Published papers

These years residential energy consumption has been increasing sharply in China along with the high economic growth. Thus people pay much more attention to the issues of reducing the energy consumption and CO2 emission. This study chose Shanghai, a big city of China as a subject, and developed a Macro-model to forecast the CO2 emission of residential buildings up to 2050. By combining such Global warming count measures into the Macro-model it was able to forecast the CO2 emission of Shanghai’s residential buildings in several energy-efficient scenarios.

In urban areas where population and city functions are aggregated, there are calls for the construction of business continuity districts, in which energy supply is secured in times of disaster. A decentralized and self-reliant community-level energy network is expected to contribute to improving resilience and regional vitalization, as well as to reducing carbon emissions. However, the initial investment is high and the stakeholders involved are diverse, creating potential obstacles to the introduction of such an energy network because the necessary measures are of larger scale than a simple construction project. Prior studies have shown the need for accurate recognition of non-energy benefits (NEBs) in addition to energy benefits such as energy cost savings. Moreover, evaluation methods for various co-benefits have been proposed. Yet, NEBs accrued through risk reduction have not been evaluated with respect to temporal changes in business and daily life activities associated with lifeline utilities such as electricity, water, and gas. In this study, we conducted a questionnaire survey of city residents and non-manufacturing workers. Using the data from the questionnaire, we developed an evaluation method for improvements in resilience. In addition, we verified the effect of improving resilience through a case study of a real urban district and a housing complex district. The results of this research are summarized below. (1) Proposal of an evaluation method for resilience in the business sector In the questionnaire survey, we asked non-manufacturing workers about the effect on business activities of lifeline stoppages (electricity, water, and gas) and derived a “Resiliency Factor” according to the type of business. Then, we proposed a method for resilience improvements based on Resiliency Factor and a recovery curve for business activity according to the lifeline stoppage time, and we plotted a recovery curve for business activity according to the lifeline stoppage time. In addition, we expressed the resilience improvement in the business sector in monetary terms. (2) Proposal of an evaluation method for resilience in the housing sector In the questionnaire survey, we asked residents about the losses incurred as a result of electric power failure. Then, we derived a basic unit of loss due to electric power failure according to stoppage time. This basic unit was then used in an estimation model considering housing type and location to assess resilience improvements in the housing sector in monetary terms. (3) Case study We performed a case study of the effect on resilience of introducing a community energy network under the assumption of a large-scale earthquake. In the evaluation, the Tamachi Station district was taken as an example of urban areas and the Hamamidaira housing complex district was taken as an example of areas around existing housing complexes We found that by introduction of the community energy system, the Tamachi Station district would accrue NEBs of 140 million yen per year and the Hamamidaira housing complex district would accrue NEBs of 5.11 million yen per year.

According to Healthy Japan 21 (Second Term), reducing the average systolic blood pressure (BP) by 4 mmHg would prevent an estimated 14,000 deaths from cardiovascular disease (including 9,300 deaths from cerebrovascular disease and 4,700 deaths from ischemic heart disease) each year in Japan. Accordingly, reducing average BP is one of the country’s major public health goals. Moreover, it is recognized that individual efforts alone, such as lifestyle modification, cannot be relied on to achieve this goal. Measures are therefore needed that involve large numbers of people, such as environmental improvement (e.g., home renovation). Against this background, some studies have looked at the effects of the indoor thermal environment on BP. Most BP data are obtained from repeated measurements in particular individuals, so an appropriate statistical method such as multilevel modeling should be applied to the data. This study aimed to clarify the relationship between indoor thermal environment and home BP based on a multilevel model. By using this model, it is possible to elucidate both compositional and contextual effects of indoor temperature on home BP. These effects are respectively defined as the increase in BP per 1°C decrease in indoor temperature on a particular day and the increase in BP per 1°C decrease in average indoor temperature of houses. Data were collected through field surveys in Tosa Town and Yusuhara Town, Kochi Prefecture; Nagato City, Yamaguchi Prefecture; Uenohara City, Yamanashi Prefecture; and some other areas around Japan. The surveys were conducted in winter (2012–2014). Home BP was measured by participants twice daily: before getting into bed in the evening and after getting out of bed in the morning. Indoor temperature at 1.1 m above the floor was measured in the living room, bedroom, bathroom, and dressing room at 10-min intervals. During the survey periods, participants recorded the wake time and bedtime each day in a diary. Questionnaire surveys on personal factors and housing were also distributed. In developing the model of BP, residents who had lived in their present house for >10 years were screened and selected. The model was assumed to have a hierarchical structure in which day-level variables obtained from field measurements (e.g., BP, indoor temperature) were nested within resident-level variables obtained from questionnaire surveys (e.g., age, sex, body mass index). The objective variables were systolic BP and diastolic BP in the morning (n=3,331). Explanatory variables were the day-level and resident-level variables mentioned above. Both compositional and contextual effects on morning BP were found to be significant. The sum of the effects was 0.57 (= compositional effect + contextual effect: 0.38 + 0.19) mmHg/°C for morning systolic BP and 0.43 (=0.20 + 0.23) mmHg/°C for morning diastolic BP. The interaction of age and temperature was significant, and indicated that the effect of indoor temperature on BP was stronger in older residents. One possibility is that the higher BP was caused not only by cold exposure on a particular day but also by ongoing residence in a cold house. Lifestyle diseases such as hypertension result from the cumulative effects of various risk factors. The results of this study suggest that hypertension might result from the cumulative effect of coldness. Thus, maintaining an appropriate indoor temperature is important not just for older residents, who are sensitive to changes in indoor temperature and at high risk of cardiovascular events, but also for younger residents. These findings may have important implications for managing hypertension and preventing cardiovascular events.

