Tetsu Kubota

Hiroshima University | HU · Department of Development Technology

This study constructs a coupled simulation model of heat balance analysis and computational fluid dynamics (CFD) for naturally ventilated buildings with installed phase change materials (PCMs), and demonstrates a modeling method for the thermal storage effect of PCM in the simulation. Then, the constructed model was applied to a sensitivity analysi...

This paper presents the results from field measurements and household surveys on the severity of indoor mold risk and its impact on respiratory health in a typical unplanned neighborhood of kampungs in Bandung, Indonesia. Mold risk was investigated using fungal risk detectors (n = 102), while air pollution levels were established with total suspend...

Double-loaded affordable apartments, which are commonly seen in tropical developing countries, suffer from poor cross-ventilation, particularly on the leeward side of the buildings. This study aims to parametrically evaluate closed-vertical void configurations to improve the ventilation performance of the double-loaded apartment building using the...

We proposed a novel radiant floor cooling system using phase change materials (PCMs) with night ventilation in the hot and humid climate of Indonesia. This study aims to clarify the measures to ensure the thermal storage effect of the proposed cooling system during daytime for a naturally ventilated room within a relatively narrow diurnal temperatu...

We investigated mould risk, TSP and PM2.5, and the self-reported prevalence of respiratory diseases in a typical unplanned urban residential neighbourhood (Kampung) in Bandung, Indonesia during 2018–2019. Based on the results, this paper developed design modification plans for the selected five houses aiming to remediate the health burden the resid...

Double-loaded affordable apartments are commonly seen in tropical developing countries to maximize total floor areas. However, the double-loaded apartments would possibly cause poor cross-ventilation, particularly on the leeward side of the buildings. This study aims to propose an alternative design for double-loaded affordable apartments for effic...

Window-opening is one of the most important adaptive behaviours affecting indoor thermal comfort as well as household energy consumption in the tropics. In this study, large-scale surveys were conducted in major cities of Malaysia and Indonesia to extract various typical daily patterns of window-opening, air conditioning (AC) usage and fan usage am...

The combination of ventilative cooling and radiant cooling is a feasible approach for improving the cooling performance of buildings, thus achieving better thermal comfort of occupants in hot and humid climates. We propose a novel radiant floor cooling system using a phase change material (PCM) in Indonesia. This study aims to determine the window...

There is a possibility that sick building syndrome has already spread widely among newly constructed residential buildings in developing countries. This study investigates the current conditions of IAQ and their effects on health among occupants in two representative types of residential buildings in Jakarta and Surabaya: high-rise apartments and t...

There is an increase in the middle income class in the tropical cities of the global south. Which has lead governments to focus on the provision of sustainable housing stocks. The design of these houses is a concern as they are often designed to maximize occupancy. Based on analysis of existing building design, the standard midrise buildings of Ind...

Affordable housing for the low-income population, who mostly live in slums, is an endemic challenge for cities in developing countries. As a remedy for the slum-free city, most of the major metropolis are resorting to slum rehabilitation housing. Rehabilitation connotes the improved quality of life that provides contentment, yet what entails reside...

It was found that the standard design of multistory apartments of Indonesia and Mumbai consists of a double loaded corridor to maximize the floor area regardless of the orientation. Consequently, the occupants on the leeward side may encounter poor cross-ventilation. This study aims to determine optimum void design allowing sufficient cross-ventila...

In rapidly growing countries, such as in Indonesia, dramatic increase in new urban houses constructed of modern building materials without sufficient material standards or minimum ventilation rates may cause health problems related with indoor air quality (IAQ). This study investigates the current IAQ and health condition in Kampongs and high-rise...

This paper presents the results of a preliminary experiment using test cells constructed in Bandung, Indonesia. We particularly analysed the thermal effects by comparing green walls with wooden blinds in contrast with those of no covering materials to determine the factors affecting the improvements of indoor thermal conditions in hot-humid climate...

This paper examined the passive techniques used in the traditional courtyard houses of Kabul using on-site measurements of their thermal environment during winter and summer. It was found that the high thermal mass structure was efficient in creating a stable indoor environment during both seasons. The adaptive behavior of migrating horizontally to...

In times of rapid urbanization, increasing usage of chemicals in buildings, and energy saving measures, the topic of indoor air quality (IAQ) demands reinforced attention. Nevertheless, especially in developing countries with urgent building construction needs, IAQ has hardly been examined. This study investigates the condition of IAQ and health of...

