Kamil Dino (PhD)Yared Yalew2024-03-122024-03-122023-06https://etd.aau.edu.et/handle/123456789/2445To meet the requirements of increased thermal efficiency and reduced pollutant emissions of a conventional burner biogas cookstoves, a porous radiant burner (PRB) is added to these conventional burners. The porous radiant burner operates on an excess enthalpy approach, which asserts that recirculates the lost heat from hot combustion products to incoming fuel-air mixture. However, to achieve this excess enthalpy combustion with high reactant velocity, these porous burners employ compressed air, which requires an additional compressor. This thesis aims to investigate the performance of a naturally aspirated domestic biogas stove with a double-layer porous radiant burner cookstove. In the present work, the porous radiant burner comprising silicon carbide (SiC) and cast iron is investigated via numerical and experimental analysis. In the numerical analysis, the geometry of the existing porous radiant burner cookstove is modified with new features such as an orifice and slots (for air entrance) to get higher reactant velocity and lower pressure drop without using an external compressor. Then, the experimental investigation follow-up to evaluate the performance of the new naturally aspirated porous radiant burner, and compared it with the existing conventional burner. The numerical results indicate that naturally aspirated porous radiant burner has a better pressure distribution and higher reactant velocity than the existing burner and it can be operate without external pumping . The experimental results show that the naturally aspirated PRB has improved thermal efficiency in the range of 51-59%, reduced carbon monoxide (CO) and nitric oxides (NOx) pollutant emissions in the range of 41-55 and 4-10 parts per million at gas flow rates of 6-8 liters per minute, respectively. The new self-aspirated porous radiant burner biogas cook stove has 3.5% improved efficiency, 79.4% CO, and 28.7% NOx lower pollutant emissions compared to conventional burner cookstoves. Finally, this self-aspirated porous radiant burner biogas stove will have better efficiency if the best thermal resisting material is used and utilizes the biogas at a pressure greater than the atmospheric pressure.en-USporous radiant burner, biogas, conventional burnerThesis