Generally, Rankine cycle is used in MSW furnaces to recover the energy. The brake efficiency of Rankin cycle should be lower if the capacity is too small. Therefore, we try to use a reciprocal SI-ICE for the recovery in MSW furnace. The gas from MSW gasifier, MSW-syngas, has very low LHV. We developed a small gasifier for bio-syngas from wood. This bio-syngas is used to arrange a surrogate MSW-syngas. In this study, the surrogate MSW-syngas means the diluted bio-syngas with N2 or CO2. The experimental parameters are 1) N2 fraction, 2) CO2 fraction. The measured parameters are COV of IMEP.

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Agricultural residues can be an energy resource. However, alkali materials in their ashes are the causes of slagging and agglomeration problems. To reduce alkali materials, hydrothermal carbonization process was selected. Thai rice husk was used as sample to study. It was heated under different temperature ranged from 180°C to 250°C, as operated pressure ranges from 12 bar to 42 bar with holding time 1 hour. The results show that the percentage by mass of fixed carbon are increased, but volatile matter and ash content are decreased as temperature increases. Meanwhile, the X-Ray fluorescence (XRF) analysis results show the decreasing of alkali materials.

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Cultivation microalgae in open raceway pond to produce biofuel is popular in last decade. Algae Biomass research and development (ABES), the University of Tsukuba cultivating polyculture (native) microalgae in Minamisoma, Prefecture, Japan to produce biofuel. The native polyculture microalgae were used to maintain the stability of the ecosystem and adapt to temperature fluctuation. The availability of meteorological information (temperature) is potential to estimate the microalgae growth. In this research, we proposed the polynomial model to predict the productivity of microalgae (g/m2/day) with the depth of culture were 0.3 meters. The result of this study indicated that the meteorological parameter (air temperature) success to estimate the microalgae growth.

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In this work, crude palm oil was produced by the single-step distillation of alkali trans-esterification process to provide pure palm oil biodiesel (POB) fuel. The pure POB fuel was improved by using repeated-distillation process in order to apply effectively in 4-cylinders high-speed diesel engine. The influences of pure POB and improved POB on exhaust emission from internal combustion engine were studied under the comparison with commercial diesel fuel. The physical properties of all tested fuels were characterized under ASTM. The experimental results show that the POB fuel yielded at 84.54% under consuming raw materials of 400 grams. Fuel viscosity of improved POB fuel can provide the effective improvement under criterion value of the ASTM standard (≤ 8.0 cSt.) for high-speed engine as compared with pure-POB fuel. The Kinematic viscosity values are of 121.41% and 35.71% for pure POB and improved POB, respectively, which are more than commercial diesel fuel by 8.02% and 7.41%, respectively. Similarity of cetane index values of all tested POB fuel are under ASTM standard, which are less than the diesel fuel by 28.98% and 26.72%, respectively. Heating value of all tested POB provided less value than the diesel fuel. Meanwhile, exhaust emission from the tested engine at 2,000 - 3,000 rpm was studied under using different POB fuels. It shows at 2,000 rpm the effective decrease of CO2 by 1.6% and 3.69% for using pure POB and improved POB, respectively, while 3,000 rpm CO2 decreased by 3.41% and 11.67% for using pure POB and improved POB, respectively as compared with using commercial diesel fuel. CO results show the same reduction trend with CO2 emission. However, NOx emission results show a small amount of increase in exhaust by 1.73% and 0.06% from the engine at 2,000 rpm and by 3.30% and 2.86% from the engine at 3,000 rpm using pure POB and improved POB, respectively as compared with using diesel fuel. Meanwhile, improved POB fuel can relieve the increase of HC emission of pure POB by 76.45% and 18.37% from the engine at 2,000 rpm and by 30.56% and 3.73% from the engine at 3,000 rpm, respectively. This study suggests that improved POB fuel has the high potentiality for as a clean and alternative fuel.

