日本建築学会環境系論文集
Online ISSN : 1881-817X
Print ISSN : 1348-0685
ISSN-L : 1348-0685
86 巻 , 783 号
選択された号の論文の15件中1~15を表示しています
  • 大宮 喜文, 姜 昇具
    2021 年 86 巻 783 号 p. 409-418
    発行日: 2021/05/30
    公開日: 2021/05/30
    ジャーナル フリー

    The aim of this study is to quantitatively grasp the effect of excess fuel gas on the temperature distribution of the fire plume ejected from an opening when the amount of combustible gas generated in the compartment was changed using a large-scale model.

    In this study, the experiment device composed of compartment and facade. The compartment size was Width 2 [m] x Depth 2 [m] x Height 2 [m]. The dimensions of the facade were Width 3 [m] and Height 3.5 [m]. The urban gas was used as a fire source, and a gas burner (Width 0.3 [m] x Length 1.8 [m]) was installed in the center of the compartment floor. The measurement items were temperature inside compartment and temperature of the fire plume ejected from an opening, which were measured using a thermocouple. As the experimental conditions, the opening shape and the heat release rate of the fire source were changed. The opening aspect ratio was in the range of 1 to 6, and the opening conditions were 6 conditions and the heat release rate of the fire source was set to 6 conditions.

    The following findings were obtained from this study.

    (a)The central axis of fire plume ejected from an opening

    ・The central axis of fire plume ejected from an opening tends to be away from the facade surface under the opening

    condition with the opening aspect ratio of 3 or less, and move along the vicinity of the facade surface under the opening condition with the opening aspect ratio of 4 or more.

    (b) Relationship between average temperature rise within the compartment and of ejected fire plume at opening

    ・Under the condition that the heat release rate is set by Qvcrit, the change in the dimensionless temperature within the compartment and above neutral plane of the opening is not remarkable even if AT/AH1/2 increases.

    ・The non-dimensional temperature ΔTo,p/ΔTf,p obtained by dividing the average temperature rise of ejected fire plume at opening by the average temperature rise within the compartment is about 0.8 to 0.9.

    ・The non-dimensional temperature ΔTo,p/ΔTf,p exceeds 1 under the condition that the flame is ejected from the opening where value of AT/AH1/2 is small.

    (c) Temperature distribution of fire plume ejected from an opening

    ・By using the non-dimensional value Z*/Q*ef,w2/3 in consideration of excess fuel gas and temperature rise ΔTz, the temperature rise of RegionⅢ could be nearly expressed by Eq.(15) as Z*/Q*ef,w2/3 increases.

  • 劉 娜, 姜 叡, 西名 大作, 陸 偉, 金 華, 田中 貴宏
    2021 年 86 巻 783 号 p. 419-429
    発行日: 2021/05/30
    公開日: 2021/05/30
    ジャーナル フリー

    At present, the development of inbound tourism has become an important issue of tourism policy in Japan, since the population decrease, low birth rate and aging population problem make it difficult to expand the domestic demand. Therefore, in order to obtain some basic information about ways to attract a large number of Chinese tourists in the future, we took Chinese and Japanese students as subjects and conducted a landscape evaluation experiment with text information. By comparing the results of psychological evaluation experiments of Chinese and Japanese students between the two conditions of “only image” and “text + image”, the different influence of text information on the evaluation of landscape images due to the difference of knowledge and experience is clarified.

     

    The following conclusions can be drawn from the study.

    ● For most landscapes, the evaluation of “Willingness to visit” in the “text + image” mode had a higher evaluation than the “only image” mode in case of Japanese students like Chinese students, even though they have more knowledge or experience. In addition, Japanese students are less likely to change the way they perceive “Likeness of Japan” by adding text information.

    ● According to the correlation coefficients between the comprehensive evaluation items, for both Chinese and Japanese students, “Likeness of Japan” was not related to “Willingness to visit” in the “only image” mode, while, there was such relationship in the “text + image” mode for Chinese students.

    ● The factor analysis was applied to the data combined the image evaluation of four subject groups. Based on the pairs of bipolar adjectives with high factor loadings, factor one to four extracted were interpreted as “Inherency”, “Openness”, “Harmony” and “Traditionality” respectively. According to the results of multiple regression analysis, in two modes, Japanese students have lower determination of coefficients than Chinese students, who are familiar with the landscape. This reason is considered that they have a unique evaluation criterion different from that of Chinese students.

    ● SEM analysis showed that the biggest difference between Chinese and Japanese students was the influence of “Japanese characteristics” on “Preference”. For Japanese students, “Inherency” affected “Preference” directly in two modes, while for Chinese students, “Inherency” affected “Preference” indirectly through “Japanese characteristics” in the “text + image” mode more than the "only image" mode.

