FUJI ELECTRIC JOURNAL 2000 Vol.73-No.4


Present Status and Trends of Fuel-Cell Power Generation
Tomoyoshi Kamoshita, Noriyuki Nakajima
This paper reviews the system configurations, development status, and future problems of Fuji Electric's phosphoric acid fuel cell (PAFC) and polymer electrolyte fuel cell (PEFC), as well as other companies' attitudes. As a PAFC plant is continuously working over 10,000 hours, the reliability of the PAFC is considered to have reached a commercial level. The PEFC itself has been improved enough in reliability, and efforts are now concentrated on the application of reformed gas to the system. Cost reduction is a prior subject in commercializing them. Applications making the most of cleanness and energy saving characteristic of fuel cells will be investigated.

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Application to Hotel of Fuel-Cell Power Units
Noriyuki Nakajima, Yoshimi Horiuchi
With the cooperation of Toho Gas Co., Ltd. Fuji Electric set up a 100kW phosphoric acid fuel-cell unit in "Nagoya Sakae Washington Hotel Plaza" in february 1999. In this case, the unit is used as a cogeneration system. The low-temperature waste heat (about 50°C) is used to preheat the feed water of the warm water heater. The high-temperature waste heat (about 90°C) is used for the heat source of air conditioning by the absorption machine and hot water tank. The effect of fuel cell introduction on environmental preservation are 9.5% reduction in the amount of primary energy and 12% reduction in the amount of carbon dioxide exhaust.

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Fuel-Cell Power Units Using Biogas from Garbage
Yoshitaka Togo, Noriyuki Nakajima, Kenichi Kuroda
Fuji Electric has so far accumulated technologies of applying liquid petroleum gas (propane, butane, etc.), naphtha, and hydrogen, a by-product from electrolytic plants, as well as town gas to the fuel of phosphoric acid fuel-cell (PAFC) power generation. Recently, the application of biogas produced by anaerobic processing of organic waste has been under study. Now the opportunity is taken of participating into the Kajima Corporation's project sponsored by New Energy and Industrial Technology Development Organization (NEDO). This paper outlines the features of PAFC power generation using biogas from garbage and its experimental operation.

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Development of Phosphoric Acid Fuel Cells
Akitoshi Seya, Takashi Harada
Fuji Electric has continued improving the reliability and cost of phosphoric acid fuel-cell stacks. We have developed a new stack of the first commercial type. Based on the result of our basic studies on phosphoric acid behavior, we developed a new cell, which is expected to operate 60,000 hours without phosphoric acid replenishment. Also we reconsidered the functions of the structural parts of the stuck to reduce their costs and improved the reliability of the cooling plate. The new stacks of the first commercial type continue satisfactory operation on site. We are now pursuing an advanced type.

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Development of a Compact Reformer for Fuel Cell
Hirao Kudo, Hisanobu Yokoyama
In marketing fuel-cell power units, the most important problem is now reduction in cost. The fuel reforming system is required to be simplified and reduced in size as the whole system. The first phase of the system improvement was the development of a reformer with a built-in heat exchanger and a combination of a desulfurizer and a carbon monoxide (CO) shift converter to reduce the number of components. In the second phase, to reduce the reformer size developed in the first phase, a new compact reformer is manufactured and evaluated. This paper describes the development of the compact reformer.

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Development of On-Site Fuel-Cell Power Units
Takashi Ouchi, Masakazu Hasegawa, Harumasa Takeda
Fuji Electric has developed the second-phase commercial type of on-site fuel-cell power units with the aim of further reducing cost, improving durability, and enhancing functions. The first unit has been installed in our factory and put in operation. In the development, the system has been simplified and the number of parts has been reduced toward our target cost of ¥400,000/kW. In addition, Fuji Electric is tackling the developments of advanced functions such as steam extraction and a system incorporating heat utilization equipment.

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Fuel Switching Technology in a Fuel-Cell Power Plant
Tadashi Komatsu, Yoshihito Chida, Donghui Xiang
Fuji Electric developed fuel switching technology for a fuel-cell power unit in continuous operation and succeeded in the demonstrative test of switching town gas to liquid petroleum gas (LPG) in a 100 kW fuel-cell power plant. In fuel switching technology, it is important to control reforming steam and adapt to variations in gas composition at the reformer inlet. Fuji Electric made a dynamic model of a fuel switching system to grasp the behavior of gas composition at each part and applied the result to the demonstrative test.

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Development of Polymer Electrolyte Fuel Cells
Makoto Aoki, Akitoshi Seya
This paper outlines the development of Fuji Electric's polymer electrolyte fuel cells (PEFCs). We intensively researched on the PEFC without humidification which have the advantage of further improving in reliability, cost, and size. The hydrogen-air PEFCs of a 50 cm2 single cell and a stack of ten 100 cm2 cells reached stable and high performance. A hydrogen-air 1 kW PEFC stack will soon be in operation without humidification. We are also developing a reformed gas-air PEFC stack and a PEFC fuel processor, and plan to develop a natural gas-air PEFC system including other components in fiscal 2000.