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This paper aims to investigate the influence of liquid flow on the mass transfer in bubble column from an immersed downward nozzle in the cubic container filled with the water without oxygen. The temporal oxygen concentration is measured with the DO meter. The flow visualization technique includes the computational fluid dynamics (CFD). The height of the downward nozzle is set at h=6.0, 20, 60 and 210[mm] from the container bottom against the liquid depth of HL=220[mm]. The mass transfer coefficient is then found not to be affected by liquid flow although the volumetric mass transfer becomes large in small h due to large specific gas-liquid interfacial area.

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Biodiesel fuel (Fatty acid methyl esters: FAME) shows high boiling temperature, so that it allows to accumulate in the engine oil, causing the premature engine wear. Recently, it was reported that the distillation characteristics of FAME is adjusted to that of petro-diesel fuel by the cross-metathesis reaction with ruthenium catalyst. The purpose of this study is to be clear the influence of the cross-metathesis reaction conditions on distillation characteristics of waste cooking oil methyl ester(WME) and to reveal the reaction condition adjusting to distillation characteristics of petro-diesel fuel. In experiment, the cross-metathesis reaction of WME and 1-hexene with Umicore Grubbs catalyst M51 was carried out at various reaction temperature and molar ratio of catalyst. Form the result, it was found that the oleic acid methyl ester and linoleic acid methyl ester in major component in WME are sensitive to reaction temperature and molar ratio of catalyst. And it was shown that the reaction condition adjusting to distillation characteristics of petro-diesel fuel is 0.24 mol-% in catalyst per WME and 50 degrees Celsius in reaction temperature.

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The main objective of the present work is to compare the characteristics of synthesis gas obtained from different types of biomass. The paper considers the technology of raw material heat treatment, which includes a two-stage pyrolytic conversion of biomass into gaseous fuel. The experimental data on composition and quantity of the gaseous products formed in the process of thermal treatment of various types of raw material are presented. The results indicated that the method allows obtaining 1.23-1.48 m3 of synthesis gas from 1 kg of organic raw materials of various types and with the calorific value of 16.0-35.1 MJ/m3.

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Kitchen garbage from department stores and hotel restaurants is grinded by a disposer and transported to a biogas system (methane fermentation tank) via piping. Biogas produced by methane fermentation of kitchen garbage and kitchen waste water treatment sludge is used as gas fuel consumed in the process of boiler and cogeneration, and can reduce gas consumption. Based on long-term operation, energy return on investment, economy and CO2 reduction were verified.

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Erianthus, a perennial C4 grass related quite close to sugar cane, is receiving increasing attention as a raw material crop for cellulosic bioethanol production because of its high biomass productivity and strong tolerance to environmental stresses. We investigated the development of both the canopy and root system in Erianthus and examined its superior performance, even under poor soil conditions. Leaf area increased with development to make the higher spatial distribution in the second-year, which might worsen the light conditions in the canopy. Our findings indicated that biomass yield to get much total yield during the growth period could be improved by thinning out and reducing the planting density, which will improve the light conditions in the canopy. The root system distribution got larger and deeper every year. The root turnover supplied considerable amounts of carbon into the soil, which might be a countermeasure against global warming. Different harvesting times and pretreatments for drying Erianthus were examined to reduce its water content to less than 15% using less energy. Harvesting Erianthus in March and injury pretreatment followed by air-drying were found to significantly reduce the energy required to effectively dry Erianthus biomass.

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We examined the economic and environmental impact of biomass utilization in order to clarify the influence of stakeholder engagement. For this study, Oki town which is the where the utilization of food waste biomass has been actively implemented in Japan selected as the target region. the income and expenses and the Greenhouse Gas (GHG) emissions was used for calculating the environmental efficiency. Five scenarios were developed to estimate the environmental efficiency of the food-waste biomass utilization which were gradually extended and expanded by the appropriate procedures of stakeholder engagement. As a result, the implementation of businesses using food-waste as a source of feedstock can generate higher economic returns as well as decreasing GHG emissions. In conclusion, it was indicated that development of biomass utilization in cooperation with stakeholders of the region is able to accelerate the regional activation in terms of economic and environmental issues in local regions such as Oki town.

