J. Eng. Technol. Sci., Vol. 53, No. 5, 2021, 210507 Received August 26 th , 2020, 1 st Revision February 28 th , 2021, 2 nd Revision March 31 st , 2021, Accepted for publication Juy 12 th , 2021. Copyright ©2021 Published by ITB Institute for Research and Community Services, ISSN: 2337-5779, DOI: 10.5614/j.eng.technol.sci.2021.53.5.7 Thermal Performance Analysis of a Newly Designed Circular Firewood Boiling Salt Stove Apichart Srichat 1 , Weerapol Kaewka 1 , Ponthep Vengsungnle 2 , Songkran Wiriyasart 3 & Paisarn Naphon 3,* 1 Department of Mechanical Engineering, Faculty of Technology, Udon Thani Rajabhat University, Udon-Thani, 4100, Thailand 2 Department of Agricultural Machinery Engineering, Faculty of Engineering and Architecture, Rajamangala University of Technology Isan, Nakhonratchasima 30000, Thailand 3 Thermo-Fluids and Heat Transfer Enhancement Research Lab. (TFHT), Department of Mechanical Engineering, Faculty of Engineering, Srinakharinwirot University, Ongkharak, Nakhorn-Nayok, 26120, Thailand *E-mail: paisarnn@g.swu.ac.th Highlights:  The thermal efficiency of the newly designed stove was higher than that of a traditional stove and an improved traditional stove.  The final amounts of salt crystals and salt flowers obtained from the newly designed stove were higher compared to those obtained from the traditional stove and the improved stove.  The payback periods were 50, 21, and 16 days for the traditional stove, the improved stove, and the newly designed stove, respectively. Abstract. Different biomass stoves are introduced and distributed among people living in rural and urban areas, especially in developing countries. For salt crystal production in Thailand’s rural north-eastern area, open fire stoves are used in domestic and small productive activities. Their thermal efficiency is very low for converting heat into utilization energy. A new stove with a circular configuration was designed and constructed to consider its thermal efficiency and economics, which were compared with those from a traditional and an improved traditional stove. The obtained thermal efficiency of the newly designed stove was 14.77% higher than that of the improved stove and 81.45% higher than that of the traditional stove. For the same initial saline volume, the final amounts of salt crystals and salt flowers obtained from the newly designed stove was higher compared with those obtained from the improved stove and the traditional stove, respectively, resulting in a 69.25% shorter payback period. Keywords: biomass; economic analysis; firewood; salt stove; thermal performance.