Papers - Ikaga, Toshiharu

建築設備が地球環境に関わる問題の枠組み

IKAGA Toshiharu

空気調和・衛生工学 (The Society of Heating, Air-Conditioning and Sanitary Engineers of Japan)  70 ( 2 ) 3-11 1996.02

Research paper (scientific journal), Joint Work

[第8回振興賞技術振興賞受賞物件／北信越支部] 飯綱山荘の自然エネルギー複合利用環境・設備

IKAGA Toshiharu

空気調和・衛生工学 (The Society of Heating, Air-Conditioning and Sanitary Engineers of Japan)  68 ( 12 ) 94-97 1994.12

Research paper (scientific journal), Joint Work,  ISSN  0386-4081

[講座]　大気環境の問題と対策(4)　CO2削減対策

IKAGA Toshiharu

空気調和・衛生工学 (The Society of Heating, Air-Conditioning and Sanitary Engineers of Japan)  68 ( 9 ) 43-49 1994.09

Research paper (scientific journal), Joint Work

[第28回学会賞技術賞受賞物件 建築設備部門] 東京ドームの空気調和・衛生設備と空気膜構造維持設備

IKAGA Toshiharu

空気調和・衛生工学 (The Society of Heating, Air-Conditioning and Sanitary Engineers of Japan)  64 ( 12 ) 23-35 1990.12

Research paper (scientific journal), Joint Work,  ISSN  0386-4081

[技術報告] 東京ドームの設備計画と実施 (その3)衛生設備・防災関連設備

IKAGA Toshiharu

空気調和・衛生工学 (The Society of Heating, Air-Conditioning and Sanitary Engineers of Japan)  64 ( 5 ) 59-68 1990.05

Research paper (scientific journal), Joint Work,  ISSN  0386-4081

[技術報告] 東京ドームの設備計画と実施 (その2)空調設備

IKAGA Toshiharu

空気調和・衛生工学 (The Society of Heating, Air-Conditioning and Sanitary Engineers of Japan)  64 ( 4 ) 59-70 1990.04

Research paper (scientific journal), Joint Work,  ISSN  0386-4081

[第27回学会賞技術賞受賞物件 建築設備部門] 伊藤忠横浜港北ビルの空気調和設備

IKAGA Toshiharu

空気調和・衛生工学 (The Society of Heating, Air-Conditioning and Sanitary Engineers of Japan)  63 ( 12 ) 19-30 1989.12

Research paper (scientific journal), Joint Work,  ISSN  0386-4081

建築物のライフサイクルとサステイナブルデザイン

IKAGA Toshiharu

生産研究 (東京大学生産技術研究所)  50 ( 12 ) 27-32 1998.12

Research paper (bulletin of university, research institution), Single Work

LCCM住宅評価ツールの開発

IKAGA Toshiharu

建築環境・省エネルギー情報IBEC (財団法人建築環境・省エネルギー機構)  32-6 ( 189 ) 39-44 2012.03

Research paper (scientific journal), Single Work,  ISSN  0389-2638

健康の経済価値評価

IKAGA Toshiharu

コミュニケーション・レポート (財団法人住宅産業研修財団)   ( 189 ) 10-19 2012.02

Research paper (other academic), Single Work

知的生産性研究最前線　経済性と評価／格付部会

IKAGA Toshiharu

建築環境・省エネルギー情報IBEC (財団法人建築環境・省エネルギー機構)  32-2 ( 185 ) 31-34 2011.07

Research paper (bulletin of university, research institution), Single Work,  ISSN  0389-2638

低炭素化と健康維持増進を両立する住まいづくり

IKAGA Toshiharu

住宅金融 (独立行政法人住宅金融支援機構)   ( 16 ) 61-69 2011.02

Research paper (bulletin of university, research institution), Single Work

特集：住まいと健康、 快適な暮らしは、健康的な住まいから

Toshiharu IKAGA

きづき (ＯＭソーラー（株）)  23   8-16 2014.01

Research paper (scientific journal), Single Work

対談：家づくりは家族の健康のために

Toshiharu IKAGA and Akihisa IIDA

チルチンびと (株式会社風土社)   ( 44 ) 46-51 2013.12

Research paper (scientific journal), Joint Work,  ISSN  06150-01

Item response theory in building environment engineering: a novel approach to identifying key residential environment items

Shun Kawakubo, Tomomitsu Kamata, Shiro Arata, Shuzo Murakami, Toshiharu Ikaga, Yoshihisa Fujino, Junta Nakano, Shintaro Ando

