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IWAMAE Atsushi

    Department of Architecture　Professor/Vice President
Last Updated :2024/04/25

Researcher Information

URL

J-Global ID

Research Interests

  • 環境負荷   耐用性   耐久性   快適性   省エネルギー   エネルギー消費   Insulation   Save energy   Humidity   

Research Areas

  • Social infrastructure (civil Engineering, architecture, disaster prevention) / Construction environment and equipment

Education

  •        - 1986  Kobe University  工学研究科  環境計画学専攻
  •        - 1984  Kobe University  Faculty of Engineering  環境計画学科

Association Memberships

  • 空気調和・衛生工学会   日本建築学会   

Published Papers

  • Koji Fujita; Satoshi Matsuoka; Atsushi Iwamae; Noriaki Ota
    AIJ Journal of Technology and Design 25 (60) 753 - 758 2019/06 [Refereed]
  • Toshiharu Ikaga; Rika Eguchi; Shuzo Murakami; Atsushi Iwamae; Tanji Hoshi; Tadashi Mizuishi; Shun Kawakubo; Kumi Okumura
    Journal of Environmental Engineering 76 (666) 735 - 740 1348-0685 2011/08 [Refereed]
     
    It takes many years to recover the initial investment cost for installing housing insulation through savings from energy reduction (Energy Benefit:EB), since construction cost is very high in Japan. This long payback time is the major barrier to the promotion of well-insulated houses. However, it has been found that if Non-Energy Benefits (NEB) of well insulated houses, such as improvement in personal health, reduction of medical expenses and decline in absences from work are all taken into account, the time required to recover the initial investment cost would change from 29 to 16 years. Therefore recognition of NEB is expected to encourage residents to invest in residential thermal insulation. NEB of well-insulated houses is thus evaluated regarding human health in this study.
  • Yasushi Kondo; Atsushi Iwamae; Yasuhiro Nagasawa; Tetsuo Fujimoto; Yusuke Kikuchi; Taichi Tasaka
    Journal of Environmental Engineering 75 (649) 261 - 269 1348-0685 2010/03 [Refereed]
     
    In order to save energy consumption for air-conditioning of buildings throughout those lifecycle, thermal performance of insulation materials applied in buildings should be kept in required value. On the other hand, there are many factors of ageing of insulation materials such as ambient temperature, vibration and moisture etc. In the previous paper, main factors of thermal performance change were discussed and several experimental results were shown. This paper examines the influences of moisture on thermal performance of various insulations based on three kinds of experiment. In first experiment, the relationship between equilibrium moisture content and thermal conductivity of fiber insulations is obtained. Second experiment is on the influence of gaseous moisture on fiber insulations and the results show that the dimension change of fiber insulations is small even in very humid condition. Third experiment is on the reversibility of thermal conductivity after the internal dew condensation process and the dry process, and the results show that many insulation materials have reversibility except for several plastic insulation foams.
  • Yasushi Kondo; Atsushi Iwamae; Yasuhiro Nagasawa; Tetsuo Fujimoto; Yusuke Kikuchi; Taichi Tasaka
    Journal of Environmental Engineering 74 (643) 1049 - 1057 1348-0685 2009/09 [Refereed]
     
    Thermal performance of insulation materials decreases with the passage of time. Such ageing of insulations should be considered in the design stage of buildings to keep insulation performance within the required one throughout the lifecycle of buildings. Firstly this paper focused various factors that affect performances of insulations. The main factors for fiber insulations are moisture vibration and microbe. The main factor for plastic insulation foams is ambient temperature that accelerates the diffusion of blowing agent. Secondly real performances of sold new insulations and scraped old ones were measured and compared the required value by Japanese standard. Performances of some insulations were lower than standard values and performance change was detected. Finally this paper discussed the influence of vibration on performance for fiber insulations based on the experimental data. The changes of insulation depth and thermal resistances were observed after the vibration test.
  • Hisaya Nagai; Hirotaka Suzuki; Yukie Kitadani; Atsushi Iwamae; Kazuya Kominami; Yuzo Sakamoto
    Journal of Environmental Engineering 74 (638) 457 - 463 1348-0685 2009/04 [Refereed]
     
