Refrigeration & Heat Pump Systems Laboratory · KMOU

Research in
Refrigeration &
Heat Pump Systems

Led by Dr. Jaedeok Ko at Korea Maritime & Ocean University, the RHPS Lab advances refrigeration, heat pump systems, heat exchangers, and sustainable thermal engineering for next-generation applications.

Explore Research Get in Touch
20+
Journal Papers
13
Research Projects
14
Conference Papers
Focus Area
Natural refrigerants, energy efficiency & sustainable thermal engineering
About the Lab

Who We Are

The Refrigeration and Heat Pump Systems (RHPS) Laboratory at Korea Maritime & Ocean University is led by Assistant Professor Jaedeok Ko. Our research focuses on the fundamentals and applications of vapor compression refrigeration and heat pump systems, with particular emphasis on natural refrigerants, energy efficiency, and sustainable thermal engineering.

We investigate household refrigerator-freezers, electric vehicle air-conditioning, CO₂ transcritical systems, two-phase flow phenomena, and advanced heat exchanger design — combining experimental investigation with computational modeling to deliver practical, high-impact solutions.

We collaborate closely with industry partners such as LG Electronics and national research programs funded by the National Research Foundation of Korea, bridging fundamental science and real-world thermal engineering challenges.

Research Outputs & Collaboration

Journal Papers
20+
Conference Papers
14
Research Projects
13
Industry Partners
3+
Refrigeration
Heat Pumps
EV Thermal
CO₂ Cycles
TPMS
Two-Phase Flow

Scopus metrics (Author ID: 57200070314), as of Oct 2026.

Principal Investigator

Jaedeok Ko

Current Position

Sept. 1, 2024 – Present
Assistant Professor Division of Mechanical Engineering, Korea Maritime & Ocean University, Busan, Republic of Korea

Education

Oct. 1, 2018 – Sept. 24, 2021
Ph.D. Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka, Japan
Mar. 2, 2016 – Feb. 23, 2018
M.S. School of Mechanical Engineering, Pusan National University, Busan, Republic of Korea
Mar. 2, 2010 – Feb. 24, 2016
B.Eng. Division of Mechanical Engineering, Korea Maritime & Ocean University, Busan, Republic of Korea

Experience

Feb. 4, 2025 – Present
Junior Member, Commission B2, International Institute of Refrigeration (IIR)
Sept. 1, 2024 – Present
Assistant Professor, Division of Mechanical Engineering, Korea Maritime & Ocean University, Busan, Republic of Korea
Mar. 1, 2023 – Aug. 31, 2024
Research Professor, BK4 Education and Research Center for Advanced Machinery and Materials, School of Mechanical Engineering, Pusan National University, Busan, Republic of Korea
Nov. 8, 2021 – Jan. 20, 2023
Senior Engineer, Computer Aided Engineering (CAE) Team, Asia Pacific Innovation Center, Hanon Systems Inc., Daejeon, Republic of Korea
Apr. 1, 2018 – Jul. 31, 2018
Research Assistant, Institute of Nuclear Safety and Protection, Pusan National University, Busan, Republic of Korea
Research & Projects

Areas of Investigation

Refrigeration cycle diagram
01

Refrigeration Systems

Household refrigerator-freezer performance, capillary tube behavior, non-equilibrium two-phase flow, and fault diagnostics using natural refrigerants.

  • R-600a / R-290
  • Capillary tube
  • Two-phase flow
  • Energy efficiency
Heat pump cycle diagram
02

Heat Pump Systems

Environment-friendly air-to-water and water-source heat pump systems operating with natural refrigerants for domestic hot water and space heating applications.

  • R-290
  • Water-source HPs
  • Space heating
  • COP optimization
EV thermal management diagram
03

EV Thermal Management

Vapor compression air conditioning and heat pump systems for electric vehicles, including CO₂ transcritical cycles and start-up transient behavior.

  • EV heat pumps
  • CO₂ transcritical
  • Transient analysis
  • Cabin heating
CO2 transcritical P-h diagram
04

CO₂ Transcritical Cycles

Energy-saving strategies through heat rejection pressure management and cascaded cycle configurations using CO₂ as a natural refrigerant.

  • Supercritical CO₂
  • Gas cooler
  • Cascade cycle
  • Pressure control
TPMS lattice heat exchanger illustration
05

Heat Exchangers & TPMS

Advanced heat exchangers including TPMS-based structures, brazed plate heat exchangers, microchannel HXs, and capillary tube–suction line heat exchangers.

  • TPMS structures
  • Gyroid / Diamond
  • Microchannel HX
  • Topology optimization
Two-phase flow in a tube illustration
06

Two-Phase Flow & Heat Transfer

Refrigerant distribution, maldistribution in microchannel headers, foam flow friction, and moisture evaporation models to improve thermal system accuracy.

