investigation of optimum energy efficiency for heating system retrofit in high-rise residential buildings in iran

This study delves into the potential for enhancing the efficiency of domestic non-condensing boilers. the focus is on a simple modification that leverages moderate or intense low-oxygen dilution (mild) combustion, a technique known for its high efficiency and low emission characteristics. the process involved a comprehensive technical assessment and financial evaluation of a sample building and recuperator. the modification was aimed at improving boiler efficiency, reducing short cycling losses, and making efficiency changes under partial load conditions less noticeable. the simulation results were encouraging, showing a 7.7% increase in the boiler’s overall efficiency. this improvement translates into a significant saving of 1416 cubic meters of natural gas annually. the economic analysis was conducted in two scenarios: the post-operational phase and the design phase of the building. the outcomes were promising in both scenarios, indicating the cost-effectiveness of the modification. the study’s novelty lies in examining a wide range of optimal flue gas recirculation (fgr) rates for various boiler-recuperator systems under partial load conditions. the findings demonstrate that mild combustion can benefit any domestic non-condensing boiler, making this study a valuable contribution to the field of energy efficiency.