Hom B. Rijal

• PhD
• Professor at Tokyo City University

A field survey of indoor environmental measurements and questionnaires on thermal sensation, overall comfort, and behaviors was conducted in four office buildings in Japan by visiting each office every month over a duration of more than a year during the coronavirus disease 2019 (COVID-19) pandemic. The indoor environment was measured concurrently....

This study was undertaken to investigate seasonal adaptation to temperature in Japanese offices, with a view to suggesting an adaptive model for them. We measured temperatures in seven office buildings and conducted thermal comfort transverse surveys of occupants for over a year in the Aichi prefecture of Japan. We collected 1,228 samples. The occu...

This study focuses on the behavioural aspects of the occupants in Japanese office buildings. The behavioural adaptations such as window opening, heating/cooling use, clothing adjustments are important contributor factors for the adaptive thermal comfort. Therefore, understanding the behavioural aspects of the office workers can lead to have the gui...

The Carbon Neutral Declaration has been issued in Japan and various initiatives are introducing to realise it, but in the housing sector it is essential to improve the energy efficiency of the stock of over 50 million homes. However, the progress of insulation retrofitting is slow. In particular, there are many challenges in implementing insulation...

The purpose of this study is to investigate the potential mitigation strategies to overcome the overheating issue at the attic of the landed residential house located in a hot and humid climate area. An existing terrace house with 178 m ² was selected for this research. A building simulation model was created and calibrated by using the previous si...

In the context of climate change and global warming, the nexus between energy and buildings is self-explanatory. As per the ministry of statistics and program implementation, Govt. of India data, the primary energy consumption in the building sector is 37% of total primary energy consumption and about 24% to total CO2 emissions. It is evident from...

Thermal comfort in office buildings is instrumental in improving the productivity of employees while maintaining their health. The primary objectives of this research were to analyze the comfort temperature in Japanese office buildings and investigate its relationship with outdoor air temperature. Additionally, we examined the differences in comfor...

In the context of climate change and global warming, the nexus between energy and buildings is self-explanatory. As per the ministry of statistics and program implementation, Govt. of India data, the primary energy consumption in the building sector is 37% of total primary energy consumption and about 24% to total CO2 emissions. It is evident from...

Buildings not only provide shelter to the occupants but also security, safety and comfort, as well as signifying economic and socio-cultural status. The high energy intensity of buildings has become a matter of concern worldwide in the context of climate change and global warming. Adaptive comfort principles and guidelines afford greater design opp...

Comfort temperature is important to investigate because the chosen office indoor temperatures affect the energy used in a building, and a thermally comfortable environment makes the occupants be more productive. The effects of temperature on comfort are broadly recognized for thermal comfort. Japanese office buildings are well equipped with air-con...

In recent decades, the pedestrian's outdoor thermal comfort has been critical for designing sustainable cities, which can be affected by wind flow in urban spaces. Urban forms influence wind speed, changing the urban air quality, and causing pedestrians' thermal comfort or discomfort. Therefore, it is required to design the urban spaces in such a w...

The adaptive model of thermal comfort is an essential method for the design of resilient buildings because it embraces both place, and season specific temperatures ranges within its comfort zones. This chapter demonstrates the importance of this fact by quantifying seasonal differences of comfort temperature in twenty-three offices in Japan. Monthl...

This work investigated future building resilience, regarding thermal comfort, energy, health, and accommodating user behaviours and individual requirements by comparing mixed mode (MM) and fully air conditioned (HVAC) offices. Recently, offices are designed, as a fully HVAC sealed box, while no particular guidelines or standards cover MM buildings....

Overcooling indoor spaces in hot-and-humid regions indicate excessive usage of air conditioner (AC). Understanding the occupants' thermal perception in AC settings helps navigate the cooling energy required. This study investigated thermal comfort in biased and non-biased environments and examined the occupants’ preferences. Four set-point temperat...