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In metropolises, it is unlikely to use the renewable energy sources to pursue zero carbon building design. But it would become possible if biofuel-driven trigeneration system (BDTS) is adopted. As such, it is essential to assess the application potential of BDTS under various loading, operating and climatic conditions. Besides the energy and environmental assessment of BDTS, it is paramount to evaluate the economic aspect in terms of carbon price. In this study, it was found that BDTS had definite primary energy saving and carbon emissions reduction in a high-rise hotel building as compared to the conventional system. In economic analysis, the BDTS primed with compression-ignition engine was not viable even in running cost due to the local biodiesel price level. The BDTS primed with spark-ignition engine and fueled by biogas, however, would have economic merit when carbon price was considered in Hong Kong. Adoption of carbon tax and social cost could have the payback of 4.1years and1 year respectively.

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All over the world, electricity production depends on non-renewable sources i.e. oil, gas and coal, which are limited natural resources. Under developed country like Bangladesh are always in shortage of electricity which is a clear barrier for development. It is high time to search for alternating energy sources. This paper introduces a new renewable biomass source in Pathor Kuchi Leaf (PKL) or Bryophyllum pinnatum solution. PKL has already undergone several testing processes and in this paper the pH behavior and Cell Potential is under investigation. These parameters are quite necessary before fully integrating PKL in Energy Grid. The experiment was conducted on 6 different PKL cell with different concentration of PKL juice. Cell no. 1 & cell no. 6 showed an initial pH of 3.37 and 3.40, which is quite acidic. PKL cells were also tested with a 5% CuSO4.5H2O solution which after being mixed together showed pH of 3.37. As for Cell Potential, a more theoretical approach was followed. For each unit cell 1.85 V cell potential was found which add up to 11.1 V for 6 cells. These results indicate a threshold for highest electricity generation from 6 unit PKL Battery.

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Operations of grinding logging residues and transporting wood chips were investigated in Japan and the U.S. The total cost of the U.S. grinding and transporting operations was calculated as 69.4 US$/BDT, resulting in the equivalent level with the Japanese operation (71.2 US$/BDT), although the productivity of the U.S. grinder was higher than that of the Japanese grinder as well as the capacity of chip van in the U.S. was larger than that of truck in Japan. This study discusses the detail of cost calculation by comparing the cost breakdown structure between Japanese and American operations.

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We have been developing a MEA with a self-water management on PEFC since 2007 for the cost reduction and the system efficiency improvement. Although we were able to confirm that graphite rubbish functioned as water absorption/feed grain and the grain diameter and the additive rate of graphite rubbish were optimized last year, the reaction mechanism of the added graphite in the membrane was not elucidated. Therefore, this paper aims to elucidate it by changing the kind and the particle size of graphite. As a result, the carbon black powder enhanced the activation polarization by improving proton transportability.

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We performed the structure analysis of Nb doped titanium oxides oxygen reduction electro-catalysts in order to understand the effect of Nb doping on enhancing oxygen reduction reaction activity. Nb doping makes effects on stabilization of anatase phase of TiO2 with high ORR activity, lowering of particle size, and introduction and increment of Ti3+related to the ORR active sites. Large amount of Nb doping causes the suppression of ORR activity due to the covering of ORR active sites by non-active outer layers contain rutile, Ti4O7, and TiNb2O7 phases.

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Thermosetting composites are thought to be one of promising candidate materials for fabricating bipolar plates (BPs) used in ultra-lightweight fuel cells. Nevertheless, it is difficult to meet desirable electrical conductivity when using the composite plates while maintaining processability. The production of BPs via conductive composite formulating is an important approach in material invention and modification for fuel cells. The electrical conductivity of BPs significantly affects on the fuel cell performance. In this regard, relationships among the conductive filler loading, the electrical conductivity of BPs, and the fuel cell performance are interesting to be studied. Experimental activities reported in this article were created to predict changes in fuel cell performance when the conductivity of BPs changed due to a variation in material types or conductive filler concentrations. The BPs made from functionalized graphene nanoplatelet filled polybenzoxazine composites were used as one of case studies for the comparative investigation of theoretical estimations and experimental results.

