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154 results on '"Maeda, Tetsuhiko"'

9. Thermal management and power saving operations for improved energy efficiency within a renewable hydrogen energy system utilizing metal hydride hydrogen storage

Author

Kiyotaka Goshome, Naruki Endo, Maeda Tetsuhiko, Tsuyoshi Nozu, Eisuke Shimoda, and Yuta Segawa

Subjects
Materials science, Hydrogen, Renewable Energy, Sustainability and the Environment, business.industry, Hydride, Nuclear engineering, Photovoltaic system, Energy Engineering and Power Technology, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, 0104 chemical sciences, Renewable energy, Hydrogen storage, Fuel Technology, chemistry, Hydrogen fuel, 0210 nano-technology, business, Hydrogen production, Efficient energy use
Abstract

To ensure the energy efficiency of renewable hydrogen energy systems, power conservation and thermal management are necessary. This study applies these principals to the operation of metal hydride tanks (MHTs) in a bench-scale hydrogen system, named Hydro Q-BiC™, comprising photovoltaic panels (20 kW), an electrolyzer (5 Nm3/h), MHTs containing a TiFe-based MH (40 Nm3), fuel cells (FC; 3.5 kW(power)/2.5 kW(heat)), and Li-ion batteries (20 kW/20 kWh). Here, we show that in a modified hydrogen production operation, with limited use of auxiliaries for cooling the MHTs, the power consumption of the MHTs was reduced by more than 99% compared to a typical operation. The thermal requirements for the MHTs were reduced by ceasing production in a pressurized state. During the hydrogen use operation, the power consumption was reduced to 1/4 and the FC heat output could be fully used; hence, the overall energy efficiency (power-to-hydrogen-to-power/heat) was as high as ~ 60% (43% for the typical operation).

Published
2021
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12. Evaluation of a BCC alloy as metal hydride compressor via 100 MPa-class high-pressure hydrogen apparatus

Author

Naruki Endo, Kiyotaka Goshome, and Maeda Tetsuhiko

Subjects
Materials science, Hydrogen, Hydride compressor, Alloy, Analytical chemistry, Energy Engineering and Power Technology, chemistry.chemical_element, 02 engineering and technology, engineering.material, 010402 general chemistry, 01 natural sciences, Metal, High pressure hydrogen, Renewable Energy, Sustainability and the Environment, Hydride, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, Fuel Technology, chemistry, High pressure, visual_art, visual_art.visual_art_medium, engineering, 0210 nano-technology, Gas compressor
Abstract

In the study presented here, an apparatus that correctly measured pressure–composition isotherms (PCi) at high pressures (up to 100 MPa) and temperatures (up to 200 °C) was developed. The PCi characteristics of a vanadium–titanium–chromium alloy at high pressure and temperature were examined with the apparatus to develop a metal hydride (MH) compressor. It was revealed that it is possible to use a 40 V 20Ti 40Cr (at%) alloy with a heat source below 200 °C for hydrogen compression in the approximate range of 2.1–30.0 MPa. The compressed content reached approximately 1.8 wt%, which is almost the same as the reversible hydrogen capacity at 20 °C.

Published
2019
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13. Characterization of mechanical strength and hydrogen permeability of a PdCu alloy film prepared by one-step electroplating for hydrogen separation and membrane reactors

Author

Naruki Endo, Maeda Tetsuhiko, Yaegashi Satoshi, Furukawa Yoshitomo, Kiyotaka Goshome, and Kin-ichi Mashiko

Subjects
Materials science, Hydrogen, Renewable Energy, Sustainability and the Environment, Scanning electron microscope, Alloy, Energy Engineering and Power Technology, chemistry.chemical_element, One-Step, 02 engineering and technology, Electron microprobe, engineering.material, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, 0104 chemical sciences, Fuel Technology, chemistry, Permeability (electromagnetism), Electrode, engineering, Composite material, 0210 nano-technology, Electroplating
Abstract

A single phase, dense PdCu alloy film was prepared by one-step electroplating. The electroplated film was easily delaminated from the SUS electrode by cutting around the edge, and the single alloy film was thus collectable. The phase structure, surface morphologies, and alloy compositions were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). The plated film before and after hydrogen permeation tests consisted of a single face-centered cubic α phase and an ordered body-centered cubic β phase, respectively. The atomic ratios of Pd and Cu were 49 and 51 at%, respectively; the Pd and Cu contents were slightly higher and lower than Pd47Cu53, which shows the highest hydrogen permeability among Pd-Cu systems. The as-plated film exhibited high mechanical strength, and its load force at break point and displacement were 3 and 1.7 times those of the as-rolled Pd47Cu53 films. The hydrogen permeability of the plated film with the β phase was almost the same as that of the rolled film and the values reported in literature.

