2023/09/26 更新

写真a

ジャンネッティ ニコロ
ジャンネッティ ニコロ
所属
附属機関・学校 高等研究所
職名
准教授(任期付)
学位
博士(工学) ( 早稲田大学 )

経歴

  • 2021年04月
    -
    継続中

    早稲田大学   早稲田高等研究所   准教授   准教授(任期付)

  • 2019年04月
    -
    2021年03月

    早稲田大学   高等研究所   講師

  • 2017年04月
    -
    2019年03月

    早稲田大学   機械科学・航空学科   講師

  • 2014年04月
    -
    2017年03月

    早稲田大学   機械科学・航空学科   助手

  • 2013年03月
    -
    2013年08月

    University of Florence   Department of Industrial Engineering   Scholarship holder Researcher

学歴

  • 2013年09月
    -
    2016年03月

    早稲田大学   機械科学・航空学科   博士課程  

  • 2012年10月
    -
    2013年01月

    Association of Professional Engineers of Florence (Italy)   Industrial Engineer (Professional Qualification)  

  • 2010年09月
    -
    2012年10月

    University of Florence (Italy)   Department of Industrial Engineering, Mechanical Engineering   Graduate school of Engineering (Master program)  

  • 2007年09月
    -
    2010年12月

    University of Florence (Italy)   Department of Industrial Engineering, Mechanical Engineering   Undergraduate school of Engineering (Bachelor program)  

  • 2002年02月
    -
    2007年07月

    Niccolo Rodolico high school, Florence (Italy)   Science oriented program  

委員歴

  • 2023年07月
    -
    継続中

    International Standard Organization - ISO  TC 86/SC 6, TESTING AND RATING OF AIR-CONDITIONERS AND HEAT PUMPS, WG 15, Advanced performance standards

  • 2022年10月
    -
    継続中

    International Energy Agency - IEA  Annex 88 - Subtask B2 leader - heat pump testing methodologies

  • 2014年08月
    -
    継続中

    Waseda University, International Institute of Refrigeration  ISHPC Organizing Committee

  • 2019年07月
    -
     

    14th IIR-Gustav Lorentzen Conference on Natural Refrigerants - GL2020  Organizing Committee, Secretary General

所属学協会

  • 2019年09月
    -
    継続中

    日本機械学会

  • 2019年05月
    -
    継続中

    International Institute of Refrigeration (IIR)

  • 2014年01月
    -
    継続中

    公益社団法人日本冷凍空調学会

  • 2013年01月
    -
    継続中

    Association of Professional Engineers of Florence (Italy)

研究分野

  • 制御、システム工学 / 熱工学   熱・物質移動 / 熱工学   熱力学的な最適化 / 熱工学   吸収・吸着 / 流体工学   流体力学 / 熱工学   冷凍空調 / 熱工学   エネルギーストレージ / 熱工学   ターボ機械

研究キーワード

  • ターボ機械

  • エネルギーストレージ

  • 冷凍空調

  • 流体力学

  • 吸収・吸着

  • 熱力学的な最適化

  • 熱・物質移動

▼全件表示

受賞

  • 学術賞

    2023年05月   日本冷凍空調学会   遺伝的冷媒流路生成アルゴリズムを用いた熱交換器の最適化に関する研究  

    受賞者: ジャンネッティ ニコロ

  • 令和3年度 (2021年度年次大会講演)優秀講演賞

    2021年09月   日本冷凍空調学会   流下液膜式吸収器の濡れ性とマランゴニ対流の評価  

    受賞者: ジャンネッティ ニコロ

  • Outstanding contribution in Reviewing

    2018年06月   Elsevier, Applied Energy  

    受賞者: ジャンネッティ ニコロ

  • Outstanding contribution in Reviewing

    2018年02月   Elsevier, International Journal of Refrigeration  

    受賞者: ジャンネッティ ニコロ

  • ISHPC2017, Young Researcher Award

    2017年08月   2017 International Sorption Heat Pump Conference Organizing Committee   Simplified expressions of the transfer coefficients on a partially wet absorber tube  

    受賞者: ジャンネッティ ニコロ

  • 日本冷凍空調学会賞・会長奨励賞

    2016年09月   公益社団法人日本冷凍空調学会   流下液膜式冷媒吸収プロセスの熱流体力学的挙動に関する研究  

    受賞者: ジャンネッティ ニコロ

▼全件表示

 

論文

  • Experimental verification of artificial neural network scalability for performance monitoring of multi-split type air conditioners

    Sholahudin, Niccolo Giannetti, Yoichi Miyaoka, Kiyoshi Saito, Katsuhiko Tanaka, Hiroto Ogami

    Journal of Building Engineering   76   107427 - 107427  2023年10月  [査読有り]

    DOI

    Scopus

  • Circuitry optimization using genetic programming for the advancement of next generation refrigerants

    N. Giannetti, J.C.S. Garcia, C. Kim, Y. Sei, K. Enoki, K. Saito

    International Journal of Heat and Mass Transfer   217   124648 - 124648  2023年08月  [査読有り]

    担当区分:筆頭著者, 責任著者

  • エミュレーター式負荷試験装置によるエアコンディショナーの動的試験

    宮 岡 洋 一, 森 稜 平, ジャンネッティ ニコロ, 鄭 宗 秀, 富 樫 英 介, 齋 藤 潔

    日本冷凍空調学会論文集   22 ( 17 )  2023年02月  [査読有り]

  • Dynamic analysis of single–double-effect absorption chiller with variable thermal conductance during partial-load operation

    Arnas Lubis, Niccolo Giannetti, Muhammad I. Alhamid, Kiyoshi Saito, Hajime Yabase

    Applied Thermal Engineering   218  2023年01月  [査読有り]

     概要を見る

    A numerical model for the dynamic analysis and control of a solar-assisted single–double-effect absorption chiller is presented. The mathematical model relies on energy and mass balances, which consider the heat and mass storage in each component. The resistance ratio method is introduced to capture the variation in the thermal conductance representing system disturbances and load variations according to the internal and external flow rates. The model was validated with reference to the outlet temperatures of hot, cooling, and chilled water from field test data for a given gas flow rate and corresponding inlet temperatures. The agreement between the field test and simulation results demonstrates the reliability of the model. Deviations between simulated and experimental temperatures mostly stays below 0.5 °C. The model was used to establish an effective operating strategy capable of minimizing the primary energy consumption without affecting the stability of the cooling output capacity and to verify the corresponding beneficial effect. The proposed operational approach increases the coefficient of performance by as much as 32 % compared with the previously implemented operation strategy, reaching up to a maximum value of 10.7 at 60 % cooling capacity.

    DOI

    Scopus

  • Development and validation of a variational formulation of Two-Phase flow distribution

    Mark Anthony Redo, Niccolo Giannetti, Hiroaki Yoshimura, Kiyoshi Saito, Manabu Watanabe

    International Journal of Multiphase Flow   155   104190 - 104190  2022年10月  [査読有り]

    担当区分:責任著者

    DOI

    Scopus

  • Emulator-type load-based tests for dynamic performance characterization of air conditioners

    Niccolo Giannetti, Shun Matsui, Ryohei Mori, Jongsoo Jeong, Hifni Mukhtar Ariyadi, Yoichi Miyaoka, Eisuke Togashi, Kiyoshi Saito

    Energy and Buildings   273   112411 - 112411  2022年10月  [査読有り]

    担当区分:筆頭著者, 責任著者

    DOI

    Scopus

    3
    被引用数
    (Scopus)
  • 遺伝的冷媒流路生成アルゴリズムを用いた熱交換器の最適化に関する研究

    ジャンネッティ ニコロ, ガルシア ジョン, カルロ・ヴァレラ, リチャード ジェイソン, 清 雄一, 榎木 光治, 鄭 宗秀, 齋藤 潔

    冷凍空調学会論文集   39 ( 3 ) 223 - 239  2022年09月  [査読有り]

    担当区分:筆頭著者, 責任著者

  • Experimental performance of a three-fluid desiccant contactor using a novel ionic liquid

    Richard Jayson Varela, Niccolo Giannetti, Kiyoshi Saito, Xinming Wang, Hiroshi Nakayama

    Applied Thermal Engineering   210   118343 - 118343  2022年06月  [査読有り]

    DOI

    Scopus

    11
    被引用数
    (Scopus)
  • Multiobjective geometry optimization of microchannel heat exchanger using real-coded genetic algorithm

    John Carlo S. Garcia, Hiroki Tanaka, Niccolo Giannetti, Yuichi Sei, Kiyoshi Saito, Mamoru Houfuku, Ryoichi Takafuji

    Applied Thermal Engineering   202   117821 - 117821  2022年02月  [査読有り]

    DOI

    Scopus

    19
    被引用数
    (Scopus)
  • Performance assessment of an R32 commercial heat pump water heater in different climates

    Muhamad Yulianto, Takaoki Suzuki, Zheng Ge, Takashi Tsuchino, Masakazu Urakawa, Shigeru Taira, Yoichi Miyaoka, Niccolo Giannetti, Liang Li, Kiyoshi Saito

    Sustainable Energy Technologies and Assessments   49   101679 - 101679  2022年02月  [査読有り]

    DOI

    Scopus

    6
    被引用数
    (Scopus)
  • Variational formulation of non-equilibrium void fraction

    Niccolo Giannetti, Moojoong Kim, Hiroaki Yoshimura, Kiyoshi Saito

    International Journal of Heat and Mass Transfer   183   122119 - 122119  2022年02月  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    A general variational formulation of the dissipative two-phase flows based on the extremization of the entropy production is developed. The entropy generation rate is written outside phase equilibrium by introducing interfacial contributions due to surface tension as well as heat and mass transfer between the two phases. Prigogine's theorem of minimum entropy production is used to estimate the steady state void fraction of the two-phase flow. The corresponding flow representation is investigated out of phase equilibrium for an annular flow, experiencing friction, surface tension effects, and interphase heat and mass transfer, within a diabatic channel. It is demonstrated that the present formulation generalises previous theories by capturing the effect of mass and heat fluxes variations, and that the widely accepted expression from Zivi represents a particular case obtained under certain simplifying assumptions. Finally, a first validation of the developed formulation of two-phase void fraction is presented for different flow conditions, heat flux from the external environment, and thermophysical properties of the refrigerant with reference to data obtained from a dedicated experimental apparatus adopting a capacitance sensor and from previous literature. (c) 2021 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • Thermodynamic investigation of asynchronous inverse air cycle integrated with compressed-air energy storage