    There are two points of view for the prevention design of moisture problem in the building insulated envelope. One is the strictly prevention of high moisture condition in the insulated wall cavity. The other one is the permission of short-term high moisture condition, condensation and high moisture content of the wooden material as long as keeping physical durability. If the later standpoint were chosen, the insulated envelope design of every variety for Japan would be possible. Nevertheless, there are no criteria to estimate the damage of physical durability of wood by the biological factors related high moisture condition. In the previous paper, we reported about the concept of the prevention design of moisture problem in the building insulated envelope and the relationships between water content and decay various woods under hygrothermal steady conditions. In this paper, the relationships between water content and decay of various woods under two kinds of hygrothermal transient conditions are shown.
  • Hirotaka Suzuki; Yukie Kitadani; Atsushi Iwamae; Hisaya Nagai; Kazuya Kominami; Yuzo Sakamoto
    Journal of Environmental Engineering 73 (627) 591 - 597 1348-0685 2008/05 [Refereed]
     
    There are two points of view for the prevention design of moisture problem in the building insulated envelope. One is the strictly prevention of high moisture condition in the insulated wall cavity. The other one is the permission of short-term high moisture condition, condensation and high moisture content of the wooden material as long as keeping physical durability. If the later standpoint were chosen, the insulated envelope design of every variety for Japan would be possible. Nevertheless, there are no criteria to estimate the damage of physical durability of wood by the biological factors related high moisture condition. The points of this paper are as follows 1) The importance of estimation damage of woods by the moisture problems is describes. 2) 2 case of hygrothermal steady state experiments were done to get basic acknowledge of woods damage by biological factors considering term, water content, temperature and humidity, physical durability.
  • Koji Fujita; Atsushi Iwamae; Takayuki Matsushita; Hiroshi Nakagawa; Hiroshi Yokoyama; Kyoji Ishizu
    Journal of Environmental Engineering 73 (626) 479 - 486 1348-0685 2008/04 [Refereed]
     
    We present a heating system with thermal storage using a heat pump which supplies heat to the thermal storage installed in a crawl space of a residential house insulated at the foundation walls. We used latent thermal storage materials. This system can charge heat by using cheap nighttime electricity and discharge the stored heat at daytime. We showed equations to determine the air volumes of the heat pump and the ventilator, and equations to determine the phase transition temperature and the amount of the latent thermal storage materials to keep the room setting temperature. We constructed a computer simulation program of this heating system and confirmed the validity of these equations.
  • Koji Fujita; Atsushi Iwamae; Takayuki Matsushita; Kyoji Ishizu; Hiroshi Nakagawa
    Journal of Environmental Engineering 73 (626) 471 - 478 1348-0685 2008/04 [Refereed]
     
    We present a heating system with thermal storage using a heat pump which supplies heat to the thermal storage installed in a crawl space of a residential house insulated at the foundation walls. We used sensible thermal storage materials. This system can charge heat by using cheap nighttime electricity and discharge the stored heat at daytime. It is revealed by experimental studies that thermal behavior of the room is greatly influenced by the heat capacity of the thermal storage. We constructed a computer simulation program of this heating system and showed the ratio of the stored heat for generated heat by the heat pump with the volume of the thermal storage materials. We showed the way to determine the volume of the thermal storage materials and the capacity of the heat pump.
  • Koji Fujita; Atsushi Iwamae; Takayuki Matsushita
    Journal of Environmental Engineering 73 (625) 291 - 297 1348-0685 2008/03 [Refereed]
     