     

    From the results, the similarities and differences between Chinese and Japanese students were obtained. Especially for Chinese students, in the “text + image” mode, the text information of the tourism landscape might have affected the evaluation positively. In the future, it will be necessary to clarify that what kind of text contents can reflect the “Inherency” of landscape better.

  • 都市計画指標・物理評価・心理評価を連携する河川景観評価に関する研究 その4
    金子 京平, 西名 大作, 姜 叡, 金田一 清香
    2021 年 86 巻 783 号 p. 430-440
    発行日: 2021/05/30
    公開日: 2021/05/30
    ジャーナル フリー

    1 Introduction

    In order to help us understanding river landscape better and create value as urban river landscape resources, we need more objective and quantitative cognition. Therefore the purpose of this study is to construct a multi-level evaluation system that predict the physical evaluation of a river landscape by the city planning indexes around the river and then predict the psychological evaluation of the river landscape by the physical indexes.

    2 Outline of the study

    As a result of a factor analysis of psychological evaluations in the previous study, it was also confirmed that four factors predicted satisfaction, which was an overall psychological evaluation. In two of these factors, it was not sufficient in the prediction by the physical indexes. Therefore, the purpose of this paper was to create new physical indexes that can explain these two, “Openness” and “Complexity”.

    3 Method of the study

    We conducted two preliminary experiments and a main experiment of psychological evaluation about the river landscape. At first, preliminary experiment 1 was conducted to identify factors related to the “Openness” and “Complexity” of river landscape images. In addition, 65 CG pictures were created that are expected to show variable evaluations related to these factors, and preliminary experiment 2 was conducted to reduce the number of CG pictures from 65 to 45. Based on the above results, we conducted the main experiment and confirmed the usefulness of the new physical indexes by considering the relationship between psychological and physical evaluation.

    4 Conclusion    Major findings are as follow:

    1) From the results of preliminary experiment 1, it was confirmed that various factors have an influence on “Openness” and “Complexity”, unlike “Green-visibility” and “Constructivenss”. Therefore, it was shown that it is necessary to pay attention not only to the amount of simple elements in the landscape images but also to the positional relationship such as arrangement, density, and overlapping, as factors of “Openness” and “Complexity”.

    2) Assuming that one image is composed of multiple images, the new physical indexes obtained by disassembling the image enabled us to grasp more detailed physical evaluation, and understand the features at each point. In particular, the physical evaluation concerned with “the Buildings forming 1st Line-of-Sight Area” was confirmed to be related to the various psychological evaluation items.

    3) According to the results of multiple regression analysis, we obtained high multiple correlation coefficients in "Sense of openness" and “Sense of complexity" explained by the new physical indexes. And the proposal of new physical indexes led to the construction of a more precise predictive model.

     

    In the future, we will explore ways to further improve the accuracy of psychological evaluation prediction models. Furthermore, we will examine the relationship between physical evaluation and urban planning indexes in order to construct the multi-level evaluation system.

  • 徳村 朋子, 高橋 祐樹, 桑山 絹子, 和田 一樹, 黒木 友裕, 高橋 幹雄, 秋山 幸穂, 高橋 秀介, 篠田 純, 中川 純, 田辺 ...
    2021 年 86 巻 783 号 p. 441-450
    発行日: 2021/05/30
    公開日: 2021/05/30
    ジャーナル フリー

    As a measure to prevent the spread of COVID-19, telecommuting has been recommended by many companies since March 2020 in Japan. Even after the COVID-19 pandemic is over, the telecommuting implementation rate, including working from home, may continue to increase.

    The purpose of this study is to clarify the impact of working from home on the individual satisfaction and productivity of workers in companies that introduced the telecommuting system from April 2020 as a countermeasure against COVID-19.

    Questionnaire surveys of workers who normally work at an activity-based working office were conducted in order to compare the effects of working from home and at the office. The survey targets were workers of a research and development institute located in Chiba Prefecture, Japan. Approximately 210 employees work in the facility, of which 85% are researchers and 15% are in clerical positions. In this study, the results of three questionnaire surveys are described. We conducted a survey of “conventional office work period” in February 2020, a survey of “recommended work from home period” in April 2020, and a survey of “combined work from home and at the office period” in July 2020 where workers could choose to go to work or work from home.

    From the survey results, it was found that the working environment at home had large individual differences, and the illuminance and CO2 concentration levels often deviated from the standards of the “Ordinance on Health Standards in the Office”. Despite the environment with large differences, the satisfaction level of the thermal environment, air quality and sound was significantly higher at home. It was also found that when working from home, self-efficacy regarding control of the indoor environment increases. This is considered to be one of the reasons for the increase in satisfaction of environmental qualities at home.

    As an advantage of working from home, most office workers chose “reduction of coronavirus infection risk”. Next, more than half of the respondents chose “having no commuting stress” and “having a reduced dress code” as advantages. On the other hand, “lack of face-to-face communication” became the highest disadvantage of working from home. The degree of satisfaction with interpersonal communication was significantly lower at home than at work. In particular, the decrease in the satisfaction of informal communication was large.