    Niccolò Giannetti, Adriano Milazzo, Kiyoshi Saito

    Journal of Energy Storage   45   103750 - 103750  2022年01月  [査読有り]

    担当区分:筆頭著者, 責任著者

    DOI

    Scopus

    2
    被引用数
    (Scopus)
  • Intelligent performance prediction of air conditioning systems based on refrigerant temperatures

    Sholahudin, Niccolo Giannetti, Yoichi Miyaoka, Kiyoshi Saito

    Thermal Science and Engineering Progress   27   101150 - 101150  2022年01月  [査読有り]

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • Design of a Numerical Simulator for Finned-Tube Heat Exchangers with Arbitrary Circuitry

    John Carlo S. Garcia, Niccolo Giannetti, Daryl Anne B. Varela, Richard Jayson Varela, Seiichi Yamaguchi, Kiyoshi Saito, Menandro S. Berana

    Heat Transfer Engineering     1 - 19  2021年11月  [査読有り]

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • Variational formulation of stationary two-phase flow distribution

    Niccolo Giannetti, Mark Anthony Redo, Kiyoshi Saito, Hiroaki Yoshimura

    Case Studies in Thermal Engineering   26   101082 - 101082  2021年08月  [査読有り]

    担当区分:筆頭著者, 責任著者

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • Absorption heat transformer - state-of-the-art of industrial applications

    Falk Cudok, Niccolò Giannetti, José L. Corrales Ciganda, Jun Aoyama, P. Babu, Alberto Coronas, Tatsuo Fujii, Naoyuki Inoue, Kiyoshi Saito, Seiichi Yamaguchi, Felix Ziegler

    Renewable and Sustainable Energy Reviews   141   110757 - 110757  2021年05月  [査読有り]

    DOI

    Scopus

    24
    被引用数
    (Scopus)
  • Non-Equilibrium Formulation of Void Fraction in Two-Phase Flows

    Niccolo Giannetti, Moojoong Kim, Hiroaki Yoshimura, Kiyoshi Saito

    6TH IIR CONFERENCE ON THERMOPHYSICAL PROPERTIES AND TRANSFER PROCESSES OF REFRIGERANTS (TPTPR2021)     127 - 134  2021年

     概要を見る

    A general variational formulation of the void fraction in dissipative two-phase flows is developed. In particular, the steady-state void fraction is extracted by the extremization of the entropy generation rate, based on a comprehensive non-equilibrium expression that introduces interfacial contributions due to surface tension between different phases and fluxes due to heat and mass transfer.Such formulation opens up to the possibility of obtaining different theoretical formulas by the direct application of Prigogine's theorom of minimum entropy production and it is investigated in terms of different assumptions for showing the effect of different flow conditions, flow pattern interfacial geometry, entrainment ratio, heat flux from the external environment, and thermophysical properties of the refrigerant. Consequently, the widely-accepted Zivi's expression of void fraction is obtained as a particular case of this general formulation.

    DOI

  • A cost effective and non-intrusive method for performance prediction of air conditioners under fouling and leakage effect

    Sholahudin, Niccolo Giannetti, Seiichi Yamaguchi, Kiyoshi Saito, Katsuhiko Tanaka, Hiroto Ogami

    Sustainable Energy Technologies and Assessments   42   100856 - 100856  2020年12月  [査読有り]

     概要を見る

    Realistic performance predictions are required for efficient operation strategy of air conditioners. In this study, the application of a cost effective and non-intrusive black box model utilizing artificial neural networks (ANN) to predict the cooling capacity of air conditioning systems is investigated, while considering the effect of fouling and leakage that may occur after prolonged operation. The effect of various leakage and fouling combinations on the output cooling capacity were numerically simulated. The training data set is first generated for a system that is ideally operating without any fouling or leakage. The developed ANN model is tested to predict cooling capacity in "faulty" systems. The results indicated that, as long as leakage and fouling are limited below 10% and 4% respectively, the ANN model trained by the data generated with the ideal system, can predict cooling capacity with a relative averaged cooling capacity difference (Delta(Q) over bar (e,rel)) of approximately 13%. Moreover, the inclusion of data with different leakage and fouling combinations in the training set enables accurate predictions of the cooling capacity of the air conditioning system during the entire timespan of its operation. It suggests that cooling capacity under the fouling and leakage phenomena can be predicted using limited input information.

    DOI

    Scopus

    8
    被引用数
    (Scopus)
  • Semitheoretical formulation of annular flow void fraction using the principle of minimum entropy production

    Niccolò Giannetti, Seiichi Yamaguchi, Kiyoshi Saito, Hiroaki Yoshimura

    International Journal of Thermal Sciences   158  2020年12月  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    © 2020 Elsevier Masson SAS The two-phase flow void fraction is a critical parameter for characterising the pressure drop as well as heat and mass transfer capability of the working fluid within thermal systems, the accurate estimation of which drives heat exchanger design and control optimisation. A semitheoretical expression for the void fraction of two-phase flows, also applicable to small-sized channels, is obtained from an analytical study based on the principle of minimum entropy production and the introduction of empirical coefficients to be fitted to experimental data available in the open literature. These coefficients embody the importance of the simplified physical terms of this formulation while recovering the accuracy loss owing to nonlinear phenomena, heat and mass transfer, and three-dimensional effects. By accounting for surface tension, this model generalises previous theories and describes the influence of smaller-sized channels in terms of the stable void fraction. This mathematical framework can be used to summarise data covering different refrigerants, channel diameters, and operating conditions.

    DOI

    Scopus

    6
    被引用数
    (Scopus)
  • Experimental implementation of artificial neural network for cost effective and non-intrusive performance estimation of air conditioning systems

    Sholahudin, Niccolo Giannetti, Seiichi Yamaguchi, Kiyoshi Saito, Yoichi Miyaoka, Katsuhiko Tanaka, Hiroto Ogami

    Applied Thermal Engineering   181   115985 - 115985  2020年11月  [査読有り]

     概要を見る

    Owing to the high variability of operating conditions and the complexity of dynamic phenomena occurring within air conditioning cycles, the realistic performance estimation of these systems remains an open question in this field. This paper demonstrates the applicability of a cost-effective estimation method based on an artificial neural network exclusively using four refrigerant temperatures as the network input. The experimental datasets are collected from a reference experimental facility. The system is operated with variable cooling load, outdoor temperature, and indoor temperature settings, as representative of the actual operation. The artificial neural network structure was optimized by considering the effect of previous time step inputs, number of neurons, sampling time, and number of training data. The results reveal that the developed model can successfully estimate the cooling capacity of an air conditioning system during on-off, continuous unsteady, and steady operation, using four temperature inputs with relative averaged error below 5%.

    DOI

    Scopus

    9
    被引用数
    (Scopus)
  • Prediction of two-phase flow distribution in microchannel heat exchangers using artificial neural network

    Niccolo Giannetti, Mark Anthony Redo, Sholahudin, Jongsoo Jeong, Seiichi Yamaguchi, Kiyoshi Saito, Hyunyoung Kim

    International Journal of Refrigeration   111   53 - 62  2020年03月  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    © 2019 Due to the intrinsic complexity of two-phase flow distribution and the limited mathematical flexibility of conventional formulations of the phenomenon, previous attempts generally fall short in the accuracy and applicability of their prediction. To address these issues, this study focuses on methods with higher mathematical flexibility. Specifically, the construction and training of Artificial Neural Network (ANN) is presented for the identification of this complex phenomenon. The interaction of the numerous physical phenomena, occurring at different scales, is thus represented by the network structure, offering a formulation capable of achieving higher accuracy. Experimental data from a full-scale heat exchanger of an air-conditioning system operating over a wide range of conditions are used to train and test the ANN. The network optimisation with Bayesian regularisation against experimental data leads to a structure featuring 4 inputs, 3 hidden layers, and 3 neurons for each layer, which demonstrates deviations on the single output mostly lower than ± 10% and a correlation index higher than 98%, when the whole data set is used for training the ANN. The analysis of the network optimisation for different shares of data used for the network testing, shows higher training and testing accuracy as the number of training data increases, along with no apparent overfitting.

    DOI

    Scopus

    29
    被引用数
    (Scopus)
  • Formulation of steady-state void fraction through the principle of minimum entropy production

    Niccolo GIANNETTI, Kiyoshi SAITO, Hiroaki YOSHIMURA

    Journal of Thermal Science and Technology   15 ( 3 ) JTST0025 - JTST0025  2020年  [査読有り]

    担当区分:筆頭著者, 責任著者

    DOI

    Scopus

    2
    被引用数
    (Scopus)
  • Film rupture and partial wetting over flat surfaces with variable distributor width

    Niccolo Giannetti, Piyatida Trinuruk, Seiichi Yamaguchi, Kiyoshi Saito

    Science and Technology for the Built Environment   25 ( 10 ) 1313 - 1324  2019年11月  [査読有り]

    担当区分:筆頭著者, 責任著者

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • Optimization of HVAC system energy consumption in a building using artificial neural network and multi-objective genetic algorithm

    ジャンネッティ ニコロ

    Sustainable Energy Technologies and Assessments   35   48 - 57  2019年10月  [査読有り]

  • Simplified expressions of the transfer coefficients on a partially wet absorber tube

    Niccolo Giannetti, Seiichi Yamaguchi, Kiyoshi Saito

    International Journal of Refrigeration   105   135 - 147  2019年09月  [査読有り]

    担当区分:筆頭著者, 責任著者

    DOI

    Scopus

    6
    被引用数
    (Scopus)
  • Seasonal Performance Evaluation of CO2 Open Refrigerated Display Cabinets

    ジャンネッティ ニコロ

    Applied Thermal Engineering   ( 114354 )  2019年09月  [査読有り]

  • Characterization of two-phase flow distribution in microchannel heat exchanger header for air-conditioning system

    ジャンネッティ ニコロ

    Experimental Thermal and Fluid Science   106   183 - 193  2019年09月  [査読有り]

    DOI

    Scopus

    32
    被引用数
    (Scopus)
  • A practical heat and mass transfer model between air and ionic liquid solution in an internally cooled dehumidifier with partial wetting.

