Design of a Numerical Simulator for Finned-Tube Heat Exchangers with Arbitrary Circuitry

Abstract

A numerical simulator that can handle a finned-tube heat exchanger with a complex refrigerant circuitry is presented. The model is based on a tube-by-tube approach in which each tube is considered as the control volume in the analysis of the mass, energy, and momentum conservation. A mathematical representation of the refrigerant circuitry is also developed using the concepts in graph theory. The tube–tube adjacency matrix provides a unique representation of the tube connectivity and can also be utilized for constraints handling. With the implementation of the constraints, nonphysical and infeasible circuitries are removed from the solution space, which is advantageous for an evolutionary search for an optimum solution. The numerical simulator is verified against two sets of experimental data, and the calculated heat duty and pressure drop are within ±6% and ±20%, respectively. Sample simulations of the performance of different refrigerants in three circuitry configurations, and circuitry optimization are conducted to investigate the reliability and effectiveness of the tube-tube adjacency matrix and simulation model in the search for an optimal solution.

Acknowledgments

This paper is based on results obtained from a project commissioned by the New Energy and Industrial Technology Development Organization (NEDO).

Additional information

Funding

The authors would like to acknowledge the Department of Science and Technology – Engineering Research and Development for Technology (DOST-ERDT) for the funding provided to Mr. Garcia under the Foreign PhD Scholarship program.

Notes on contributors

John Carlo S. Garcia

John Carlo Garcia is an assistant professor of the Department of Mechanical Engineering at the University of the Philippines Diliman, Philippines. He obtained both his B.S. and M.S. degrees in Mechanical Engineering from the University of the Philippines Diliman. He is currently a doctoral student at Saito Laboratory, Department of Applied Mechanics and Aerospace Engineering, Waseda University, Japan. His research interests include HVACR, and optimal design of thermal systems.

Niccolo Giannetti

Niccolo Giannetti is an assistant professor of Waseda Institute for Advanced Study at Waseda University, Japan. He obtained his B.S. and M.S. degrees in Mechanical Engineering from the University of Florence, Italy, and his Ph.D. in Engineering at Waseda University, Japan. His research is focused on the physical modeling of transfer processes within thermal systems.

Daryl Anne B. Varela

Daryl Anne Varela is a research assistant at Saito Laboratory, Waseda University, Japan. She obtained her B.S. and M.S. in Electronics and Communication Engineering degrees from the Mindanao University of Science and Technology and University of San Carlos, Philippines, respectively. Her research focuses on artificial neural networks and performance optimization of heat pump systems.

Richard Jayson Varela

Richard Jayson Varela is currently working as a research associate at the Research Innovation Center, Waseda University, Japan. He obtained his B.S. and M.Eng. in Mechanical Engineering degrees from the Eastern Visayas State University and the University of San Carlos, Philippines, respectively. He received his D.Eng. degree from the Department of Applied Mechanics and Aerospace Engineering at Waseda University, Japan. His main research interests include hybrid liquid desiccant air conditioning systems, heat and mass transfer analysis, and energy efficiency.

Seiichi Yamaguchi

Seiichi Yamaguchi is an associate professor of the Department of Applied Mechanics and Aerospace Engineering at Waseda University, Japan. He obtained his B.S., M.S., and D.Eng. degrees at Waseda University. His research interests include optimal design and control of energy systems, and heat and mass transfer control.

Kiyoshi Saito

Kiyoshi Saito is a professor of the Department of Applied Mechanics and Aerospace Engineering at Waseda University, Japan. He obtained is B.S., M.S., and D.Eng. degrees at Waseda University, Japan. He is currently the director of the Interdisciplinary Institute for Thermal Energy Conversion Engineering and Mathematics, as well as the executive director of the Consortium for the Research Strategy of Next-Generation Heat Pump Technology. His research interests include analysis theory of energy systems, control of energy saving systems, thermal fluid dynamics of micro- and nano-phenomena, and next-generation heat pump technology.

Menandro S. Berana

Menandro Berana is a professor of the Department of Mechanical Engineering at the University of the Philippines Diliman (UPD). He obtained his Master and Doctor of Engineering degrees, both major in Mechanical Engineering, from Toyohashi University of Technology, Japan, and his Master of Science, major in Machine Design, and Bachelor of Science in Mechanical Engineering from the UPD. He is currently the laboratory head of the HVACR laboratory, and the Administrative Assessment and Development Officer of the department. His research interests include HVACR, thermal power conversion, engineering education, and humanitarian engineering.