Faculty Directory

Hwang, Yunho

Hwang, Yunho

Research Professor
Co-director - Center for Environmental Energy Engineering
Mechanical Engineering
Center for Environmental Energy Engineering
Maryland Applied Graduate Engineering
Maryland Energy Innovation Institute
4164 Glenn. L. Martin Hall Building


  • Ph.D. ('97), M.S. ('95) - Mechanical Engineering

    University of Maryland (College Park, USA)
  • B.S. ('83) - Mechanical Engineering 

    Korea University (Seoul, South Korea)


Dr. Yunho Hwang is a research professor and co-director of the Center for Environmental Energy Engineering (CEEE).  He is a worldly-renowned expert for “Energy Efficiency and New Innovative Energy Systems Research” in the field of refrigeration and air-conditioning (RAC). He started his industrial career at Samsung Electronics in 1983, developed energy-efficient heat pump systems, and replaced ozone-depleting R12 with R134a in household refrigerators. Since joining the University of Maryland in 1993, he developed R-22 alternative refrigerants for air-conditioning systems and then started researching enhanced CO2 systems. In 1997, he started the Energy Efficiency and Heat Pumps Consortium as a director and successfully developed multiple innovative energy-efficient and sustainable RAC technologies. In addition to developing energy-efficient technologies such as two-stage CO2 split cycle, saturation cycle, and hybrid separate sensible and latent cooling technology, he has initiated new innovative research on “Not-in-kind” Refrigeration Systems beyond sorption technologies such as elastocaloric cooling systems and electrochemical compression for natural refrigerants. As an educator and researcher, he advised UMD student teams for multiple national and international collegiate design competitions, introduced innovative thermal systems concepts, and helped teams win First or Second place.  

He is an ASME Fellow, an ASHRAE Fellow, and a member of ASME, ASHRAE, SAE, and IIR.  He served as a President of Commission B1, a chair of the LCCP Working Group for the IIR, and an operating agent of ANNEX 54 for IEA HPT.  He also serves Energy, Elsevier (Netherlands) as a subject Editor since 2015, and Int. Journal of AC&R, World Scientific (US), as an editor since 2013.


    • Gustav Lorenzen Medal Award from IIR, August 2023

    • The Wilbur T. Pentzer Award from USNC/IIR, July 2022.

    • A. James Clark Student Competition Advisors Award, December 2021.

    • Peter Ritter von Rittinger International Heat Pump Award, IEA HPT, April 2021.

    • The University of Maryland, Dean’s Award for Professional Track Faculty Research, September 2020

    • ASHRAE Fellow, 2019

    • ASME Fellow, 2014



Working Fluids, Heat Transfer, Compact Heat Exchangers, Vapor Compression, Sorption Cycles and Caloric Cooling, Electrochemical Transport, Alternative Cooling Technologies and Applications, Advanced Energy Conversion Systems and Integration of Thermal Systems, Renewable Energy, and Waste Heat Utilization

The following list shows current research projects being conducted.

  • Cold Climate Heat PUMP (DOE)
  • High-Temperature Heat Pump (DOE)
  • Heat Pump Driven Multi-stage Dryer (DOE)
  • Next Generation PHX (DOE)
  • Thermal Management of Dehydrogenation (DOE)
  • Isothermal Compression (DOE)
  • Elastocaloric cooling (DOE)
  • PCM Heat Exchangers (DOE)
  • VRF System Modleing and Field Test

The following list shows research projects completed between 2022 and 2023.

  • Next Generation Heat Exchanger (DOE)
  • Electrochemical Compression (ARPA-e)
  • Electrochemical Dehumidification (DOE)
  • Roving Comforter

He teaches following courses:

  • ENPM808C: Ocean Energy Harvesting
  • ENME635: Energy Conversion Systems
  • ENME701: Sustainable Energy Production and Utilization
  • ENPM 651: Heat Transfer for Modern Applications
  • ENME423: Building Cooling, Heating, and Power Integration
  • ENME489M: Special Topics in Mechanical Engineering, Ultra-low Energy Use Appliance Design II
  • ENME489M: Special Topics in Mechanical Engineering, Ultra-low Energy Use Appliance Design I
  • ENME808L: Ultra-low Energy Use Appliance Design II
  • ENME808P: Ultra-low Energy Use Appliance Design I


His innovative research during the last 39 years has resulted in 382 publications, including two books, ten book chapters, and 20 patents. Scopus data prove his high research impact: h_index 47 with 7,1571 citations. He was selected as an author of one of the top 1% most highly cited papers in the author's field worldwide (2016).  His six publications were selected as either the most cited articles or the most downloaded articles from Elsevier. 