    アリヤディ, ヒフニ ムクタル

    Proceedings of the 25th IIR International Congress of Refrigeration: Montréal , Canada, August 24-30, 2019.    2019年08月  [査読有り]

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • Comparative analysis of ionic liquids as sorptive media for absorption cooling systems.

    アリヤディ, ヒフニ ムクタル

    Proceedings of the 25th IIR International Congress of Refrigeration: Montréal , Canada, August 24-30, 2019.    2019年08月  [査読有り]

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • Dynamic modeling of room temperature and thermodynamic efficiency for direct expansion air conditioning systems using Bayesian neural network

    ジャンネッティ ニコロ

    Applied Thermal Engineering   158   113809  2019年07月  [査読有り]

    DOI

    Scopus

    13
    被引用数
    (Scopus)
  • Semi-theoretical model of the wetting characteristics of aqueous ionic liquid on an aluminium finned-tube desiccant contactor

    Niccolo Giannetti, Richard Jayson Varela, Hifni Ariyadi, Seiichi Yamaguchi, Kiyoshi Saito, Xin Ming Wang, Hiroshi Nakayama

    Refrigeration Science and Technology   2019-August   4616 - 4623  2019年  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    © 2019 International Institute of Refrigeration. All rights reserved. A new design of an internally cooled desiccant contactor which uses a new ionic liquid (IL) solution as sorptive medium is targeted. To optimise its operative performance, a semi-theoretical model based on a variational thermodynamic principle is developed to predict the film rupture and wetting ability of the IL solution for different values of the IL mass fraction over a comprehensive range of liquid spray density. The minimum Reynolds number Reb allowing the film-like flow configuration and, below this value, the wetted fraction of the solid substrate are firstly formulated on an analytical basis. Successively, the theoretical formulation is used as a reference to minimise deviations between predicted results and measured data by calibrating dedicated characteristic coefficients. Predicted film rupture, wetting ability and wetting hysteresis behaviour are strongly affected by the IL mass fraction and found in good agreement with the measurements.

    DOI

    Scopus

    2
    被引用数
    (Scopus)
  • Semitheoretical Prediction of the Wetting Characteristics of Aqueous Ionic Liquid Solution on an Aluminum Finned-Tube Desiccant Contactor

    Niccolo Giannetti, Richard Jayson Varela, Hifni Ariyadi, Seiichi Yamaguchi, Kiyoshi Saito, Xin-Ming Wang, Hiroshi Nakayama

    Journal of Fluids Engineering   140 ( 12 )  2018年12月  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    This study involves exploring a new design of an internally cooled/heated desiccant contactor by using a new ionic liquid (IL) solution as the sorptive solution. In order to optimize its operative performance, a semitheoretical model based on the principle of minimum energy is developed to predict the film rupture and wetting ability of the IL solution over a comprehensive range of IL mass fraction and flow rates. A first experimental validation of the fundamental equations of the theoretical model is presented and used as a reference to minimize deviations between predicted results and measured data by calibrating dedicated characteristic coefficients. The noteworthy quantitative and qualitative agreement in the whole range of IL mass fractions and flow rates is promising for contributing to the design of optimized system configurations and control strategies.

    DOI

    Scopus

    12
    被引用数
    (Scopus)
  • Development and validation of an analytical formulation of the Nusselt and Sherwood numbers on a partially wetted absorber tube

    Niccolo Giannetti, Ryosuke Moriwaki, Seiichi Yamaguchi, Kiyoshi Saito

    Science and Technology for the Built Environment   24 ( 8 ) 850 - 860  2018年09月  [査読有り]

    担当区分:筆頭著者, 責任著者

    DOI

    Scopus

    3
    被引用数
    (Scopus)
  • Numerical simulation of Marangoni convection within absorptive aqueous Li-Br

    Niccolo Giannetti, Seiichi Yamaguchi, Kiyoshi Saito

    International Journal of Refrigeration   92   176  2018年08月  [査読有り]

    担当区分:筆頭著者, 責任著者

    DOI

    Scopus

    7
    被引用数
    (Scopus)
  • Operation performance enhancement of single-double-effect absorption chiller

    Arnas Lubis, Jongsoo Jeong, Niccolo Giannetti, Seiichi Yamaguchi, Kiyoshi Saito, Hajime Yabase, Muhammad I. Alhamid, Nasruddin

    Applied Energy   219   299 - 311  2018年06月  [査読有り]

     概要を見る

    Absorption chillers constitute a valuable option for utilising solar energy. Specifically, when installed in tropical regions, this technology ideally matches the needs for refrigeration and air-conditioning because of the abundance of solar energy throughout the year. A single-double-effect absorption chiller combines the single and double-effect configurations to compensate for the unpredictable instantaneous availability of solar radiation and cooling load fluctuations. The operative performance of this system is strongly affected by internal parameters such as the absorber outlet solution flow rate and the solution distribution ratio, which connect the operability of the single and double-effect configurations. Therefore, these important parameters are currently used to maximise system performance while assuring its stability. This study discusses how the COP of a single-double-effect absorption chiller, for solar cooling applications in tropical areas, can be maximised (1.55 at full load, and up to 2.42 at 60% partial load) by manipulating those internal parameters. The simulation results were compared with the experimental data (field test data) and, by adopting the appropriate control method, showed an improvement of the system performance between 12 and 60% when compared to a corresponding double-effect configuration.

    DOI

    Scopus

    38
    被引用数
    (Scopus)
  • General correlations for the heat and mass transfer coefficients in an air-solution contactor of a liquid desiccant system and an experimental case application

    Richard Jayson Varela, Seiichi Yamaguchi, Niccolo Giannetti, Kiyoshi Saito, Masatoshi Harada, Hikoo Miyauchi

    International Journal of Heat and Mass Transfer   120   851 - 860  2018年05月  [査読有り]

     概要を見る

    This paper presents general types of correlation for the heat and mass transfer coefficients inside an air-solution contactor as expressions of Reynolds-Prandtl numbers and Reynolds-Schmidt numbers, respectively. These general equations summarize the physical and thermophysical properties of the air, the solution, and the contactor, which make them capable to be used for parametric studies provided they are fitted in a wide range of experimental data that include all the properties involved. In this work, a liquid desiccant system with an adiabatic structured packed bed as contactor and an aqueous lithium chloride as solution was constructed. The experimental data taken at various air superficial velocities and solution flow rates were fitted to the general correlations, and comparisons between the predicted and experimental results for both coefficients are within ±10%, for both dehumidification and regeneration processes. In addition, the calculated values of the outlet air humidity ratio and temperature agree well with the experimental data for both processes. The particular equations for the heat and mass transfer coefficients can be used to perform parametric studies at different air superficial velocities and solution flow rates with very good accuracy. Results from this study can help improve the system design and operation methods of air-solution contactors.

    DOI

    Scopus

    20
    被引用数
    (Scopus)
  • Heat and mass transfer coefficients of falling-film absorption on a partially wetted horizontal tube

    Niccolò Giannetti, Andrea Rocchetti, Seiichi Yamaguchi, Kiyoshi Saito

    International Journal of Thermal Sciences   126   56 - 66  2018年04月  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    Detailed, reliable, and time-saving methods to predict the transfer characteristics of horizontal-tube falling-film absorbers are critical to control system operability, such that it is closer to its technical limitations, and to optimise increasingly complex configurations. In this context, analytical approaches continue to hold their fundamental importance. This study presents an analytical solution of the governing transport equations of film absorption around a partially wetted tube. A film stability criterion and a wettability model extend the validity range of the resulting solution and increase its accuracy. Temperature and mass fraction fields are analytically expressed as functions of Prandtl, Schmidt, and Reynolds numbers as well as tube dimensionless diameter and wetting ratio of the exchange surface. Inlet conditions are arbitrary. The Lewis number and a dimensionless heat of absorption affect the characteristic equation and the corresponding eigenvalues. Consequently, local and average transfer coefficients are estimated and discussed with reference to the main geometrical and operative parameters. Finally, a first comparison with the numerical solution of the problem and experimental data from previous literature is presented to support the simplifying assumptions, which are introduced and as a first model validation.

    DOI

    Scopus

    32
    被引用数
    (Scopus)
  • 18
    被引用数
    (Scopus)
  • Experimental investigation of the wetting characteristics of an aqueous ionic liquid solution on an aluminum fin-tube substrate

    Richard Jayson Varela, Niccolò Giannetti, Seiichi Yamaguchi, Kiyoshi Saito, Xin-Ming Wang, Hiroshi Nakayama

    International Journal of Refrigeration   88   472 - 482  2018年04月  [査読有り]

     概要を見る

    In falling film liquid desiccant systems, finding a suitable pair of liquid desiccant and contact surface is of primary engineering interest. This requires knowledge on the wetting characteristics of the liquid on the solid substrate, which consequently requires intensive experimental investigation. In this study, the wetting characteristics of a new ionic liquid aqueous solution in an aluminum fin-tube substrate were experimentally investigated. Then, a simple method for estimating the wetted area on the substrate through image processing was developed. Visual analysis of the surface wetting was also conducted, and three types of wetting patterns are discussed. Experimental results on the static contact angle and contact angle hysteresis suggest that the ionic liquid solution is mostly wetting, and the aluminum surface is slightly to moderately rough. It was found that the wettability of the ionic liquid solution increases as the ionic liquid mass fraction increases. The wetting hysteresis phenomenon and the factors contributing to its occurrence were also clarified. The results from this study would be useful for the development of a new model or improvement of existing wetting models, which can help improve the prediction and control of the heat and mass transfer performance in internally cooled/heated fin-tube contactors.

