Yoshiaki Tanzawa

Effect of operating methods of wind turbine generator system on net power extraction under wind velocity fluctuations in fields

The effect of how a wind turbine generator system is operated is discussed from the viewpoint of net power extraction with wind velocity fluctuations in relation to the scale and the dynamic behavior of the system. On a wind turbine generator system consisting of a Darrieus-Savonius hybrid wind turbine, a load generator and a battery, we took up two operating methods: constant tip speed ratio operation for a stand-alone system(Scheme1) and synchronous operation by connecting a grid(Scheme2). With our simulation model, using the result of the net extracting power, we clarified that Scheme1 is more effective than Scheme2 for small-scale systems. Furthermore, in Scheme1, the appropriate rated power output of the system under each wind condition can be confirmed.

Classification of gaze preference decision for human-machine interaction using eye tracking device

This paper aims at classifying a gaze preference decision made taking individual difference into account. A proposed method focuses on a likelihood of a chosen face to the subject’s eye movement data measured by an eye tracking device and classifies the decision using an inferential statistical theory. A system is designed as changing displayed visual stimuli flexibly using the measured eye movement data as an image switcher. In order to discuss the proposed method, experiments using the image switcher are done. Two conditions are compared in experiments, i.e., one is when two faces are displayed side by side statically, and the other is when the face the subject tries to look at disappears dynamically. Thus, the proposed classification method is enhanced by discussing interesting results of the visual-psychophysical experiments, to supplement and progress the gaze cascade effect, which is a well known hypothesis of a psychophysical experiment.

Experimental results of an ammonia-water mixture turbine system (Part 2: Effect of the Ammonia Mass Fraction)

This paper is an additional report to the paper by Amano (2001). In this paper, the authors report the additional experimental results of the effect of an ammonia mass fraction at the inlet of the AWM (Ammonia-Water Mixture) vapor generator in the AWM turbine system. The AWM turbine system features the Kalina Cycle technology. The 70KW-experimental facility was built in order to gain knowledge for practical applications. The heat source is the exhaust steam from a back-pressure steam turbine. The AWM turbine system is installed at the bottoming stage of a combined cycle which has a gas turbine, a steam turbine and an AWM turbine for cascade utilization of heat. The authors designed and constructed an experimental facility, the ACGS (the Advanced Co-Generation System), to investigate various energy-saving technologies for a distributed energy supply system in the Advanced Research Institute for Science and Engineering at Waseda University. One of the main targets is a hybrid combined heat and power supply system that uses AWM as its working fluid. The AWM turbine system was developed for the bottoming stage of a “trinary turbine cycle system” which is composed of a gas turbine, a steam turbine and the AWM turbine systems. The experimental results of the ammonia mass fraction to the cycle efficiency are investigated with a range of the ammonia mass fraction between 0.4 [NH3 kg/kg] to 0.7 [NH3 kg/kg]. It shows that there are optimal operating conditions depending on the heat source temperature with an ammonia mass fraction of the cycle. The simulation model of the AWM turbine system shows good agreement with the experimental data.Copyright

Optimum Method of Operating the Wind Turbine-Generator Systems Matching the Wind Condition and Wind Turbine Type

Publisher Summary The optimum method of operating the wind turbine-generator systems matching the wind condition and wind turbine type is discussed in light of net power extraction under field wind conditions. This chapter examines three types of wind turbines: the Darrieus–Savonius hybrid wind turbine, the Darrieus turbine proper, and the Propeller turbine. The operating methods matching utilization types of wind energy take up a constant tip speed ratio operation for stand-alone power systems and a synchronous operation for utility power systems (Scheme2). The computed results using dynamic simulation model show that the inherent characteristics of each wind turbine have an effect on net power extraction in fields. Thus, an appropriate scaling of the system and operating method exist for each wind condition, and each wind turbine type.

