2023 Fiscal Year Final Research Report

Thermal design and optimization of a low temperature exhaust heat recovery heat exchanger for marine engines by next generation low GWP working fluids

Research Project

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Project/Area Number	20H02364
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 24020:Marine engineering-related
Research Institution	Tokyo University of Marine Science and Technology
Principal Investigator	Inoue Norihiro 東京海洋大学, 学術研究院, 教授 (80251677)
Co-Investigator(Kenkyū-buntansha)	広瀬正尚鳥羽商船高等専門学校, その他部局等, 准教授 (50824207) 渡邊和英海上保安大学校(海上保安国際研究センター), 海上保安国際研究センター, 准教授 (90811000)
Project Period (FY)	2020-04-01 – 2024-03-31
Keywords	熱交換器 / 低GWP / マイクロチャンネル / 細径 / 排熱回収 / 蒸発 / 凝縮 / 圧力損失
Outline of Final Research Achievements	This research targeted pure and mixture working fluids with low global warming potential (GWP) and the layered-microchannel heat exchangers that can be applied not only to vessels equipment for exhaust heat recovery but also to high efficiency and energy saving of refrigeration and air-conditioning, heating and hot water supply, which account for 60% of consumer-use energy consumption. Using the performance of previous working fluids in various tubes as standard values, the fundamental characteristics of low-GWP working fluids were compared. In addition, the heat transfer performance and flow patterns due to differences in flow channel geometries were visualized in layered-microchannel heat exchangers and the superiority of this heat exchanger was demonstrated through analysis including the results of the joint researchers, and the practical possibility of using exhaust heat sources and the direction of optimization of the flow channel geometries were shown.
Free Research Field	船舶海洋・冷凍空調工学
Academic Significance and Societal Importance of the Research Achievements	IMOで国際海運のカーボンニュートラルが求められ、モントリオール議定書/キガリ改定では温暖化係数(GWP)の小さい作動媒体への転換が動力用、産業・民生機器で求められている。そのためLNG、水素、アンモニア燃料の船舶機関が開発され、これら排ガスは低温腐食がなく、未利用低温域まで排熱回収でき、低温で沸騰する低GWP作動媒体が期待できる。研究で船舶機関の省エネ・スペース化のため積層型マイクロチャンネル熱交換器で低GWP作動媒体の基礎特性を把握して高い伝熱性能、圧力損失を軽減する最適な流路構成・形状の指針は学術・理論的にも重要であり、海運におけるカーボンニュートラル達成に向けて社会的意義も大きい。