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Polymer electrolyte membrane fuel cells (PEMFCs) utilized for portable applications must supply uninterruptible and reliable power with constant voltage. The PEMFC is, however, limited for transient peak power demand that confines it for being applied in a high power system, especially using for transportations. To overcome this issue, PEMFC hybridization with supercapacitor (SC) based on power balance strategy will support the PEMFC system in desired operating conditions, positively affecting on an increase in PEMFC performance. The aim of this work is to observe performance characteristics and voltage degradation of a PEMFC/SC hybrid system compared with a traditional PEMFC system. To achieve this purpose, a quasi-static profile was created to separately investigate the influences of stationary conditions, load variations, and start-stop conditions on the voltage degradation of a PEMFC/SC single cell. Polarization curves, hysteresis loops, voltage degradation rates were determined. The cell performance was also analyzed using electrochemistry impedance spectroscopy (EIS).

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In order to reduce CO2 emission from power production, energy carriers to transport carbon free energy are attracting interest. Hydrogen is one of the promising energy carriers, but in order to introduce hydrogen energy network widely in the world, the cost to establish supply chain has to be carefully examined. IHI is focusing on ammonia as a carbon free energy carrier because it is already used widely in the world as a fertilizer and chemical feedstock, and social cost to establish supply chain would be rather lower than other carriers. Also, ammonia is a combustible gas and can be directly used in power plant, which will also reduce the cost for usage. However, some issues like NOx emission should be solved before installation. IHI is developing technology to use ammonia directly as a fuel in coal fired boiler, gas turbine and SOFC with the support from Strategic Innovation Promotion Program (SIP) by Cabinet Office of Japan. In this paper, some of the activities are presented.

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Distribution of oxide ion diffused through an electrolyte film of an anode-supported solid oxide fuel cell was visualized using oxygen isotope (Oxygen18) labeling technique. A bi-layer anode-supported electrolyte with LSM/YSZ cathode was performed Oxygen16/Oxygen18 exchange under current flow at 650ºC(fuel cell operating condition) and was rapidly cooled from 650ºC to below 200ºC within 1 second using a cooling system of helium-gas impinging jet installed inside an SOFC test equipment in order to stop movement of the oxide ion. The concentration distribution of the incorporated oxygen isotope in frozen state was then imaged by a secondary ion mass spectrometry (SIMS).

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To introduce electricity from renewable energy into the grid a lot, it is required to control the electric power supply. Hydrogen electric power storage is one of the promising candidates for large capacity and long term application. The SOEC method has the highest efficiency of hydrogen production comparing the other conventional technologies. However, the relatively high operating temperature of SOEC causes some difficulties such as degradation of cell and stack materials. In this paper, the SOEC test stack was fabricated with two kinds of seal materials. The gas seal and durability properties of the SOEC test stack were studied.

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Hydrogen refueling stations (HRSs) to supply hydrogen to fuel cell electric vehicles have been constructed, and 101 stations are in operation as of May 2018 in Japan. Hydrogen production by renewable energy resources contributes to the mitigation of CO2 emission. We have been developed a mid-scale polymer electrolyte membrane electrolysis system (EL-Plant) using photovoltaics (PV) cooperated with a HRS. The outlines including a system configuration of the EL-Plant connected with a PV system and power grid are presented. A concept on operational strategies of the PV-based EL-Plant, power leveling by a threshold by grid electricity, is proposed, and its effects were evaluated by a simulation.

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Solid oxide electrolysis cells can produce syngas from H2O and CO2 by utilizing renewable energy-derived electricity (co-electrolysis). When operation temperature is lowered, methanation reaction occurs in cathode and direct methane synthesis will be realized. In this study, Ni-Ce0.9Gd0.1O1.95 cathode was impregnated by Ru, Co and Pd. From catalytic analyses, it was shown that hydrogen spillover from noble metals to adjacent Ni species played a role in enhancing CO2 methanation activity. In electrochemical tests, both CO2 conversion and CH4 selectivity increased along with applied potential. Cathode surface can be electron-rich under polarization, and that might affect the catalytic performance.