The purpose of this study was to investigate the effects of building microclimate on the indoor thermal environment of traditional Japanese houses, focusing especially on the shading effect of trees as well as the cooling effect of spraying water. Basically, the indoor thermal environment was found to follow the outdoor conditions due to the open-p...

The purpose of this study was to investigate the thermal functions of internal courtyards in traditional Japanese houses and to identify the effects of water spraying in the courtyards on the thermal environment of their surrounding spaces. It was found that the indoor thermal environment follows the outdoor environment due to the large openings, a...

Children are very special and unique creatures as their emotional, intellectual and their physical developments are closely intertwined with their environment. With certainty, the children participatory design workshop was viewed as an appropriate platform in providing them an early appreciation on the values of their actions in order to enhance th...

This chapter presents the results of detailed field investigations of thermal conditions and occupants’ window-opening behaviour in several apartments located in the city of Surabaya, Indonesia. In the public apartments, almost all of the respondents did not use air-conditioning, and approximately 70–80% opened their windows/doors on both front and...

Urban climate of rapidly growing cities such as Hanoi will alter not only owing to land use changes but also global warming effect. This chapter investigates the contributions of land use changes and global warming to the future increases in urban temperature in Hanoi for 2030 through a numerical simulation using the Weather Research and Forecastin...

In 2015, we constructed a full-scale experimental house in the city of Johor Bahru, Malaysia, in order to determine comprehensive energy-saving modification techniques through passive cooling for existing urban houses in the hot-humid climates. First, this chapter presents the results of numerical simulation to examine optimum combinations of modif...

This chapter starts with a brief history of Dutch colonial architecture in Indonesia. The arrival of Europeans in the early fifteenth century had a great impact on building construction in Indonesia. The material and spatial concepts of European buildings were completely different from those of the Indonesian indigenous people. With the passage of...

Indonesia has been experiencing population and high economic growth in line with rapid urbanization. As a consequence, the need for living areas increased, and an enormous number of residential buildings have been developed in major cities, such as Jakarta and Bandung. The household sector contributes to the nationwide final energy consumption by 2...

This chapter presents the results of a comparative analysis of the window-opening behaviour of residents in Southeast Asian cities. Using face-to-face interviews with a questionnaire, a total of 1,315 samples were obtained from typical households in 3 cities: Surabaya, Indonesia; Bandung, Indonesia; and Johor Bahru, Malaysia. Then, a hierarchical c...

This chapter presents the results of a survey on household energy consumption in existing slum settlements and the resettlement site in the city of Tacloban, Philippines. The results showed that the household income level in the resettlement site was surprisingly not improved compared to that of the existing slums. It was found that both groups sha...

This study aims to identify the thermal functions of internal courtyards in traditional Chinese shophouses (CSHs) located in the hot-humid climate of Malaysia with the aim of providing useful passive cooling strategies for modern urban houses. This chapter investigates the detailed thermal environments of the selected two traditional CSHs with diff...

This book provides information on the latest research findings that are useful in the context of designing sustainable houses and living in rapidly growing Asian cities. The book is composed of seven parts, comprising a total of 50 chapters written by 53 authors from various countries, mainly in the Asian region. Part I introduces vernacular houses...

This study aims to investigate the impacts of land use changes brought by the Hanoi Master Plan 2030 (HMP) to the urban heat island (UHI), using the Weather Research and Forecasting (WRF). A scenario analysis was carried out to assess the effectiveness of urban greening for mitigating UHI. The urban climate under the influence of global warming was...

Hanoi City, Vietnam, presented the Hanoi Master Plan 2030 in 2011 to cope with rapid population growth and urbanisation. The main objective of this two-part study was to investigate the impacts of land use changes from the master plan on urban climate in Hanoi by 2030. This paper focuses on the assessment of the proposed green strategies in the mas...

Hanoi City, Vietnam, presented the Hanoi Master Plan 2030 in 2011 to cope with rapid population growth and urbanisation. The main objective of this two-part study was to investigate the impacts of land use changes brought by the master plan on urban heat islands in Hanoi by 2030. This paper analyses the contributions of land use changes and global...

The main purpose of this study was to identify the thermal functions of internal courtyards in traditional Chinese shophouses (CSHs) located in the hot-humid climate of Malaysia with the aim of providing useful passive cooling strategies for modern urban houses. The CSHs are deep-plan brick row houses that are located in relatively dense urban area...

