Journal of Environmental Engineering (Transactions of AIJ)
Online ISSN : 1881-817X
Print ISSN : 1348-0685
ISSN-L : 1348-0685
Volume 75, Issue 658
Displaying 1-8 of 8 articles from this issue
  • Hiroyuki SUNAHARA, Takahiro ISHIHARA, Ken MATSUYAMA, Shin'ichi SUGAHAR ...
    2010Volume 75Issue 658 Pages 1009-1017
    Published: December 30, 2010
    Released on J-STAGE: March 02, 2011
    JOURNAL FREE ACCESS
    Oxygen Consumption Calorimetric Method is generally used for measuring heat release rate (HRR) of combustible items. However, this method might have an uncertain result for gas concentration in case of during water discharged such as sprinkler.
    In this study, we tried to find out an appropriate and simple method for measuring HRR during water discharged. A relation between HRR in free burning condition, which was calculated by mass loss rate, and radiative heat flux was obtained experimentally. The Mie theory was applied to estimate a radiative attenuation by the absorption of water droplet, because the radiative heat flux during water discharged needs to take it into account. As a result, the radiative attenuation calculated by the theory was verified by experimental data.
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  • A survey of residents' cooling behavior in prefabricated houses part 2
    Tomoaki SAWASHIMA, Naoki MATSUBARA, Yoshihito KURAZUMI
    2010Volume 75Issue 658 Pages 1019-1025
    Published: December 30, 2010
    Released on J-STAGE: March 02, 2011
    JOURNAL FREE ACCESS
    We conducted a questionnaire survey to clarify the relationships among residents' seasonal changes of lifestyle, cooling behaviors, complaints about thermal environment and residential satisfaction in summer. The people who answered our questionnaire were residents of detached houses prefabricated by a major housing company. The results or our analysis are as follows.
    All residents change their behaviors in their houses in summer, and average of number of seasonal changes is 1.5 per a family. But those seasonal changes do not reduce the use of air-conditioner, and do not increase the residential satisfaction. And some seasonal changes are correlated with the resident's complaints about indoor thermal environment. It is thought that the seasonal changes of resident's behaviors in this survey mean the lifestyle restricted by uncomfortable indoor thermal environment.
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  • Satoru OZAWA, Satoshi NAKAYAMA, Motoyasu KAMATA, Noriyoshi ICHIKAWA
    2010Volume 75Issue 658 Pages 1027-1032
    Published: December 30, 2010
    Released on J-STAGE: March 02, 2011
    JOURNAL FREE ACCESS
    This paper describes the calculation results of the potential quantity of available water resources in each prefecture. At present, there is only the data of the potential quantity of available water resources which is divided into 14 areas in Japan. It is inadequate discussion about the water resources with a viewpoint from prefecture level, so the authors adopt new calculation method. The authors focus on the regional characteristics of potential quantity of available water resources from stochastic method analysis, coefficient of variation and rate of water resources use. Kagawa, Osaka and Saitama have small amount of the potential quantity of available water resources, large coefficient of variation and high rate of water resources use. So the authors estimate that the possibility of water shortage is high in these prefectures.
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  • Weirong ZHANG, Shinsuke KATO, Yoshihiro ISHIDA, Kyosuke HIYAMA, Toshia ...
    2010Volume 75Issue 658 Pages 1033-1040
    Published: December 30, 2010
    Released on J-STAGE: March 02, 2011
    JOURNAL FREE ACCESS
    The contribution ratio of indoor climate (CRI) based on CFD was developed to estimate the individual contribution of heat factors to any location inside a room. With the index of CRI, a more precise building energy simulation or real-time systematic control can be expected, within the defined accuracy by means of CFD but with a much reduced calculation load. However most of the studies related to CRI involve forced convection airflow fields. Thus the purpose of this study is to make the CRI effective also in natural convection air flow fields. In this study, a new calculation method was proposed by means of setting a uniform heat sink, by which the steady calculation of CRI could be achieved. A CFD simulation coupled with convection and radiation has been performed in an atrium without air conditioning or ventilation. With the new method the CRI of the north wall was calculated and its influence to the air temperature at some representative locations was analyzed as an example. In addition the time response of CRI was also discussed in this paper.
