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Phase-change HT

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Interfacial Phenomena 


Energy Systems


Research at Energy-X

Energy-X is particularly interested in scientific and engineering challenges that lay at the intersection of thermal-fluid, material, and energy sciences. Our current research focuses on understanding the fundamental transport science of important energy carriers (such as fluid particles, phonons, photons, exciton, and charged particles) at micro, nano, and molecular scales. We design, fabricate, and examine a wide range of meso-, micro-, and nano-devices/systems to understand their underlying physics and explore new technologies and performance breakthroughs.

Our research includes four thrusts as follows:

  • Research Thrust 1: Selective gas capture and adv. SSLC heat pumps for sustainable, energy-efficient buildings 

  • Research Thrust 2: High-T thermal energy exchange, transport, and storage for clean energy production

  • Research Thrust 3: Desalination and high-salinity ZLD water treatment for clean water production

  • Research Thrust 4: Thermal management and phase change heat transfer for future EVs and electronics


Research Thrust 1: Selective gas capture and advanced SSLC-based heat pumps for sustainable, energy-efficient buildings 

Global demand for sustainable buildings including energy-efficient air conditioning (AC) systems is boosting due to rising consumer awareness over energy efficiency, growing energy bills, and climate change concerns. Buildings’ latent cooling (i.e., humidity) load, for instance, can account for up to 85% of total AC energy consumption in mixed-humid and hot-humid climate zones. While the latent cooling load is a key contributor to the overall AC demand, existing vapor-compression-based AC technologies cannot efficiently treat humidity since latent and sensible cooling loads are highly coupled in current systems. Therefore, selective and/or independent gas capture including humidity and carbon dioxide is a key concept to the development of future energy-efficient buildings systems.

Sample related journal publications:

J27. “A novel lung-inspired 3D-printed desiccant-coated heat exchanger for high-performance humidity management in buildings”, Umamaheswar Puttur, Masoud Ahmadi, Behzad Ahmadi, Sajjad Bigham, Energy Conversion and Management,  Vol. 252, 2022.   PDF

J25. “Performance Analysis and Limiting Parameters of Cross-flow Membrane-based Liquid-desiccant Air Dehumidifiers”, Behnam Ahmadi, Masoud Ahmadi, Kashif Nawaz, Ayyoub M. Momen, Sajjad Bigham, International Journal of Refrigeration, Vol. 132, 2021.   PDF

J23. “Energy-efficient Sorption-based Gas Clothes Dryer Systems​”, Masoud Ahmadi, Kyle Gluesenkamp, Sajjad Bigham,

Energy Conversion and Management,  Vol. 230, 2021.   PDF

J15. “Impact of micromixing on performance of a membrane-based absorber”, R. N. Isfahani, S. Bigham, M. Mortazavi, S. Moghaddam,  Energy, (2015) 1-8.   PDF

J14. “Absorption characteristics of falling film LiBr (lithium bromide) solution over a finned structure”, M. Mortazavi, R. N. Isfahani, S. Bigham, S. Moghaddam, Energy, VOl 87 (2015) 270-278.   PDF

J13. “Moving beyond the limits of mass transport in liquid absorbent microfilms through the implementation of surface-induced vortices”, S. Bigham, D. Yu, D. Chugh, S. Moghaddam, Energy, Vol. 65 (2014) 621-630.   PDF

J12. “Direct Molecular Diffusion and Micro-mixing for Rapid Dewatering of LiBr Solution”, S. Bigham, R. N. Isfahani, S. Moghaddam, Applied Thermal Engineering, Vol. 64 (2014) Issues 1–2, 371–375.   PDF

J11. “Physics of lithium bromide (LiBr) solution dewatering through vapor venting membranes”, R. N. Isfahani, A. Fazeli, S. Bigham, S. Moghaddam, International Journal of Multiphase Flow, Vol. 58 (2014) 27-38.   PDF

Sample related conference presentations:

C23• Masoud Ahmadi, Behnam Ahmadi, “Role of Surface Structures in Liquid-Desiccant-Based Air Dehumidifiers”, Presentation, Paper number: SHTC2021-63988, ASME SHTC 2021, Online, Virtual. Link to presentation

C21• Behnam Ahmadi, Masoud Ahmadi, Sajjad Bigham, “Experimental Evaluation of a Membrane-Based Liquid-Desiccant Regenerator”, Presentation, Paper number: SHTC2021-64006, ASME SHTC 2021, Online, Virtual. Link to presentation

C20• Behnam Ahmadi, Masoud Ahmadi, Sajjad Bigham, “Two-Phase Multispecies CFD Modeling of a Liquid Desiccant Dehumidifier”, Presentation, Paper number: SHTC2021-63994, ASME SHTC 2021, Online, Virtual. Link to presentation

C15• Behnam Ahmadi, Masoud Ahmadi, Sajjad Bigham, “Two-Phase Multispecies Modeling of a Liquid Desiccant Dehumidifier”, Presentation, Paper number: ICNMM2020-13210, ASME ICNMM 2020, Online, Virtual.