In order to develop low energy and low carbon residential buildings, it is important to understand their detailed energy profiles. This study provides the results of life cycle assessment of energy and CO2 emissions for residential buildings in Jakarta, Indonesia. A survey was conducted in the city in 2012 to obtain both material inventory and hous...

This paper discusses the effects of courtyards on indoor thermal environment in a traditional shophouse in Malacca, Malaysia based on the results of field measurement. The results showed that the indoor air temperatures in the living hall (ground floor) and the master bedroom (first floor) were approximately 0.3-1.7°C lower than the corresponding o...

This study aims to investigate the detailed thermal environments in apartments of Surabaya, Indonesia and discuss their potential passive cooling strategies. Major thermal parameters, vertical distribution of air temperature and surface temperature of walls/ceiling were measured in one of the representative units of three types of apartments respec...

First, this paper evaluates the current building material stock and future demolition waste for urban residential buildings in the cities of Jakarta and Bandung using a material-flow analysis. The actual on-site building measurements were conducted in Jakarta (2012) and Bandung (2011), focusing particularly on unplanned houses, to obtain building m...

This study aims to investigate the detailed thermal environments in apartments of Surabaya, Indonesia. Major thermal parameters and air tightness were measured in one of the representative units of three types of apartments respectively, under different natural ventilation conditions. The results revealed that the unit in the old public apartment s...

The objective of this study is to analyze life cycle energy and CO2 emission profiles by employing an input-output analysis method for urban houses in major cities of Indonesia. Two surveys investigating building material inventory and household energy consumption within individual houses were conducted in Bandung in 2011 and 2012. The results show...

The main objective of this study was to examine the effectiveness of energy-saving renovation techniques through passive cooling for urban houses in hot-humid climate of Malaysia. Effects of two strategies, i.e. complete natural ventilation (NV) strategy and partial air conditioning (AC) strategy were simulated using TRNSYS. The results revealed th...

The study aims to assess the urban heat island (UHI) effects in the city under the present land use conditions as well as those conditions proposed by the Hanoi Master Plan 2030 through numerical simulation, using Weather Research and Forecasting (WRF). Furthermore, this paper assesses additional land use scenarios with different spatial and green...

The purpose of this study is to determine factors affecting QOL among residents in major cities of Indonesia. A survey (n=236) was carried out in the city of Bandung from September to November 2012 for the above purpose, focusing especially on unplanned houses in Kampung. The results showed that approximately 60.1% of the respondents gave positive...

The main objectives of this study were to investigate vernacular passive cooling techniques and their potential application for improving indoor thermal comfort of naturally ventilated, modern brick terraced houses in Malaysia. Field measurement was conducted in two traditional timber Malay houses and two traditional masonry Chinese shophouses to e...

The main purpose of this paper is to determine potential vernacular passive cooling strategies for improving thermal comfort of modern urban houses in hot-humid climate of Malaysia. Field measurements were carried out in two traditional timber Malay houses and two traditional masonry Chinese shophouses to investigate their indoor thermal environmen...

In the context of rapid population growth and urbanization in recent years, Southeast Asian countries are facing many urban environmental issues. One of them is urban heat island (UHI) phenomenon which alters urban climate compared to the surrounding rural areas. The UHI intensity (UHII) is expected to increase further in the future because most of...

Koch-Nielsen (2002) defined a courtyard building as a building that has an internal space opened to the sky. Edwards et al. (2006) highlighted that the courtyard design had been used since the Neolithic settlements and was extensively used from China to Morocco. One of the primary roles of courtyard spaces is to protect the occupants from the harsh...

This study aims to investigate the factors influencing occupants' window-opening behavior in apartments in the major cities of Indonesia. For this purpose, a field survey was carried out for 347 respondents in the city of Surabaya, covering detailed household and building profile, cooling energy consumption, thermal conditions, satisfactions and pr...

This study aims to assess the impacts of land use changes brought by the Hanoi Master Plan on its urban climate using the Weather Research and Forecasting (WRF), focusing on the cooling effect of the green strategies that were proposed in the master plan. The results show that even after implementing the master plan, the peak air temperature in the...

The objective of this study is to evaluate the current building material stock and future demolition waste for urban houses using a material-flow analysis in Jakarta and Bandung. Their embodied energy and CO 2 emissions are also analyzed by using an input-output analysis method. The actual on-site building measurements were conducted in Jakarta (20...