    Compared to the period when workers could only work at the office or at home, the period with relative freedom to choose between both options showed a great increase in the satisfaction with the work environment and a decrease in the difficulty of performing office activities.

    In addition, a high correlation was found between the frequency of working from home and commuting time. Workers with longer commuting hours tended to work at home more frequently. Furthermore, it was confirmed that the higher the frequency of working from home, the higher the degree of satisfaction with the working environment at home.

    The most common response to the ideal rate of working from home was two times a week, but the actual rate was only 25% in the survey conducted in July. It is presumed that there were many situations in which employees chose to come to the office in order to proceed with their work duties more efficiently.

  • 山本 竜也, 三宅 博行, 山口 秀樹, 吉澤 望
    2021 年 86 巻 783 号 p. 451-461
    発行日: 2021/05/30
    公開日: 2021/05/30
    ジャーナル フリー

    While improvements in the energy-saving performance of buildings are required, productivity improvements and health management are also getting more necessary due to work style reforms. This trend demands the development of new methods which enable us to quantitatively assess the physiological and psychological quality of the built environment from the design stage. In terms of the light and visual environment, spaciousness is one of the factors that affect the comfort, intellectual productivity, and health of users of interiors.

    In this research, definition of “spaciousness” by Inui will be used, but the purpose of this study was to propose a comprehensive quantitative spaciousness evaluation index of the interiors, including spaces of different sizes and shapes, considering various factors related to light and visual environment.

    In recent years, technological developments have made complex data processing possible and expanded the range of experiment methods. VR technology is one of them, and there are many merits of using it in promoting spaciousness evaluation, such as to virtually compare spaces that are separated from each other by a great distance. This research aims to verify the validity of using VR with HMDs for spaciousness evaluation, through subject experiments in six real spaces with different volumes and usages. Volumes ranged from a minimum of 35 m3 to a maximum of 1,969 m3, and vertical illuminance ranged from 30 lx to 720 lx at the subject’s observation position. Openings were blocked from line of sight and daylight was shut off by closing the blinds. VR spaces with several lighting environments for each space were reproduced. In experiments using ME method, we compared and verified the cases where the real space and the VR space were used as the reference stimulus for the comparative stimulus of the real space. Major findings are as follows:

    1) In order to verify how well the VR space could reproduce the real space from the point of view of the optical environment, we compared the luminance of the targeted real space and the VR space, and found that high-luminance parts could not be reproduced on HMD: Oculus Quest, which has an output limit of approximately 100 cd/m2 or higher in luminance. However, the overall luminance balance, including main parts such as the floor, walls, and ceiling, could be well reproduced on VR display.

    2) There were no statistically significant differences (5% level) in 62 pairs among 65 pairs. As to the remaining 3 pairs, the light source had a large effect on the reproducibility of luminance and the relative error from the real space was relatively large. In particular, when the subject's evaluations were divided around 2.0, as in Experiment III, where the reference stimulus was 120lx and the comparative stimulus was 30lx, a reversal phenomenon occurs in which the average luminance of the real space of 30 lx including the light source is larger than that of the VR space of 120 lx including the light source due to the influence of the large light source. In conclusion, it is approximately possible to use the VR space, which does not cause luminance problems, as a reference stimulus for spaciousness evaluation.

  • 残響時間と吸音率の測定およびバイノーラル録音による住空間の音環境の印象評価
    羽入 敏樹, 星 和磨, 鈴木 諒一, 渡辺 大助
    2021 年 86 巻 783 号 p. 462-473
    発行日: 2021/05/30
    公開日: 2021/05/30
    ジャーナル フリー

    The authors conducted various studies, considering the importance of sound absorption design in realizing a comfortable sound environment in a living space. In this study, as a basic study in a real house, we measured the reverberation time, average sound absorption coefficient, and background noise level for three types of rooms: a bedroom, living/dining room, and child’s room in three model houses. In addition, we recorded the sounds in these rooms via binaural recording and conducted subjective experiments using Scheffe’s paired comparison method to analyze the impression of the sound environment in each room. The results obtained were as follows:

    1) The reverberation time of the houses surveyed was 0.34–0.51 s in the bedroom, 0.52–0.84 s in the living/dining room, and 0.36–0.67 s in the child’s room. The average sound absorption coefficient was 0.16–0.24 in the bedroom, 0.13–0.18 in the living/dining room, and 0.12–0.21 in the child’s room.

    2) As a general tendency of the average sound absorption coefficient, the sound absorption coefficient tended to be low in the band above 500 Hz regardless of the type of room.

    3) The test subject was able to evaluate the difference in the sound environment of the room by listening to the sound reproduced from the binaural recording through headphones. Therefore, with regard to the evaluation items used, the sound environment of the actual living space can be evaluated through a subjective experiment using binaural recording.

