Design and performance evaluation of Korean traditional heating system—Ondol: Case study of Nepal

Poor infrastructure in developing countries, combined with challenging geographical characteristics, is associated with problems of limited access to resources, poor transportation and environmental health issues. In some developing countries, there are no heating systems during the winter season, which causes problems for both people and livestock. The most common heating source is from open fires using biomass from animal and plant residue, which are also used for cooking. Fireplaces are typically located inside the house, which can lead to respiratory health problems because of limited ventilation. Thus, heating systems with proper ventilation are desirable to mitigate health problems and improve living conditions. Here we describe the application of ‘Ondol’, a traditional Korean heating system that was redesigned for improved efficiency, in remote villages in a mountainous region of Nepal. Total 10 models of Ondol were designed and fabricated, and the temperature profile and uniformity were characterized to select the optimal design. The height and type of the ‘Gorae’ were the most important factors in determining the efficiency. The optimal design was provided to local people, who were trained to replicate and build the Ondol on their own. A post-installation survey was carried out to evaluate the effectiveness of the system.