Research Interests

Alternative Cooling Technologies and Applications

• Vapor injection cycle.

• Multi-stage cycle.

• Expander-compressor integration.

• Evaluation of Variable Refrigerant Volume systems.

• Solar cooling technologies

• Thermoelectric subcooler.

• Transcritical CO2 cycle for transport-and-stationary air-conditioning and heat pumping applications.

• R32 and R32-rich mixtures as substitutes for R-410A in unitary equipment.

• Hydrocarbons and their mixtures as substitutes for R-22 in unitary equipment.

Cycle Components Design, Development, and Testing 

CO2 compressors.
Microchannel heat exchangers
Maldistributionin microchannel evaporator

Oil circulation & distribution analysis

Heat Transfer and Modeling
Heat transfer and pressure drop measurements of CO2/oil mixture for boiling and gas cooling processes.
Refrigerant/Oil mixture flow visualization.
Working fluid properties routines for EES, FORTRAN, Visual Basic and ACTIVE-X Controls
Cycle components and system modeling

Sensor Development and Testing 
OCR Sensor for CO2/PAG mixture.

OCR Sensor for HFC/POE.

Refrigerant/Oil Flow Visualization Movie
Depending upon the refrigerant flow velocity, the flow pattern of the refrigerant/oil mixture is either "Chun flow" or "Annual flow".  The following movies show two flow patterns that were observed in the vertical suction line.

  Chun Flow Movie                                            Annual Flow Movie

Click on Movie to Start, Need RealPlayer to View Movie