2018 Fiscal Year Final Research Report

Development of absorption refrigeration cycle with separable ionic liquids utilizing low grade heat sources

Research Project

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Project/Area Number	16H04643
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Research Field	Energy engineering
Research Institution	Tokyo University of Agriculture and Technology
Principal Investigator	Akisawa Atsushi 東京農工大学, 工学(系)研究科(研究院), 教授 (10272634)
Co-Investigator(Kenkyū-buntansha)	大野弘幸東京農工大学, 工学(系)研究科(研究院), 学長 (00176968) 中山政行東京農工大学, その他の研究科, 特任助教 (30772868)
Project Period (FY)	2016-04-01 – 2019-03-31
Keywords	吸収冷凍機 / イオン液体 / 逆浸透膜 / 疎水性多孔質膜 / 排熱利用
Outline of Final Research Achievements	This study investigated a new absorption refrigeration cycle using separable ionic liquid and CaCl2 solution as the working fluids. The refrigerant of water is absorbed into the solution and compressed up to very high pressure so that the water passes through a reverse osmosis membrane. The water is then mixed with the ionic liquid solution. When it is heated to 60 degC, the water is finally separated from the solution. Cycle simulation was employed to estimate the behavior of the cycle and the required pumping power. It was found that there would be optimal flow rate of the ionic liquid solution to maximize the cooling power, and the COP would be approximately 0.5. The cycle was expanded to use a hollow fiber membrane in stead of reverse osmosis one in order to eliminate the drawback of the high pressure compression process of the cycle.
Free Research Field	熱駆動ヒートポンプサイクル
Academic Significance and Societal Importance of the Research Achievements	地球温暖化問題への対応が求められている一方，空調用の冷熱需要は増加傾向にある．省エネルギー的に冷熱を発生するために比較的低温の排熱を活用できる冷凍機が有効である．本研究は60℃程度の環境温度に近い排熱を用いて空調用冷熱を製造する吸収冷凍機を提案した．その特徴は60℃程度に加熱されると水と分離するイオン液体を使用することにある．従来の吸収冷凍機はこの温度域では動作しない．一方で，提案したサイクルは高圧に加圧する逆浸透プロセスを含む点に課題がある．そこで，吸収溶液からイオン液体水溶液に水を移行させる際に疎水性多孔質膜を用いるサイクルに拡張し，サイクルとして成立することを示した．