This study investigates the overall comfort and productivity of Japanese office workers in mixed-mode office buildings. The indoor thermal environment is adjusted using the air-conditioning in Japanese office buildings to maintain thermal comfort and productivity. Thus, it is necessary to research thermal comfort and productivity to understand how...

The purpose of this study was to conduct a winter indoor thermal environment measurement and a subjective thermal comfort survey on detached houses in Nagano City. In addition, we estimated the neutral temperature and acceptable temperature range from the obtained data and explored the incidence of cold stress. The neutral temperature calculated us...

In the international movement to combat the threat of climate change, the timely implementation of residential energy-saving practises is becoming an urgent issue. Because the number of apartments is increasing, we analysed data from home energy management systems (HEMSs) and data from questionnaire surveys of 309 households in a condominium. We fo...

Energy-saving strategies are required to address the increasing global CO2 and electrical energy consumption problems. Therefore, the determinant factors of electrical energy consumption consist of socio-demographic changes, occupant behavior, house and appliance characteristics, or so-called techno-socioeconomic factors, which all need to be asses...

Energy-saving and efficiency represent a crucial role in achieving a clean environment as well as economic and social development, providing substantial benefits to stakeholders, including householders. Better cost savings can be achieved by simply changing behavior. However, real energy users lack proper technical energy knowledge, awareness, and...

A residential cogeneration system (CGS) is highlighted because of its efficient energy usage on both the supplier and consumer sides. It generates electricity and heat simultaneously; however, there is insufficient information on the efficiency according to the condition of usage. In this study, we analysed the performance data measured by the home...

Natural ventilation is usually adopted to provide required indoor air quality (IAQ) and thermal comfort. IAQ to be represented by CO2 concentration and ventilation is correlated with the academic performance of students. Most Nepalese school buildings are relying on natural ventilation through windows and have no glass sheets within them. This stud...

Comfort temperature and sleep quality involving 20 participants were determined in two cases: Case A (arbitrary, controlled air-conditioner setting) and Case B (adjustment of 3 °C higher than the setting of Case A with cool bed linen). Data of indoor thermal comfort and electricity consumption were collected every night throughout the measurement p...

The energy use in schools relates to various factors such as local climate, architectural design, thermal comfort, and so on. The present study explores the thermal comfort of students in higher secondary schools in the temperate climatic region of Nepal during the summer of 2019. Altogether 246 students aged 12-18 years have participated in the su...

In residential buildings, accurate forecast of time-varying electricity demands is important for the estimation and prediction of electricity consumption. Information of the end user's electricity consumption patterns is necessary as it has a significant impact on the load curve in the utility grid. Thus, this study aims to provide detailed informa...

Energy is an important input for socioeconomic development and human well-being. The rationality of energy transitions toward cleaner energy resources is not only to improve individual living conditions, but also to enhance the economic growth of a nation. Nepal is considered to be one of the countries with a low per-capita electricity use, heavily...

The use of an air conditioner (AC) becomes essential in residential buildings, particularly in a hot and humid climate to optimize indoor thermal comfort. To accelerate the process of space cooling, occupants tend to use the lowest set point of the AC thermostat setting to achieve the desired thermal comfort in the indoor environment. A field study...

Electricity-saving strategies are an essential solution to overcoming increasing global CO2 emission and electricity consumption problems; therefore, the determinant factors of electricity consumption in households need to be assessed. Most previous studies were conducted in developed countries of subtropical regions that had different household ch...

Nepalese households have been using electricity from hydropower plants at almost the lowest rate among other countries. Residents adjust their indoor environments by relying on very primitive methods. This study focuses on the thermal comfort of residents in Nepalese households and how it can be improved by enhancing the thermal insulation of the h...

Difficulties in controlling the effects of outdoor thermal environment on the human body are attracting considerable research attention. This study investigated the outdoor thermal comfort of urban pedestrians by assessing their perceptions of the tropical, micrometeorological, and physical conditions via a questionnaire survey. Evaluation of the o...

The thermal adaptation of buildings and their residents is important in extreme cold climates for energy-saving building design. A thermal measurement and a thermal comfort survey were conducted in traditional houses during the winter in the extreme cold climate of the Himalayan region of Nepal. Measurements were taken in 9 houses over 7 days to as...