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Toluene-methylcyclohexane organic chemical hydride has been expected as the energy carrier system for the large-scale transport and storage of hydrogen generated from renewable energy. In this study, we improved the performance of toluene direct electro-hydrogenation electrolyzer. The electrolyzer was optimized for cathode flow-field, the chemical-hydrogenation Pt catalyst in cathode flow-field, and the application of fine mesh anode. Porous-carbon flow-field was the best structure as cathode flow-field. Pt particles loaded cathode flow-field confirmed the function of chemical hydrogenation with toluene and hydrogen. Furthermore, the fining of anode mesh also functioned efficiently. Each modification showed the significant improvement of cell voltage and current efficiency. The conversion from toluene to methylcyclohexane with one-through operation achieved 92 -95%.

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This paper presents the purpose, benefits, operation method and feasibility evaluation of H2OneTM Off-Grid Solution. Central to this study problem is confirmation whether it is possible to supply electric power to meet the electricity demand only by renewable energy in the isolated areas. Therefore, we have evaluated economic efficiency using specifications and costs based on actual data. As a result, we are sure to make the feasibility of power cost below 40cent/kWh with H2OneTM Off-Grid Solution.

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For many countries, the role of power–to-gas system is important because the ratio in the overall generating equipment of renewable energy has increased. In this paper, a control method to achieve both hydrogen generation and demand response using renewable energy is proposed. This control method is designed to add an integrator to PI controller. Hydrogen generation equipment and power conditioning system for photovoltaics are controlled according to the operation schedule. The results of the numerical simulation of the proposed control method show the reduction of the receiving power and hydrogen generation error in consideration of the change rate restriction of each of the equipment.

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The research aims to investigate the effect of ZrO2 promoter over 10wt.%Ni/Al2O3 catalyst for the dry methane reforming (DMR). The physicochemical properties and DMR performance of the catalysts prepared by impregnation and co-impregnation method with different ZrO2 loadings (0, 3, 5 and 7 wt.%) were investigated. The catalysts were characterized by XRD, SEM, H2-TPR and O2-TPO. The catalytic performance of catalysts in DMR was demonstrated in a tubular fixed-bed reactor at 620 degrees Celsius under atmospheric pressure for 12 h. It was found that ZrO2 promoter decreased the metal-support interaction resulting in the enhancement of the number of active site on the catalyst surface. Consequently, ZrO2 promoted the catalytic activity of Ni/Al2O3 catalyst. Although some Ni sites was covered by ZrO2 when the ZrO2 loading as high as 7 wt.%, these interface was indicated to prevent carbon deposition. It can be attributed to the effect of oxygen mobility as oxygen was conveyed from the CO2 dissociation on ZrO2 to carbon on the Ni sites.

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Hydrogen H2 for fuel-cell power plants is commonly manufactured from hydrogen-rich materials such as hydrocarbons CnHm and alcohols CoHp(OH)q, using steam-reforming methods with catalysts. Recently, using a household-use-scale reactor with well-controlled temperature distribution, the authors have shown that the Cu/ZnO/Al2O3 catalyst has rather high performance with high hydrogen concentration CH2 at low values of reaction temperature TZ=600mm(Shinoki et al., 2011). In the present study, the authors investigate the optimum conditions as well as Shinoki et al., especially focusing on the influences of liquid-hourly space velocity LHSV upon concentrations such as CH2, CCO2,CCOand CCH4. As a result, all the concentrations are close to the theory of Shinoki et al. except for the case at low TZ=600mm and high LHSV. To settle the inconsistency of this exceptional case, the authors propose a new theory using some chemical reactions related with acetaldehyde CH3CHO.

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Hydrogen storage behaviors of BCN compounds modified with transition metals were studied. The BCN compounds, which had graphite-like layered structures composed of boron, carbon and nitrogen, were prepared by two different methods employing melamine and boric acid. The maximum hydrogen content at 77 K under 0.8 MPa of hydrogen was 1.403 mass% for Pt-Fe modified BCN prepared via melamine formaldehyde resin with specific surface area (SSA) of 441.9 m2g-1. That content was higher than the predicted physisorption limit. The enhancement of the hydrogen capacity would be due to the spillover phenomenon caused by supported metals and substituted heteroatoms.