  • Flow distribution
  • Maldistribution
  • Condensation
  • Evaporation
Publications

Peer-Reviewed Journal Articles

Scopus metrics (Author ID: 57200070314), as of Oct 2026.

2026
Water-source heat pumps in practice: case studies from domestic and international environments
Ko, J. & Jeong, J.H.
Korean Journal of Air-Conditioning and Refrigeration Engineering, Vol. 38(9), pp. 523–529.
2026
Effects of material and bonding method of capillary tube-suction line heat exchanger on the compressor power consumption of household refrigerator-freezers
Ko, J., Park, J., Kim, B., Lee, H., Kim, H.S., & Jeong, J.H.
Applied Thermal Engineering, Vol. 300, 131517.Cited by 0
2026
Energy-saving potential of an R600a household refrigerator through mixing with R290 and changing compressor revolution speed
Kazmi, A., Ko, J., & Jeong, J.H.
Case Studies in Thermal Engineering, Vol. 77, 107549.
2026
Development and evaluation of a dual-loop vapor compression refrigerator-freezer for improved energy efficiency
Lee, K.H., Jeong, J.H., & Ko, J.
Applied Thermal Engineering, Vol. 282, 128912.Cited by 4
2025
Experimental investigation of the performance of a household refrigerator-freezer operating with various R600a/R290 mixing ratios
Kazmi, A., Ko, J., & Jeong, J.H.
Applied Thermal Engineering, Vol. 274, 126657.Cited by 9
2025
A novel mass transfer effectiveness model incorporating water activity for moisture evaporation rate prediction from fabric clothes
Jeong, D., Ko, J., Sung, I., Miyazaki, T., Thu, K., & Jeong, J.H.
Drying Technology, Vol. 43(3), pp. 492–509.Cited by 6
2025
Advanced model for a non-adiabatic capillary tube considering both subcooled liquid and non-equilibrium two-phase states of R-600a
Jeon, S., Ko, J., Lee, H., & Jeong, J.H.
International Journal of Refrigeration, Vol. 169, pp. 140–151.Cited by 5
2025
Development of a friction factor correlation for a foam flow in a horizontal circular pipe
Lee, H., Ko, J., & Jeong, J.H.
Annals of Nuclear Energy, Vol. 211, 110996.Cited by 1
2025
Adverse effects of compressor lubricant on household refrigerator-freezer performance and sustainable, feasible remedies
Ko, J. & Jeong, J.H.
Renewable and Sustainable Energy Reviews, Vol. 207, 114967.Cited by 12
2024
Effect of the suction pipe material in a non-adiabatic capillary tube on refrigeration system performance
Ko, J., Jeon, S., & Jeong, J.H.
Korean Journal of Air-Conditioning and Refrigeration Engineering, Vol. 36(10), pp. 500–506.
2024
Investigation of two-phase flow distribution in the vertical annular distribution header in a variable refrigerant flow heat pump system
Ko, J., Choi, S., & Jeong, J.H.
Applied Thermal Engineering, Vol. 257, 124248.Cited by 3
2024
Status and challenges of vapor compression air conditioning and heat pump systems for electric vehicles
Ko, J. & Jeong, J.H.
Applied Energy, Vol. 375, 124095.Cited by 42
2024
Impact of heat infiltration on the cooling capacity evaluation of an evaporator for household refrigerator-freezers with a non-adiabatic capillary tube
Ko, J., Jeon, S., & Jeong, J.H.
Applied Thermal Engineering, Vol. 248, 123247.Cited by 7
2024
Development of a friction factor correlation applicable to both wet and dry foam flow in circular vertical pipes
Lee, H., Sung, E., Ko, J., & Jeong, J.H.
Journal of the Taiwan Institute of Chemical Engineers, Vol. 159, 105509.Cited by 4
2024
Effects of 3-way valve faults and capillary tube clogging on the dynamic behavior of compressor power consumption during start-up operation of a household refrigerator-freezer
Ko, J. & Jeong, J.H.
Applied Thermal Engineering, Vol. 244, 122680.Cited by 7
2024
Effects of capillary tube clogging on the energy consumption of a household refrigerator-freezer with a dual evaporation circuit
Ko, J. & Jeong, J.H.
Applied Thermal Engineering, Vol. 238, 122219.Cited by 10
2023
Investigation on energy-saving potential from heat rejection pressure management in a CO₂ transcritical vapor compression system
Ko, J., Thu, K., & Miyazaki, T.
Applied Thermal Engineering, Vol. 235, 121397.Cited by 3
2021
Transient analysis of an electric vehicle air-conditioning system using CO₂ for start-up and cabin pull-down operations
Ko, J., Thu, K., & Miyazaki, T.
Applied Thermal Engineering, Vol. 190, 116825.Cited by 26
2021
Investigation of a cascaded CO₂ refrigeration system using phase change materials for energy-saving potentials
Ko, J., Thu, K., & Miyazaki, T.
Applied Thermal Engineering, Vol. 182, 116104.Cited by 25
2020
Dynamic modeling and validation of a carbon dioxide heat pump system
Ko, J., Takata, N., Thu, K., & Miyazaki, T.
Evergreen — Joint Journal of Novel Carbon Resource Sciences & Green Asia Strategy, Vol. 7(2), pp. 172–194.Cited by 34
2018