A climate responsive building makes the greatest use of climatic elements (air temperature, relative humidity, wind, irradiation and rainfall) to reduce energy use for heating and cooling. Based on topography and distinct climatic features, Nepal is broadly classified into three climatic regions: subtropical , temperate and cold. With the introduct...

A comfortable indoor environment is essential for students' health and academic performance in schools. As no major concerns were raised on the thermal comfort of students in Nepalese schools, we investigated the present condition of students’ thermal comfort in school buildings in the temperate climatic region of Nepal. A survey was conducted on t...

There are limited studies on the impact of room temperature on sleep quality, particularly outside laboratories. Also, limited studies investigated the impact of thermal control on sleep quality and energy related matters, while heating and cooling are responsible for 40% of the energy use in buildings. This work investigated the impact of thermal...

In the last decades, the household’s energy demand has increased significantly in various countries including Nepal. In the case ofNepal, 94% of energy use is in the domestic sector. There is a possibility of a huge increase in electricity production, but we are stillsuffering from load shedding due to the high electricity demand. Electricity use i...

Nepal has low per-capita energy use and a majority of its rural residents use firewood as their primary energy source. Excessive use of firewood in improperly ventilated buildings degrades the indoor environment and health condition of the inhabitants. This study aims to assess the influence of hourly firewood consumption patterns on CO2 emissions...

Office workers use a variety of adaptive opportunities to regulate their indoor thermal environment. The behavioural adaptations such as window opening, clothing adjustments, heating/cooling use are one of the important factors for the adaptive thermal comfort. It is well-known that they are the most important contributors in the adaptive thermal c...

Natural disasters and wars are main reasons that force people to leave their homes and consequently require urgent needs including temporary shelters. After massive earthquake 2015, thousands of Nepalese who lost their home were doomed to live in temporary shelters, mostly self-built by using zinc/tarpaulin sheets which can hardly provide sufficien...

Most of the classroom in Nepalese school buildings are thermally less acceptable due to the poor thermal insulation. They are extreme cold in winter and extreme hot in summer season leading for the discomfort in classroom. Thermally uncomfortable classroom causes the negative impact in the academic performance of students. Therefore, there should b...

Thermal adjustment is one of the most important behaviours. In daily life, we use some behavioural adjustments. It is not always obtained the optimal condition by the thermal adjustments. For example, it happens to use excessive air conditioning for thermal adjustments. Especially, the excessive air conditioning use is important issue not only for...

The energy use in residential dwellings has been increasing due to increasing use of modern electric appliances to make the lifestyle easier, entertaining and better. One of the major purposes of indoor energy use is for improving indoor thermal environment for adjusting thermal comfort. Along with the use of passive means like the use of mechanica...

The traditional houses are well adapted to the climate and socio-culture using local building materials and techniques. However, traditional practices are being replaced by the artificial materials, modern design and new technology. It requires strong policies to sustain the traditional architecture. The objectives of this study are to evaluate the...

Preference of thermal environment varies with respect to different groups of people depending on their respective local climatic characteristics that elude their thermal histories on their own. It can be an important factor to consider when a thermally acceptable built environment is created for people who migrate from a different climatic region t...

The adaptive approach to thermal comfort shows that there is not a single comfortable temperature. A wide range of the temperatures which occur in indoor environments can be found acceptable to building occupants depending on their individual experiences and circumstances. This paper extends the approach introduced in a recent paper [1] to learn th...

Thermal environment adjustment is one of the most important behaviours. In our daily life, we use some behavioural adjustments for thermal comfort such as fan use. The occupant-behavioural stochastic models were proposed by some previous studies. However, the relative proportion of each behaviour has not yet been fully understood. It is important t...

Energy use is required for securing a certain living standard. Availability of energy sources, electricity in particular, is the basic requirement for the quality of living. The rationality of household energy use is not only for improving individual living conditions, but also for the economic growth of a nation. To formulate the national energy s...