    4) The “sense of silence” and “feeling of serenity” of the sound environment of the room could not be evaluated only by the background noise level, and the effect of the average sound absorption coefficient of the room was significant.

    5) Even in an actual house, the impressions of the sound environment due to the difference in the sound absorption coefficient differed significantly. Specifically, bedrooms with higher sound absorption coefficients resulted in a higher “sense of silence,” “feeling of serenity,” and “sense of quality” compared with the living/dining and child’s rooms with lower absorption coefficients.

    The results show that a design that enhances the sound absorption coefficient may be able to create a “sense of silence,” “feeling of serenity,” and “sense of quality” in the sound environment of a real house. The experimental results from binaural recordings, including footsteps, suggest that people may evaluate the sound environment of a living space by the indoor sound generated by actions in daily life. This indicates that to realize a comfortable sound environment in a living space, it is important to consider not only a sound insulation that controls the sound from the outside, but also a sound absorption that controls the sound generated indoors.

  • 鹿倉 潤二, 井上 勝夫
    2021 年 86 巻 783 号 p. 474-485
    発行日: 2021/05/30
    公開日: 2021/05/30
    ジャーナル フリー

    To predict the heavy floor impact sound insulation, the concrete slab performance is calculated at the beginning. Moreover, the reduction performance of the floor finish structure is added to the result. Thus, it is essential to reduce prediction error about the concrete slab performance.

    The impedance method is used to predict the performance of the heavy floor impact sound of concrete slabs. The difference between the calculation result of the heavy floor impact sound by impedance method and the experimental result is affected by the error due to the condition setting of calculation and the parameters’ averaging error.

    The driving-point impedance in impact time and the basic impedance level were compared to confirm the error’s influence due to the condition setting. The results confirmed that a good correspondence was obtained by using the actual slab thickness and Young’s modulus of the concrete. Thus, the error due to the condition setting of calculation can be reduced by considering the site’s construction condition and managing it accurately at the site.

    It is necessary to improve the amount of impedance reduction by resonance because the driving-point impedance in the response time has a large prediction error even at the point, without edge fixing influence. Thus, we propose a method using an approximate function to calculate the amount of impedance reduction by resonance.

    It was confirmed that the amount of impedance reduction by resonance significantly affects the parameters’ averaging error. It was also confirmed that the prediction error can be reduced using the approximate function that is continuous at this parameter.

    Although some prediction error remains even if these results are used, considering the impedance method versatility, it is better to express the calculation result that includes the error.

  • −均等配置された全般照明方式の作業空間における検討−
    山本 竜也, 吉澤 望, 鈴木 直行, 望月 悦子
    2021 年 86 巻 783 号 p. 486-497
    発行日: 2021/05/30
    公開日: 2021/05/30
    ジャーナル フリー

    In recent years, with heightened environmental awareness and the development of new lighting control technology, various energy-saving measures for luminous environment have been adopted in offices. Among them, partial-off or dimming lighting on the ceiling, which was performed in the aftermath of the Great East Japan Earthquake, is certainly one of the effective means for energy saving, however it may cause uncomfortable non-uniformity in luminous environment. Uniformity ratio has been generally used as an index for evaluating the uniformity of lighting environment on task areas, whereas it would not always be a robust index for the uniformity of ambient lighting environment. This study aims to examine and verify several indexes for evaluating the non-uniformity of ambient lighting by comparing the occupants’ evaluation in some real work areas with the potential indexes which are calculated from luminance and illuminance distribution. The workspaces in this study are limited to open-plan offices under evenly distributed ambient lighting.

    In the experiment the occupants evaluated the lighting environment after spending at least one week under each lighting condition. The experiments were conducted at three different actual work areas. The first experiment was conducted in a room of the university laboratory. The size of the space was 4,350 mm wide, 9,650 mm deep and 2,700mm high. The graduate students in their early 20s participated in the first experiment. The second and the third experiments were conducted in the actual office. Each size of the space was 8,550mm wide, 14,350 mm deep and 2,600mm high, and 7,645mm wide, 14,350mm deep and 2,600mm high, respectively. The occupants in their 20s to 50s evaluated the luminous environment in these experiments.

    As a result of the analysis, a single regression analysis between the coefficient of variation (explanatory variable) calculated from the true values of the ceiling luminance (including light sources) and the mean values of the occupants’ assessment on non-uniformity of the spatial brightness (objective variable) showed a relatively high coefficient of determination of 0.54. Path analyses suggested that the spatial brightness had an effect on the evaluation of the non-uniformity, therefore, a regression analyses was also performed by adding the arithmetic or the geometric averages calculated from the true values of the illuminance and the luminance. The highest coefficient of determination 0.73 was obtained when both the coefficient of variation and the arithmetic mean calculated from the true values of the ceiling luminance (including light sources) were used as the explanatory variables. However, there were still some gaps between the estimated values and the evaluated ones, suggesting that there may be differences in evaluation tendencies among the different spaces. Therefore, trivariate multiple regression analyses were also performed by adding dummy variables 1on the spaces. The result showed that the explanatory power of the multiple regression analysis using the illuminance and the luminance increased from the bivariate cases to 0.87 and 0.83, respectively.