C14• Masoud Ahmadi, Sajjad Bigham, “Thermodynamic Modeling of a Novel Gas-Driven Dryer System”, Presentation, Paper number: ICNMM2020-26434, ASME ICNMM 2020, Online, Virtual.

C4• Rasoul Nasr Isfahani, Sajjad Bigham, W. Xing, Saeed Moghaddam, “3D Surface Microstructures for Micro-mixing of Lithium Bromide (LiBr) Desiccant”, IMECE2014-40425, ASME 2014, Montreal, Canada.

C3• Sajjad Bigham, Saeed Moghaddam, “Moving Beyond the Limits of Mass Transport in Liquid Absorbent Microfilms through the Implementation of Surface-Induced Vortices”,​ 12th International Conference on Nanochannels, Microchannels, and Minichannels (ICNMM2014), Paper No.: FEDSM2014-21759.

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Sample project: A novel lung-inspired 3D-printed desiccant-coated heat exchanger for high-performance humidity management in buildings.

Sample project: Microscale transport phenomena in multi-species microfilms constrained by nano-porous superhydrophobic membranes. 

Research Thrust 2: High-T thermal energy exchange, transport, and storage for clean energy production

A significant portion of primary energy utilized in several key industrial applications including conventional and advanced power generation cycles, aviation, and metal/glass production is currently wasted at high temperatures. More importantly, next-generation supercritical carbon dioxide and concentrated solar power plants, future on-demand mobility and air-transport-class aircraft, and very-high-temperature reactor (VHTR) concepts are all expected to operate at temperatures exceeding 1000°C under extreme environments. A substantial improvement in thermal conversion efficiency accompanied by a simultaneous reduction in fuel consumption, system footprint, and carbon dioxide emissions can be realized if the high-temperature thermal energy can be harvested in the case of industrial waste heat recovery or exchanged in the case of future power and mobility systems. Current heat exchanger technologies, however, fail under severe operating conditions imposed by high temperatures present in several aforementioned applications.

State-of-the-art materials for high-temperature heat exchanger applications are metals and superalloys including high-grade steels and nickel-based alloys. For instance, compact metallic printed circuit heat exchangers (PCHXs) have been proposed for supercritical carbon dioxide power plants. Heat exchangers made of metals and superalloy materials, however, experience an intense degradation in critical material properties at elevated temperatures and particularly lose their strength at temperatures exceeding 800°C. Ceramic heat exchangers (CHXs), on the other hand, offer favorable high-temperature thermo-mechanical properties including superior mechanical strength and excellent corrosion, oxidation, creep, wear, and abrasion resistance, thereby making them a promising alternative solution to metallic heat exchangers.

Sample related journal publications:

J28. “Toward extreme high-temperature supercritical CO2 power cycles: leakage characterization of ceramic 3D-printed heat exchangers”, Rasoul Bayaniahangar, Ikechukwu Okoh, Joseph Cesarano, Kashif Nawaz, Nikolas Ninos, Sajjad BighamAdditive Manufacturing, Vol. 54, 2022.   PDF

J26. “Performance Evaluation of hi-k Lung-inspired 3D-printed Polymer Heat Exchangers”, Behzad Ahmadi, Sajjad Bigham, Applied Thermal Engineering, Vol. 204, 2022.   PDF

Sample related conference presentations:

C19• Behzad Ahmadi, Sajjad Bigham, “Experimental Evaluation of Ceramic 3D-Printed Heat Exchangers at High-Temperatures”, Presentation, Paper number: SHTC2021-64028, ASME SHTC 2021, Online, Virtual. Link to presentation

C18• Rasoul Bayaniahangar, Sajjad Bigham, “Toward Extreme High-Temperature/high-Pressure Energy Systems: Leakage Characterization of Ceramic 3D-Printed Structures”, Presentation, Paper number: SHTC2021-64034, ASME SHTC 2021, Online, Virtual. Link to presentation

Research Thrust 3: Desalination and high-salinity ZLD water treatment for clean water production

Freshwater scarcity due to population growth, pollution of water bodies, industrialization, and climate change has imposed a major threat to the prospect of the world economy, environmental sustainability, and human life quality. Desalination of sea, waste, or brackish water has been largely considered as a potential solution to growing concerns on freshwater demands. Conventional desalination techniques, however, generate a substantial amount of a highly concentrated discharge brine significantly disturbing the aquatic environment, natural hydrologic cycles, and public health quality. Zero liquid discharge (ZLD) systems, on the other hand, completely recover the liquid wastewater, thereby minimizing adverse environmental risks and high effluent disposal costs. Current ZLD systems are, however, inefficient to purify saline water with high total dissolved solids (TDS) concentration values (TDS>100,000 ppm), and often unable to economically achieve ZLD operation desired in many industrial applications with high brine disposal costs.