The higher education sector in the UK is responsible for large amount of the country's energy consumption. Space heating, which is the largest and most expensive part of the energy used in the UK educational buildings is a potential target for improving energy efficiency. However, the role of thermal comfort in students' productivity in academic en...

Although various cooling approaches have been proposed to overcome the thermal discomfort in residential buildings, tropical developing countries still lack affordable and effective retrofitting methods. The objective of this study was to evaluate the effectiveness of an affordable retrofitting method with high-density polyethylene (HDPE) nets as r...

Energy use is required for securing a certain living standard. Availability of energy sources, electricity in particular, is the basic requirement for the quality of living. The rationality of household energy use is not only for improving individual living conditions, but also for the economic growth of a nation. To formulate the national energy s...

In order to quantify the seasonal differences in the comfort temperature and to develop a domestic adaptive model for highly insulated Japanese dwellings, thermal measurements and a thermal comfort survey were conducted. We collected 19,081 thermal comfort votes from 94 residents of 69 flats. The results suggest that the residents are highly satisf...

Abstract: Considering the prevalence of the different climatic conditions in Northern and Midland regions of the UK, this study investigated the occupants’ thermal comfort requirements in two university campuses in Scotland and England, UK. The aim of this investigation is to develop a practical, energy-efficient, and thermally comfortable environm...

Nepal is a mountainous country with low energy use so far and its climatic patterns remarkably differ from one place to another due to its geographical variation. In the north, summer is cool and winter severe, while in the south, summer is tropical and winter mild. Each year, harsh thermal environment creates serious health problems ranging from d...

Maintaining the thermal comfort of occupants along with minimising the related energy consumption is necessary in educational buildings in the UK. Thermal comfort is particularly important in this context as it affects how well students learn in the classroom. This study aims to identify comfort temperature ranges in different classroom types, lect...

In recent years, “green curtains” have become one of the most prevalent thermal mitigation methods in Japan. They can be considered as green infrastructure for achieving thermal comfort and reducing energy use. To examine the thermal mitigation effect of the green curtain for practical applicability in the condominium, the indoor and balcony temper...

Abstract: Thermal comfort in learning environments influences the students’ attention, concentration and learning productivity. Due to the impact of the thermal environment on students’ thermal comfort and consequently their productivity in line with the impact on energy consumption, this topic has attracted substantial attention among researchers...

In daily life, we conduct the various occupants’ behaviours for thermal comfort and health. The stochastic models of occupants’ behaviours were analysed by some previous studies. Especially, the models of window open in previous studies were analysed by Gaussian function, polynomial logit and logistic regression linked to linear function in FR mode...

Nepal has sub-tropical to cold regions due to large altitude difference. The traditional houses are well adapted to the local climate with the use of local building materials. However, traditional practice has been diminished by more introduction of the artificial building materials, modern design and new technology. Under this circumstance, some s...

Thermal adjustment is one of the most important behaviours. In daily life, we use some behavioural adjustments for thermal comfort. Especially, fan use is most common adaptive behaviour for the active thermal adjustments. The occupant behaviour stochastic models were proposed by some previous studies. However, the relative proportion of each behavi...

After massive earthquake 2015, thousands of Nepalese who lost their permanent houses by the hardest hits were forced to live in makeshift temporary shelters. The people residing in these shelters are facing extreme coldness that causes various health-related problems in winter. The field measurement on indoor thermal environment was conducted in on...

Most of the Nepalese school buildings are naturally ventilated and poor in thermal insulation which causes thermal discomfort during cold and hot seasons. Thermally uncomfortable classroom causes a negative impact on the academic performance of students. So, there should be serious attention to improve and optimize the indoor thermal environment of...

Controlling and reducing electric energy consumption is a critical issue across all over the countries for human wellbeing. However, approaches to achieve energy consumption reduction of individual occupants have not been established yet as both problems of collecting a large amount data of energy consumption and constructing prediction models are...