    It was found that the luminance distribution on the ceiling (including light sources) can roughly estimate the the evaluation of the non-uniformity of lighting environment in workplaces under evenly distributed ambient lighting, however, there is a possibility that the other characteristics of space that could not be analyzed in this paper would also affect the non-uniformity evaluation, and further study would be necessary on that.

  • 富樫 英介
    2021 年 86 巻 783 号 p. 498-505
    発行日: 2021/05/30
    公開日: 2021/05/30
    ジャーナル フリー

    This study investigates the history of the first recommended illuminance level in Japan as proposed by the Meishi Special Committee. The Meishi special committee was organized at the Illuminating Engineering Institute of Japan in 1935. At the time, the Luckiesh “Better Light, Better Sight” movement was popular in the United States. This movement was based on a new doctrine, “The science of seeing”, which was put forward by Luckiesh. The movement soon spread to Japan and the electric utilities used it for self promotion. At that time, Japan had a surplus of electricity and the movement encouraged architecture to be very well-illuminated.

    However, as this doctrine was somewhat commercialistic and did not take into account the different sensitivities that to Americans and Japanese have to brightness, a new “science of seeing” was required for Japan. In Japanese, this new theory was named “Meishi-ron”. The Meishi Special Committee was organized for developing the new “science of seeing”.

    The activities of the Meishi Special Committee were noteworthy in three ways. Firstly is that this committee was the first in Japan to work on establishing illuminance standards. This committee created the pre-war lighting standards, that have been carried over to the current Japanese Industrial Standards (JIS Z9110-2010).

    Secondly, this was an interdisciplinary committee of experts in the fields of physiology, psychology, lighting, and architecture. To ensure the success of its work it held a total of 50 meetings, with sufficient study periods, to ensure terminology and knowledge sharing among the experts.

    Thirdly, there were significant social changes during the period when this Committee was active. At the time when it was formed, Japan had a large electricity surplus. However, the year it ended was the year that Japan entered the Pacific War, therefore, the situation changed to one in which there was a strong need to conserve electricity. Thus, the criteria for illuminance were also strongly influenced by the social environment, the committee members were required to strike a balance between the changing social environment and the science.

  • -東北地方都市部を対象とした36年間の変化-
    長谷川 兼一, 増田 早也花, 吉野 博, 松本 真一, 竹内 仁哉
    2021 年 86 巻 783 号 p. 506-516
    発行日: 2021/05/30
    公開日: 2021/05/30
    ジャーナル フリー

    As part of an investigation aimed at gaining a better understanding of indoor thermal environments, energy consumption levels, and occupant behavior, the householders of 587 detached houses in six cities of the Tohoku City region were surveyed in the winter of 2018 via a questionnaire and recorded liquid crystal thermometer measurements. Houses in the cities of Sapporo and Fuchu were used as references. Similar investigations have been performed at 10-year intervals since 1982. The obtained data were then applied to create an overview covering the past 36 years, which resulted in additional information that will be useful for future indoor environmental design. This paper begins by describing wintertime occupant behavior changes and indoor temperature in each city over a 20-year period and then discusses changes to space-heating energy consumption during the cold winter periods. The influence of various factors on indoor morning temperatures and space heating energy consumption are then analyzed using a multivariate analysis method.

    1. The results of this investigation show that the thermal performance levels of houses the Tohoku City region are becoming increasingly similar to those of Sapporo City and that differences among all cities examined have lessened in the last 16 years. In particular, it was confirmed that the thermal performance levels of cities in the northern Tohoku City region had become closer to those of Sapporo City. From the viewpoint of thermal performance levels, these cities can be classified into the following groups: i) the cities of Aomori, Morioka, Akita and Yamagata (which have similar performance levels to Sapporo City); ii) Sendai City (including households with high energy consumption levels); and iii) the cities of Fukushima (which show performance levels similar to Fuchu).

    2. The average floor area of Tohoku City detached houses was almost the same as recorded in 2002. Additionally, we found that the use of double windows or double-paned windows has increased among Tohoku region cities since 2002, while heating times have shown overall increasing trends over the last 36 years. Previously, kerosene heaters, including both vented and portable types, were popular among Tohoku region residents, but this investigation found that kerosene heater usage rates have been decreasing since 2002 while the use of electric heaters has increased.

    3. Early morning room temperatures have been trending upward for the last 36 years. In fact, the average temperature recorded during this investigation was 17.1 ℃, which is a 1.0 ℃ increase from 2002. It is believed that this increase in the early morning temperature level was not only due to improvements resulting from insulation and airtight building envelope conditions, but also due to increased heating times.

