Research and development for alternatives to fossil fuels such as coal and petroleum have progressed considerably worldwide. Among clean fuels, bio-diesel has been a representative fuel and it was used for the following advantages; renewable, ready to use with low fine dust emission and non-toxicity. But it is expensive and cause strain on local resources. In our study, to resolve these issues, we developed two types of heating systems by direct input of waste cooking oil, and the heating system was optimized through mechanical design and design process. In addition, we conducted an environmental test to evaluate the reliability and environmental characteristics of the developed device. Firstly, through the design modification of heat recirculation system, more efficient combustion for the complete combustion of bio-fuel(waste cooking oil), was possible. As for the heating system, two products (tube heating system, agricultural hot air blower) were optimized for management convenience, space utilization, and efficiency improvement by 6-step design. From the environmental test result, the combustion efficiency of the heating system was up to 99%, the average oxygen concentration was 8.3%, and the CO concentration was 7.9 ppm for a stable combustion, NOx was up to 67 ppm, and SOx was not detected.