Nepal is a mountainous country with low energy use so far and its climatic patterns remarkably differ from one place to another due to its geographical variation. In the north summer is cool and winter severe, while in the south summer is tropical and winter is mild. Indoor thermal environment and household energy use of residential buildings are i...

An effective passive cooling strategy is essential for reducing energy consumption in a residential building without ignoring thermal comfort. Therefore, a field measurement on the thermal performance of a corner terrace house in Kuala Lumpur was conducted to reveal the effectiveness of free running (FR) with four different approaches – no ventilat...

This study aims to determine the indoor comfort temperature before sleep and after wake up in air-conditioning (AC) mode with different adaptive cooling strategies. Two units of guest rooms on the university campus were used with a total of 20 participants. The arbitrary-controlled AC setting (case 1) and control of thermostat setting by 3∘C higher...

In order to quantify the seasonal differences in the comfort temperature and to develop a domestic adaptive model for Japanese dwellings, thermal measurements, a thermal comfort survey, and an occupant behaviour survey were conducted for 4 years in the living and bedrooms of dwellings in the Kanto region of Japan. We have collected 36,114 thermal c...

Office workers use a variety of adaptive opportunities to regulate their indoor thermal environment. The behavioural adaptations such as window opening, clothing adjustments, and use of heating/cooling are important factors for adaptive thermal comfort. It is well-known that they are the most important contributors in the adaptive thermal comfort m...

After massive earthquake 2015, thousands of Nepalese who lost their permanent houses by the hardest hits were forced to live in makeshift temporary shelters. The field measurement on indoor thermal environment in five shelters was conducted in one of the district hit by the earthquake, Lalitpur, in winter. The mean indoor and outdoor air temperatur...

The widespread use of air-conditioning to achieve indoor cooling of residential buildings has caused increased electricity consumption. Effective passive cooling strategies, such as natural ventilation, are important for reducing energy consumption. Field measurements of thermal performance for a corner terrace house in Kuala Lumpur were conducted...

A classroom thermal environment quality has an important role in a student’s life as it influences student’s performance and well-being. It is well known that at each educational stage, curricula demands different activities, different learning approaches and systematic thinking, requiring increasing levels of concentration. With increasing awarene...

This study recommends the application of “preferred temperature” rather than neutral temperature in thermal comfort studies, particularly when focused on finding the range of comfort temperatures. Currently, neutral temperature is considered as comfort temperature of the occupants in thermal comfort research. This study challenged this view and que...

The Visual Thermal Landscaping (VTL) model provides a practical solution to balance energy and comfort tailored for the context and the immediate needs of individual occupants in that context through a thermal visualisation analysis. The aim is to provide a solution to the limitations of current tools employed in practice which do not account for t...

Energy use is made by residents, not by buildings. Therefore, how much of energy saving effect is possible by residents' behavior must be important. But at least in Japan, it has not yet been made clear. In recent years, it is expected to achieve energy saving effect by installing home _ electric appliances embedded network system. There are some r...

This study aims to analyze the temperature of preference of thermal environments (preferred indoor air temperature) inside the classroom of naturally ventilated school buildings in Autumn of 2017. A questionnaire survey for personal response and measurement survey to measure the environmental parameters was conducted. The data analysis is based on...

A home energy management system (HEMS) shows the energy used indoors so that the energy waste can be easily identified and reduced. Thermal comfort is related to the trend of energy use in buildings. We conducted a survey in a condominium equipped with a HEMS to determine the indoor thermal environment and various behaviors of the occupants taken f...

The current indoor thermal comfort standards and guidelines for hospital wards in the tropics may be insufficient for maintaining thermal comfort for occupants and ensuring energy efficiency in hospitals. Therefore, field survey assessments of thermal comfort were conducted in three Malaysian hospitals with air conditioning capabilities for patient...

This study recommends the application of “preferred temperature” rather than neutral temperature in thermal comfort studies, particularly when focused on finding the range of comfort temperatures. Currently, neutral temperature is considered as comfort temperature of the occupants in thermal comfort research. This study challenged this view and que...