Effects of a non-equilibrium two-phase refrigerant flow at subcooled temperatures on the performance of an R-600a refrigeration system
Ko, J. & Jeong, J.H.
International Journal of Refrigeration, Vol. 87, pp. 118–130.Cited by 12
2016
Non-equilibrium two-phase refrigerant flow at subcooled temperatures in an R600a refrigeration system
Lee, W.J., Seo, J.Y., Ko, J., & Jeong, J.H.
International Journal of Refrigeration, Vol. 70, pp. 148–156.Cited by 23
2026
Understanding and mitigating flow maldistribution in microchannel heat exchangers for high-efficiency heat pump systems
Kim, H.J., Ko, J., & Jeong, J.H.
The 21st International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, Indiana, US, Jul. 12–16, 2026.
2025
Comparison of two-phase flow distribution according to the installation orientation of an annular distribution header
Ko, J., & Jeong, J.H.
The 12th International Conference on Multiphase Flow (ICMF 2025), Toulouse, France, May 12–16, 2025.
2025
Evaluation of thermal resistance based on materials and joining methods of capillary tube-suction line heat exchangers
Park, J., Ko, J., Sung, I., Lee, H., & Jeong, J.H.
2025 KSME Thermal Engineering Division Annual Conference, Jeju, Republic of Korea, Apr. 23–26, 2025.
2024
Effect of the suction pipe material in a capillary tube-suction line heat exchanger on a refrigeration system performance
Ko, J., Jeon, S., Sung, I., Lee, H., Park, J., & Jeong, J.H.
The 3rd Pacific Rim Thermal Engineering Conference (PRTEC 2024), Honolulu, Hawaii, US, Dec. 15–19, 2024.
2024
Performance of domestic refrigerator using different blending ratios of refrigerants R600a and R290
Kazmi, A., Wang, Z., Ko, J., & Jeong, J.H.
2024 KSME Annual Conference, Jeju, Republic of Korea, Nov. 6–9, 2024.
2024
Experimental investigation of capillary tube clogging on the dynamic behavior of a domestic refrigerator-freezer with a dual evaporation circuit
Ko, J., & Jeong, J.H.
The 11th Asian Conference on Refrigeration and Air-conditioning (ACRA 2024), pp. 1–4, Jeju, Republic of Korea, Apr. 21–24, 2024.
2024
Experimental investigation of R600a through a capillary tube-suction line heat exchanger under the non-equilibrium subcooled two-phase flow inlet conditions
Jeon, S., Ko, J., & Jeong, J.H.
The 11th Asian Conference on Refrigeration and Air-conditioning (ACRA 2024), pp. 5–8, Jeju, Republic of Korea, Apr. 21–24, 2024.
2023
Experimental investigation of R600a through a non-adiabatic capillary tube under the non-equilibrium state at the capillary tube inlet
Jeon, S., Ko, J., & Jeong, J.H.
The 25th Cross Straits Symposium on Energy and Environmental Science and Technology (CSS 2023), Fukuoka, Japan, Nov. 20–22, 2023.
2019
Dynamic simulation of a thermal management system consisting of a CO₂ heat pump and a water-loop
Ko, J., Takata, N., Thu, K., & Miyazaki, T.
The 5th International Exchange and Innovation Conference on Engineering & Science (IEICES 2019), pp. 39–43, Fukuoka, Japan, Oct. 24–25, 2019.
2019
Dynamic simulation of a CO₂ refrigeration system with a fluctuation of outdoor temperature in Simscape
Ko, J., & Miyazaki, T.
The 5th International Conference on Polygeneration (ICP 2019), Fukuoka, Japan, May 15–17, 2019.
2018
Effects of a thermodynamic non-equilibrium two-phase flow of R-600a at subcooled temperature condition on the performance of a vapor compression refrigeration system
Ko, J., & Jeong, J.H.
The 13th IIR Gustav Lorentzen Conference on Natural Refrigerants (GL 2018), pp. 77–83, Valencia, Spain, Jun. 18–20, 2018.
2017
Effects of a non-equilibrium two-phase flow of R-600a on the performance of a vapor compression refrigeration system under the subcooled temperature conditions
Ko, J., & Jeong, J.H.
2017 Winter Annual Conference of the Society of Air-Conditioning and Refrigerating Engineers of Korea, pp. 13–16, Seoul, Republic of Korea, Nov. 29, 2017.
2017
The existence of non-equilibrium two-phase flow of R600a at subcooled temperature in a vapor compression refrigeration system
Ko, J., Seo, J.Y., Lee, W.J., & Jeong, J.H.
The 5th IIR International Conference on Thermophysical Properties and Transfer Processes of Refrigerants (TPTPR 2017), Seoul, Republic of Korea, Apr. 23–26, 2017.
2016
Thermodynamic non-equilibrium state of isobutene at the subcooled condition in a vapor compression refrigeration system
Ko, J., Seo, J.Y., Lee, W.J., & Jeong, J.H.
The 18th Cross Straits Symposium on Energy and Environmental Science and Technology, Shanghai, China, Dec. 4–6, 2016.
2016
Non-equilibrium two-phase flow of R600a at subcooled temperature condition in a vapor compression refrigeration system
Ko, J., Lee, W.J., Seo, J.Y., & Jeong, J.H.
2016 Winter Annual Conference of the Society of Air-Conditioning and Refrigerating Engineers of Korea, pp. 321–324, Seoul, Republic of Korea, Nov. 25, 2016.
Projects

