In operating an energy supply system, it is important to determine the operational strategy such as on/off status of operation and energy flow rates for constituent equipment properly based on predicted energy demands. However, actual energy demands may differ from the predicted ones. In this paper, a method of estimating prediction intervals for energy demands based on the density distribution of prediction error is proposed. Absolute and relative prediction intervals are estimated and used selectively to make the prediction intervals narrow so that they are suitable for robust optimal operation. This method is applied to cooling demand prediction of a commercial building, and its effectiveness is ascertained.

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The thermoacoustic system has attracted attention as an effective utilization of low-temperature waste heat. The purpose of this study is to enhance the performance of the thermoacoustic cooling system by examining the cooling characteristics of the thermoacoustic refrigerator. In this paper, a straight-tube type thermoacoustic refrigerator is constructed and evaluated based on the temperature difference between the stack's edges and work intensity of sound by focusing on the geometric influence of the stack, such as the density and length. Air is employed as a working gas, and the sound source is supplied by a woofer speaker with a sound generator and power amplifier. As a result, the consumed energy in the stack increases as the length and density of the stack become longer and higher, and there is an optimum stack length to have a higher temperature difference between the stack's edges.

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This paper presents the result of the evaluation of the catalytic performance by cyclic voltammetry method and power generation experiment for a direct ethanol fuel cell at room temperature. The compound anode catalysts mass ratio of platinum to ruthenium (Pt:Ru) was adjusted at 9:1, 1:1, 3:1 and 1:3. The catalyst was used in a membrane electrode assembly. A passive fuel cell was used in the power generation experiment, and ethanol concentration was set at 1.1M (5wt%), 3.3M(15wt%), 5.4M(25wt%) and 7.7M(35wt%). It was found that the addition of ruthenium is effective for the oxidation of ethanol, and Pt:Ru=3:1 was the best catalyst mass ratio. The optimal ethanol concentration, with this catalyst, was 5.4M (25wt.%). In comparison with a platinum catalyst, the addition of ruthenium was found to be capable of achieving a better performance at a higher concentration in an aqueous ethanol solution.

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This paper shows the temperature of aqueous solution of salt as an electrolyte and the on the output of the magnesium fuel cell. Measurements were conducted under the condition of 15×15mm in reaction section, concentration of 40.0wt% and a distance of 6mm with changing the temperature of aqueous solution of salt between 10 to 60℃. As results, it is found that the maximum output can be obtained at a temperature of 60℃. I understood that the difference of the DO (Dissolved Oxygen) was proportional to electric energy.

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Since a fuel cell operating at room temperature uses platinum as catalysts and nafion as electrolyte membrane, its cost becomes high. If the fuel cell doesn't need to use nafion, platinum is also no needed. If ager is adopted for the electrolyte substituting the nafion, nickel can be used for the catalyst. In this work, the fuel cell using ager as a electrolyte was contracted and its performance test was carried out. The conditions to which electric power becomes the largest were the cases where electrode distance was 5mm and fuel concentration was 20wt%, as a result of the experiment. When the catalyst on the anode side was used nickel, electric power decreased by 30%, and when a catalyst was not used, it decreased by 45%.

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The Eco-Island Concept Demonstration Project has been implemented in Teuri Island. In order to implement an environmentally responsible power supply system for the island, a system based on solar energy generation is being considered. Since there is not any example of solar generation system in the island, there is not any study on the efficiency of the solar farm in this place. Also, since the efficiency of plant depends on the surface temperature of the cells, there is a need to study the wind condition in the island which affects this temperature. By using Solid Works, this work reproduces the solar farm and the terrain condition of the island. Then, by analyzing the heat transfer, the surface temperature considering the wind condition is studied, and in this way the conversion efficiency of the installation site is defined. Based on this result the optimal location of a solar farm was decided.

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Solar thermosyphon(TS) can transport solar heat by spontaneous circulation of working fluid without pump. The working fluid of the TS is water. We attempted hydroelectricity generation by the TS for the first time. At present, the observed power output was 10^<-6>W in the order of magnitude under the solar irradiation of 1000 to 1200W. Considering Carnot's coefficient, there is a large margin for the improvement. To increase the present low efficiency, it is needed to understand the flow characteristics and to establish proper design of hydroelectric generation unit.

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The self-circulating thermosyphon can operate without an external power supply, and as simple structure. The authors developed a self-circulating thermosyphon for transport of solar thermal energy. The solar radiation varies time to time. Therefore, the transient behaviors against varying thermal energy are important subjects. We examined about the tangent characteristics for fluctuations of thermal energy in this study. A thermosyphon showed good response to the stepwise variation of input thermal energy.

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It is necessary to research about development of renewable energy for energy source problems in the future. Development of wave activated generation is also one of those researches, and it is expected as the available way that obtains electric power from marine energy. However, it is severe problem how to construct the device that is available for complicated motion of wave on the sea surface, and this influences whether useful system is constructed. In this research, wave activated generator with device that linear motion of piston is changed to rotation is made experimentally, and the first measuring experiment is performed to evaluate whether our generator is practical. And we confirmed the generator indicates the performance similar to that of inspection at factory, and sufficient outputs that are expected for practical use.

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Gas hydrate is a compound that consists of guest molecules and water molecules, is formed by pressuring and cooling to become a condition of certain pressure and temperature. When the gas hydrate formed into a gas-tight container is heated, the dissociation of the gas hydrate increases pressure in the container. The magnitude of this pressure increase is comparable to that of the cylinder pressure of an internal combustion engine. In this paper, it is considered that two approaches for improving the thermal efficiency of the power generator. The first approach is is to be reused with each reaction heat of formation and dissociation. And second approach is to use recovery heat that occurs when the working gas expands in the turbine for formation of hydrate. Numerical analysis was carried out to investigate of above approaches using Englezos-Bishnoi model.

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In this study, a structure of "Piezoelectric generator" that can generate by using a pressure difference like blood pressure was proposed, also the generator was made and a performance of it was evaluated. An apparatus for evaluating the generator was constructed to simulate blood pressure. The relationship of voltage difference to amount of displacement was obtained when frequency and pressure difference changed. The maximum voltage difference of 45.8mV and the maximum amount of displacement of 31μm was shown when the pressure difference was 8kPa and the frequency was 0.1Hz.

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