Published
2019
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15. Operational strategies of networked fuel cells in residential homes

Author

Aki, Hirohisa, Yamamoto, Shigeo, Ishikawa, Yoshiro, Kondoh, Junji, Maeda, Tetsuhiko, Yamaguchi, Hiroshi, Murata, Akinobu, and Ishii, Itaru

Subjects
Fuel cells -- Usage, Dwellings -- Energy use, Housing -- Energy use, Business, Electronics, Electronics and electrical industries
Abstract

Residential fuel cells (FCs) have been recently launched in the commercial markets in Japan. The introduction of FCs in residential homes has become a realistic option. We previously proposed energy networks that enabled the interconnection of homes via electricity, heat, and hydrogen networks in order to allow consumers to interchange energy. Further, we have developed a PC-based simulator and an experimental system to evaluate the proposed energy networks. In this paper, analyses on the strategies of the electricity dispatch of FCs and their load sharing in the interconnected homes equipped with the energy networks were performed. The analyses were conducted with the experimental system, PC-based simulator, and a newly constructed mathematical model that optimizes the operation of the FCs with the minimization of both annual energy cost and C[O.sub.2] emission. The basic characteristics of FC stacks were obtained by experimentations, and these were stored in the PC-based simulator. Four different operational strategies were carried out for four FC stacks, and these strategies were compared. It was concluded from the results that the operational strategies, which have different advantages with regard to efficiency in electricity generation and heat recovery, should be applied depending on the seasonal demand variations. Index Terms--Energy network, fuel cell (FC), hydrogen, operational strategies.

Published
2006

24. Experimentalstudy on porouscurrentcollectors of PEMelectrolyzers

Author

Ito, Hiroshi, Maeda, Tetsuhiko, Nakano, Akihiro, Hwang, Chul Min, Ishida, Masayoshi, Kato, Atsushi, and Yoshida, Tetsuya

Abstract

Experimentalstudy on proton exchange membrane (PEM) electrolyzer was carried out focusing on the effect of pore structural properties of currentcollectors, such as porosity and pore diameter. Various titanium (Ti)-felt substrates with different porosities and pore diameters (measured by capillary flow porometry) were used as the anode currentcollector. Results show that when the mean pore diameter of the currentcollector was larger than 10 μm, the electrolysis performance improved with decreasing pore diameter. In contrast, changes in porosity had no significant effect on the cell performance when the porosity exceeded 0.50. The flow pattern of two-phase flow in the flow channel was discussed in terms of its relationship to bubble size and to pore diameter of the currentcollector. Finally, correlation between the calculated membrane resistance and the measured pore diameter of the currentcollectors suggest that larger bubbles generated from larger pores tend to become long bubbles in the channel, thus hindering the water supply to the membrane.

Published
2012

25. Influence of properties of gas diffusion layers on the performance of polymer electrolyte-based unitized reversible fuel cells

Author

Hwang, Chul Min, Ishida, Masayoshi, Ito, Hiroshi, Maeda, Tetsuhiko, Nakano, Akihiro, Hasegawa, Yasuo, Yokoi, Naoto, Kato, Atsushi, and Yoshida, Tetsuya

Abstract

Polymer electrolyte-based unitized reversible fuel cells (URFCs) combine the functionality of a fuel cell and an electrolyzer in a single device. In a URFC, titanium (Ti)-felt is used as a gas diffusion layer (GDL) of the oxygen electrode, whereas typical carbon paper is used as a GDL of the hydrogen electrode. Different samples of Ti-felt with different structural properties (porosity and fiber diameter) and PTFE content were prepared for use as GDLs of the oxygen electrode, and the relation between the properties of the GDL and the fuel cell performance was examined for both fuel cell and electrolysis operation modes. Experimental results showed that the cell with a Ti-felt GDL of 80 μm fiber diameter had the highest round-trip efficiency due to excellent fuel cell operation under relatively high-humidity conditions despite degradation in performance in the electrolysis mode.

Published
2011

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