Building and Environment (Elsevier BV)  262   111764 - 111764 2024.06

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0360-1323

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The residential environment significantly influences residents’ health, quality of life, and well-being. Therefore, it is essential to assess the residential environment and implement improvement measures when problems are identified. In this context, the use of assessment tools such as BREEAM, LEED, and CASBEE has increased rapidly in recent years. Identifying key items with these assessment tools is crucial for prioritizing improvements to residential environment. This study introduces the novel application of item response theory (IRT) to building environment engineering data in order to identify key items from the CASBEE Residential Health Checklist. The strength of IRT lies in its ability to consider variations in scores for each item and the relative relationships between items, thereby enabling the identification of significantly influential key items. Examining Japanese residences, IRT identified 6 environmental items and 7 spatial items from a total of 44 items in the CASBEE Residential Health Checklist. Additionally, these environmental and spatial components were ranked by their explanatory power for the overall assessment of the residential environment. These findings contribute to prioritizing improvements in residential environments and provide a brief assessment method. IRT can be applied to other regions and building types, potentially enabling the identification of key items unique to each case. Thus, IRT is a versatile method with broad applicability for identifying key items in residential environment assessments.

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SEASONAL PATTERNS OF PHYSICAL ACTIVITY AND SEDENTARY BEHAVIOR AND INDOOR THERMAL ENVIRONMENT AMONG ADULTS LIVING IN SUBURBAN RESIDENTIAL AREA

Ito M., Ando S., Umishio W., Oguma Y., Saito Y., Ikaga T.

Journal of Environmental Engineering (Japan) (Journal of Environmental Engineering (Japan))  89 ( 820 ) 340 - 350 2024.06

Research paper (scientific journal), Joint Work, Accepted,  ISSN  13480685

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This study examined the seasonal patterns of physical activity (PA) and sedentary behavior (SB) and the relationship between PA and SB and the indoor thermal environment in each season. 98 of 131 the participants were analyzed. 1) Daily moderate-to-vigorous PA was significantly greater in fall than in winter. 2) Adjusting the accelerometer wearing time, outdoor PA and SB were not significantly related to season, but indoor moderate-to-vigorous PA were significantly greater in fall and summer than in winter. 3) Using a kotatsu in winter was associated with longer SB and less light-intensity PA than using an air conditioner.

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Spatial and temporal indoor temperature differences at home and perceived coldness in winter: A cross-sectional analysis of the nationwide Smart Wellness Housing survey in Japan.

Wataru Umishio, Toshiharu Ikaga, Yoshihisa Fujino, Shintaro Ando, Tatsuhiko Kubo, Yukie Nakajima, Naoki Kagi, Tanji Hoshi, Masaru Suzuki, Kazuomi Kario, Takesumi Yoshimura, Hiroshi Yoshino, Shuzo Murakami

Environment international (Environment International)  186   108630 - 108630 2024.04

Research paper (scientific journal), Joint Work, Accepted,  ISSN  01604120

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Residents themselves are responsible for controlling their living environment, and their perception of coldness is important to protect their health. Although previous studies examined the association between perceived coldness and indoor temperature, they did not consider the spatial-temporal differences in indoor temperatures. This study, conducted in Japan, measured indoor temperatures in 1,553 houses across several rooms (living room, changing room, and bedroom) and heights (at 1 m above the floor and near the floor) over two weeks and obtained the perceived coldness from 2,793 participants during winter. Results showed substantial temperature differences between rooms (horizontal differences): 3.8 °C between living and changing rooms, and 4.1 °C between living rooms and bedrooms. The average vertical and diel (evening-morning) temperature differences in the living room were 3.1 °C and 3.0 °C, respectively. Regional analysis revealed that the Tohoku region experienced larger horizontal and diel indoor temperature differences, primarily due to its practice of intermittent and partial heating in living rooms only, in contrast to Hokkaido's approach of heating the entire house continuously. Despite Hokkaido's comprehensive heating system, it exhibited the largest vertical temperature difference of 5.1 °C in living rooms, highlighting the insufficiency of heating alone and the necessity for enhanced thermal insulation. The multivariate logistic regression analyses showed that average temperatures and vertical temperature differences were associated with perceived coldness, while horizontal and diel differences did not show a significant association, further emphasizing the importance of improved thermal insulation. Moreover, factors like individual attributes (age and gender), and lifestyle choices (meal quantity, exercise habits, alcohol consumption, and clothing amount) were significantly associated with coldness perception. Notably, older adults were less likely to perceive coldness but more vulnerable to the health impacts of low temperatures, underscoring the necessity of not solely relying on human perception for indoor temperature management to protect cold-related health problems.