    DOI

    Scopus

    18
    被引用数
    (Scopus)
  • Thermodynamic analysis of irreversible desiccant systems

    Giannetti N, Yamaguchi S, Rocchetti A, Saito K

    Entropy   20 ( 8 )  2018年  [査読有り]

    担当区分:筆頭著者, 責任著者

    DOI

    Scopus

    4
    被引用数
    (Scopus)
  • Performance evaluation method of heat pump driven refrigerated display cabinets

    Keisuke Ohno, Mark Anthony Redo, Niccolo Giannetti, Seiichi Yamaguchi, Kiyoshi Saito

    Refrigeration Science and Technology   2018-   294 - 301  2018年  [査読有り]

     概要を見る

    Annual heat load, energy consumption and COP of open refrigerated display cabinets (ORDC) driven by heat pump in supermarkets are assessed by means of a dedicated performance evaluation method. The system modelling approach is firstly presented, and subsequently fitted to experimental data measured within actual equipment working in a comprehensive range of operative conditions. The obtained characteristic equations for estimating the heat load of the ORDC and energy consumption of the condensing unit are employed for a first screening of the results with reference to the effect of the display cabinet set temperature, refrigerant evaporating temperature and supermarket room temperature. Seasonal temperature distributions of three representative locations are applied for the performance calculation of a selected arrangement of 5 different models of ORDCs in a store. This methodology is integrated in a dedicated software, with a user friendly interface, which is generally capable of predicting the annual performance of various combinations of different ORDCs and can therefore be used for benchmarking and identifying energy conservation opportunities.

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • Annular flow stability within small-sized channels

    Niccolo Giannetti, Daisuke Kunita, Seiichi Yamaguchi, Kiyoshi Saito

    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER   116   1153 - 1162  2018年01月  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    An analytical study based on a variational thermodynamic principle is presented to evaluate the influence of surface tension on the stability of annular flow within small-sized channels. The model introduces phenomenological assumptions in the interfacial structure of the flow regime and theoretically draws the equilibrium transition line from an annular regime to the initiation of the partial wetting condition on the inner surface. By including surface tension, this model expands previous theories and identifies the stable flow configuration in terms of void fraction and interfacial extension. The significant influence of a higher surface tension and smaller diameter (i.e. lower Weber number) are responsible for a lower stable void fraction and higher slip ratio. A complete screening of the main influential parameters is conducted to explore the descriptive ability of the model. This analysis aims at contributing to the understanding of the stability of two-phase flow regimes and can be extended to the transition between other neighbouring regimes, including wall friction as well as liquid entrainment phenomena. (C) 2017 Elsevier Ltd. All rights reserved.

    DOI

  • GRE 論文集

    Ariyadi Hifni Mukhtar, Giannetti Niccolò, Yamaguchi Seiichi, Saito Kiyoshi

    グランド再生可能エネルギー国際会議論文集   1 ( 0 )  2018年

     概要を見る

    Due to their unique characteristics, recently ionic liquids have been proposed as a novel absorbent for absorption systems to eliminate the drawbacks of conventional water/LiBr working fluids, particularly crystallization and corrosion. Studies on the cycle performance of absorption cooling systems using water/ionic liquid working pairs have been published in many literatures. However, specific studies on the absorption characteristics of these new working pairs still remains open. Present study theoretically analyses the absorption characteristics of water vapor by aqueous ionic liquid solutions in a vertical tube falling film absorber. The model is developed by employing three ordinary differential equations describing the absorption process and is validated. The results are analyzed and the performances of water/ionic liquid are compared with those of conventional water/LiBr working fluid.

    CiNii

  • Cascade refrigeration system with inverse Brayton cycle on the cold side

    Niccolo Giannetti, Adriano Milazzo, Andrea Rocchetti, Kiyoshi Saito

    APPLIED THERMAL ENGINEERING   127   986 - 995  2017年12月  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    temperature refrigeration of cold stores poses some specific issues: single stage, vapour compression cycles have modest COP at low evaporation temperature; cold evaporator surfaces require de-frosting and a fan for air circulation; a part of the refrigeration load may be delivered at intermediate temperature levels, e.g. for the cold store loading dock. Cascade system may improve the COP and add flexibility on the temperature levels and working fluids, but the problems related to the cold evaporator surface remain unsolved.
    The refrigeration system presented herein features a cascade configuration combining a vapour compression cycle and an inverse Brayton cycle. Both cycles use "natural" fluids, complying with strictest regulations. The top cycle uses Ammonia in order to increase efficiency, while the bottom cycle uses air, which directly circulates in the cold space and hence eliminates the cold heat exchanger. A detailed thermodynamic analysis allows a complete screening of the relevant design parameters for an overall system optimization.
    The results show that, notwithstanding the intrinsic gap of efficiency suffered by the Brayton cycle, the proposed system features an acceptable global performance and widens the implementation field of this technology. This system configuration shows a COP 50% higher than the corresponding simple Brayton cycle at temperatures of the refrigerated storage of -50 degrees C. (C) 2017 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    20
    被引用数
    (Scopus)
  • Experimental performance of a double-lift absorption heat transformer for manufacturing-process steam generation

    Arnas Lubis, Niccolo Giannetti, Seiichi Yamaguchi, Kiyoshi Saito, Naoyuki Inoue

    ENERGY CONVERSION AND MANAGEMENT   148   267 - 278  2017年09月  [査読有り]

     概要を見る

    As widely known, some industrial processes produce a large amount of waste heat while others require a large amount of steam to heat the process flow. The main difference involves the temperature level of these heat quantities. Absorption heat transformers play a strategic role in waste heat recovery and heat supply to manufacturing processes due to their ability to utilize heat at a certain temperature level and release the enthalpy of mixing of the refrigerant at a different temperature level with a negligible amount of mechanical work input. However, given the lack of examples that find application as operative plants, the feasibility of the technology is questioned in academic and technical domains. In this study, the operability of a double-lift absorption heat transformer that generates pressurized steam at 170 degrees C is studied across a full range of operative conditions. The results demonstrate and clarify the manner in which the system can operate steadily and efficiently when driven by hot water temperature at approximately 80 degrees C while safely generating steam at a temperature exceeding 170 degrees C. The conditions yielding maximum system efficiency and capacity are identified, and the obtained experimental results are used to define an optimal control strategy. (C) 2017 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    23
    被引用数
    (Scopus)
  • Analytical solution of film mass-transfer on a partially wetted absorber tube

    Niccolo Giannetti, Andrea Rocchetti, Seiichi Yamaguchi, Kiyoshi Saito

    INTERNATIONAL JOURNAL OF THERMAL SCIENCES   118   176 - 186  2017年08月  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    This work presents a two-dimensional analytical solution of the governing differential equation for falling film vapour-absorption around a plain horizontal tube. The solution of the species transport equation gives the LiBr mass fraction distribution within the liquid absorptive film flowing along the tube surface and can be used to characterize the mass transfer performance of falling film absorbers or generators. By means of the inclusion of partial wetting effects at reduced solution mass flowrates, this study obtains an analytical expression of the mass transfer coefficient of these devices applicable over an extended range of operative conditions. The hypotheses of small penetration for physical absorption and constant heat flux condition are applied at the film interface to reach a closed-form solution. Fourier method is used to solve the problem and the eigenvalues obtained from the characteristic equation depend on Lewis number, Biot number and the dimensionless heat of absorption. Given the boundary condition at the wall, the two-dimensional mass fraction field of the laminar film can be expressed analytically as a function of Schmidt, Reynolds numbers, the tube dimensionless diameter and the ratio of the wetted area to the total exchange surface. Finally, mass transfer coefficient and absorbed mass flux are locally and globally investigated as functions of the influent dimensionless groups to clarify their effects on the physical process and screen the potentiality of the model. Results show notable qualitative and quantitative agreement with previous numerical solutions and experimental results from previous literature. This model constitutes a widely applicable and time-saving tool for actual system simulations, design and control. (C) 2017 Elsevier Masson SAS. All rights reserved.

    DOI

    Scopus

    15
    被引用数
    (Scopus)
  • マイクロチャンネル垂直ヘッダーにおけるR410Aの二相流分配特性

    レド マーク, ジャンネッティ ニコロ, 鄭 宗秀, 榎木 光治, 太田 育秀, 齋藤 潔, 金 鉉永

    環境工学総合シンポジウム講演論文集   2017.27   427  2017年

    DOI CiNii

  • EXPERIMENT AND VISUALIZATION OF R410A FLOW DISTRIBUTION WITHIN THE VERTICAL HEADER OF MICROCHANNEL HEAT EXCHANGER

    Mark Anthony Redo, Niccolo Giannetti, Jongsoo Jeong, Koji Enoki, Ikuhide Ota, Kiyoshi Saito, Hyunyoung Kim

    5TH IIR INTERNATIONAL CONFERENCE ON THERMOPHYSICAL PROPERTIES AND TRANSFER PROCESSES OF REFRIGERANTS (TPTPR)     236 - 243  2017年

     概要を見る

    This paper reports an initial step to obtain an equally distributed fluid flow in an evaporator heat exchanger and eventually increase its performance. Experiments are carried out for R410A, using a vertical header where 20 horizontal parallel flat tubes are connected and the protrusion depth is half of the header width. The flow enters the header from a bottom inlet port and there is no heat load applied on the flat tubes. Inlet vapor quality before the header is varied for a fixed total mass flow rate of 60 kg/h. For each set of conditions, the mass flow rate and quality at different vertical positions of the header are singularly measured. Visualization data and experimental results have shown that 0.6 vapor quality before the header produces a more even distribution having a more homogeneous two-phase flow compared to 0.2 where phases are distinctly separated yielding dryouts on the top channels.

    DOI

  • EXPERIMENT AND VISUALIZATION OF R410A FLOW DISTRIBUTION WITHIN THE VERTICAL HEADER OF MICROCHANNEL HEAT EXCHANGER

    Mark Anthony Redo, Niccolo Giannetti, Jongsoo Jeong, Koji Enoki, Ikuhide Ota, Kiyoshi Saito, Hyunyoung Kim

    5TH IIR INTERNATIONAL CONFERENCE ON THERMOPHYSICAL PROPERTIES AND TRANSFER PROCESSES OF REFRIGERANTS (TPTPR)     891 - 898  2017年

     概要を見る

    This paper reports an initial step to obtain an equally distributed fluid flow in an evaporator heat exchanger and eventually increase its performance. Experiments are carried out for R410A, using a vertical header where 20 horizontal parallel flat tubes are connected and the protrusion depth is half of the header width. The flow enters the header from a bottom inlet port and there is no heat load applied on the flat tubes. Inlet vapor quality before the header is varied for a fixed total mass flow rate of 60 kg/h. For each set of conditions, the mass flow rate and quality at different vertical positions of the header are singularly measured. Visualization data and experimental results have shown that 0.6 vapor quality before the header produces a more even distribution having a more homogeneous two-phase flow compared to 0.2 where phases are distinctly separated yielding dryouts on the top channels.