戸建と集合住宅のモデルを設定して、全国6気候地域区分毎に、年間暖冷房負荷シミュレーションを行い、日本の全住宅の暖冷房CO2排出量を2010年まで計算した。さらに、発泡断熱材に使用されているフロンガスの漏洩による温暖化影響と断熱強化によるCO2削減とのトレードオフ関係などを明らかにした。また、新築だけではなく既存住宅の対策の必要性を明らかにした。

Toward low-carbon society, much higher use of renewable energy and unused energy should be promoted. For this purpose, area-wide energy utilization is expected to play an important role in commercial and residential sectors. Along with the compact city policy, area-wide energy utilization in rather wide scale such as in a community and in a city should be strategically planned and implemented. Among various carbon reduction measures, those of higher reduction potential and higher cost-benefit ratio should be prioritized. This paper describes an appropriate way of determining the priority by use of marginal abatement cost (MAC), taking the following viewpoints into consideration.; 1) Setting payback-periods based on functional lifetime of each reduction measure 2) Qualifying non-energy benefits (NEB) to be deducted from the MAC of each reduction measure A case study for a community-scale energy utilization by use of incineration waste heat is undertaken to validate the above concept.

Various researches highlight that indoor air quality affects performance of workers in offices. Although good indoor air quality improves work performance, it also increases energy consumption. In this study, we achieved a field survey in a real office in order to investigate the relationship between thermal environment, productivity, and energy consumption. In addition to the monitoring of indoor environmental quality and energy consumption, subjective experiments were conducted. In order to evaluate subjective performance, workers and students responded to questionnaires, and to evaluate objective performance, students simulated three types of office works. By calculating room temperature and worker's subjective performance, we demonstrate the correlation between room temperature and worker's performance (R2=0.22, p<0.01). Results show that the room temperature that maximizes worker's performance was 25.7°C.

This research describes effect of injecting rigid poly-urethane foam into walls and doubling glazing/sash as simple renovation methods for houses, according to the estimation of CO_2 emission by heating/cooling and LCCO_2 (Life Cycle CO_2). We estimated the CO_2 emission and LCCO_2 up to 2020 in Japan and obtained the following results. (l)Injecting rigid poly-urethane foam into walls where thermal insulation is little set up reduces LCCO_2 most for detached houses. (2)Renovation of openings brings more LCCO_2 reduction to houses insulated with 1993 energy saving standard in Tokyo. (3)When we choose one out of two methods above, we should take allowance for initial insulation level, house structure, and region. (4)Domestic CO_2 emission concerning thermal insulation for houses can be reduced by 13% to 19% in 2020 with the simple renovation methods.

BACKGROUND: Bath-related sudden cardiac arrest frequently occurs in Japan, but the mortality data have not been sufficiently reported.Methods and Results:This prospective cross-sectional observational study was conducted in the Tokyo Metropolis, Saga Prefecture and Yamagata Prefecture between October 2012 and March 2013 (i.e., in winter). We investigated the data for all occurrences in these areas for which the emergency medical system needed to be activated because of an accident or acute illness related to bathing. Emergency personnel enrolled the event when activation of the emergency medical system was related to bathing. Of the 4,599 registered bath-related events, 1,527 (33%) were identified as bath-related cardiac arrest events. Crude mortality (no. deaths per 100,000) during the observational period was 10.0 in Tokyo, 11.6 in Yamagata and 8.5 in Saga. According to the mortality data for age and sex, the estimated number of bath-related deaths nationwide was 13,369 in winter, for the 6 months from October (95% CI: 10,862-16,887). Most cardiac arrest events occurred in tubs filled with water with the face submerged in the water. This suggests that drowning plays a crucial role in the etiology of such phenomena. CONCLUSIONS: The estimated nationwide number of deaths was 13,369 (95% CI: 10,862-16,887) in winter, for the 6 months from October. Crude mortality during the winter season was 10.0 in Tokyo, 11.6 in Yamagata and 8.5 in Saga.

The aim of this paper was to explore the effect of seasonal temperature differences and cold indoor environment in winter on the physical performance of older people living in the community based on a field study. We recruited 162 home-dwelling older people from a rehabilitation facility in the Osaka prefecture, Japan; physical performance data were available from 98/162 (60.5%). At the same time, for some participants, a questionnaire survey and a measurement of the indoor temperature of individual houses were conducted. The analysis showed that there were seasonal trends in the physical performance of older people and that physical performance was worse in the winter compared with the autumn. Furthermore, people living in colder houses had worse physical performance. The findings indicate that keeping the house warm in the winter can help to maintain physical performance.