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AIST FREA and Fukushima Hydro Supply Co., Ltd. aim to install hydrogen stations using hydrogen made by renewable energy in Fukushima Prefecture. In Fukushima Prefecture Koriyama City and Fukushima City, we started commercial hydrogen supply to FCV using mobile hydrogen station from April 2018. This station is a first 70 MPa commercial hydrogen station utilizing the renewable hydrogen in Japan. The outline of the station will be explained.

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The catalyst layers (CLs) structure is needed to design while catalysts are efficiently used without loss. CLs structure is influenced morphology of carbon supports. In this study, Porous and non-porous catalyst was compared to reveal difference of supports by overpotential breakdown. The results indicate oxygen diffusion overpotential requires to improve porosity in CLs of porous catalyst. Interparticle correlation of porous catalyst in the ink is dominated attractive force. Porous catalyst is easy to agglomerate secondary particles compared to non-porous one. Therefore, controlling agglomeration of porous catalyst is effective to design the CLs structure for the improvement of performance.

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Hydro-VENUS (Hydrokinetic Vortex ENergy Utilization System) is a flow-induced oscillation based energy harvester using a cylindrical pendulum. The Hydro-VENUS exploiting the galloping oscillation of the pendulum with semi-elliptical cross-section is effective in harvesting energy from flowing water. This galloping excitation is found to induce not only rotational oscillation but also one-way rotation of the pendulum. In this study, the energy harvesting performances of the Hydro-VENUS using the galloping-induced oscillation and rotation are investigated through water channel experiments. Furthermore, a blade tip winglet and an elliptical curvature on the rotating pendulums are examined to improve the energy harvesting performances by suppressing the blade tip vortices.

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Research and development of a floating-submersible type tidal current power generation system which can be used with low cost and in low speed tidal current is introduced. The system consists of the power generator by a horizontal axis turbine with the “Lens” diffuser and a slack mooring system with four ropes. The “Lens” diffuser has a large buoyancy so that the power generator floats on the free-surface when the tidal current is small but it submerges in the middle layer to generate power when the tidal current is greater than certain speed. The power generator changes its direction passively according to the direction of tidal current. Results of experiments by using 1/6 scale model to confirm the performance in the reciprocating flow in the towing tank are reported in the presentation.

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Tidal current power generation using bridge piers was verified by selecting the installation optimal position of the power generator considering the turbulence. As a case study, south-east end of 4th pier of Oshima-ohashi Bridge over Obatakeseto Strait in Yamaguchi Prefecture targeted. Tidal currents observation was carried out installing AD2CP on the sea bottom. AD2CP was installed at 3.0 m south of the bridge pier. At the same time, similar observation was carried out in sea area where is not affected by bridge piers. Observation was conducted at 40.0 m south of the bridge pier. Tidal currents distribution was observed at 8 Hz in the vertical direction. The water depth range was about 1.0 m to 21.5 m deep, and the observation was carried out at 42 layers with 0.5 m thickness. Tidal currents distribution and turbulence intensity were compared vicinity the bridge piers and in sea area where is not affected by bridge piers. And the installation optimal position of tidal current power generator using bridge piers was selected considering the turbulence.

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Geomorphologic conditions of its coastal areas and the importance of its shipbuilding industry make of Nagasaki Prefecture a suitable location for exploitation of marine energies. The objective of this work is to assess the tidal energy resource at the most promising areas for tidal current stream energy in this prefecture. With this aim, an FVCOM numerical model was validated with ADCP data measured in Naru Strait, Goto Islands. Monthly power density maps for the most promising locations are presented. Results show areas with considerable potential for tidal stream energy exploitation, as well as other areas with lighter conditions, enough for high-efficiency devices.

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Ocean current power generation is considered as one of the promising marine renewable energies. In this paper a floating type device is adopted because it is advantageous in respect to cost and maintenance. It is supposed that the floating current turbine is shaken by non-uniform flow. Thus, we investigated the motion of the device. The results indicate that the influence of vertical profile is small, but that of surface waves and turbulence is not small in some cases. Therefore, it is necessary to gather more observation data to come to the final conclusion on the motion in non-uniform flow.