Our research addresses the shortcomings inherent to current ZLD techniques by an innovative desiccant-based concept in which a multiple-effect distillation (MED) unit is uniquely embedded at the heart of an absorption-desorption system. Contrary to current energy-intensive ZLD approaches, our technology employs an absorption-based thermally-driven vapor compressor concept to create a low vapor pressure environment required for the ZLD treatment. The ZLD operation is realized by the absorption process in which a strong hygroscopic solution captures a large volume of water vapor from the brine slurry.

Sample related journal publications:

J24. “Multiple-effect Desiccant-based Zero Liquid Discharge Desalination Systems”, Sunil Pinnu, Sajjad Bigham, Desalination, Vol. 502, 2021.   PDF

J10. “A general guide to design of falling film evaporators utilized in multi effect desalination units operating at high vapor qualities under a sub-atmospheric condition”, S. Bigham, R. Kouhikamali, M. P. Zadeh, Energy, Vol. 84 (2014) 279-288

J8• “Two-phase flow numerical simulation and experimental verification of falling film evaporation on a horizontal tube bundle”, S. Bigham, R. Kouhikamali, S. M. A. Noori Rahim Abadi, Desalination and Water Treatment, published online July 2014

Research Thrust 4: Thermal management and phase change heat transfer for future EVs and electronics

For more than a century, thermal management has played a key role in the advancement of various technological and industrial applications such as power generation, refrigeration, desalination, and high-power electronics. The microelectronic industry, in particular, relies on improvements in micro-scale thermal management techniques to continue its current performance growth trajectory. Among many thermal management pathways, liquid-to-vapor phase change cooling has been recognized as a promising solution for high heat flux applications. By taking advantage of latent heat of vaporization, the evaporative phase change cooling can dissipate high heat fluxes with a small streamwise temperature change while reducing the required liquid flow rate and pumping power. Over the last half-century, numerous attempts have been made to improve the efficiency of the phase-change heat transfer process in extremely demanding applications such as fusion reactor blankets as well as many military electronic systems. Our research aims to exploit advanced micro and nano-fabrication tools to understand and alter the phase-change heat transfer mechanisms at micro and nano-scale.

Sample related journal publications:

J22. “Gradient Wick Channels for Enhanced Flow Boiling HTC and Delayed CHF​”, Masoud Ahmadi, Sajjad Bigham, Int. J. Heat and Mass Transfer, Vol. 167, 2021.   PDF

J21. “Physics of the Microchannel Flow Boiling Process and Comparison With the Existing Theories”, S. Bigham, S. Moghaddam, Journal of Heat Transfer, Vol. 139, 2017

J19. “Physics of microstructures enhancement of thin film evaporation heat transfer in microchannel flow boiling”, S. Bigham, A. Fazeli, S. Moghaddam, Scientific Reports,  Published online on March 17, 2017.   PDF

J18. “Role of bubble growth dynamics on microscale heat transfer events in microchannel flow boiling process”, S. Bigham, S. Moghaddam, Applied Physics Letter, Vol. 107, Issue 24, 244103-9.   PDF

J17. “Microscale Layering of Liquid and Vapor Phases within Microstructures for a New Generation Two-Phase Heat Sink”, A. Fazeli, S. Bigham, S. Moghaddam, International Journal of Heat and Mass Transfer, Vol. 95 (2016) 368-378.   PDF

J16. “Microscale study of mechanisms of heat transfer during flow boiling in a microchannel”, S. Bigham, S. Moghaddam, International Journal of Heat and Mass Transfer, Vol. 88 (2015) 111-121.   PDF

J9• “A numerical study on natural convection heat transfer from a horizontal isothermal cylinder located underneath an adiabatic ceiling”, M. Ashjaee, S. Bigham, S. Yazdani,​ Heat Transfer Engineerig, Vol 35 (2014) Issue 10

J7• “Fluid Flow and Heat Transfer Simulation in a Constricted Microchannel: Effects of Rarefaction and Viscous Dissipation”, S. Bigham, H. Shokouhmand, R. N. Isfahani, S. Yazdani, Numerical Heat Transfer, Part A Applications, Vol. 59 (2012) Issue 3, 209-230.  

J6• “Experimental and numerical investigation on free convection from a horizontal cylinder located above an adiabatic surface”M. Ashjaee, S. Yazdani, S. Bigham, T. Yousefi,​ Heat Transfer Engineerig, Vol 33 (2012) Issue 3.  

J5• “Effects of Knudsen number and Geometry on gaseous flow and heat transfer in a constricted microchannel”H. Shokouhmand, S. Bigham, R. N. Isfahani, Heat and Mass Transfer, Vol. 47 (2011) Issue 2, 119-130.  