It is estimated that a third of carbon dioxide (CO2) emissions in Japan are created from construction and operation of buildings, and the construction industry is largely greatly responsible for this. Based on future population projections, a building floor area equivalent to that of Europe, the floor area of buildings already started, and an input and output analysis, a forecast of buildings-related CO2 emissions has been made up to 2050. If the current situation continues, CO2 emissions for the period 2008–2012 will rise by 15% compared to 1990 levels. On the other hand, if energy conservation measures are taken along with steps to prolong the life of buildings, reducing CO2 emissions by 30% in new construction work and by 15% in renovation work, and if the unit CO2 emission from electricity is reduced by 20% compared to 1990, CO2 emissions could be reduced by 6% over the period 2008–2012 and by 40% by 2050. We also examined the problems faced by the construction industry, making estimates classified by steps taken by the construction industry, steps taken by the power industry, and the year in which counter-measures are launched. © 2002, Architectural Institute of Japan. All rights reserved.

Conducting city assessments and disclosing those results to the public is important for supporting citizens’ understanding of the actual condition of their city. Such assessment and disclosure could introduce a market mechanism that can be expected to provide city governments with strong incentives to improve their city conditions and also recognizes that local policy and strategy can be the most appropriate way to address specific urban and environmental problems. The latest Comprehensive Assessment System for Built Environment Efficiency (CASBEE) tool, referred to as CASBEE-City, is presented. Designed specifically for city assessment, it supports local governments and other stakeholders in identifying the environmental, social and economic characteristics of their city and in quantifying the effectiveness of their city-wide policies. CASBEE-City is based on the concept of environmental efficiency and it provides a combined evaluation of a city embracing two aspects: the environmental load imposed by the city on the wider environment outside its boundary, and the quality of life (environmental, social, economic) inside the city. A city with low environmental load and high quality receives a high Built Environment Efficiency (BEE) value and is regarded as a sustainable city within the CASBEE framework.

Considerable potential exists for reducing life cycle environmental impacts of buildings in Japan. While energy consumption during the operation stage of a building's lifetime is usually dominant, indirect energy use and pollutant emissions associated with production and disposal of building materials during construction and demolition are significant. For sustainable building design, interactions between the performance and dynamics of the building structure and energy systems must be considered. A collaborative platform based on the distributed object-based modeling environment, DOME, and a set of component models for sustainable building design analysis is presented. Integration examples of the component models to study particular building designs are described. Copyright © 2005 Inderscience Enterprises Ltd.

Residential and commercial building sector accounts for more than 30% of final energy consumption in Japan and an increase from the past is remarkable. In order to realize a low-carbon society, further strengthening of energy saving measures is essential. Japanese government is considering a mandatory policy scheme which forces all residential and non-residential buildings to meet the energy efficiency standard by 2020. This research aims to marshal trends on regulations for energy efficiency of residential and non-residential buildings within countries which implements advanced measures, and to obtain referential knowledge for Japan’s energy efficiency measures.

It is necessary to consider measures to promote well insulated houses toward the reduction of CO2 emissions in residential sector. However, it is difficult to determine effective measures since residents’ attitude toward introducing insulation differ from one by one. Therefore, in this study, a model for predicting the diffusion process of well insulated house was developed taking residents’ attitude toward introducing insulation into account. The model enables us to consider effective measures for promoting well insulated house. As a result of case study, presenting energy benefits and non-energy benefits was more effective than giving economic incentive in the study.

The aim of this paper is to clarify the relationship between the indoor thermal environment and care prevention. A field study comprising actual measurements, questionnaire surveys, and data collection from face sheets was conducted in 2014. Participants were classified into two groups based on frequency of feeling cold in their rooms. Age at certification of needing long-term care was compared between the groups by using survival analysis. The result was significant when the classification condition was frequency of feeling cold in their dressing rooms. The age at which half of the group acquired their certification was 76 years in the high-frequency group and 80 years in the low-frequency group.

Energy consumption in the Chinese residential sector is increasing quickly. In this study, we developed a Micro-model to forecast residential CO2 emissions. The model outputs support decision making for appropriate CO2 emission reduction goals. First, for Chinese urban residential buildings, we developed a CO2 emissions forecast model for 2050 taking into account lifestyle changes and Global Warming countermeasures. Second, we used the model to estimate the CO2 reduction potential of both residential and electrical countermeasures. Compared to the business as usual (BaU) scenario, implementation of residential countermeasures achieved 38%, 24% and 23% emissions reductions for Beijing, Shanghai and Hong Kong respectively. After combining them with the implementation of electrical countermeasures the reduction rates rose to 60%. We also compared the countermeasures to see which could bring the greatest emissions reduction. For Beijing, improvement of insulation was most efficient. For Shanghai and Hong Kong, COP increase of hot water supply appears to be the most efficient countermeasure. Through this study we were able to model global warming countermeasures for the Chinese residential sector, and found that reducing CO2 emissions by 60% from BaU is an achievable goal.