Name Hom Bahadur Rijal
Official Title Professor
Affiliation Department of Restoration Ecology & Built Environment
Profile Dr. Hom Bahadur Rijal has MEng and PhD in architectural engineering from the Kyoto University, Japan. He was employed on a project developing an adaptive algorithm of window opening to predict the thermal comfort and energy use in buildings at Oxford Brookes University. He has a well established research track record, with over 80 publications in journals, with over 120 publications in international conferences, 10 chapters in books and co-edited one book. His major expertise is adaptive thermal comfort and occupant behaviour within building. In particular, he measured the thermal environments in traditional vernacular houses in Nepal, looked at the thermal comfort of their occupants and made thermal simulations of them for each climatic zones of Nepal. Currently, he is developing the adaptive model for thermal comfort in Japanese offices and dwellings.
Research Field(Keyword & Summary)
  1. (1) Thermal environment

    Traditional building and cities have been developed over many centuries without creating many serious environmental or health problems. They are well matched and adapted to the climates and cultures by using local building materials and techniques and thus they could be one of the key issues for sustainable building design. However, they are decreasing dramatically, being replaced by modern designs. It is often said that traditional buildings are cool in summer and warm in winter but not much research has been conducted. Thus, we are evaluating and improving the thermal environment of traditional and modern building and cities.

  2. (2) Adaptive thermal comfort

    Thermal adaptation is one of the most important factors in creating a comfortable indoor environment. Investigating and establishing the comfort temperature of the occupants can suggest customary temperatures for buildings. These temperatures are important because the chosen indoor temperatures affect the energy used in the building, and people in comfort are in general more productive and healthy. In order to clarify the seasonal and regional different in comfort temperature and to develop the adaptive model, we are conducting the field survey in various parts of the world.

  3. (3) Occupant behaviour

    The adaptive principle ‘if a change occurs such as to produce discomfort, people react in ways which tend to restore their comfort’ is the basis of the adaptive approach to thermal comfort. Adaptive thermal comfort depends on behavioural, physiological and psychological adaptations. People use a variety of adaptive opportunities to regulate their indoor thermal environment. We are developing various occupant behavioural models (window and door opening, fan use, clothing adjustments, heating and cooling use) relating with the indoor and outdoor thermal environment. Such models are required for the thermal simulation of buildings and automatic controls of indoor environment.

  4. (4) Energy use in building

    Firewood is the most primitive natural energy resource for human beings. In most developing countries, firewood is used as the main energy source. Especially in the rural areas, people are fully dependent on firewood without being able to access any artificial energy. Firewood could become one of the sustainable energy sources which are available locally, if managed properly. In developing countries, firewood is burned in an open fireplace, is very energy inefficient, and therefore the reduction of firewood consumption is one of the most important issues. We are doing research on energy use in building including firewood, electricity and gas.

  5. (5) Indoor air quality

    Indoor air pollution started when people began to burn firewood, and has a long history in comparison with the pollution caused by other substances such as coal, kerosene and gas. The smoke and dust from firewood combustion contains many chemical compounds which are harmful to the health, causing such problems as asthma, chronic bronchitis, cancer, and irritable eye conditions. This is the one of the major dilemmas in developing countries where firewood is used as the main energy source. Thus, we are evaluating and improving the indoor air pollution by firewood combustion.

Representative Papers
  1. (1) Rijal H.B., Yoshida K., Humphreys M.A. & Nicol J.F. (2021), Development of an adaptive thermal comfort model for energy-saving building design in Japan, Architectural Science Review, 64:1-2, 109-122,
  2. (2) Rijal H.B. (2021), Thermal adaptation of buildings and people for energy saving in extreme cold climate of Nepal, Energy & Buildings 230, 110551.
  3. (3) Rijal H.B., Humphreys M.A., Nicol J.F. (2019), Adaptive model and the adaptive mechanisms for thermal comfort in Japanese dwellings, Energy & Buildings 202, 109371.
  4. (4) Rijal H.B., Humphreys M.A. & Nicol J.F. (2018), Development of a window opening algorithm based on adaptive thermal comfort to predict occupant behavior in Japanese dwellings, Japan Architectural Review, 1(3), 310-321.
  5. (5) Rijal H.B., Humphreys M.A. & Nicol J.F. (2017), Towards an adaptive model for thermal comfort in Japanese offices, Building Research & Information 45(7), 717–729.
  6. (6) Rijal H.B., Humphreys M. and Nicol F. (2015), Adaptive thermal comfort in Japanese houses during the summer season: Behavioral adaptation and the effect of humidity, Buildings 5(3), 1037-1054.
  7. (7) Rijal H.B., Honjo M., Kobayashi R., Nakaya T. (2013), Investigation of comfort temperature, adaptive model and the window-opening behaviour in Japanese houses, Architectural Science Review 56(1), pp. 54–69
  8. (8) Rijal H.B. (2012), Thermal improvements of the traditional houses in Nepal for the sustainable building design, Journal of the Human-Environment System, 15 (1), pp.1-11, Deecmber.
  9. (9) Rijal H.B., Yoshida H., Umemiya N. (2010), Seasonal and regional differences in neutral temperatures in Nepalese traditional vernacular houses, Building and Environment 45(12), pp. 2743-2753.
  10. (10) Rijal H.B., Tuohy P., Humphreys M.A., Nicol J.F., Samuel A. and Clarke J. (2007), Using results from field surveys to predict the effect of open windows on thermal comfort and energy use in buildings, Energy and Buildings 39 (7), pp. 823-836.
  1. None
Award (1) Encouragement prize, Architectural Institute of Japan, September 2005, (2) Mahendra Vidya Bhusan “A”, His Majesty’s Government of Nepal, February 2006.
Grant-in-Aid for Scientific Research Support: Japan Society for Promotion of Science (JSPS)
Research Grants/Projects including subsidies, donations, grants, etc. Tokyo Gas, Tokyu Land Corporation, Daikin, Ministry of Land, Infrastructure, Transport and Tourism (MLIT), Japan Science and Technology (Sakura Science Exchange Program)
Recruitment of research assistant(s) No
Affiliated academic society (Membership type) (1) Associate editor of Journal of Building and Environmental Engineering (JBEE)
(2) Editorial board member of MDPI Energies
(3) Editorial board member of Japan Architectural Review (JAR)
(4) Architectural Institute of Japan (Member)
(5) The Society of Heating, Air-Conditioning and Sanitary Engineers of Japan (Member)
(6) Network for Comfort and Energy Use in Buildings (Member)
Education Field (Undergraduate level) Architectural climatology, Adaptive comfort, PBL (1)(2)
Education Field (Graduate level) Environmental architecture