J4• “Numerical solution and statistical analysis for estimation of the heat flux in thermal scanning process using conjugate gradient method”, S. Yazdani, S. Bigham, J. Yazdani, J. Comput .Theor .Nanosci ,Vol. 8 (2011) Issue 4, 707-712

J3. ​“Effects of lateral contact stiffness and geometrical parameters on torsional sensitivity of vibration modes of rectangular AFM cantilevers with sidewall”, S. Bigham, S. Yazdani, J. Yazdani, J. Comput .Theor .Nanosci, Vol. 8 (2011) Issue 7.   

J2• “A theoretical model for unsteady coupled heat and mass transfer phenomena in industrial dryers”, H. Shokouhmand, S. Bigham, S. Yazdani, Heat Transfer Research, Vol. 42 (2011) Issue 5, 415-432

J1• “Slip-flow and heat transfer of gaseous flows in the entrance of a wavy microchannel”, H. Shokouhmand, S. Bigham, Int. Comm. in Heat and Mass Transfer, 37 (2010) 695-702.  

Sample related conference presentations:

C22• Masoud Ahmadi, Sajjad Bigham, “Flow Boiling on Homogenous and Gradient Wick Surfaces”, Presentation, Paper number: SHTC2021-63370, ASME SHTC 2021, Online, Virtual. Link to presentation

C17• Gnana Vishnu Durgam, Sajjad Bigham, “Enhanced Condensation Heat Transfer of Low Surface Tension Liquids”, Presentation, Paper number: ICNMM2020-13226, ASME ICNMM 2020, Online, Virtual.

C16• Masoud Ahamdi, Sajjad Bigham, “Suppressed Critical Heat Flux during Forced Convection Boiling by 3D Wick Structures”, Presentation, Paper number: ICNMM2020-13190, ASME ICNMM 2020, Online, Virtual.

C13• Gnana Vishnu Durgam, Sajjad Bigham, “Engineered Surfaces for Enhanced Condensation Heat Transfer of Completely Wetting Liquids”, Presentation, Paper number: SHTC2019-3627, ASME SHTC 2019, Bellevue, WA, US.

C12• Masoud Ahmadi, Sajjad Bigham, “Wick Channels for Enhanced Flow Boiling HTC and Delayed CHF”, Presentation, Paper number: SHTC2019-3625, ASME SHTC 2019, Bellevue, WA, US.

C11• Mojtaba Hosseinnia, Sajjad Bigham, “Membranes for Microscale Phase Separation of Completely Wetting Liquids”, IMECE2018-88296, ASME-IMECE2018, Pittsburg, USA

C10• Mojtaba Hosseinnia, Sajjad Bigham, A Novel Multiscale Wick Structure for Delayed Critical Heat Flux in Microchannel Flow Boiling Process, IMECE2018-88292, ASME-IMECE2018, Pittsburg, USA

C9• Sajjad Bigham, Saeed Moghaddam, Microscale Analysis of Mechanisms of Heat Transfer in Microchannel Flow Boiling Process​, InterPACKICNMM2017-5624, ASME InterPACK-ICNMM 2017, Cambridge, MA, USA

C8• Sajjad Bigham, Saeed Moghaddam, Fundamentals of Microchannel Flow Boiling Sub-processes and Similarities and Differences with Pool Boiling​, InterPACKICNMM2017-5640, ASME InterPACK-ICNMM 2017, Cambridge, MA, USA

C7• Sajjad Bigham, Saeed Moghaddam, Physics of Interfacial Heat Transfer Events in Flow Boiling of FC-72 Liquid in Microchannels​, InterPACKICNMM2015-48581, ASME InterPACK-ICNMM 2015, San Francisco, USA.   PDF

C6• ​Abdy Fazeli, Sajjad Bigham, Saeed Moghaddam, “Microscale Layering of Liquid and Vapor Phases Within Microstructures for Self-Regulated Flow Delivery to Local Hot Spots”​, InterPACKICNMM2015-48632, ASME InterPACK-ICNMM 2015, San Francisco, USA.    PDF

C1• Hossein Shokouhmand, Sajjad Bigham, “Effects Of Entrance Region Transport Processes on Slip Flow Regime in a Wavy Wall Microchannel with Isothermally Heated Walls”, World Congress on Engineering (WCE), ICME 2010, June 30 - July 2, 2010, London, U.K. (ISBN: 978-988-17012-9-9)


Sample project: A detailed micro-fluidic device with embedded micro-RTDs and micro heat flux sensors to study the physics of microscale heat transfer at micro/nano-scale over smooth and textured surfaces.

Bubbly and slug flow regimes over embedded layered RTD sensors.

Sample project: Microscale layering of liquid and vapor phases within microstructures for a new generation two-phase heat sink.

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