Saibu, Japan
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Noda Z.,Kyushu University | Hirata K.,Kyushu University | Hayashi A.,Kyushu University | Takahashi T.,Tokyo Gas Co. | And 7 more authors.
International Journal of Hydrogen Energy | Year: 2016

A hydrogen pump-type hydrogen sensor cell has been developed for continuously detecting a trace amount of impurities contained in hydrogen fuels, by using the impurity poisoning effect of PEFC-type electrochemical cells. The impurity-sensitive sensor cell was produced by extremely reducing Pt catalyst loading in order to detect even a small amount of impurities. This type of sensors with the stable baseline can detect major hydrogen fuel impurities, CO, H2S, and NH3, with the ppm-level detection limit. © 2016 Hydrogen Energy Publications LLC.


Tanaka H.,Osaka Gas Co. | Suzuki A.,Tokyo Gas Co. | Yamamoto K.,Saibu Gas Co. | Yamamoto I.,Noritz Corporation | And 2 more authors.
International Gas Research Conference Proceedings | Year: 2011

The ECOWILL, a micro-CHP system using an internal combustion gas engine, was unveiled in Japan in 2003 as the world's first mass-market product of its kind and has succeeded in establishing a new market in micro-CHP for household use. The ECOWILL consists of a 1kW output gas engine-powered generator unit developed by Honda and a hot water/space heating unit developed jointly by Osaka Gas, Tokyo Gas, Toho Gas, Saibu Gas and Noritz. The system uses gas as its primary energy source and is able to make efficient use of both heat and electrical power within the home. Combining energy savings with comfort, ease of use and convenience (usually mutually exclusive characteristics), the ECOWILL has been very well received by the market and has sold a total of 100,000 units nationwide as of 2010. This report describes the development of a new model of ECOWILL system with greater commercial appeal, aimed at the further popularization of micro-CHP, that addresses such issues as the need for installation in Japan's typically small urban dwellings and compatibility with Japanese energy-efficient housing, where technical progress is continually being made.


In the past study, it was made clear that the load calculation method considering thermal sensation could calculate air conditioning load in consideration of spatial distribution of thermal sensation. However, even if air conditioning load is handled without overs and shorts because the load calculation method is not intended to cancel difference in thermal sensation in the room, thermal sensation at the examination point is kept by the required value, but thermal sensation at other points is not kept by the value that is similar to an examination point. Therefore there is concern that thermal sensation at the point except the examination point may be worsened by conditions adversely. This paper established an examination point and the reference point in the room and compared the difference of thermal sensation at the reference point with the examination point. The following results were obtained. 1) The difference of thermal sensation occurs between an examination point and a reference point, but the difference can be controlled in an acceptable range. 2) In convective air conditioning, the difference of thermal sensation does not almost occur. 3) In radiant air conditioning, the difference of thermal sensation changes by radiant panel position and required thermal sensation of examination point.


Until now, we suggested a new load calculation method which considered thermal sensation of the resident based on a point of view of comfort air conditioning. By this new load calculation method, the load is calculated for thermal energy to remove by the room to keep PMV of the indoor specific place a set point. By this new air-conditioning load calculation method, air-conditioning load changes by PMV given beforehand. Until now, the new load calculation method which set PMV of the indoor specific place a set point to zero was examined. In this paper, in order to examine the possibility of the load reduction by this new air-conditioning load calculation method, fixed tolerance level was set as PMV of the indoor specific place a set point, and the case studies ware performed. The calculation results showed that the annual load could carry out 32-44% reduction by setting tolerance level of PMV to ±0.5 compared with the present load calculation method.


Noda Z.,Kyushu University | Hirata K.,Kyushu University | Hayashi A.,Kyushu University | Taniguchi S.,Kyushu University | And 6 more authors.
International Journal of Hydrogen Energy | Year: 2012

Hydrogen purity sensor cells were newly developed with the principle of PEFC. By using the phenomena of PEFC's voltage drop seen in the presence of impurities and further minimizing the amount of Pt to make the cells more sensitive to impurities, the sensor cells were prepared. This unique sensing principle was applied to typical impurities in practical hydrogen gases, including CO, H2S, and NH3. Sensor responses were derived by analyzing various kinds of dependency on Pt loading, current density, impurity concentration, and operational temperature. Possibility of recovery from impurity poisoning was also studied by varying impurities' supply and potential charge. Consequently, our simple PEFC-type hydrogen purity sensors were verified to have ability to sense ppm-level impurities within 10 min. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Takei N.,Japan Gas Association | Makino M.,Gas Bureau | Meguro T.,Tokyo Gas Co. | Nishida S.,Osaka Gas Co. | Osajima H.,Saibu Gas Co.
International Gas Union World Gas Conference Papers | Year: 2012