The objective of this study was to determine energy-saving modifications through passive cooling to urban terraced houses in Malaysia. Effects of two strategies, i.e. complete natural ventilation (NV) strategy and partial air conditioning (AC) strategy, were simulated using TRNSYS and COMIS. The complete NV strategy relied fully on naturally ventil...

This paper aims to reveal the detailed household operational energy consumption patterns in major cities of Indonesia. A total of 297 households were surveyed in Jakarta, while 247 households were investigated in Bandung, focusing especially on unplanned landed houses. The detailed information about household appliances and gas consumption were inv...

A field survey was carried out to investigate factors influencing window-opening behavior of apartment users in hot-humid climate of Surabaya during September-October 2013. The survey obtained 347 responses through face-to-face interviews. Thermal conditions (air temperature, globe temperature and humidity) were also measured for one week in severa...

The study aims to find factors affecting QOL of residents in major cities of Indonesia. A survey (n=236) was conducted in the city of Bandung from September to November 2012 for the above purpose. The results showed that about 60.1% of the respondents gave positive answers to their QOL on average. The results of discriminant analyses indicated that...

This paper discusses environmental design considerations for courtyards in hot-humid climates through a literature review by contrasting with those in hot-dry climates. The discussion is mainly focused on shading and ventilation effects of courtyards. The results of the review revealed that the form and orientation of a courtyard were anticipated t...

The objective of this study is to determine comprehensive passive cooling strategies for urban terraced houses in hot-humid climate of Malaysia. Effects of two strategies, i.e. complete natural ventilation (NV) strategy and partial air conditioning (AC) strategy, were simulated using TRNSYS and COMIS. The complete NV strategy relied fully on natura...

This study aims to assess the impact of land use changes brought by the Hanoi Master Plan on its urban climate, using the Weather Research and Forecasting (WRF), focusing on the effect of the green strategies proposed in the master plan. The results showed that even after implementing the master plan, the peak air temperature remained at the same l...

The objective of this study was to determine potential application of vernacular passive cooling techniques to the largest stock of modern urban houses in hot-humid climate of Malaysia, which are brick terraced houses. Field measurement was conducted in two traditional timber Malay houses and two traditional masonry Chinese shophouses in March-Apri...

A field survey was conducted in apartments of Surabaya, Indonesia to investigate occupants' window-opening behavior and their thermal conditions. A total of 347 households were interviewed and about 30 houses were covered for measurements of thermal conditions. It was seen that occupants in the naturally ventilated apartments tend to open windows o...

This study investigates indoor thermal conditions in traditional Chinese shophouses (CSHs) in Malacca, Malaysia, using field measurements and focuses on the cooling effects of courtyards. The results indicate that the indoor air temperature in the living rooms of CSHs was approximately 5-6°C lower than the outdoor temperature during the day primari...

The objective of this study was to determine potential application of vernacular passive cooling techniques to the largest stock of modern urban houses in hot-humid climate of Malaysia, which are brick terraced houses. Field measurement was conducted in two traditional timber Malay houses and two traditional masonry Chinese shophouses in March-Apri...

Hanoi, the capital city of Vietnam, has been experiencing high economic growth along with rapid urbanization. This resulted significant land-use changes and increase of anthropogenic activities in the city, thus accelerated urban heat islands (UHIs). The UHIs in this tropical region would cause considerable increase in annual cooling load and raise...

This study aims to find the factors that affect QOL of people living in the major cities of Indonesia. A survey (n=236) was conducted in the city of Bandung from September to November 2012 for the above purpose. The results showed that about 60.1% of the respondents gave positive answers to their QOL on average. In particular, the respondents livin...

The objective of this study was to develop an adaptive thermal comfort equation for naturally ventilated buildings in hot–humid climates. The study employed statistical meta-analysis of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) RP-884 database, which covered several climatic zones. The data were carefull...

This study aims to develop a simplified life cycle assessment model for residential buildings in Indonesia, which can be used under relatively poor data availability conditions. In order to obtain material inventory data and household energy consumption profiles for constructing the above model, a survey was conducted in Bandung in 2011. This paper...

抄録 The main purpose of this study is to evaluate thermal comfort levels in traditional Malay houses based on a field measurement, with an interest to apply its traditional passive cooling techniques to modern houses in Malaysia. The results reveal that indoor air temperatures are 1-2°C higher than the corresponding outdoor air temperatures througho...