory, S.W. Elbel, C.D. Bowers, M. Petersen, P.S. Hrnjak, and G.Y. Sizov, 2012, "Design and evaluation of interior permanent magnet compressor motors for commercial transcritical CO2 (R-744) heat pump water heaters," 2012 IEEE Energy Conversion Congress and Exposition (ECCE), Raleigh, NC, USA, September 15-20, pp. 2790-2797
  • Zhao, H., S. Elbel, and P. Hrnjak, 2012, "Capillary flow of liquid metal occurring in micro-channel heat exchanger fabrication," 14th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 16-19, Paper 2498
  • Bowers, C.D., H. Mai, S. Elbel, and P. Hrnjak, 2012, "Refrigerant distribution effects on the performance of microchannel evaporators," 14th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 16-19, Paper 2173
  • Petersen, M., C.D. Bowers, S. Elbel, and P. Hrnjak, 2012, "Development of high efficiency carbon dioxide commercial heat pump water heater," 14th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 16-19, Paper 2168
  • Elbel, S., C.D. Bowers, M. Reichle, J.M. Cristiani, and P. Hrnjak, 2012, "Vapor jet ejector used to generate free waste heat driven cooling in military environmental cooling units," 14th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 16-19, Paper 2164
  • Elbel, S., C. Bowers, H. Zhao, S. Park, P. Hrnjak, 2012, "Development of microclimate cooling systems for increased thermal comfort of individuals," 14th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 16-19, Paper 2149
  • Lawrence, N. and S. Elbel, 2012, "Experimental and analytical investigation of automotive ejector air-conditioning cycles using low-pressure refrigerants," 14th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 16-19, Paper 2118
  • Bowers, C., M. Petersen, S. Elbel, and P. Hrnjak, 2012, "Next generation commercial heat pump water heater using carbon dioxide using different improvement approaches," 10th IIR Gustav Lorentzen Conference on Natural Working Fluids, Delft, The Netherlands, June 25-27, Paper 181
  • Elbel, S., M. Reichle, C. Bowers, and P. Hrnjak, 2012, "Integration of a two-phase ejector into a compact, lightweight unitary-type air-conditioner using R744 for energy efficient operation in hot climates," 10th IIR Gustav Lorentzen Conference on Natural Working Fluids, Delft, The Netherlands, June 25-27, Paper 180
  • Bowers, C., S. Elbel, and M. Reichle, 2012, "Research, development, and demonstration of co-generation ejector and modified organic Rankine cycle environmental control systems," Interagency Advanced Power Group, Mechanical Working Group Meeting, Arlington, VA, USA, May 1-3
  • Zhao, H., S. Elbel, P. Hrnjak, 2012, "Controlled atmosphere brazing of microchannel heat exchangers for mini-cooling systems," Proceedings of the 5th International Brazing and Soldering Conference (IBSC), Las Vegas, NV, April 22-25, pp. 183-187
  • Wang, X.F., P.S. Hrnjak, S. Elbel, A.M. Jacobi, and M.G. He, 2011, "Heat transfer performance for a falling-film on horizontal flat tubes," ASME 2011 International Mechanical Engineering Congress and Exposition (IMECE), Denver, CO, USA, November 11-17, v 10, Parts A and B, pp. 43-50
  • Elbel, S., C.D. Bowers, H. Zhao, S. Park, P. Hrnjak, 2011, "Development and analysis of miniature vapor compression cooling technology," 23rd IIR International Congress of Refrigeration, Prague, Czech Republic, August 21-26, Paper 244
  • Bowers, C.D., S. Elbel, M. Petersen, and P.S. Hrnjak, 2011, "Performance improvements in commercial heat pump water heaters using carbon dioxide," 23rd IIR International Congress of Refrigeration, Prague, Czech Republic, August 21-26, Paper 211
  • Elbel, S., J.A. Manzione, S.J. Collier, and P. Hrnjak, 2011, "Acondicionador de aire del tipo unidad compacta ligera utilizando R744 transcrítico y diseñado para funcionar con eficiencia energética en climas calurosos," Spanish translation of Elbel S., J.A. Manzione, S.J. Collier, and P. Hrnjak, 2010, "Compact, lightweight unitary-type air-conditioner using transcritical R744 designed for energy efficient operation in hot climates," 9th IIR Gustav Lorentzen Conference on Natural Working Fluids, Sydney, Australia, April 12-14, Paper 1, published in February 2011 issue of Frio-Calor-Aire Acondicionado
  • Zhao, H., S. Elbel, and P. Hrnjak, 2010, "Development of novel compact heat exchanger using aluminum brazing technology," AWS 37th International Brazing and Soldering Symposium, Atlanta, GA, November 3.