The 3/11/2011 Great East Japan Earthquake and the subsequent tsunami caused huge damages centered on the Tohoku region. This great earthquake and tsunami were the first to cause serious damage to a Japanese city gas business LNG receiving terminal. A discussion covers the damages to this LNG receiving terminal (the Sendai City Gas Bureau Minato Works) from the earthquake and massive tsunami of a scale beyond all expectations; the emergency recovery and restoration efforts; and lessons learned from this experience. This is an abstract of a paper presented at the 25th World Gas Conference (Kuala Lumpur, Malaysia 6/4-8/2012).


Yamaoka K.,Geological Survey of Japan | Matsukura S.,University of Tokyo | Matsukura S.,SaibuGas Co. | Ishikawa T.,Japan Agency for Marine - Earth Science and Technology | Kawahata H.,University of Tokyo
Chemical Geology | Year: 2015

We determined concentrations and isotopic compositions of boron in a complete section of the hydrothermally altered Cretaceous oceanic crust of the Troodos ophiolite. The boron content and δ11B value for each lithological section are: pillow lava (3.8-206.8μg/g, 63μg/g average δ11B=+0.17‰ to +15.6‰, +8.1‰ average), sheeted dike complex (0.6-18.0μg/g, 4.0μg/g average δ11B=+3.3‰ to +10.6‰, +6.0‰ average), and plutonic complex (0.3-8.4μg/g, 1.7μg/g average δ11B=-1.7‰ to +18.5‰, +4.5‰ average). These boron contents are higher than the estimated original igneous values throughout the oceanic crust, indicating uptake of boron from seawater and hydrothermal fluid at temperatures ranging from ≤50°C to >300°C. Although our boron data for the Troodos ophiolite are generally consistent with those for the Oman ophiolite of similar age, the distinctly low δ11B values of the lower gabbro section in the Troodos ophiolite (<+3‰) suggest reaction with 11B-depleted fluid at a very small water/rock ratio. The boron content of the bulk oceanic crust (12.3μg/g) estimated for the Troodos ophiolite is relatively high as a result of strong boron enrichment in the pillow lava section, which underwent prolonged seafloor weathering. Despite these differences, the weighted average δ11B value of the bulk oceanic crust (+7.6‰) is similar to that of the Oman ophiolite (+7.9‰). We also analyzed the boron isotope geochemistry of a subseafloor hydrothermal stockwork sulfide deposit in the Troodos ophiolite to investigate its formation processes. In contrast to the normal upper oceanic crust, the δ11B values of the rocks below the ore body decrease with increasing depth and have large negative values (-6‰) in the highly altered uppermost dike section. These low δ11B values are coupled with high boron contents (2.5-17μg/g) and high and uniform 87Sr/86Sr ratios (0.7064 average), and are unlikely to have resulted from interactions with fluids at a small water/rock ratio. These characteristics are better explained by interaction of ore-forming hydrothermal fluids with oceanic crust that had previously been enriched in boron through hydrothermal alteration at low temperatures. These observations demonstrate that boron and boron isotopes are useful for quantitative evaluation of fluid-related processes with multiple stages, including petrogenesis of hydrothermal ore deposits. © 2014 Elsevier B.V.


Kobayashi K.,Osaka Gas Co. | Sako T.,Osaka Gas Co. | Yoshimi Sakaguchi,Osaka Gas Co. | Morimoto S.,Tokyo Gas Co. | And 4 more authors.
Journal of Natural Gas Science and Engineering | Year: 2011

The possibility of turbocharging into a natural gas homogeneous charge compression ignition (HCCI) engine is experimentally investigated. Experiments are performed using a naturally aspirated engine fitted with an external supercharger and a butterfly valve for back pressure control to simulate a turbocharger. The results indicate that the thermal efficiency can be improved by raising the engine compression ratio and lowering the boost pressure. At an engine compression ratio of 21 and turbocharging pressure of 0.19 MPa, the brake thermal efficiency reaches 43%, with NOx emissions of only 10 ppm or less. Finally, the performance of the engine fitted with a newly developed turbocharger is demonstrated. As a result, 43.3% brake thermal efficiency, 0.98 MPa brake mean effective pressure, and 13.8 ppm NOx emission have been realized. This value shows the possibility that a power generating efficiency of 40% at a power output of 50 kW could be achieved when applied to combined heat and power (CHP), even allowing for energy losses in the generator and the power inverter. For practical use, the ignition timing control, operation control, including how to start or load input and ensuring durability, remain to be investigated. To clarify these issues, we have initiated the endurance test for a newly developed 25 kW HCCI package, although the engine is not supercharged. © 2011 Elsevier B.V.