  • Solar-assisted single-double-effect absorption chiller for use in Asian tropical climates

    Arnas Lubis, Jongsoo Jeong, Kiyoshi Saito, Niccolo Giannetti, Hajime Yabase, Muhammad Idrus Alhamid, Nasruddin

    RENEWABLE ENERGY   99   825 - 835  2016年12月  [査読有り]

     概要を見る

    Solar energy is accessible throughout the year in tropical regions. The latest development of absorption chillers has demonstrated that these systems are suitable for effective use of solar energy. The utilisation of solar energy for heat-driven cooling systems has significant advantages. Without a doubt, solar energy represents a clean energy source that is available without any additional fuel cost, and that can be proportionally accessible when the cooling load increases during the middle hours of the day. This study focuses on a single-double-effect absorption chiller machine that was installed in Indonesia. The system is driven by a dual-heat source that combines gas and solar energy. This system is characterised by simulating its performance in various conditions in terms of the cooling water (28-34 degrees C) and the hot water (75-90 degrees C) inlet temperatures. The reference operating condition of this system is 239 kW of cooling capacity. The mathematical model is validated and shows a good agreement with experimental data. In the operative range considered, simulation results yield a coefficient of performance between 1.4 and 3.3, and a gas reduction ratio from 7 to 58% when compared to a double-effect absorption chiller driven by gas. Based on the simulation results, this system is expected to have a good potential for widespread use in tropical Asia regions. (C) 2016 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    57
    被引用数
    (Scopus)
  • Wetting behavior of a liquid film on an internally-cooled desiccant contactor

    Niccolo Giannetti, Seiichi Yamaguchi, Kiyoshi Saito

    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER   101   958 - 969  2016年10月  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    Heat and mass transfer processes performed by using thin liquid films are recurrent in a series of technical applications. The circumstances under which dry spots appear on the exchange surface for the film breakage, as well as the extent of the wetted part of the surface and the liquid vapor interface, are critical to predict and control the performances of these devices. To characterize the wetting behavior of liquid films on internally-cooled desiccant contactors, this paper originates from an experimental study and, adopting a standpoint useful for a practical interpretation of wettability measurements, introduces a corresponding theoretical model based on the principle of minimum energy. Both the estimation of the wetted area by image processing of the test section and the theoretical model highlight a hysteresis phenomenon of the film wetting behavior for gradually increasing and decreasing liquid flowrates. The modeling approach, experimental results and a first comparison are hereby presented and discussed. Quantitative and qualitative agreement appears promising for a further employment of the model in actual system design and control. (C) 2016 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    24
    被引用数
    (Scopus)
  • Optimization of a cascade refrigeration system using refrigerant C3H8 in high temperature circuits (HTC) and a mixture of C2H6/CO2 in low temperature circuits (LTC)

    Nasruddin, S. Sholahudin, N. Giannetti, Arnas

    APPLIED THERMAL ENGINEERING   104   96 - 103  2016年07月  [査読有り]

     概要を見る

    This paper discusses the multi-objectives optimization of a cascade refrigeration system using refrigerant C3H8 in high temperature circuits (HTC) and a mixture of C2H6/CO2 in low temperature circuits (LTC). The evaporator temperature, condenser temperature, C2H6/CO2 mixture condensation temperature, cascade temperature differences, and the CO2 mass fraction are chosen as the decision variables. Whereas cooling capacity, cold space temperature, and ambient temperature are taken as the constraints. The purpose of this research is to design a cascade refrigeration system whose optimum performance are defined in terms of economics and thermodynamics. Accordingly, there are two objective functions that should be simultaneously optimized including the total annual cost which consists of the capital and operational cost and the total exergy destruction of the system. To this aim, the optimum operating temperature of the system and CO2 fraction should be determined so that the system has minimum exergy destruction and annual cost. Results show that, the optimum value of the decision variables for this system can be determined by trade-off between annual cost and exergy destruction. (C) 2016 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    54
    被引用数
    (Scopus)
  • Thermodynamic optimization of three-thermal irreversible systems

    Niccolo Giannetti, Andrea Rocchetti, Kiyoshi Saito

    International Journal of Heat and Technology   34   S83 - S90  2016年01月  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    Multi-temperature-level systems enlarge the prospects and degrees of freedom for an effective design and an environment-friendly use of energy. Based on a general thermodynamic model of three-thermal cycles and finite thermal capacity of the heat sources, this paper aims at the analysis and the performance optimization of these systems by considering the influence of irreversibility. Suitable dimensionless parameters for an overall optimization are introduced and their influence on the cycle efficiency is investigated. This approach identifies the limitations imposed to the physical processes by accounting for the inevitable dissipation due to their constrained duration and intensity, and constitutes a general thermodynamic criterion for the optimization of three-thermal irreversible systems. Dependence on the main factors is highlighted in a way that shows how to change them in order to improve the overall efficiency. Under this point of view, the analysis evaluates COP improvements and can be used to perform plant diagnostics, besides predicting the system performance. The use of this criterion is exemplified for the absorption chiller application case.

    DOI

    Scopus

    14
    被引用数
    (Scopus)
  • Entropy parameters for falling film absorber optimization

    Niccolo Giannetti, Andrea Rocchetti, Arnas Lubis, Kiyoshi Saito, Seiichi Yamaguchi

    APPLIED THERMAL ENGINEERING   93   750 - 762  2016年01月  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    A local entropy generation analysis, for water vapor absorption in LiBr-H2O solution, is performed referring to velocity, temperature and concentration fields obtained from the numerical solution of mass and energy transport equations. The hydrodynamic description is based on Nusselt boundary layer assumption and the actual amount of irreversibility introduced is determined for an absorptive falling film over a cooled horizontal tube inside the absorber. Results are explored in different operative conditions in order to examine the impact of the various irreversibility sources in a wide operative range. A least irreversible solution mass flow-rate can always be identified. Furthermore, a simple and general thermodynamic analysis, carried out regarding a refrigerating and a heat boosting applications, makes evidence of a dimensionless group "Q/sigma T" that separates the weight of the irreversibilities and gives the way to an optimization criterion applied to the absorber in order to improve the whole system efficiency. Both thermodynamic equilibrium and sub-cooling conditions of the solution at the inlet are considered for typical temperature and concentration of refrigerators' absorbers and heat transformers' absorbers. Results suggest the importance to work at reduced mass flow-rates with a thin uniform film. In practice, tension-active additives are required to realize this condition. Also, it is highlighted that the two parameters defined with reference to the dimensionless group "Q/sigma T" can be maximized by specific values of the tube radius, operative Reynolds number, solution sub-cooling and temperature difference between the wall and the inlet solution. (C) 2015 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    16
    被引用数
    (Scopus)
  • Analytical description of falling film absorption

    Giannetti N, Rocchetti A, Saito K, Yamaguchi S

    ACRA 2016 - 8th Asian Conference on Refrigeration and Air-Conditioning    2016年  [査読有り]

    担当区分:筆頭著者, 責任著者

  • Irreversibility analysis of falling film absorption over a cooled horizontal tube

    Niccolo Giannetti, Andrea Rocchetti, Kiyoshi Saito, Seiichi Yamaguchi

    INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER   88   755 - 765  2015年09月  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    Based on a numerical study of the water vapour absorption process in LiBr-H2O solution, for a laminar, gravity driven, viscous, incompressible liquid film, flowing over a horizontal cooled tube, irreversibilities related to fluid friction, heat transfer, mass transfer and their coupling effects have been locally and globally examined. The hydrodynamic description is based on Nusselt boundary layer assumptions. The tangential and normal velocity components, respectively obtained from momentum and continuity equations, have been used for the numerical solution of mass and energy transport equations in the two-dimensional domain defined by the film thickness and the position along the tube surface. Local entropy generation calculation can be performed referring to the calculated velocity, temperature and concentration fields. Results have been explored in different operative conditions, in order to examine comprehensively the impact of the various irreversibility sources and to identify the least irreversible solution mass flow-rate for the absorber. As a parallel, a refined understanding of the absorption process can be obtained. Considering absorption at the film interface and cooling effect at the tube wall, the analysis thermodynamically characterises the absorption process which occurs inside actual falling film heat exchangers and establishes a criterion for their thermodynamic optimisation. Results suggest the importance to operate at reduced mass flow rates with a thin uniform film. Meanwhile, tension-active additives are required to realise this condition. (C) 2015 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    14
    被引用数
    (Scopus)
  • Thermodynamic Analysis of Irreversible Heat-transformers

    Niccolo Giannetti, Arnas, Andrea Rocchetti, Kiyoshi Saito

    MAKARA JOURNAL OF TECHNOLOGY   19 ( 2 ) 90 - 96  2015年08月  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    Absorption heat transformers extend the possibilities for efficient and environment-friendly energy conversion processes. Based on a general thermodynamic model of three-thermal cycles with finite thermal capacity of the heat sources, this paper is intent upon analyzing and optimizing the performance of absorption heat transformers, by including the influence of irreversibility in the analytical expression of the system efficiency. Dimensionless parameters for an overall optimization are defined and a first screening is performed to clarify their influence. Dependence on the main factors is highlighted to suggest how to change them in order to enhance the whole system performance. Under this point of view, the analysis evaluates coefficient of performance (COP) improvements and can be used to perform existing plant diagnostics, besides predicting the system performance. The use of this criterion is exemplified for specific heat transformers data from literature. This approach identifies the limitations imposed to the physical processes by accounting for the inevitable dissipation due to their constrained duration and intensity, and constitutes a general thermodynamic criterion for the optimization of three-thermal irreversible systems.