The Visual Thermal Landscaping (VTL) model provides a practical solution to balance energy and comfort tailored for the context and the immediate needs of individual occupants in that context through a thermal visualisation analysis. The aim is to provide a solution to the limitations of current tools employed in practice which do not account for t...

We investigated window opening behaviour and thermal environment over a period of 4 years in the living rooms and bedrooms of dwellings in the Kanto region of Japan. We collected 36,144 data samples from 243 residents of 120 dwellings. The proportion of ‘open window’ in the free-running mode is significantly higher than that in the cooling and heat...

Surveys of the thermal environment and occupant behaviour were conducted in summer and winter for residents in the traditional houses of the Banke, Bhaktapur, Dhading, Kaski, and Solukhumbu districts in Nepal. The results show that residents adjust well to the thermal conditions of the houses. Both in summer and winter, the average clothing insulat...

For the purpose of evaluating passive cooling effects in summer, a thermal investigation of traditional houses was conducted in the sub-tropical region of Nepal. The results were as follows: (1) daytime indoor air temperature is 4.6 K less than outdoor air temperature. (2) The daytime surface temperature of the thatched roof is lower than the clay...

Firewood consumption and air temperature were investigated in winter and summer in traditional houses in the Banke, Bhaktapur, Dhading, Kaski, and Solukhumbu districts of Nepal. The firewood consumption rate was 235–1130 kg/capita/year. The results showed that the households in the temperate climate used less firewood than those in the subtropical...

The traditional architecture could be one of the key issues for sustainable building design for different climates and cultures. They are well matched and adapted to the climates and cultures by using local building materials and techniques. However, traditional forms of architecture are decreasing dramatically, being replaced by artificial materia...

In order to quantify the seasonal differences in the comfort temperature and to develop a domestic adaptive model for Japanese dwellings, thermal measurements, a thermal comfort survey and an occupant behaviour survey were conducted for 4 years in the living rooms and bedrooms of dwellings in the Kanto region of Japan. We have collected about 36,11...

Two surveys of the thermal environment and thermal sensations were conducted in the indoor and the semi-open spaces of traditional houses, during both summer and winter, in five districts of Nepal: Banke, Bhaktapur, Dhading, Kaski, and Solukhumbu. The surveys were carried out for 40 days, gathering a total of 7116 thermal sensations from 103 subjec...

Window opening behavior and thermal comfort were monitored in relation to the thermal environment over a 4 year period in the living rooms and the bedrooms of dwellings in the Kanto region of Japan. 36 144 sets of physical and subjective data were collected from 243 residents of 120 dwellings. This paper explores relationships between the different...

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...

People are exposed to ever-changing thermal environment. In due course they subconsciously develop their respective perception and cognition. With such general fact in mind, we designed a two-stage subjective experiment focusing on hot and humid summer weather in Yokohama, Japan, and analysed the experimental results from the exergetic viewpoint. A...

Evaluation of Seasonal Thermal Environment of Temporary Shelters Built in Nepal after Massive Earthquake 2015 Abstract: Two major earthquakes struck Nepal in 25th April and 12th May 2015, affected around 6 million people. Specially, who lost their permanent house in this hardest hit has been living under makeshift tents. In the context of Nepal, th...

Classrooms play an important role in every student’s life as the quality of thermal environments also influences a student’s performance and well-being. It is well known that at each educational stage, curricula demand different learning approaches and types of systematic thinking, requiring increasing levels of concentration. The absence of any st...

It is important and challenging to provide suitable thermal comfort conditions in hospital building due to widely varying conditions requirements by different types of occupants. The precise control of temperature and humidity is vital in hot-humid hospitals as these affect diseases, infections and allergies etc. indirectly. A field study comprisi...

It is important and challenging to provide suitable thermal comfort conditions in hospital building due to widely varying conditions requirements by different types of occupants. The precise control of temperature and humidity is vital in hot-humid hospitals as these affect diseases, infections and allergies etc. indirectly. A field study comprisin...