    4. To clarify the factors influencing morning living room temperatures and energy consumption levels for space heating, a multi-level analysis method was applied. The factors that were considered to influence temperature were sunshine levels, thermal insulation, heating equipment type, heater usage times, morning thermal environment, and indoor humidity level perceptions. As for the dispersion of energy consumption for space heating, the factors considered were sunshine levels, completion, floor area, primary heating equipment, and heater usage times. It was also shown that the average energy consumption for space heating in northern cities was the highest among the cities surveyed, and that room temperatures were less susceptible to outdoor temperature declines due to increased thermal insulation performance levels.

  • 冬季の放射・対流暖房でのヒトの想像温度の考察
    佐々木 優二, 斉藤 雅也
    2021 年 86 巻 783 号 p. 517-525
    発行日: 2021/05/30
    公開日: 2021/05/30
    ジャーナル フリー

    In recent years, ZEBs, ZEHs, and other eco-buildings have been constructed both in Japan and abroad. If their occupants can alter their “lifestyle and behavior” in a way that improves the performance of environmental architecture, it will also bring about higher levels of both thermal comfort and energy conservation. To do so, it is necessary to first clarify the conditions under which the occupants adapt to the thermal environment and how they perceive the thermal environment.

    International indices such as PMV, PPD, and SET*, which are based on data from an artificial climate laboratory under steady-state thermal conditions, have been used to evaluate thermal comfort in many countries. These indicators capture thermal comfort on the assumption that “comfortable” and “uncomfortable” states are independent of each other. In contrast, the hypothesis of the authors is that the sense of "not-uncomfortable" exists as a nesting point between “comfortable” and “uncomfortable”.

    In addition, in recent years, thermal adaptation has received significant attention. Thermal adaptation is a concept that captures thermal comfort based on the principle that, “If a change occurs which causes discomfort, people react in ways that tend to restore their comfort.” “Not-uncomfortable” is a state that occupants recognize when returning from the “uncomfortable” state, and is considered to be an unsteady state. Therefore, “not-uncomfortable” can be considered the first psychological and physiological state of thermal adaptation. From the above discussion, we assumed that the discrimination of thermal adaptation was based on “not-uncomfortable” responses.

    In this study, to quantitatively clarify the “not-uncomfortable” state that is assumed by the thermal adaptation theory, we conducted experiments on subjects whose thermal environment changed from “uncomfortable” to “not-uncomfortable” and finally “comfortable”, and discussed the results based on the cognitive temperature. The subjective experiments were conducted in two rooms with radiant (N=13) and convection (N=15) heating during winter in Sapporo. During the 30-min experiment, the subjects responded consecutively to three psychological quantities: cognitive temperature, thermal comfort, and thermal sensation.

    Following are the results of the experiments.

    1) Cognitive temperature was higher in the AC room than in the PH room for 20 min after the start of the experiment. In contrast, the temperature of the PH room was 0.3–0.5 ℃ higher than the AC room after 20 min of the experiment. This suggests that the rise in room air temperature and MRT affected their cognitive temperature. Similar results were obtained for their thermal sensation and comfort responses.

    2) The subjects in AC rooms were significantly more likely than those in PH rooms to report “not- uncomfortable” at more than 60% of the time across all time periods. In contrast, the PH room had significantly more “comfortable” declarations than the AC room from 10 min after the start of the experiment, indicating a difference between the room air temperature and the increase in MRT.

    3) As thermal comfort responses change from “uncomfortable” to “comfortable” via “not-uncomfortable,” and thermal sensation responses change from “cold” to “hot” via “neutral”, this implies that cognitive temperature rose. From this result, the existence of the “not-uncomfortable” state became clear.

    4) Cognitive temperature scale was higher than room air temperature when the subjects described being “comfortable.” Therefore, the difference between cognitive temperature scale and room air temperature can be used to estimate whether occupants have adapted to a thermal environment.

  • 風洞実験による建物間距離が建物間気流及び壁面風圧に及ぼす影響の検討
    福山 莞爾, 山中 俊夫, イム ウンス, 小林 知広, 佐嶋 俊彦
    2021 年 86 巻 783 号 p. 526-536
    発行日: 2021/05/30
    公開日: 2021/05/30
    ジャーナル フリー

    Natural ventilation is one of the most fundamental passive techniques to reduce energy usage in buildings, in particular, it is important in designing office buildings or commercial facilities. The natural wind streams determining natural ventilation within urban area is complex, and natural ventilation will be greatly influenced by outside airflow conditions. Designing buildings, it is essential to predict the value of wind pressure coefficient on the building wall and sometimes wind velocity around buildings to calculate air-flow rate through openings accurately. The purpose of this study is to offer the database and prediction method of airflow rate for natural ventilation design. In this study, as the first step, the values of wind pressure coefficient and wind velocity are acquired by wind tunnel test, which are carried out under 6 conditions, i.e., varying length between buildings within block (3 conditions) and model scale (3 conditions). Using the values of wind pressure coefficient and mean wind velocity, a new indicator, “Total pressure coefficient” is calculated. Total pressure coefficient is considered to be easily evaluated from the flow model based of the loss of total pressure of flow within the channel in blocks. Thus, evaluating three parameters, i.e., wind pressure coefficient, mean wind velocity and total pressure coefficient, figured out the wind distribution around buildings in urban area. Furthermore, relationship between Reynolds number and wall wind pressure and velocity between buildings are presented.