    DOI

  • Local entropy generation analysis of water vapour absorption in a LiBr-H2O solution film, over a horizontal cooled tube

    Niccolò Giannetti, Andrea Rocchetti, Kiyoshi Saito, Seiichi Yamaguchi

    Refrigeration Science and Technology     786 - 793  2015年  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    This study is based on a numerical analysis of water vapour absorption in a laminar, gravity driven, viscous, incompressible liquid film of LiBr-H2O solution, flowing over a horizontal cooled tube. The hydrodynamic description is based on Nusselt boundary layer assumptions. A local entropy generation calculation can be performed referring to velocity, temperature and concentration fields. From a general form of volumetric entropy generation, a suitable expression for the absorption process has been obtained and different irreversibility sources have been highlighted. The impact of each term (fluid friction, heat transfer, mass transfer and their coupling effects) has been locally examined. Results have been explored for different tube radii, wall temperatures and operative conditions (representing both chiller and heat transformer configurations), in order to characterise the process from a second law point of view and establish a criterion for the optimisation of the absorber.

    DOI

    Scopus

  • Cascade refrigeration system with inverse Brayton cycle on the cold side

    Niccolò Giannetti, Adriano Milazzo, Andrea Rocchetti

    Refrigeration Science and Technology     2846 - 2853  2015年  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    The cold store refrigeration system proposed herein features a cascade configuration which has a vapour compression cycle as the top cycle and an inverse Brayton as the bottom cycle. The cold store air is used as working fluid in the Brayton cycle. Therefore, the cold side heat exchanger (that would be the evaporator in a vapour compression cycle) is replaced by a cold air inlet. Frost formation inside the cold store, as well as the heat load due to the air circulation fan, are hence eliminated. On the other hand, the Brayton cycle has lower efficiency when compared to vapour compression cycles. This gap may be reduced once the temperature range is lowered by the cascade configuration. The top vapour compression cycle may also refrigerate the loading dock. This paper describes a first screening of the relevant design parameters for an overall system optimization.

    DOI

    Scopus

  • Entropy parameters for desiccant wheel design

    Niccolo Giannetti, Andrea Rocchetti, Kiyoshi Saito, Seiichi Yamaguchi

    APPLIED THERMAL ENGINEERING   75   826 - 838  2015年01月  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    In this work a thermodynamic analysis of a desiccant wheel is proposed to investigate and identify the optimum size and operating regime of this device. A steady state entropy generation expression, based on effectiveness parameters suitable for desiccant wheels operability, is obtained applying a control volume approach and assuming perfect gas behaviour of the binary air-vapour mixture. A new entropy generation number N-L, is defined using a minimum indicative value of the entropy generation S-L,S-min and investigated in order to obtain useful criteria for desiccant wheels optimization. The effectiveness-NTU design method is employed by combining solution of thermal exchange efficiency for rotary heat exchanger with the characteristic potential method, under the conditions of heat and mass transfer analogy. The analysis is applied to a specific desiccant wheel and N-L, variation with NTU is explored under various operative conditions and wheels characteristics in terms of dimensionless velocity and flow unbalance ratio. (C) 2014 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    14
    被引用数
    (Scopus)
  • Thermodynamic analysis of regenerated air-cycle refrigeration in high and low pressure configuration

    N. Giannetti, A. Milazzo

    INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID   40   97 - 110  2014年04月  [査読有り]

    担当区分:筆頭著者, 責任著者

     概要を見る

    A thermodynamic analysis is performed on open, regenerated, inverse air-cycles, focussing on low temperature refrigeration, in order to provide general optimization criteria, support for a rational configuration choice and potential performance improvement for this specific application. The effect of high regenerator effectiveness (0.95) is explored, showing that it may double the air cycle COP in the case at hand. Low and high pressure configurations (i.e. featuring only one heat exchanger on the cold or hot cycle side) are compared. High pressure configuration, normally preferred in the field of low temperature refrigeration, has a lower efficiency, but the gap reduces as regenerator effectiveness increases. Avoidance of a cold heat exchanger eliminates frosting problems and power input for the circulation fan, so that the small COP decrease suffered by the high pressure cycle can easily be compensated for and eventually yield higher average plant efficiency. The feasibility of such a highly effective regenerator, already reported in the literature, is demonstrated using classic Kays and London (1964) data. (C) 2013 Elsevier Ltd and IIR. All rights reserved.

    DOI

    Scopus

    25
    被引用数
    (Scopus)

▼全件表示

講演・口頭発表等

  • New characteristics and temperature limitations of surfactant-induced Marangoni convection

    ジャンネッティニコロ

    26TH INTERNATIONAL CONGRESS OF REFRIGERATION  

    発表年月: 2023年08月

  • Evolutionary optimization of heat exchanger circuitries for the advancement of next-generation refrigerants

    ジャンネッティニコロ

    26TH INTERNATIONAL CONGRESS OF REFRIGERATION  

    発表年月: 2023年08月

  • Emulator-type load-based testing methodology for air-to-air heat pumps

    ジャンネッティニコロ  [招待有り]

    発表年月: 2023年07月

  • A Variational Framework for the Theoretical Modelling of Thermal Systems

    ジャンネッティ ニコロ  [招待有り]

    ミニワークショップ「非線形現象の応用数理~モデリング,解析と計算」  

    発表年月: 2023年03月

  • Genetic refrigerant path-algorithm ~ Evolutionary optimization of heat exchanger circuitries for the advancement of next generation refrigerants

    ジャンネッティ ニコロ  [招待有り]

    「サーモインフォマティクス研究会」第 5 回研究会  

    発表年月: 2023年03月

  • Optimization of refrigerant circuitry within finned-tube heat exchangers using thermo-genetic path-algorithm

    ジャンネッティ ニコロ

    日本冷凍空調学会年次大会  

    発表年月: 2022年09月

  • Development of an Emulator-Based Assessment Method for Representative Evaluation of the Dynamic Performance of Air Conditioners

    Niccolo Giannetti

    International Refrigeration and Air Conditioning Conference  

    発表年月: 2022年07月

  • Development of a Standardized Refrigerant Evaluation Tool for Air Conditioning and Refrigeration Equipment Using a General-Purpose Energy-Analysis Simulator

    Niccolo Giannetti

    International Refrigeration and Air Conditioning Conference  

    発表年月: 2022年07月

  • Variational Framework for the Theoretical Modelling of Thermal Systems

     [招待有り]

    WOI(早稲田オープン・イノベーション・フォーラム)  

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    2021年度日本冷凍空調学会年次大会  

    発表年月: 2021年09月

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  • 低GWP 冷媒を採用した次世代冷凍空調技術の実用化評価に関する研究開発 第6報:2020年度のシミュレーター開発の取り組みと成果

    2021年度日本冷凍空調学会年次大会  

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  • リキッドデシカント調湿空調システムの高効率化

    2021年度日本冷凍空調学会年次大会  

    発表年月: 2021年09月

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  • 流下液膜式吸収器の濡れ性とマランゴニ対流の評価

    2021年度日本冷凍空調学会年次大会  

    発表年月: 2021年09月

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  • 低GWP 冷媒を採用した次世代冷凍空調技術の実用化評価に関する研究開発 第5報:ハイブリッド型性能評価装置の開発に関する取り組みと成果

    2021年度日本冷凍空調学会年次大会  

    発表年月: 2021年09月

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    2021年09月
     
     
  • 低GWP 冷媒を採用した次世代冷凍空調技術の実用化評価に関する研究開発 第4報:熱交換器の最適化に関する2020年度の取り組みと成果

    2021年度日本冷凍空調学会年次大会  

    発表年月: 2021年09月

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  • Numerically Trained Artificial Neural Network for Experimental Performance Prediction of Air Conditioning Systems

    Sholahudin, Giannetti N, Miyaoka Y, Jeong J, Saito K

    2021 60th Annual Conference of the Society of Instrument and Control Engineers of Japan, SICE 2021  

    発表年月: 2021年09月

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    2021年09月
     
     
  • Digital Cloning of Air-Conditioners: Scalable and generalizable system identification method using Artificial Neural Network

     [招待有り]

    日本機械学会環境工学部門 「サーモインフォマティクス研究会」第 2 回研究会  

    発表年月: 2021年09月

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    2021年09月
     
     
  • Non-Equilibrium Formulation of Void Fraction in Two-Phase Flows

    Niccolo GIANNETTI, Moojoong KIM, Hiroaki YOSHIMURA, Kiyoshi SAITO

    Thermophysical properties and Transfer Processes of Refrigerants Conference 2021  

    発表年月: 2021年09月

    開催年月:
    2021年09月
     
     
  • CFD investigation of the wetting characteristics of aqueous ionic liquid solution on an aluminum fin-tube substrate

    Richard Jayson VARELA, Hifni ARIYADI, Niccolo GIANNETTI, Kiyoshi SAITO

    Thermophysical properties and Transfer Processes of Refrigerants Conference 2021  

    発表年月: 2021年09月

    開催年月:
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  • Modeling of Flow Distribution in Multi-Branch Channels using the Second Law of Thermodynamics

    Mark Anthony REDO, Niccolo GIANNETTI, Hiroaki YOSHIMURA, Kiyoshi SAITO

    Thermophysical properties and Transfer Processes of Refrigerants Conference 2021  

    発表年月: 2021年09月

    開催年月:
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  • Design optimization of three-fluid desiccant contactor using genetic algorithm

    Hosho Tatsuki, Varela Richard Jayson, Giannetti Niccolo, Jeong Jongsoo, Miyaoka Yoichi, Saito Kiyoshi

    ISHPC2021  

    発表年月: 2021年08月

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  • The Influence of Temperature on Marangoni Convection during Vapor Absorption

    Giannetti Niccolo, Fukui Ryota, Fleßner Christian, Meyer Thomas, Saito Kiyoshi

    ISHPC2021  

    発表年月: 2021年08月

    開催年月:
    2021年08月
     
     
  • Scalability and generalization in HVAC performance prediction using Artificial Neural Network

    第31回 環境工学総合シンポジウム2021  

    発表年月: 2021年07月

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    2021年07月
     
     
  • Assessment of surfactant-induced Marangoni convection within high-temperature aqueous Lithium-Bromide solution

    N. Giannetti

    The 14th IIR Gustav Lorentzen Conference on Natural refrigerants  

    発表年月: 2020年12月

    開催年月:
    2020年12月
     
     
  • Numerical Investigation of CO2 Heat Pump Water Heater Performance

    M. Yulianto, N. Giannetti, co-auth

    The 14th IIR Gustav Lorentzen Conference on Natural refrigerants  

    開催年月:
    2020年12月
     
     
  • Experimental performance analysis and simulation of an internally cooled liquid desiccant air conditioning system using a novel ionic liquid