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  • Yonghui LI, Daisuke OGURA, Shuichi HOKOI, Takeshi ISHIZAKI
    2010Volume 75Issue 658 Pages 1041-1050
    Published: December 30, 2010
    Released on J-STAGE: March 02, 2011
    JOURNAL FREE ACCESS
    In this study, based on the measurement data and the records of Takamatsuzuka Tumulus in the past, the effects of excavation and preservation measures after the excavation on hygrothermal behavior in the stone chamber of Takamatsuzuka tumulus are analyzed by means of numerical simulation. The obtained main results are shown as follows:
    1. Before the excavation, the annual amplitude of temperature in the stone chamber is small and relative humidity keeps nearly 100% throughout the year, and there are few dryness and condensation occur on the inside surface of the stone chamber.
    2. After the excavation, if there are no any preservation measures taken, the temperature in the stone chamber rises to 22°C in summer, and there are obviously durative dryness and condensation on the inside surface of the stone chamber.
    3. The method by covering the exposed surface of the stone chamber with certain thickness of soil is more effective on restraining the temperature rise in the stone chamber and dryness on the inside surface. However, there are no finer effects on restraining condensation both on the north wall and nearby floor in summer.
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  • Keihou KAINOU, Satoru TAKADA, Tomoaki USHIO, Takayuki MATSUSHITA
    2010Volume 75Issue 658 Pages 1051-1060
    Published: December 30, 2010
    Released on J-STAGE: March 02, 2011
    JOURNAL FREE ACCESS
    For the prevention of the stack effect in high-rise buildings in winter, this paper studied a method to cool the shaft by natural ventilation through the opening between the shaft and out air. It was shown theoretically that the shaft is effectively cooled by putting the opening in the lower level of the shaft and thus the stack effect can be effectively prevented. By the calculation for a high-rise building based on the airflow network model and the steady heat balance analysis, it was shown quantitatively that the studied method is effective for general high-rise office buildings and that a careful survey is necessary before introducing this method for the following cases: 1)a case in which the down flow occur in the shaft influenced by the existence of another shaft, 2)a case in which there is no opening to the outside in the upper level of the shaft, 3)a case in which the humidity of the building is high.
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  • Evaluation of indoor air quality using biosensor based on Japanese killifish, medaka Part 2
    Jonghun KIM, Shinsuke KATO
    2010Volume 75Issue 658 Pages 1061-1067
    Published: December 30, 2010
    Released on J-STAGE: March 02, 2011
    JOURNAL FREE ACCESS
    In order to develop an early-warning biosensor system based on Japanese medaka (oryzias latipes) for predicting the impact on health of long-term and low-level exposure to indoor chemical compounds, we investigated the effect on behavioral changes of medaka exposed to Dichlorvos (2,2-dichlorovinyl dimethyl phosphate, DDVP), which is a kind of agricultural compounds having a potential to flows into indoors and be inhaled by resident and may affect residents' health badly and fatally in agricultural districts, as well as Formaldehyde and Toluene which are representative indoor chemicals. We used a laboratory water-quality measuring instrument to observe behavioral changes of fish. During the experiments, the three-dimensional coordinates of the fish are recorded by two CCD cameras every three seconds. P value of <0.05 was considered to indicate significance. When exposed to these chemicals in water, the fish showed the altered behaviors compared to one under a control treatment, e.g. body movement distance and duration time near the lower water column by the fish significantly decreased, while body angle near the upper water column and duration time near the upper water column by the fish increased compared to the normal state.
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  • Study on energy simulation coupling with CFD for HVAC system Part 1
    Gyuyoung YOON, Junya KONDO, Yuka SAKAI, Takuma TAKESHIMA, Satoru IIZUK ...
    2010Volume 75Issue 658 Pages 1069-1076
    Published: December 30, 2010
    Released on J-STAGE: March 02, 2011
    JOURNAL FREE ACCESS
    The subject of this study is to improve the efficiency of the air-conditioning system, and to support the life cycle energy management for HVAC system of the building. And, it is considered that the HVAC system simulation tool coupling with CFD is a useful measure to realize the subject of this study.
    In this paper, it is described the significance to apply the coupling HVAC simulation tool and CFD. And, the application possibility in each phase of the life cycle energy management is shown. Also, the case study result corresponding to HVAC system using under-floor will be shown at the design stage. The cooling load of chilled water was estimated by applying system simulation tool with coupling with CFD. We found out that it is possible to estimate the proper cooling load of chilled water while the distribution of room temperature is represented by CFD. Finally, the energy consumption and system COP for primary sub-system with cooling load of chilled water estimated by using the couple with CFD.
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