Three Most cited Articles from Elsevier

  • Review of cold storage materials for air conditioning application, Volume 35, Issue 8, December 2012, Pages 2053-2077, Int. J. of Refrigeration, Gang Li, Yunho Hwang*, Reinhard Radermacher
  • Refrigerant injection for heat pumping/air conditioning systems: Literature review and challenges discussions, Int. J. of Refrigeration, Volume 34, Issue 2, March 2011, Pages 402-415, Xing Xu, Yunho Hwang*, Reinhard Radermacher
  • Optimization of propane pre-cooled mixed refrigerant LNG plant, Volume 31, Issues 6-7, May 2011, Pages 1091-1098, Applied Thermal Eng., Abdullah Alabdulkarem, Amir Mortazavi, Yunho Hwang*, Reinhard Radermacher, Peter Rogers

Three Most downloaded Articles from Int. J. of Refrigeration

  • A review of elastocaloric cooling: Materials, cycles and system integrations, April 2016, Suxin Qian, Yunlong Geng, Yi Wang, Jiazhen Ling, Yunho Hwang*, Reinhard Radermacher, Ichiro Takeuchi, Jun Cui
  • Recent advances in vapor compression cycle technologies, December 2015, Chasik Park, Hoseong Lee, Yunho Hwang*, Reinhard Radermacher
  • Review of solar thermal air conditioning technologies, March 2014, Ali Al-Alili, Yunho Hwang*, Reinhard Radermacher

Yunho Hwang to Receive IIR Gustav Lorentzen Medal

IIR awards the medal every four years to an individual who mas made an outstanding acheivement in research.

CEEE: Three Decades of Innovation

The UMD-based center marked its 30th anniversary at a gala event on June 9.

Safe Storage

Yunho Hwang, colleagues develop refrigeration guidelines for COVID-19 vaccines.

CEEE Awarded Peter Ritter von Rittinger International Heat Pump Award

This year the award was presented virtually at 13th International Heat Pump Conference.

Dean Briber Honors Faculty with Research, Teaching Awards

Each year, the dean of the University of Maryland’s A. James Clark School of Engineering honors exemplary faculty members for their dedication to excellence in research and teaching.

Dr. Yunho Hwang Receives 2020 Dean's Outstanding Performance Award in Research

Dr. Hwang has spent over 20 years at CEEE and now serves as co-director for the center

Hwang Becomes Operating Agent of IEA Annex 54

Also new Associate Editor of ASME Journal

Prof. Yunho Hwang Recognized as ASHRAE Fellow

Received the award at the Society's Winter Conference in Atlanta, Georgia.

Mechanical Engineering at ASME IMECE Conference

Professor Radermacher was a plenary speaker and ME alumnus Ryan Kennett won Best Student Paper at this year’s conference.

Researchers Introduce RoCo, a Mobile Personal Heating and Cooling Device

UMD Invention Has Potential to Cut Energy Costs in Residential and Large Building AC

The University of Maryland Receives $50,000 Grant from Dominion Foundation

Award supports new research on high efficiency solar-powered cooling systems.

UMD Startup To Solve Energy Conversion Challenges in Thermal Systems

Optimized Thermal Systems provides engineering consulting for HVAC&R systems.

Desai Named ASME Fellow

Mechanical Engineering Professor Jaydev Desai named ASME Fellow.

Dasgupta, Fourney and Hwang Named ASME Fellows

Three Mechanical Engineering faculty named American Society of Mechanical Engineers Fellows

Hwang Invited to Energy Editorial Board, Chairs ASME 2015 Conference and Delivers Keynote

Professor Yunho Hwang invited to Energy editorial board, chairs ASME 2015 conference and delivers keynote at International Symposium on Refrigeration Technology.

Radermacher and Hwang Awarded New Patent

Mechanical Engineering professors awarded patent for advancements in air conditioning technology.

UMD Team Wins First Place in MaxTech Competition

Team UMD Dryer wins the first place gold medal for their energy saving heat pump dryer.

Yunho Hwang to Receive Exceptional Service Award from ASHRAE

Associate research professor awarded for his active involvement in the organization.

UMD Researchers Win $1.5 Million Department of Energy Award to Improve Home Cooling Efficiency

The Center for Environmental Energy Engineering to collaborate with the Oak Ridge National Laboratory.

Mechanical Engineering Wins First Place in Max Tech and Beyond Design Competition

Yunho Hwang led a student team that designs winning energy efficient cooling system.

CEEE to Host CO2 Transcritical Cycle: Fundamentals and Current Status Webinar

Dr. Hwang, Associate Director and Professor with (CEEE), to host new webinar on  May 11, 2012.

Radermacher and Hwang Receive Funding Through Trento-ISR Collaboration

Mechanical Engineering faculty participate in joint project wtih Italian province and Clark School's Institute for Systems Research.

Yungho Hwang Named Chairperson of IIR Working Party

CEEE Associate Director heads investigation on the climate performance of refrigeration systems for the International Institute of Refrigeration.

Collaborative international projects funded in solar power, cell-based systems, and ultra-low power systems

Research is part of agreement between Autonomous Province of Trento, Italy, and University of Maryland.

Eisele, Hwang, and Radermacher Win Best Technical Paper Award

SAE/IMechE Vehicle Thermal Managment Systems Conference Awards Best Technical Paper

Abdullah A. Al-Abdulkarem Receives Honorable Mention for Poster

ME Student acknowledged by ASME for poster on enhanced oil recovery.

Eisele, Hwang, and Radermacher Win Best Technical Paper Award

CEEE professors and ME grad student have strong showing at VTMS 10 Conference.

Hwang Honored with ASHRAE's Distinguished Service Award

Dr. Yunho Hwang, CEEE Associate Director, to be recognized for his service contributions.

PI Holds 1st Annual Research Workshop

ME delegation travels to Abu Dhabi to promote research collaborations.

Hwang Appointed Associate Director of CEEE

Dr. Hwang will oversee day-to-day operations of the world renowned research facility.

Other professional society fellows

American Society of Mechanical Engineers (ASME)

American Society of Heating and Air-conditioning Engineers (ASHRAE)