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Kuroshio current flowing near coastal areas of Japan is one of the strongest ocean currents, and IHI is developing the floating type ocean current turbine system. In this study, we have carried out technical development of the floating type ocean current turbine system, engineering, fabrication, integration, and commissioning of 100kW turbine demonstration machine. After that, we implemented demonstration test on August-2017. As a result, the power generation from Kuroshio current was achieved, and we collected data for future practical applications, such as performance validation of the autonomous control system that stabilizes its underwater position

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The results of circular tank and towing tank tests of an 880mm diameter model of an ocean current turbine are presented. The experimental data include measurements of torque and momentum for a range of tip speed ratios and pitch settings for various conditions in shear flow and uniform flow. A simulation model based on blade element momentum theory was developed and verified using these measurements. In addition, the influence of shear flow compared with uniform flow is discussed. The results demonstrate that the numerical model developed can provide a useful tool for the hydrodynamic design and operation of ocean current turbines.

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Ocean thermal energy conversion (OTEC) is a renewable system, which convert the thermal energy in the ocean into the electricity. For design and development of heat exchangers to achieve substantial net power in the OTEC, the suitable performance evaluation method is required because, in general, the enhancement of heat transfer performance and the increment of the pressure drop is a trade-off. In this research, theoretical model of the maximum work by an ideal heat engine with finite heat transfer performance of the heat exchangers are organized and the performance evaluation method is proposed based on the optimum value of the heat capacity flow rate in the finite-time thermodynamics. The evaluation method is applied to evaluate a cross-flow type plate heat exchanger. As the result, the maximum power output over the heat transfer area and the optimum heat source mean velocity in the heat exchanger are revealed.

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In this paper we propose a new type of bidirectional and Double Rotor turbine, for OWC. It is combined Wells and Impulse rotors. These are set concentrically each other for the purpose of high efficiency and good starting characteristic. We describe a concept and performances of the turbine examined with numerical simulations. The results show that a maximum efficiency of the turbine is obtained at low flow coefficient, which is advantage to generate electricity. They also show large torque coefficient at high flow coefficient, which is advantage for starting characteristic. However the maximum efficiency is smaller than the conventional Wells and Impulse turbines at present.

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We are developing the wave overtopping type wave power generation which is wave energy is converted into potential energy by letting waves run up along the slope, the water level becomes different between the experimental water tank and peripheral sea area, and flow energy is generated. We reported the relation of the volume of overtopping for various waves in the past this time, the simulation about wave feeding into this overtopping-type wave-power generation model for various irregular waves and regular waves are reported. It is evident that Qm increased with increasing wave energy regardless of the wave type, and the pipe length 5D has high drainage characteristics. It was also suggested that Qm has a tendency to be larger for irregular waves.

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Hydraulic power take-off (PTO) system is the optional transmission for oscillating-bodies wave energy converters. This paper establishes the nonlinear dynamic model of typical hydraulic PTO system. Considering stiction, the Stribeck friction model and improved Wilson model are introduced to describe friction characteristics of hydraulic cylinder and hydraulic motor respectively. The pressure bound of high-pressure accumulator is also considered. Simulation of the dynamic model is done in MATLAB. Its results demonstrate that the hydraulic PTO system has Coulomb damping characteristic and that the high-pressure accumulator can stabilize pressure and flow. The tiny variation of piston velocity around zero is also displayed.

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Blow-Hole wave energy converter is novel type of oscillating water column wave energy converter which creates inclined oscillating water column by drilling shore rock. A real field experiment of Blow-Hole wave energy converter was carried out at fukui test site since 2014. Owing to the durability of shore-rock, this system has superior reliability. Three tunnels with 1.4m diameter and 18°inclination is drilled at the test site as collectors. A connecting duct and a single turbine generator with 0.8m diameter is installed at top of three tunnels. In this paper, the performance of the Blow-Hole wave energy converter measured at the test site is presented.