Research Projects

2026–2029
Fundamental study on the development of a triply periodic minimal surface (TPMS) heat exchanger for a water-cooled condenser in household refrigeration systems
Mar. 1, 2026 – Feb. 28, 2029
National Research Foundation of Korea, Ministry of Science and ICT, Republic of Korea.
2026–2027
Performance analysis by cycle component in a size reduction in compact machine room of household refrigerator-freezer
Mar. 1, 2026 – Feb. 28, 2027
LG Electronics Inc., Republic of Korea.
2025–2026
A group of experts on the thermal properties database for the development of high-efficiency R-290 air-to-water heat pumps for domestic hot water and heating water supply
Aug. 14, 2025 – Aug. 13, 2026
National Research Foundation of Korea, Ministry of Science and ICT, Republic of Korea.
2025–2029
Water-energy graduate school program
Mar. 1, 2025 – Dec. 31, 2029
Korea Environment Corporation, Ministry of Climate, Energy, and Environment, Republic of Korea.
2024–2025
Improvement of refrigerant distribution in brazed plate heat exchangers and establishment of freeze test method
Oct. 15, 2024 – Oct. 14, 2025
LG Electronics Inc., Republic of Korea.
2024–2025
Type-specific performance evaluation of capillary tube-suction line heat exchangers for household refrigerator-freezers
Sept. 1, 2024 – Jan. 31, 2025
LG Electronics Inc., Republic of Korea.
2024–2029
Development of environment-friendly high-efficiency air-to-water heat pump systems operating with natural refrigerant R-290
May 1, 2024 – Apr. 30, 2029
National Research Foundation of Korea, Ministry of Science and ICT, Republic of Korea.
2024–2025
Establishment of air-cooled heat exchanger performance evaluation database
Jun. 1, 2024 – May 28, 2025
LG Electronics Inc., Republic of Korea.
2023–2024
Eco-friendly Smart Ship Parts Technology Innovation Center
Mar. 1, 2023 – Aug. 31, 2024
National Research Foundation of Korea, Republic of Korea.
2023
Evaluation of the non-equilibrium flow characteristics of R600a in household refrigerator-freezer
May 1, 2023 – Nov. 30, 2023
LG Electronics Inc., Republic of Korea.
2018–2021
Joint research on a thermal management system of EVs utilizing the exhaust heat from the motor and inverter
Oct. 1, 2018 – Mar. 31, 2021
Aisin AW Co., Ltd., Japan.
2017–2018
Improving the efficiency of a household refrigerator-freezer considering the non-equilibrium two-phase flow of R-600a at the outlet of the condensing system
Sept. 1, 2017 – Jul. 31, 2018
LG Electronics Inc., Republic of Korea.
2016–2017
Investigation to reduce the commissioning duration of finished household refrigerator-freezer units
Jun. 1, 2016 – May 31, 2017
LG Electronics Inc., Republic of Korea.
Contact

Get In Touch

We welcome inquiries from prospective collaborators, graduate students, and postdoctoral candidates interested in refrigeration, heat pump systems, and thermal engineering. Please reach out via the form or directly through the contact details below.

📍
Address727, Taejong-ro, Yeongdo-gu
Busan 49112, Republic of Korea
Office: Rm. 415, Bldg. A1 · Lab.: Rm. 314, Bldg. A1
🏛️
DepartmentDivision of Mechanical Engineering
Korea Maritime & Ocean University
📞
Tel.+82 51 510 4365
🌐
Websiterhps-lab-kmou.vercel.app
TPMS Level-set Equation