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EFFECT OF MOVING TO HOUSES WITH THERMAL INSULATION PERFORMANCE ON HEALTH FOR CHILD-REARING AGE WOMEN

Ishii A., Ikaga T., Fukushima F., Tomioka Y., Mine T., Ohashi M.

Journal of Environmental Engineering (Japan) (Journal of Environmental Engineering (Japan))  89 ( 817 ) 123 - 134 2024.03

Research paper (scientific journal), Joint Work, Accepted,  ISSN  13480685

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The purpose of this study was to clarify the effect of winter indoor thermal environment on the health for Child-Rearing Age Women. Follow-up surveys on Residents' health and indoor thermal environment were conducted in winter(2015-2022) before, after and 5-6years after moving to houses with thermal insulation performance. Repeated measure analysis of variance showed that increased indoor temperature reduce the symptoms such as cough and phlegm, stuffy or runny nose, stiff shoulders, back pain, cold extremities, injury, and catching a cold. It also improved subjective sleep quality and subjective health status.

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Association between indoor temperature during winter and falls at home in the past year among community-dwelling older adults: A cross-sectional analysis of the nationwide Smart Wellness Housing survey in Japan

Ito M., Ikaga T., Oguma Y., Saito Y., Fujino Y., Ando S., Murakami S.

Japanese Journal of Geriatrics (Japanese Journal of Geriatrics)  61 ( 2 ) 218 - 227 2024

Research paper (scientific journal), Joint Work, Accepted,  ISSN  03009173

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Aim: Some studies have reported a higher incidence of falls during winter with similar proportions of indoor and outdoor falls. We investigated the relationship between indoor temperature during winter and falls at home in the past year among community-dwelling older adults. Methods: This cross-sectional study enrolled 964 individuals of ≥65 years of age in Japan. Participants answered questions about falls (including trips) at home within the past year, and the living room temperature was measured for 2 weeks during winter. Participants were divided into those living in cold (mean temperature near the floor <12̊C), slightly cold (12-17.9℃), and warm (≥18̊C) houses. The association between indoor temperature (cold vs. slightly cold vs. warm houses) and falls at home in the past year was examined using a logistic regression analysis adjusted for potential confounding factors. Results: Valid data were obtained from 907 participants (mean age: 72.0±6.3 years), of whom 265,553, and 89 lived in cold, slightly cold, and warm houses, respectively. In the past year, falls occurred once in 325 (35.8%) participants and multiple times in 148 (16.3%) participants. In warm houses, the odds ratio of falling once and multiple times in the past year was 0.49 (p=0.032) and 0.34 (p=0.035), respectively, in comparison to cold houses. Conclusions: Living in cold houses may be associated with an increased risk of falling at home among older adults. Maintaining an appropriate indoor thermal environment during winter may reduce the risk of falling among individuals who spend most of their time at home.

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PV/T solar panel for supplying residential demands of heating/cooling and hot water with a lower environmental thermal load

Kohei Terashima, Haruki Sato, Toshiharu Ikaga

Energy and Buildings (Elsevier BV)  297   113408 - 113408 2023.10

Research paper (scientific journal), Joint Work, Last author, Accepted,  ISSN  0378-7788

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The practical efficiencies of existing commercial m-Si and CIS PV modules measured in reality by our group were less than 15 % because of the higher temperatures of the PV modules, and the rest of more than about 85 % of solar energy would be the exhaust heat to the environment. It was already reported in 2020 that the principle of an environmentally-friendly PV/T (Photovoltaic/Thermal) solar panel using an m-Si PV module to utilize 71.3 % solar energy for electricity and 40 °C hot water, as well as suppress heat radiation from the panel. The panel was designed to confirm the principle, i.e., it was an experimental PV/T solar panel. In this paper, a new practical environmentally-friendly PV/T solar panel is proposed for aiming the application to BIPVT (Building-integrated Photovoltaic/Thermal) systems. The new panel uses a CIS PV module, and all the functions, including a heat exchanger using flat aluminum tubes, are placed in the panel box, which is almost the same size as a simple CIS PV panel. The proposed PV/T solar panel converts 73.5 % of solar energy with 13.0 % power generation efficiency and 60.5 % heat collection efficiency at a 40 °C hot water supply in Yokohama, Japan. The efficiency is higher than the previous experimental panel. The proposed panel also can suppress heat radiation at about 50 °C even in the case of 60 °C hot water supply. The proposed PV/T solar panel can supply all residential heat demands, such as domestic hot water (DHW) and space heating or cooling, using solar heat with a lower environmental thermal load.

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