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Development of an On-Site Hydrogen Generator
Kokan Kubota, Hideo Nishigaki
Fuji Electric and Osaka Gas Co., Ltd. developed the on-site hydrogen generator "HG-100" which produces hydrogen from town gas or propane gas. This equipment consists of a steam reforming unit, a reformed gas compressor, and a pressure swing absorption unit. The main specifications are :
(1) Output of hydrogen : 100 m3/h (normal state).
(2) Hydrogen purity : 99.999% or higher.
(3) Town gas : 35 m3/h (normal state).

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Development of Partial Oxidation Reforming Technology
Shunsuke Ohga, Toru Kiyota, Isao Nakagawa
Fuji Electric is developing a small methanol reforming system which combines exothermic partial oxidation reforming and endothermic steam reforming. The adavantage of the combined partial oxidation reforming is the structure made simple and compact because the catalyst heating structure is not necessary. The evaluation of the combined partial oxidation reforming system with an output of 60 m3/h (Normal) hydrogen proved that the combined method had a possibility of reducing the volume per output to about a fifth compared with the former steam reforming method.

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Preventive Maintenance of Fuel-Cell Power Plants
Yoshihiro Oka, Makoto Mikami, Hideyuki Miwa
Fuji Electric is tackling improvement in cost and reliability with the aim of commercializing on-site phosphoric acid fuel cells. This paper describes the present status of the reliability based on the on-site operation results and also preventive maintenance technology according to plant data observation system supporting improvement in reliability. The results of operation at more than 90 sites have been reflected and steadily improved reliability. Especially, the reliability of the second-generation and subsequent fuel-cell plants has almost reached a commercial level.

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Present Status and Trends of Photovoltaic Generation Systems
Norio Kanie, Michiru Fujita
To prevent global warming, photovoltaic generation capable of converting solar energy directly into electricity attracts attention. Fuji Electric has been developing film-substrate, amorphous-silicon solar cells which has lower efficiency than crystal silicon cells, but the time in which the production energies of PV cell are withdrawn is short, and it is possible to aim at making a low price. Also, we have completed a series of inverters to convert generated DC into AC. In addition, to reduce the influence of weather, we are developing a hybrid system in which photovoltaic generation is combined with wind power or micro hydropower generation.

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Development of Amorphous-Silicon Solar Cells
Yukimi Ichikawa, kouichi Harashima
Fuji Electric proposed an original monolithic series-connection structure for amorphous-silicon (a-Si) solar cells "SCAF" and has developed a-Si-based solar cells with plastic-film substrates. On the basis of fundamental studies of fabrication technologies, we have constructed a prototype mass-production line for 40 cm x 80 cm SCAF solar cells and attained a conversion efficiency of 9%. Currently, the device structure and process technology are under improvement to reach 10% efficiency. Application technology for a-Si solar cells is also under development through field and durability tests.

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Photovoltaic System for Preserving Reservoir Water Quality
Souichirou Yamamoto, Masatoshi Ono
This system operates a series of equipment to collect, treat, and discharge out the algae that grow in a reservoir. It consists of three pieces of equipment : the photovoltaic generation and water quality preservation system as the core installed on the surface of a reservoir with the aim of preserving water quality, the electric ship "Hidamari" to transport algae collected and treated by the above-mentioned system, and the photovoltaic generation system installed on shore to charge the ship. It was installed in fiscal 1998 and is scheduled to be evaluated in cooperation with the Bureau of Waterworks, Tokyo Metropolitan Government for four years from 1999 to 2002.

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Advanced Power conditioner for Photovoltaic Generating Systems
Satoshi Kusumoto, Masaki Kato, Hisashi Fujimoto
A photovoltaic power generation system consists of solar cells made of silicon crystals, a current collector for photovoltaic power, and a power conditioner to convert photovoltaic DC into power frequency AC. The newly developed power conditioner is not of a conventional transformer-insulating type but of a tranformerless type, and is improved in size, weight, and efficiency. This paper describes two types of power conditioners with a single-phase 200 V, 3.5 kW output for home use and a three-phase 200 V, 10 kW output for industrial use.

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Demonstrative Research on a Hybrid System Using Photovoltaic Power and Micro Hydropower Generation
Hiromitsu Ota, Masahiro Sakurai, Norio Kanie
A demonstrative research on an independent hybrid system with photovoltaic power generation and micro hydropower generation combined, sponsored by New Energy and Industrial Technology Development Organization, is implemented in the middle highland of Vietnam from fiscal 1997 to 2000. It aims at optimizing the system configuration and operations from the point of view of reliability and cost. The system was completed in September 1999, and now data related to weather conditions and system operation are being collected and analyzed.

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