    'Crawl-space heating' is a heating system using the crawl space as a duct for heat transport from a heat pump. The purpose of this study is to grasp the convective heat-transfer coefficient at the slab-concrete surface and the floor-under surface, under the condition of crawl-space heating. When the crawl-space heating is operated, the air velocity in the crawl space is generally 0.05-0.20m/s and the heat transfer is caused by both the forced convection and the natural convection. We measure the convective heat-transfer coefficient by the wind tunnel test. It is revealed that the convective heat-transfer coefficient at the slab-concrete surface is about 1.0-4.0W/m 2K and that at the floor-under surface is about 6.0-10.0 W/m 2K.
  • Atsushi Iwamae
    BUILDING SIMULATION 2007, VOLS 1-3, PROCEEDINGS TSINGHUA UNIVERSITY PRESS 6 (7) 231 - 237 2007 [Refereed]
     
    It is well known that humidity influences cooling load, thermal comfort and durability of buildings and various items in them. Many works on prediction of humidity variation in a room have regarded the humidity as unique in a space. However, it does depend on air movement. This paper describes calculations of minute moisture distributions in a room affected by moisture buffering of porous walls. The air velocity distribution is calculated by CFD using two different turbulence models. Then the heat and vapor transient transport in walls and space is calculated. This shows that moisture distribution is not negligible. The difference between the two turbulence models is also determined.
  • FUJITA Koji; IWAMAE Atsushi; MATSUSHITA Takayuki; KITAGAWA Kenji; HANIBUCHI Haruo
    Journal of Environmental Engineering (Transactions of AIJ) Architectural Institute of Japan 71 (607) 65 - 70 1348-0685 2006/09 [Refereed]
     
    In this paper, we report the experimental studies which were carried out in an experimental house with thermal insulation for its foundation walls, concerning (a) the indoor thermal environment and (b) the heat flow in the crawl space to the ground and to the floor, under the condition of crawl space heating. The main results which we obtained are as follows: 1. The temperature in the room ranges from 18 to 21℃, and that of the floor surface becomes over 23℃. 2. When a fan is put in operation in order to control a current of air in the crawl space, the flow of the heat towards the floor increases, but that towards the ground also increases out of the warm air blowing out zone. 3. It is suggested that most of the heat to the ground is brought by radiation from the lining of the floor.
  • IWAMAE Atsushi
    Techinical Papers of Annual Meeting the Society of Heating,Air-conditioning and Sanitary Engineers of Japan The Society of Heating, Air-Conditioning Sanitary Engineers of Japan 14 (1) 277 - 280 2002/08
  • IWAMAE Atsushi; MATSUMOTO Mamoru; CHIKADA Toshiya; MATSUSHITA Takayuki; MATSUMURA Osamu
    Journal of Architecture and Planning (Transactions of AIJ) Architectural Institute of Japan 65 (528) 29 - 36 1340-4210 2000/02 [Refereed]
     
    We found many houses have condensation in the crawl space in summer. These houses have enough openings on the foundation to ventilate and vapor retarder at the ground surface for the recommend in the building code. The temperature and humidity in the crawl space have great influences to durability of the house. We made clear the annual variations of hygro-thermal environment of the crawl space by the field measurements and numerical analysis. We monitored the temperature and humidity variations of 36 houses in Japan for 2 years. The numerical calculations based on the vertical one dimension heat transfer model represented the monitored results. The results show the houses in Japan normally have condensation in crawl space in summer. The condensation term is from one week to one month. The daily average of crawl space's vapor pressure is nearly equal to that of the outdoors. The difference of 2 years results is so great that we think the main factor is outdoor condition. The thermal resistance of the floor and moisture of the ground do not have great effect on the crawl space humidity.
  • 本間義規; 鈴木大隆; 坂本雄三; 永田明寛; 岩前 篤
    計画系論文集 525 (525) 33 - 38 1999/11 [Refereed]
  • IWAMAEA Atsushi; MATSUSHITA Takayuki; MATSUMOTO Mamoru
    Techinical Papers of Annual Meeting the Society of Heating,Air-conditioning and Sanitary Engineers of Japan The Society of Heating, Air-Conditioning Sanitary Engineers of Japan 11 (1) 125 - 128 1999/08
  • 岩前 篤; 松本 衛
    計画系論文集 468 (468) 17 - 25 1995/02 [Refereed]

