Nigerian researcher, Abiola Samuel Ajayi, in collaboration with Sugyeong Kim and Rin Yun of Hanbat National University, South Korea, has developed new experimental-based models that improve the prediction of condensation heat transfer coefficients and frictional pressure drops across a wide range of reduced pressures.
The study, published in the International Journal of Air-Conditioning and Refrigeration, analysed 1,960 data points from 10 scientific articles, covering 11 refrigerants including R1234ze(E), R134a, R290, R32, and CO₂.
The models, specifically designed for industrial heat pump systems, outperformed traditional ones such as those by Traviss, Shah, and Dobson, which showed deviations of up to 80 per cent. The new models demonstrated greater accuracy, with mean deviations of ±22.6 per cent for heat transfer coefficients and ±32.7 per cent for pressure drops.
According to Ajayi, the research team applied MATLAB regression analysis and used non-dimensional parameters such as the Bond number, Weber number, and Lockhart-Martinelli parameter to strengthen predictive reliability. By categorising data across different reduced pressure ranges, they achieved higher precision.
The findings are expected to accelerate the transition to environmentally friendly refrigerants, particularly Hydrofluoroolefins (HFOs) and Hydrocarbons (HCs), which are gradually replacing high-global-warming-potential refrigerants like R410A and R407C.
“Accurate prediction of condensation heat transfer and pressure drop is critical for designing efficient, safe, and eco-friendly industrial heat pump systems,” he stated.
The work comes at a time when the global industrial heat pump market, valued at $8.8 billion in 2021, is projected to double to $17.7 billion by 2031, driven by demand for sustainable refrigerant solutions. The study was supported by funding from the National Research Foundation of Korea.
Ajayi, currently a student at Texas Southern University (TSU), Houston, has also been active in aerospace research. He recently completed an internship at U.S.-based aviation company, World Aerospace, where he designed a benchmarking framework for evaluating top aerospace programmes globally. His contributions, which transformed raw data into a decision-support tool, are now guiding the company’s partnerships with leading institutions.
Reflecting on his internship, Ajayi described it as a pivotal moment.
“This experience has strengthened my ability to contribute to advancing aerospace innovation, talent development, and global partnerships. Moving forward, I aim to leverage my engineering and computational background to support research-driven initiatives,” he stated.
At World Aerospace, Ajayi worked under the leadership of Mr. Brian Hanrahan, where he explored unmanned aerial systems, propulsion technologies, and sustainable aviation solutions. Beyond technical contributions, he emphasised how the internship deepened his appreciation of collaboration, communication, and the broader role of research in shaping the future of aviation.
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