dc.description.abstract | Today's world of technology, especially steam power generation technology, there is a very important generating system, namely the boiler. A boiler is a device that functions to heat water to become steam at high pressure and temperature, using heat from the combustion of fuel in the combustion chamber. However, in its application, boilers still use a lot of fossil fuels which over time will run out if alternative energy is not found that can replace them. In fact, before switching to fossil energy, humans used biomass energy for daily life. However, with the discovery of fossil energy, the use of biomass began to be replaced. "Biomass is a renewable and sustainable energy source with enormous potential of 146.7 million tons per year." This research aims to design a boiler unit with a closed combustion system using biomass fuel to utilize biomass energy and maximize combustion efficiency in the boiler. Therefore, a boiler design is needed that is able to maximize combustion in the boiler so that it can be utilized optimally. The design procedure in this research is 1. Determine the boiler capacity based on heat requirements. 2. Select the type of boiler that will be used and determine the boiler tank material 3. Determine the fuel 4. Determine the size or dimensions of the boiler based on fuel requirements 5. Draw the boiler design using AutoCAD software 6. Look for the temperature contour that occurs in the boiler combustion chamber using the ANSYS application. The boiler designed is a Water Tube boiler. The working principle is that water flows in a pipe and is then heated by fire from the combustion chamber. From the calculation results, it was found that the total pipe length was 33.5 m. The pipe material used was carbon steel with an outer diameter of 38.1 mm 0.0381 m, an inner diameter of 35.1 mm with a thickness of 3 mm. Based on the simulation, the results obtained include: Water inlet temperature: 30°C Water outlet temperature: 155°C Average temperature in the combustion chamber 208°C Highest temperature in the combustion chamber: 624℃ | en_US |