     

    The remarks of this study are:

    ・The wind pressure on the walls between buildings is negative, and the absolute value becomes larger not only at the higher position but also between large distance between buildings.

    ・The velocity between buildings is larger at the high position, but there is no distinct difference regardless of the distance between buildings.

    ・It is foreseen it can be possible to calculate airflow by the ventilation model based on the loss of total pressure using the wall pressure on the wall of sealed model from the investigation on the total pressure distribution.

    ・The slight effect of number of blocks on the wind pressure on the wall between buildings were observed

    ・The convey of kinetic energy from above airflow into the channel flow between buildings at leeward is suggested if the area of surrounding buildings are larger.

    ・In the case of large building models, the wind pressure on the wall between buildings tend to becomes large, which is considered to be the effect of local Reynolds number between buildings. This, however, can be caused by the low static pressure near the wind tunnel floor inside approach flow caused by the wake of roughness blocks arrayed in the windward of wind tunnel because the wind velocity is not clearly affected by the model size.

  • 明石 大, 小林 知広, 山中 俊夫, 佐藤 可奈
    2021 年 86 巻 783 号 p. 537-547
    発行日: 2021/05/30
    公開日: 2021/05/30
    ジャーナル フリー

    Mid- to high-rise buildings are often provided with a 2-D anemometer on the roof top. The measured data of external wind is not only to be stored into BEMS data, but available for control of building operation as well, such as natural ventilation (NV). However, both velocity and direction around the roof top could significantly depend on location due to the flow separation and vortex, and it becomes difficult to determine the position of the anemometer. Therefore, the authors first aim to arrange basic data regarding horizontal distribution of wind velocity and direction above the building. For this purpose, in this paper, velocity fields are analyzed focusing on the vicinity of the roof top while changing external wind direction. Regarding the CFD analysis, the Large Eddy Simulation (LES), is used to investigate instantaneous velocity fields. As the first step, probability density of difference between monitored and actual wind direction were examined by LES and wind tunnel experiment. It was shown that at the low position the monitored direction differed from actual external wind direction i.e., when θ = 0° and 22.5° and measurement accuracy of direction is high if the measurement height is high as shown in Fig. 6 and Fig. 7. Second, by comparing probability of dimensionless velocity, it was indicated that wind velocity is low in separation area, and accuracy of measurement is often high when θ = 45° as shown in Fig. 10 and Fig. 11.

     

    The conclusions obtained in this paper are summarized as follows.

    (1) The probability of monitoring the same wind direction as that of external wind direction was compared at different points above roof top. In most of the cases, the higher the measurement position was, the higher the probability was. The measurement accuracy was particularly low at the lower section on the leeward except when θ = 45°. On the other hand, when θ= 45°, the measurement accuracy is high in most of the cases regardless of the measurement positions.

    (2) When only one 2-D anemometer was installed at the center of roof top, the ideal height would be at Y = 0.2L (L is the plane dimension of building model). When an anemometer was installed at Y = 0.1L, the measurement accuracy would be higher when installed at the corner than at the center.

    (3) When θ = 0°, the monitoring wind velocity was lower than that of external wind at lower section in most of the cases. However, when θ = 45°, monitored velocity was almost the same as that of external wind but at θ = 45°, regardless of the measurement height. When θ = 22.5°, the flow characteristic was the combination of θ = 0° and 45°. The decrease of wind velocity caused by separation flow at side AB was relatively small, while there existed weak wind region at side AD, as well as θ = 0°.

     

    As a future prospect, by providing the reliable monitoring method of external wind direction and velocity, the proposal of advanced control for NV such as real-time control of openings, adjusting the opening condition of selected openings, is expected. Additionally, in order to choose the appropriate measurement position, more data need to be accumulated, under many conditions such as building shapes and surrounding buildings.

  • 金 ジョンミン, 田辺 新一
    2021 年 86 巻 783 号 p. 548-556
    発行日: 2021/05/30
    公開日: 2021/05/30
    ジャーナル フリー

    Since the Great East Japan Earthquake, although it has been required to introduce renewable energy and save energy in houses, the supply and demand of electric power remains an important issue. This study’s purpose is to verify the effectiveness of combined power generation using photovoltaic power generation (PV) and solid oxide fuel cells (SOFCs) by lifestyle. We created a simulation model for a household distributed energy system with PV, SOFC, and a storage battery (BT). Focusing on understanding the impact of different lifestyles on energy consumption and the equipment capacity and power generation method to achieve a zero energy house (ZEH), we evaluated the equipment introduction effect and economic efficiency in multiple life patterns.