MISC

Research Grants & Projects

  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2015/04 -2019/03 
    Author : HAMADA Nobuo
     
    Contamination of thermophilic fungi (grown at 40 C) in house dust was studied. The number of A. fumigatus in house dust was affected by temperature and humidity in the climate. Moreover, the number of thermophilic fungi in Okinawa with subtropical climate was larger than that in Osaka or Kochi Prefecture. Thus, the higher humidity as well as temperature in the outdoor environment seems to affect the thermophilic fungal contamination indoors. Global warming translation is thought to bring apparently a more suitable environment for thermophilic fungi. i.e. A. fumigatus.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2012/04 -2015/03 
    Author : YOSHINO Hiroshi; HASEGAWA Kenichi; YANAGI U; IWAMAE Atushi; ZHANG Qingyuan; KAGI Naoki; GOTO Tomonobu
     
    We conducted questionnaire survey and field measurements on 6 cities in China. Results of the questionnaire survey suggested the association between mold and chemical pollution and children’s allergic diseases. The results also showed that the prevalence of allergic diseases in southern three cities was higher than that in northern three cities. On the other hand, results of the field measurements showed that there was no difference in air concentrations of fungus and chemical substances between the groups with and without allergic diseases. However, concentrations of TVOC and PM2.5 were higher in southern cities than in northern cities, and it is not contradictory to the prevalence of allergic diseases. Measured indoor temperature and humidity suggested that Chinese houses were little improved on thermal insulation but reduced air change rate in this decade. We proposed the minimum thermal resistance of houses for preventing winter dew condensation from the aspect of mold prevention.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2008 -2011 
    Author : YOSHINO Hiroshi; HASEGAWA Kenichi; IWAMAE Atsushi; YANAGI U; ITO Kazuhide; MITAMURA Teruaki; NOZAKI Atsuo; IKEDA Koichi; KISHI Reiko; MOCHIDA Akashi
     
    The purpose of this research is to clarify the optimal design method and lifestyle for solving the problem of a damp building. Therefore, nationwide survey about the damp building was conducted, and the relationship between living environment and a resident's health was clarified statistically. The use effect of high humidity environmental relief technology, such as hygroscopic material was evaluated using the experiment and the simulation.
  • 住宅におけるエネルギー消費構造
    Date (from‐to) : 2001 -2007
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2004 -2006 
    Author : SAKAMOTO Yuzo; IWAMAE Atsushi; NAGAI Hisaya; SAWACHI Takao; SUZUKI Kentaro
     
    Research results are composed of the following two terms. 1. Experiments on wood decay Principal members of the investigators had visited famous laboratories in Canada and Germany and surveyed the state-of-the art researches about wood decay. On basis of these surveys, Hygro-thermal simulations were performed to predict temperature and humidity inside insulated wood-frame envelopes. Experimental conditions in temperature and humidity were defined using these simulation results. Long term experiments on wood decay had been conducted under those conditions. In these experiments, periodical observation of wood specimens regarding mould, activity of rot bacteria, color change and deformation was carried out, and measurements were also done in weight and dimension. In addition, mechanical strength, such as longitudinal compressive strength, was measured every month after drying out wood specimens 2. Formulation of biological damage function on wood products By analyzing the above experimental results, knowledge about wood decay was systematized. New biological damage function was formulated according to that knowledge and is also a goal of this project. In the damage function, damage is expressed with durability deterioration. Furthermore the durability deterioration is indicated by degree of decay. Finally degree of decay is formulated with moisture content, time equivalent to hypha growth and so forth, which is an important result of the project. Consequently the damage function enables engineers and designers to predict degree of decay and durability deterioration in wood products numerically, if they will conduct hygro-thermal simulation in insulated envelopes and can obtain temperature, humidity and moisture content.
  • 建築熱湿気環境と耐用性に関する研究
    Date (from‐to) : 1998 -2006
  • Heat and mass transfer in the porous medium Save energy for heating and cooling Thermal impact to human Insulation technique for residential houses

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