Development of wide angle fovea telescope

This paper describes a wide angle fovea (WAF) telescope developed for supporting rangers to help the people floating on the sea because of serious Tsunami disaster. The WAF telescope is designed using a proposed Multiple-Stage WAF model which has a wide field of view (FOV) not to miss a moving target captured inside once and a high magnification in the central FOV to observe in detail, simultaneously. This design concept has been inspired from a smart function of the actual human eye. In other words, the authors have given an optical telescope multiple functions of both wide-angle surveillance and detailed observation in order to improve its availability. Specification of the prototype has been determined paying attention to this point of view. The produced prototype has achieved a handy size by using two aspherical surfaces in the whole lens compound system.

A study on color information corrected in human brain — Measurement and evaluation of color propagation

There exists a well-known visual illusion with respect to color propagation. That is, a human subject confuses a color in the subjects peripheral field of view (FOV) as another color in the central FOV (with a shape of circular disk) spreads into the peripheral FOV or as a color in the peripheral FOV erodes another color in the central FOV (also with a shape of circular disk) when he/she keeps gazing at a specific color visual stimulus in his/her central FOV for more than several seconds. In this paper, the authors experiment this illusion using multiple naive subjects in conditions of the visual stimuli as the central or peripheral colors and the disk size change. This paper has proposed a rate of propagation as a criterion and has analyzed and discussed the illusion using it.

Wind Direction Characteristics of a Vertical Axis Wind Turbine Using the Mechanism of a Bird’s Wing With a Wind Collector

This paper describes the wind direction characteristics of the wind collector used for our 8th model of the vertical axis wind turbine using the mechanism of a bird’s wing. The 8th model is divided into two sections top and bottom. Each section looks like a Savonius wind turbine. The blade is divided into seven rows of plates. Each 0.18mm stainless plate has only one side attached to the frame. Wind from the outside enlarges the space between the blades, and passes through. However, wind from the inside closes the space. In the wind collector, four wind collection boards are located every 90 degrees around this wind turbine. In an earlier paper, it was confirmed that these collection boards collected 1.6 times the wind and resulted in twice the output. In this paper, the variations in the wind collector characteristics due to the wind direction are clarified experimentally. A wind tunnel experiment using six different wind directions shows that the output increases for four wind directions and decreases for one wind direction. Additionally, the computer simulation confirms the wind direction and the wind speed distribution around the wind turbine when the wind collection boards are in place.© 2011 ASME

Flexible heat-to-power ratio co-generation system with ammonia-water mixture cycles at bottoming

This paper presents the experimental study of a unique cogeneration system which the authors call the “Advanced Co-Generation System (ACGS)”. It mainly consists of three turbine systems and an ammonia absorption refrigerator (AAR). The specialty of the ACGS is the bottoming stage employing an ammonia-water mixture (AWM) as the working fluid. First, the overall system configuration and some experimental results at the steady state are shown. The experimental investigation shows that the AWM bottoming cycles contribute to a higher efficiency of the system. An increase of 5–10% in electric power compared to a conventional co-generation system (CGS) is confirmed. Next, a hybrid configuration of the AWM turbine (AWMT) cycle and the AAR is investigated. A simulation model is constructed. The results of the simulation show that the hybrid configuration performs at about 14% higher efficiency.Copyright

Design of a Wind Turbine-Generator System Matching Wind Conditions and Dynamic Behavior of the System.

The conformability of rated power output of the system to wind conditions is investigated theoretically with our simulation model on a wind turbine-generator system consisting of a Darrieus-Savonius hybrid wind turbine and a load alternator. As a computed result of the dynamic behavior of the systems which are operated at a constant tip speed ratio, it is clear that a large-scale system is effective with net extracting power in catching wind power at high velocities. However, an excessively large-scale systems do not always have an advantage over small-scale systems because the rotational speed allowed by the strength of the blade and excessively high velocities limits the power extraction. Regarding the effective power coefficient, it is clarified that a small-scale system is more effective than a large-scale one because of the dynamic characteristics of the system. Hence, it is shown that a conformable rated power output of the system exists for each wind condition.