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Power generation using ocean wave energy is attracting attention because it can generate electricity regardless of weather, day and night. And practical application is desired. However, there are the following problems. ・Small-scale power generation cannot satisfy economic efficiency (depreciation years) when installation is carried out on the coast or the seabed. ・There are very few practical equipment that can evacuate by moving the equipment during bad weather such as typhoons. We have developed a wave power generator that can be installed on quay and other walls in order to solve.

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We developed the generator control system by model predictive control methodology, MPTC (Model Predictive Tuning Control), that enables WEC to tune every wave and then yield strictly maximum electric power considering copper loss. The system was implemented at a small test device and this amazing technology was verified practical through tank tests. We also made computer simulator of MPTC for design use. The simulated results for typical configurations of commercial size WEC were those correct the fallacy about viability of wave energy.

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Methods for generating electricity from renewable energy sources are of growing interest for achieving a stable energy supply and as countermeasures against climate change. Tidal current power generation systems with variable speed operation are now gaining attention for their high efficiency in converting tidal energy to electrical energy. The tidal current power generation system we have investigated employs a variable-speed DFIG. We investigated the annual capacity factor when the generated maximum current speed was changed for the tidal current power generation system using the control scheme of constant rotor voltage. As a result, the annual capacity factor reached 35.16% at maximum.

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Power generation utilizing energy of tidal current is attracting attention because it can generate electricity regardless of weather; day and night. However, there are the following problems. In small-scale power generation, installation work on the coast or the seabed can not satisfy the economic efficiency (depreciation years). There are very few examples of practical applications that can evacuate by moving the equipment during bad weather such as typhoons. With the aim of solving the above problem, we developed a self-supporting levitation type tidal power generating equipment.

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Recently, ocean energy has attracted attention as the renewable energy that can generate electricity all the time regardless the weather condition. Thus, we developed the basic structure of tidal current power generation equipment. However we found the following problems. The currents of tide at high tide and low tide are opposite each other. Thus, the blade of water turbine made a straight line. However, the generated electric power is lower than the curved blades. In order to solve the above problems, it was possible to select optimum shape of blades and provide the auxiliary buoyant body to confirm the appropriate waterline position of water turbine.

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Surveys were carried out to obtain the opinion of fishermen about offshore wind farms in Aomori Prefecture, Japan. Results of the survey: Out of the 473 fishermen surveyed, 17.3% 「Unacceptable」 offshore farms, 58.1% 「Accepted according to conditions」, 11.6% 「Accepted」, 12.1 % 「Not sure」 and 0.8% 「No answer」. The response ratio of 「Unacceptable」 varied depending on the area of sea and showed a relatively higher opposition rate on the coast of Mutsu Bay. As a result of the survey about 「Anxiety」, 「Essential conditions」 and 「Great expectations」 when accepting offshore wind farms, the responses of 「Abandonment of facilities after project」, 「Installation in areas that does not disturb the fishery」 and 「Stability of the fisheries cooperative management」had the most numbers, respectively.

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We fabricated anion exchange membranes (AEMs) with a pore-filling structure and introduced a binding between the catechol and amine groups to form new quaternary ammonium groups. In the case of polyethyleneimine (PEI) treatment, E2C1-PEI membrane exhibited a lower area resistance (0.683 Ω·cm2) and higher ion exchange capacity (1.38 meq.·g-1), compared with the E2C1 membrane. Moreover, in the case of E4C1-PEI membrane, the theoretical power density was the highest among all the samples owing to its low resistance and high transport number. Therefore, we suggested an alternative process for quaternary amination and proposed the potential application of AEMs in RED systems.

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A marine environmental data integrated acquisition platform (abbreviated MIA) was developed for offshore wind farms as a joint project of five companies in Nagasaki, Japan. The MIA consists of a spar type floater system, a Doppler LIDAR for assessment of wind power resources and sensors for assessment of animal habitat status. Demonstration test of the MIA was carried out on this newly developed platform off the Goto Islands in Nagasaki, and the practical use has been confirmed. In this paper, the authors introduce the specifications, capabilities and part of the field test results of the MIA.

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