  • Zhao, H., S. Elbel, and P. Hrnjak, 2010, "The potential of open cell aluminum foams as fin structures for CAB brazed heat exchangers," AFC-Holcroft’s 14th Annual Aluminum Brazing Invitational Seminar, Novi, MI, USA, October 27-29
  • Wang, X., P.S. Hrnjak, S. Elbel, A.M. Jacobi, and M. He, 2010, "Flow patterns and mode transitions for falling-film on flat tubes," 13th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 12-15, Paper 2461
  • Elbel, S. and P. Hrnjak, 2010, "Design, build-up, and performance investigation of a 35 kW (10 Ton) military environmental control unit using transcritical R744 technology," 13th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 12-15, Paper 2205
  • Zhao, H., S. Elbel, P. Hrnjak, 2010, "Transport phenomena involved in controlled atmosphere brazing of microchannel Al heat exchanger," 13th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 12-15, Paper 2046
  • Elbel S., J.A. Manzione, S.J. Collier, and P. Hrnjak, 2010, "Compact, lightweight unitary-type air-conditioner using transcritical R744 designed for energy efficient operation in hot climates," 9th IIR Gustav Lorentzen Conference on Natural Working Fluids, Sydney, Australia, April 12-14, Paper 1
  • Elbel, S. and P. Hrnjak, 2009, "Refrigeración con eyector en aplicaciones de aire acondicionado visión general de la evolución desarrollos históricos y actuales," Spanish translation of Elbel, S. and P. Hrnjak, 2008, "Ejector refrigeration: an overview of historical and present developments with an emphasis on air conditioning applications," 12th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 14-17, Paper 2350, published in July/August 2009 issue of Frio-Calor-Aire Acondicionado
  • Elbel, S., 2008, "Next generation ECU," Presentation given at the c-dig Meeting at CETIAT/CETHIL, Lyon, France, November 3-4
  • Elbel, S. and P. Hrnjak, 2008, "Ejector refrigeration: an overview of historical and present developments with an emphasis on air conditioning applications," 12th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 14-17, Paper 2350
  • Elbel, S. and P. Hrnjak, 2007, "Experimental investigation of transcritical CO2 ejector system performance," 22nd IIR International Congress of Refrigeration, Beijing, China, August 21-26, Paper ICR07-E1-72
  • Elbel, S. and P. Hrnjak P., 2007, "Experimental validation of a prototype ejector with integrated high-side pressure control designed to reduce throttling losses encountered in transcritical CO2 system operation," Presentation given at the VDA Alternative Refrigerant Winter Meeting at Saalfelden, Austria, February 14-15, www.vda-wintermeeting.de
  • Elbel, S. and P. Hrnjak, 2006, "A thermodynamic property chart as a visual aid to illustrate the interference between expansion work recovery and internal heat exchange," 11th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 17-20, Paper R165
  • Elbel, S. and P. Hrnjak, 2006, "Experimental validation and design study of a transcritical CO2 prototype ejector system," 7th IIR Gustav Lorentzen Conference on Natural Working Fluids, Trondheim, Norway, May 28-31, Paper 149
  • Elbel, S. and P. Hrnjak, 2006, Experiments and modeling of ejector systems, Presentation given at the c-dig Meeting at Purdue University, West Lafayette, IN, USA, March 16-17
  • Elbel, S. and P. Hrnjak, 2006, "Development of a prototype refrigerant ejector used as expansion device in a transcritical CO2 system," Presentation given at the VDA Alternative Refrigerant Winter Meeting at Saalfelden, Austria, February 15-16, www.vda-wintermeeting.de
  • Memory S., J. Yin, S. Collier, M. Gunter, P. Hrnjak, S. Peuker, S. Elbel, J. Manzione, N. Schultz, and J. Dolney, 2005, "Using R744 (CO2) to cool an up-armored M1114 HMMWV," Vehicle Thermal Management Systems Conference and Exhibition (VTMS7) at Toronto, Canada, May 10-12, Paper 2005-01-2024
  • Elbel S., and P. Hrnjak, 2004, "Flash gas bypass in transcritical R744 systems using microchannel evaporators," Presentation given at the c-dig Meeting at the University of Illinois at Urbana-Champaign, Urbana, IL, USA, October 7-8
  • Elbel S.W. and P.S. Hrnjak, 2004, "Effect of internal heat exchanger on performance of transcritical CO2 systems with ejector," 10th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, USA, July 12-15, Paper R166