    R.J. Varela, N. Giannetti (co-author)

    The 14th IIR Gustav Lorentzen Conference on Natural refrigerants  

    開催年月:
    2020年12月
     
     
  • Thermodynamic investigation of asynchronous open inverse air cycle integrated with compressed air energy storage

    A. Milazzo, N. Giannetti, K. Saito

    The 14th IIR Gustav Lorentzen Conference on Natural refrigerants  

    開催年月:
    2020年12月
     
     
  • Semi-Theoretical Formulation of Annular Flow Void-Fraction

    Niccolo Giannetti

    The 11th International Meeting on Advances in Thermofluids  

    発表年月: 2019年11月

    開催年月:
    2019年11月
     
     
  • Numerical investigation of mixed refrigerants flow in the expansion valve

    ジャンネッティ ニコロ

    JSRAE Annual Conference  

    発表年月: 2019年09月

  • Development of Assessment Techniques for Next Generation Refrigerant with Low GWP Values

    ジャンネッティ ニコロ

    JSRAE Annual Conference  

    発表年月: 2019年09月

  • Semi-theoretical model of ionic liquid wetting characteristics on a gas-liquid finned-tube contactor

    ジャンネッティ ニコロ

    25th IIR International Congress of Refrigeration  

    発表年月: 2019年08月

  • A practical heat and mass transfer model between air and ionic liquid solution in an internally cooled dehumidifier with partial wetting

    ジャンネッティ ニコロ

    25th IIR International Congress of Refrigeration  

    発表年月: 2019年08月

  • Comparative analysis of ionic liquids as sorptive media for absorption cooling systems

    ジャンネッティ ニコロ

    25th IIIR International Congress of Refrigeration  

    発表年月: 2019年08月

  • Development of Finned-Tube Heat Exchanger Simulator for Heat Pumps

    ジャンネッティ ニコロ

    International Workshop on Environmental Engineering  

    発表年月: 2019年06月

  • Theoretical Formulation of Two-phase Flow Distribution in Microchannel Heat Exchangers using Electric Circuit Analogy

    ジャンネッティ ニコロ

    International Workshop on Environmental Engineering  

    発表年月: 2019年06月

  • Numerical Simulation of Falling-Film Absorbers at High Temperature

    ジャンネッティ ニコロ

    International Workshop on Environmental Engineering  

    発表年月: 2019年06月

  • Numerical simulations of finned-tube heat exchangers with arbitrary connectivity and flexible set of input conditions

    The 5th International Symposium on Innovative Materials and Processes in Energy Systems  

    開催年月:
    2018年10月
     
     
  • フィンチューブ型気液接触器におけるイオン液体水溶液の濡れ性の理論的検討

    ジャンネッティ ニコロ

    年度日本冷凍空調学会 年次大会  

    発表年月: 2018年09月

  • Annual performance evaluation of CO2 refrigerated display cabinets relative to geographical location

    ジャンネッティ ニコロ

    年度日本冷凍空調学会 年次大会  

    発表年月: 2018年09月

  • Influence of the Fluid Distribution Width on the Wettability of Rivulet Flow over Vertical Flat Surfaces

    ジャンネッティ ニコロ

    17th International Refrigeration and Air Conditioning Conference at Purdue  

    発表年月: 2018年07月

  • Film Rupture and Partial Wetting over Flat Surfaces

    ジャンネッティ ニコロ

    17th International Refrigeration and Air Conditioning Conference at Purdue  

    発表年月: 2018年07月

  • Modelling of water vapor absorption by aqueous ionic liquid fluids in a vertical-tube falling film absorber

    ジャンネッティ ニコロ

    Grand Renewable Energy 2018  

    発表年月: 2018年06月

  • MULTISTAGE TYPE-II ABSORPTION HEAT PUMP FOR STEAM GENERATION UP TO 180°C; Development and Performance Demonstration

    ジャンネッティ ニコロ  [招待有り]

    9th Asian Conference on Refrigeration and Air Conditioning  

    発表年月: 2018年06月

  • Thermodynamic analysis of irreversible desiccant systems

    ジャンネッティ ニコロ

    Entropy 2018: From Physics to Information Sciences and Geometry  

    発表年月: 2018年05月

  • Performance evaluation method of heat pump driven refrigerated display cabinets

    ジャンネッティ ニコロ

    5th IIR Conference on Sustainability and the Cold Chain  

    発表年月: 2018年04月

  • Thermodynamic modelling of Two-Phase Flow within Heat Pump systems

    ジャンネッティ ニコロ  [招待有り]

    International Workshop on The Multi-phase Flow  

    発表年月: 2017年12月

  • Two-phase Flow Distribution at Wider Flow Range within the Vertical Header of Microchannel Heat Exchanger

    ジャンネッティ ニコロ

    年度日本冷凍空調学会 年次大会  

    発表年月: 2017年09月

  • Annual Performance Evaluation of Refrigerated Display Cabinets

    ジャンネッティ ニコロ

    年度日本冷凍空調学会 年次大会  

    発表年月: 2017年09月

  • 流下液膜式吸収器の熱・物物質移動係数に関する解析的検討

    ジャンネッティ ニコロ

    年度日本冷凍空調学会 年次大会  

    発表年月: 2017年09月

  • フィンチューブ接触器における流下液膜の濡れ性の解明

    ジャンネッティ ニコロ

    年度日本冷凍空調学会 年次大会  

    発表年月: 2017年09月

  • Numerical simulation of Marangoni convection within horizontal tube falling film absorbers

    ジャンネッティ ニコロ

    28th International Symposium on Transport Phenomena  

    発表年月: 2017年09月

  • Numerical simulation of Marangoni convection within absorptive aqueous Li-Br

    ジャンネッティ ニコロ

    International Sorption Heat Pump Conference  

    発表年月: 2017年08月

  • Simplified expressions of the transfer coefficients on a partially wet absorber tube

    ジャンネッティ ニコロ

    International Sorption Heat Pump Conference  

    発表年月: 2017年08月

  • Correlations for the Heat and Mass Transfer Coefficients in a Structured Packed Bed Regenerator

    ジャンネッティ ニコロ

    International Sorption Heat Pump Conference  

    発表年月: 2017年08月

  • Two-phase flow distribution of R410A within the vertical header of a microchannel heat exchanger

    ジャンネッティ ニコロ

    第 27 回 環境工学総合シンポジウム  

    発表年月: 2017年07月

  • Thermodynamic modelling of humid-air expansion within an R717/R729 cascade refrigeration system for cold store applications

    ジャンネッティ ニコロ

    5th IIR International Conference on Thermophysical Properties and Transfer Processes of Refrigerants  

    発表年月: 2017年04月

  • Experiment and Visualization of R410A Flow Distribution within the Vertical Header of Microchannel Heat Exchanger

    ジャンネッティ ニコロ

    5th IIR Int. Conference on Thermodynamics and Transport Processes  

    発表年月: 2017年04月

  • Derivation and Validation of Dimensionless Models for the Heat and Mass Transfer Coefficients of a Structured Packed Bed Dehumidifier

    ジャンネッティ ニコロ

    2nd International Conference on Energy and Indoor Environment for Hot Climates  

    発表年月: 2017年02月

  • Effect of internal and external wetting on the global transfer coefficients inside high temperature absorbers

    ジャンネッティ ニコロ

    27th International Symposium on Transport Phenomena  

    発表年月: 2016年09月

  • Marangoni convection within absorptive falling films over an inclined wall, Modelling and numerical simulations

    ジャンネッティ ニコロ

    年度日本冷凍空調学会 年次大会  

    発表年月: 2016年09月

  • 流下液膜式吸収器における吸収現象に関する実験研究

    ジャンネッティ ニコロ

    年度日本冷凍空調学会 年次大会  

    発表年月: 2016年09月

  • Analytical description of falling film absorption

    ジャンネッティ ニコロ

    8th Asian Conference on Refrigeration and Air Conditioning  

    発表年月: 2016年05月

  • Energy-based criterion for annular two-phase flow stability in mini- and micro-channels

    ジャンネッティ ニコロ

    第50回空気調和・冷凍連合講演会  

    発表年月: 2016年04月

  • Energy-based model for the prediction of mini-channels dry-out condition

    ジャンネッティ ニコロ

    9th International Conference on Multiphase Flow  

    発表年月: 2016年04月

  • 吸収器の水平管流下膜構成における熱と物質移動係数の解析式

    ジャンネッティ ニコロ

    年度日本冷凍空調学会 年次大会  

    発表年月: 2015年10月

  • Analytical study of falling film absorption on a partially wetted horizontal tube

    ジャンネッティ ニコロ

    26th International Symposium on Transport Phenomena  

    発表年月: 2015年10月

  • Local entropy generation analysis of water vapour absorption in a LiBr-H2O solution film, over a horizontal cooled tube

    ジャンネッティ ニコロ

    24th IIR International Congress of Refrigeration  

    発表年月: 2015年08月

  • Cascade refrigeration system with inverse Bryton cycle on the cold side

    ジャンネッティ ニコロ

    24th IIR International Congress of Refrigeration  

    発表年月: 2015年08月

  • Thermodynamic optimization of three-thermal irreversible systems

    ジャンネッティ ニコロ

    Constructal Law & Second Law Conference  

    発表年月: 2015年05月

  • A new model for partial wetting of inclined surfaces

    ジャンネッティ ニコロ

    第49回空気調和・冷凍連合講演会  

    発表年月: 2015年04月

  • 濡れ性を考慮した水平流下液膜式熱交換器の熱物質移動特性

    ジャンネッティ ニコロ

    年度日本冷凍空調学会 年次大会  

    発表年月: 2014年09月

  • Semi-theoretical wettability model for falling film heat exchangers

    ジャンネッティ ニコロ

    第48回空気調和・冷凍連合講演会  

    発表年月: 2014年04月

  • Hysteresis phenomena of annular flow dryout within small-size channels, Development of a thermodynamic model

    ジャンネッティ ニコロ

    年度日本冷凍空調学会 年次大会  

▼全件表示

共同研究・競争的資金等の研究課題

  • JST・ラグランジュ・ディラック力学の展開とその応用

    科学技術振興機構 

    研究期間:

    2019年04月
    -
    2024年03月
     

  • 省エネ化・低温室効果を達成できる次世代冷凍空調技術の最適化及び評価手法の開発/低GWP冷媒を採用した次世代冷凍空調技術の実用化評価に関する研究開発

    国立研究開発法人新エネルギー産業技術総合開発機構 

    研究期間:

    2018年04月
    -
    2023年03月
     

  • 2段ターボ冷凍機の非定常解析に関する研究

    三菱重工サーマルシステムズ株式会社 

    研究期間:

    2021年04月
    -
    2022年03月
     

  • 機械学習によるビル用マルチエアコンの能力推定手法の研究

    東京電力ホールディングス株式会社 

    研究期間:

    2020年04月
    -
    2022年03月
     

  • Collaborative research on solar cooling absorption technologies in sub-tropical countries

    研究期間:

    2021年04月
    -
     
     

    アルナス、 ジャンネッティ ニコロ

  • 未利用熱エネルギーの革新的活用技術研究開発/未利用熱エネルギーの革新的活用技術研究開発

    国立研究開発法人新エネルギー産業技術総合開発機構 

    研究期間:

    2015年04月
    -
    2021年03月
     

  • Analysis of inverse air cycle refrigeration systems for low temperature applications with particular regard to the problem of frost formation

    Research grant service, biomedical and technological center of the University of Florence  Post-graduate research grant, Call for proposal no. 185 of December 17th, 2012

    研究期間:

    2013年03月
    -
    2013年08月
     

    ジャンネッティ ニコロ

  • Study on Marangoni convection within high temperature absorbers for heat transformer applications

    早稲田大学  2017B-122特定課題B; 2017年度特定課題研究助成費

    ジャンネッティ ニコロ

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Misc

▼全件表示

 

現在担当している科目

▼全件表示

担当経験のある科目(授業)

  • ダイナミクス B

    早稲田大学  

    2020年04月
    -
    継続中
     

  • ダイナミクス A

    早稲田大学  

    2020年04月
    -
    継続中
     

  • 熱力学 B

    早稲田大学  

    2019年09月
    -
    継続中
     

  • 熱力学 A

    早稲田大学  

    2019年09月
    -
    継続中
     

  • Heat Transfer (伝熱工学)

    School of Fundamental Science and Engineering  

  • Control Engineering (制御工学)

    School of Fundamental Science and Engineering  

  • Dynamics of Engineering Systems 1 (工学系の解析設計演習)

    School of Fundamental Science and Engineering  

  • IPSE Science and Engineering Laboratory 2A (Applied physics)

    School of Fundamental Science and Engineering  

  • IPSE Science and Engineering Laboratory 1B (Applied physics)

    School of Fundamental Science and Engineering  

▼全件表示

 

他学部・他研究科等兼任情報

  • 理工学術院   基幹理工学部

特定課題制度(学内資金)

  • New characteristics and temperature limitations of surfactant-induced Marangoni convection

    2022年  

     概要を見る

    Starting from the prototype constructedthe previous year and the preliminary results gathered, numerical simulations havebeen conducted to investigate the research hypothesis of weaker Marangoniconvection at higher absorption temperatures and the existence of a possible temperaturelimitation where the phenomenon is not observable. Additionally, the design andassembling of an advanced test section where an extended temperature range canbe tested and real time absorption rate can be measured from high precision initialtemperature and concentration conditions while performing direct visualobservations of the interfacial turbulence as well as the internal velocityfield using UV-light-irradiated fluorescent uranine and Particle ImageVelocimetry measurements, respectively. The numerical model is referred fordynamic simulation published in the journal Applied thermal Engineering [1] andnumerical results are summarized in a conference paper [2] to be presented inAugust 2023 at the 26TH INTERNATIONAL CONGRESS OF REFRIGERATION, in Paris (France).These results confirm the research hypothesis and were used for guiding thedesign of the testing equipment that is presently being assembled by showingthat, contrarily to common absorption, higher solution temperatures yield areduction of the absorption rate of approximately 33% as the temperatureincreases from 30°C to 80°C. Following experimental measurements of theabsorbed mass and numerical simulations will be performed to support, argue andquantify the suggested conclusions. Finally, the physical understanding gainedin this study will be used to guide the design and control of absorption heatpumps (heat amplifiers and heat transformers).

  • New characteristics and temperature limitations of surfactant-induced Marangoni convection

    2022年  

     概要を見る

    Apartfrom a relation with surface tension gradients, the knowledge of Marangoniconvection remains incomplete, especially in the operative range ofhigh-temperature absorption cycles. Preliminary surface tension measurementshave shown weaker surface tension gradients at higher temperatures.Consistently, this research demonstrates that the intensity of Marangoni convectionweakens in the temperature range of absorption heat transformers and heatamplifiers, and suggests that, owing to the higher surfactant solubility athigher solution temperature, a temperature-limitation of the phenomenon may be identified.A dedicated experimental equipment was constructedto test this research hypothesis. Tests are conducted to induce, quantify, andvisualize Marangoni convection in a temperature- and pressure-controlledenvironment. Fluorescent uranine and measurements of the absorption rate areused, respectively, to clarify the intensity of the phenomenon qualitativelyand quantitatively in a range of solution temperatures between 30°C and 80°C. Initialtemperature and mass fraction of the Lithium-Bromide solution are generatedwith a thermal bath and a pressure-controlled vapor environment, respectively.Subsequently, absorption is initiated by releasing vapour at higher pressurethan equilibrium. Finally, the intensity of Marangoni convection is measured bycomparing average absorption mass flux from tests without surfactants toresults obtained at corresponding conditions with 80 ppm of 1-Octanol.

  • The Influence of Temperature on Marangoni Convection during Vapor Absorption

    2021年   Thomas Meyer, Kiyoshi Saito

     概要を見る

    A dedicated experimental facility was designedfor reproducing and visualizing Marangoni convection in a wide range ofsolution temperatures representative of the operative conditions of differentabsorption systems. Experimental measurements of the absorbed vapour mass were conducted with and without surfactant additives, which trigger Marangoni convection. A methodology was devised for ensuringcoherence in the mass fraction condition of the solution while generating differentsolution temperatures. Parallel visualization of the phenomenon withfluorescent uranine and UV lights enabled the observation of the intensity ofthe interfacial turbulence and thickness variations due to Marangoni convection.The study has newly demonstrated and quantified the research hypothesis thatthe intensity of Marangoni convection weakens at higher operative temperatureand suggest the existence of a temperature limitation where the interfacialturbulence does not occur. Correspondingly, a 2-dimensional numerical modelable to reproduce the characteristics of the phenomenon in the same range wasconstructed and validated. These finding are critical for the scientificclarification of Marangoni convection phenomenon and for its technicalapplication within absorption thermal systems. The developed model may accordingly guide the design of these systems for taking maximum advantage from this phenomenon.

  • Modelling thermal engineering processes with variational principle of non equilibrium thermodynamics

    2020年  

     概要を見る

    A generalizable understanding of the fundamental transportphenomena occurring within thermal systems is necessary to keep up with theirfast-paced technological progress, which is evolving towards advancedconfigurations and new working substances. Accordingly, this research targetsthe generalized modeling of interfacial multiphase processes for thermalsystems optimization and control through an interdisciplinary effort clusteringengineering experiments, artificial intelligence AI, and physical modeling. Research outcomes resulted into general formulations ofinterfacial multiphase processes (surface wetting, flow pattern transition,void fraction arrangement of two-phase flows, and two-phase flow separation) atsteady-state within the theory of nonequilibrium thermodynamics while providingcorresponding experimental validations. The above-mentioned formulation is thenused as the basis for a variational representation which extends the classicalLagrangian formulation in mechanics to nonequilibrium thermodynamic systemsincluding irreversible processes.The theoretical framework consequently obtained is combinedto corrective coefficients from computational fluid dynamics and experimentaldata to achieve phenomenon representations with higher accuracy. The use of machine learning tools is then guided by thegained theoretical understanding of the process to select the essentialtraining parameters for generalizing the applicability of such tool, whiletaking advantage of the powerful ability of AI to reconstruct complexintercorrelations between input and output quantities.

  • Interdisciplinary Theory of Interfacial Multiphase Processes for Advanced Modelling and Control of Engineering Thermal Systems

    2019年  

     概要を見る

    The first outcomes of this research project cover the application of variational principle for the mathematical formulations ofengineering phenomena recurrent in thermal systems, development of semi-theoretical phenomena combining the above-said mathematical formulations with collected experimental data, in parallel to the investigation of Artificial Intelligence approach for device optimisation procedures . Specifically, the Principleof minimum energy and Prigogine’s Theorem of minimum entropy generation have been applied tofalling-film wetting and two-phase refrigerant distribution in microchannelheat exchangers, respectively, along with the construction of a Lagrangian formulation able to include time evolution and unify different variational approaches.  A simplified formulation through Taylor series approximation was implemented as the mathematical framework for modelling open refrigerated display cabinets in combination with the representation given by collected experimental data. Other semi-theoretical models were obtained for desiccant wetting and two-phase flow void fraction. Genetic Algorithm has beenimplemented for circuitry optimisation in finned-tube heat exchangers andsystem-scale optimal operation. 

  • Study on Marangoni convection within high temperature absorbers for heat transformer applications

    2017年  

     概要を見る

    Absorption heat pumps and low exergy heat recovery have been named as keytechnologies for contributing to the solution of energy provision problems andrelated environmental issues. In order to achieve a better understanding and predictive models for thephenomena occurring in high temperature absorption heat transformers thisproject focus on Marangoni convection and high temperature absorption phenomenaas critical aspects yet to be clarified.To achieve this goal, experimental investigations at high temperatureoperability and direct visualization of falling film absorbers have beencarried out as terms of comparison for refining and validate the developednumerical models. Preliminary results have been summarized into papers,presented to domestic and international conferences and submitted tointernational journals.Finally, the equipment for the fundamental characterization and PIVmeasurement of Marangoni convection in a nearly-bi-dimensional space wasdesigned, constructed and instrumented for investigating the driving force ofthis phenomenon, the most suitable surfactant characteristics and theabsorption performance enhancement with respect to pure aqueous Lithium-Bromidemixtures.

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