Journal of Japan Society of Energy and Resources
Online ISSN : 2433-0531
ISSN-L : 2433-0531
Volume 34, Issue 4
Displaying 1-4 of 4 articles from this issue
Research Paper
  • Sho Kono, Atsushi Akisawa, Yuki Ueda
    Article type: Research Paper
    2013 Volume 34 Issue 4 Pages 1-9
    Published: 2013
    Released on J-STAGE: March 13, 2019
    JOURNAL FREE ACCESS
    When Fuel Cells(FC) are installed to households, the performance of FC depends on electricity and heat consumption which results from the behavior of the households. This paper aims at investigating optimal electric-apparatus management to be matched optimal operation of FC. Two kinds of energy saving actions are considered. One is time rearrangement of electric apparatus use, and the other is replacement of conventional apparatus with more efficient one. A mathematical model in which apparatus selection and FC operation were simultaneously considered was developed to evaluate the optimal management. This model represents those behaviors with the minimization of total cost. The results show that the case of shifting the operation of the apparatus appropriately improves energy saving by 1% than the case simply installing FC. Moreover, it was found that the energy saving is possible to increase by 4-5% without additional cost when the optimal time management and the replacement are implemented.
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  • Hiroshi Shibukawa, Shuji Himeno, Toshiya Komatsu
    Article type: Research Paper
    2013 Volume 34 Issue 4 Pages 10-17
    Published: 2013
    Released on J-STAGE: March 13, 2019
    JOURNAL FREE ACCESS
    This study focuses on the evaluation of energy balance and greenhouse gas (GHG) balance on mesophilic anaerobic co-digestion of sewage sludge and rice straw between co-generation of electricity system and production of methane gas system. The boundary for this evaluation was assumed from rice collection to final disposal of sewage sludge. As the result of evaluation, 132Nm3 of methane gas was obtained from 1Mg of rice straw. It was also found that the smallest energy consumption and the largest reduction of GHG emission were given by co-generation of electricity system including the co-digestion with sewage sludge and rice straw. Although the waste heat from the co-digestion could contribute to heat solubilizing and digesting reactor, it could not be used for drying dewatering sludge cake. Besides, the production of solid fuel from sewage sludge cake was essential for the anaerobic co-digestion system because it improved the energy and GHG balance.
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  • Norihiro Kose, Tsuguhiko Nakagawa
    Article type: Research Paper
    2013 Volume 34 Issue 4 Pages 18-26
    Published: 2013
    Released on J-STAGE: March 13, 2019
    JOURNAL FREE ACCESS
    Recently, carbon dioxide (CO2) emission is a worldwide concern. In order to introduce and expand the use of natural energy, “SMART GRID” which manages the energy balance in the specific region has been proposed.
    In this study, focusing on the integrate system with photovoltaic power generation (PV) and electric vehicle (EV), we have studied the CO2 reduction and economics. In this system, PV is constructed in the company and EV can be charged there by PV power. Moreover, EV can supply the electricity from EV’s battery to the home.
    As a result, we found that the integrate system can reduce the CO2 emission of a house by 30%. Also, we compared this system with “The current energy system” and “The energy system which is introduced PV and EV under the Feed-in Tariff”. The results showed that the integrate system with PV and EV can resolve the matters of the CO2 reduction, economics and power system load.
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  • Ryuichi Mori, Yohji Uchiyama, Keiichi Okajima
    Article type: Research Paper
    2013 Volume 34 Issue 4 Pages 27-33
    Published: 2013
    Released on J-STAGE: March 13, 2019
    JOURNAL FREE ACCESS
    We proposed two types of the hybrid coal integrated gasification combined cycle (IGCC) systems utilizing biomass fuel; the diluted type with a biomass combustion boiler and the gasification one with biomass gasification. Both systems have a superior feature to capture CO2 gas by low auxiliary load. These hybrid systems have also unique characteristics to make the function of electricity storage possible because most of liquid oxygen is able to be produced during nighttime and is uniformly supplied to a combustion turbine. We developed a new method to evaluate the corresponding thermal efficiency contributed by biomass by means of exergy concept. The net generating efficiency and corresponding efficiency contributed by biomass of the diluted type were estimated to be 37.5 % and 43.3 %, higher than 33.3 % and 35.0 % of the gasification one. The CO2 capture costs of the hybrid plants were lower than that of IGCC/CO2 capture power plant with the chemical absorption process of CO2 capture. It was found that the electricity storage function to produce the liquid oxygen during nighttime contributes to improve the electric power generating cost in the hybrid systems.
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