Pending Articles

  • Zhang Y., Elbel S., 2021, "Synchronized measurements of noise characteristics and flow regimes near the thermal expansion valve using R134a refrigerant," Manuscript submitted to Int. J. Refrig. (under review)
  • Che M., Elbel S., 2021, "Experimental quantification of air-side row-by-row heat transfer coefficients on fin-and-tube heat exchangers," Manuscript submitted to Int. J. Refrig. (under review)
  • Lawrence N., Wenzel M., Hrnjak P., Elbel S., 2021, "Performance evaluation of a prototype multi-temperature refrigerated container using advanced R744 technology," Manuscript submitted to Int. J. Refrig. (under review)

Invited Lectures

  • Understanding Refrigerant Sensors
  • Thermal Management of Electrical Vehicles: New Engineering Challenges
  • Verification of a new absorption-based experimental method to quantify local air-side heat transfer coefficient on fundamental geometries
  • Recent developments in HVAC&R systems utilizing two-phase ejector for expansion work recovery
  • CO2 - the refrigerant of the past & the future: examples of successful implementation
  • Current research on ejectors at UIUC - ACRC
  • Current research activities at UIUC - ACRC
  • Two-phase ejectors for expansion work recovery in HVAC&R systems
  • Ejectors to improve refrigeration system performance through expansion work recovery
  • Thermodynamic considerations on reversible air-conditioning and heat pump systems for use in vehicles (in German)
  • Recent developments in two-phase ejector refrigeration systems utilizing expansion work recovery
  • Transcritical CO2 for mobile air-conditioning and heat pump systems
  • Recent advances in transcritical CO2 ejector refrigeration and air-conditioning systems
  • Improvement of cooling capacity and COP through the use of two-phase ejectors in transcritical CO2 automotive air-conditioning systems (in German)
  • Technology developments in air-conditioning and refrigeration
  • Emerging component and system technologies for HVAC&R
  • Recent technology developments in HVAC & refrigeration
  • Electrically driven automotive air-conditioning systems: potentials, challenges and major differences in comparison to conventional technology (in German)
  • The next decade: a US perspective of expected technology trends in air-conditioning and refrigeration
  • Historical and present developments of ejector refrigeration systems with emphasis on transcritical carbon dioxide air-conditioning applications

Professional Societies

  • Society of Automotive Engineers (SAE); Member of Interior Climate Control Committee (Jan. 2008 - present); Member of Steering Committee of Cooperative Research Program on Next Generation Thermal Management Refrigerant (Nov. 2020 - present)
  • International Institute of Refrigeration (IIR); US Representative of IIR Commission D2 (June 2019 - present); Treasurer of IIR U.S. National Committee (Jan. 2020 - present)
  • International Institute of Ammonia Refrigeration (IIAR)
  • Deutscher Kaelte- und Klimatechnischer Verein (DKV)
  • American Society of Mechanical Engineers (ASME)
  • American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE); Research Administration Committee (RAC) Member / Research Liaison for Technical Committees of Section 6 (July 2020 - present); TC 10.6: Program Subcommittee Chair and Voting Member (July 2018 - present); TC 1.3: Voting Member (Jan. 2019 - present); Member of ASHRAE’s COVID-19 Task Force: Practical Guidance for Vaccine Refrigerated Transportation and Storage (Jan. - May 2021)

Teaching Honors

  • List of Teachers Ranked as Excellent, University of Illinois at Urbana-Champaign (Fall 2017)
  • List of Teachers Ranked as Excellent, University of Illinois at Urbana-Champaign (Fall 2015)
  • List of Teachers Ranked as Excellent, University of Illinois at Urbana-Champaign (Fall 2014)
  • List of Teachers Ranked as Excellent, University of Illinois at Urbana-Champaign (Spring 2012)

Research Honors

  • International Journal of Refrigeration Best Paper Award (2019)
  • HEFAT Conference Best Paper Award (2019)
  • Eurammon Natural Refrigeration Award (2009)
  • IIR Willis H. Carrier Young Researcher's Award (2007)
  • IIR Gustav Lorentzen Conference Best Paper Award (2006)
  • US Army Award for Environmental Excellence (2005)

Public Service Honors

  • Recognition Award from the Society of Automotive Engineers (2005)

Other Honors

  • Behr GmbH & Co Award of Excellence (2000)
  • Award of Excellence from Verein der Förderer der Fachhochschule Esslingen (2000)
  • Dr.-Ing. H.C.F. Porsche AG Award of Excellence (2000)

Courses Taught

  • ME 401 - Refrigeration and Cryogenics
  • ME 402 - Design of Thermal Systems

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