     

    The following observations are reported in this article:

     

    1) With regard to the energy evaluation, in single power generation, which uses only PV power generation, as the amount of PV power generation increased, the amount of sales energy increased, and the amount of purchased energy decreased. On the other hand, in combined power generation, which uses PV and SOFC, the amount of sales energy increased, however, there was no amount of purchased energy. The self-consumption decreased with the increase in PV capacity in single power generation and combined power generation.

     

    2) With regard to the evaluation of primary energy reduction rate and ZEH achievement ratio, the average primary energy reduction rate was 17% for single power generation, 37% for combined power generation (selling only PV surplus power), and 56% for combined power generation (selling surplus power of PV and SOFC). By selling surplus power from the PV and SOFC, the primary energy reduction rate increased by 19% on average. In addition, the ZEH achievement ratio increased as the amount of PV power generation increased in single power generation and combined power generation.

     

    3) With regard to the economic evaluation, the annual cost was evaluated in terms of the combination of equipment capacity by lifestyle. When selling only the PV surplus power, combined power generation reduced the annual cost by an approximately JPY 21,000 under two-person household condition and an approximately JPY 84,000 under four-person household condition compared to single power generation. When selling surplus power of PV and SOFC, combined power generation reduced the annual cost of approximately JPY 118,000 compared to single power generation.

     

    In this study, when introducing single power generation and combined power generation, we propose appropriate equipment capacity according to each power method by lifestyle and evaluated the economic efficiency. The results confirmed that combined power generation has a higher primary energy reduction rate and ZEH achievement ratio than single power generation. Moreover, the annual cost of combined power generation was less than that of single power generation. However, in this study, we fixed the BT capacity at 7.2kWh, and there were restrictions on the capacity and price of PV and SOFC, and the power price of selling and purchasing with the grid. The evaluation of equipment combination considering the BT capacity and power generation mode of SOFCs is a future task.

  • 長谷川 舞, 森 太郎, 羽山 広文, 林 基哉
    2021 年 86 巻 783 号 p. 557-566
    発行日: 2021/05/30
    公開日: 2021/05/30
    ジャーナル フリー

    Purpose

    Among the causes of death in Japanese, there are many reports that heart disease, cerebrovascular disease, respiratory disease, and unexpected drowning increase in winter. However, there are few studies on the long-term relationship between outside temperature and mortality. In this study, we analyzed the relationship between mortality statistics and the weather data from 1972 to 2015 (44 years) and explained the seasonal variation of death. The purpose of this study is to clarify the seasonal variation using the results and to use it as an index for healthy and safe architecture and city planning.

    Method

    We merged the mortality statistics from 1972 to 2015 with AMeDAS weather data to add the daily average outside air temperature on the day of death to each death data. After that, we analyzed (1) CSVM, (2) Death Index, and (3) the relationship between a monthly average outside temperature and monthly mortality rate (MOTMMR).

    Result

    (1) Calculation of the CSVM in Tokyo, Hokkaido, and the whole country showed that there was a peak of CSVM in 1998 nationwide. Next, when the CSVM for each disease was calculated, it was found that this peak was prominent in respiratory diseases. Comparing the CSVM in European countries and Japanese prefectures, the CSVM was low in cold regions and high in warm regions common to Japan and Europe. (2) In Tokyo, the Death Index in the summer season (from July to September) was high until the 1920s and decreased after the 1930s, but in Hokkaido, the Death Index in the summer season was high until 1940 and began to decline after 1950. In recent years, both Tokyo and Hokkaido have tended to rise in winter and decrease in summer. (3) We found the regression line of MOTMMR has three segments. The low-temperature part has a negative correlation, and the high-temperature part has a positive correlation. The slope of the regression line in the low-temperature was steeper in the southern region. Also, In the regression coefficients of MOTMMR from 1972 to 2011, no significant change was observed in Hokkaido, but the tendencies to approach 0 were found in southern prefectures.

    Conclusion

    (1) CSVM peaked in 1998, and the tendency was remarkable in respiratory diseases. It may be related to influenza vaccine coverage. In addition, common in Japan and Europe, the CSVM was lower in cold regions than in warm regions, and the heating habit reduced the number of deaths in winter in cold regions. (2) About the Death Index, The Death Index in Tokyo and Hokkaido showed a different tendency until 1950 and showed a similar tendency. That implied the development of water supply and sewerage improve summer death. (3) In many areas other than Hokkaido, such as Tokyo, the fluctuations in the monthly mortality rate due to outside temperatures have improved since around 1980.

    From the above, low outside air temperature is related to the rise in mortality in winter, which can be prevented by vaccination, improvement of infrastructure, improvement of building performance, and improvement of heating habits.

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