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Engineering, Japan

Honma M.,Nikken Sekkei Ltd. | Kawase T.,Chiba University
Journal of Light and Visual Environment | Year: 2011

In a system that automatically adjusts the slat angles of horizontal blinds, it is possible to allow skylight in while shielding direct sunlight. This can lead to good energy savings since it can reduce the need for artificial lighting without increasing the air-conditioning load. Our research has previously demonstrated this effect of reducing the amount of energy consumed by artificial lighting by controlling the blind slate according to the amount of skylight in an existing office building. However, it was confirmed that the occupants were dissatisfied with the system since it controlled the blinds to shut even though toe occupants observed no direct sunlight and they could not clearly see out the windows. Therefore, this study was conducted with the aim of setting threshold values between the existence and non-existence of direct sunlight based on daylight conditions, so that the automatic controlling of blind slat angles would be ceased to allow slats open when they do not need to block direct sunlight. Source

Shinomiya N.,Kobe University | Takada S.,Kobe University | Ushio T.,Nikken Sekkei Ltd.
Journal of Environmental Engineering (Japan) | Year: 2015

In winter, environmental problems caused by the stack effect occur in high-rise buildings. In order to prevent the stack effect, it is necessary to estimate the behavior of the natural ventilation quantitatively for a whole building. In this study, we measured pressure difference at elevator doors in an actual building through one winter, and at the same time, the numerical analysis by the airflow network model were performed. As the results, the calculated pressure differences at the elevator door on the top and bottom floor showed good agreement with the measured values for both mghttime and commuting time. Source

Yamaguchi T.,Nikken Sekkei Ltd. | Katsura T.,Hokkaido University | Nakamura Y.,Nippon Steel and Sumikin Engineering
Journal of Environmental Engineering (Japan) | Year: 2015

The authors established a technique for measuring calorie output from a variable refrigerant flow air conditioning system by applying the refrigerant enthalpy method. In this paper, the advantages of the measuring technique and its detailed estimation process of the calorie output are introduced. In addition, the measurement with water cooled variable refrigerant flow air conditioning system was carried out in order to confirm the accuracy of technique. In this actual measurement, it was shown that measuring the appropriate pressure of refrigerant in the heat pump is important to achieve the measurement accuracy. As the another results of actual measurement, the error of estimation values of heat quantity between the established technique and the conventional one is less than 20 % for cooling and heating, respectively. Therefore, the technique for measuring calorie output that the authors established has the high measurement accuracy. In addition, the authors suggested operation improvement method by analyzing measured values such as pressure, calorie output, electric power consumption and so on. As the results, it was confirmed that COPs is improved in the cooling period by lowering the high side pressure of refrigerant in the heat pump depending on the inlet water temperature in the primary side of the pump. Source

The purpose of this paper is to propose simulated earthquake ground motions for the structural design of buildings subjected to a surface rupture with a large permanent displacement (fling step). The seismic waveform is synthesized as a pulse, with the Fourier amplitude based on the1.model and the Fourier phase consisting of uniform phase differences. It is shown that the time history of the displacement, obtained by integrating the synthesized wave, can be interpreted as the source time function associated with fling step, which is characterized by a large and permanent displacement of the ground in one direction. Moreover, it is demonstrated that the dynamic behavior of buildings is properly evaluated when the synthesized wave is used as input. The average slip velocity of fling step will provide an effective index for the dynamic analysis of structures. Source

Yamane T.,Nikken Sekkei Ltd. | Nagahashi S.,Chiba Institute of Technology
Journal of Structural and Construction Engineering | Year: 2010

The purpose of this paper is to present a superposition technique for seismic waves from consecutive earthquakes. Seismic waves from each earthquake are synthesized by the waveform generation methods proposed in previous papers. The consecutive seismic waveforms are superposed so as to match the positions on the time history axis with respect to a wave arriving from the border between fault planes, considering the relationship between the distribution of phase differences and the time history of the accelerogram. By analyzing the dynamic behavior of high-rise buildings using the proposed superposition technique, it is indicated that a proper evaluation of ground motions is important in the case of consecutive earthquakes. Source

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