Chai Y.W.,Tokyo Institute of Technology | Oniki T.,Tokyo Institute of Technology | Kenjo T.,Tokyo Institute of Technology | Kenjo T.,Saibu Gas Co. | Kimura Y.,Tokyo Institute of Technology
Journal of Alloys and Compounds | Year: 2016

The microstructure and thermoelectric properties of an off-stoichiometric quaternary (Ti0.2,Zr0.8)Ni1.1Sn half-Heusler (HH) alloy was investigated in three heating cycles. A high density of coherent nanoprecipitates with an average diameter of ∼13 nm and an interprecipitate spacing of ∼6 nm was observed in the alloy. Formation of the extremely fine nanoprecipitates, most likely to be the 'full' Heusler (FH) phase, was not only strongly related to the degree of excess Ni concentration ratio in the alloy, but also appeared to be affected by the Ti-Zr substitutions. We noticed the behaviour of both electrical resistivity (ρ) and Seebeck coefficient (S) of the alloy was closely associated with the microstructure evolution of the FH-nanoprecipitates, which depended on their phase instability at elevated temperature and the cyclic heating process. The ρ and S reduced after the 1st heating cycle and stabilised thereafter in the subsequent heating cycles. Despite of the presence of the metallic FH-nanoprecipitates, the stabilised S maintained similar magnitudes to S of the ZrNiSn (without FH-nanoprecipitates) and did not show degradation of S as previously seen in the ZrNi1.1Sn containing relatively much larger FH-nanoprecipitates. The high density of FH-nanoprecipitates and the presence of Ti-Zr point defects were responsible for the significant reduction of thermal conductivity (κ) of the alloy, about 30% and 20% less than κ of the ZrNiSn and ZrNi1.1Sn alloys, respectively. Moreover, further reduction of κ was noticed due to formation of the diffuse HH/FH interfaced FH-nanoprecipitates from the cyclic heating process. Consequently, the alloy has shown a maximum dimensionless figure of merit (ZT) up to 0.81 at 870 K. © 2015 Elsevier B.V. All rights reserved.


Nomiyama O.,Saibu Gas Co.
International Gas Research Conference Proceedings | Year: 2011

Polyethylene (PE) pipes for gas supply, which have been widely used in recent years, have superiority in installability, seismic performance and corrosion resistance, while their resistivity against external force such as from strikes by excavator bucket edges is inferior to metal pipes. Under some installation conditions, it is necessary to take appropriate protection measures for PE pipes. Use of protective steel sheets or concrete plates that are laid directly on pipes is commonly applied. However, their poor installability due to their heavy weight, as well as a high total cost including installation expense, remains a challenge. To resolve this issue, the authors developed a unique PE pipe protective sheeting, which is superior compared to conventional protectors. It is characterized by decreasing the damage to a buried PE pipe surface within the rated value against assumed external force, for instance, due to being struck by an excavator bucket edge. It also contributes to an improvement in installability and workability as well as reduction in total cost including installation expense. This protective sheeting is comprised of two types of materials with different properties: reinforcing fiber and nonwoven material. The reinforcing fiber, which has a superior failure-bearing effect, protects against damage attributable to direct strike by an excavator bucket edge to a PE pipe surface. Nonwoven material is effective in mitigating external force and impact absorption. To verify protection ability, we conducted performance testing by simulating two types of load: an impact load and a pressing load, which may be applied by an excavator bucket edge, by using both testing apparatus and an actual excavator used on site. As a result, we successfully attained the required protection ability using three-layered sheet wrapping around a PE pipe with a nominal diameter of 100 bore, as well as two-layered sheet wrapping around PE pipes with 150 and 200. It was also validated that installation expense can be cut by up to 30%, since this product features flexibility and light weight materials, and can be installed quickly. This product has been applied company-wide since 2007, and has been available in the Japanese market. As of March 2011, about 13,000m2 of this protective sheeting had been installed in Japan.

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