Study On Real-time Testing Protocol For Performance Evaluation Of Solid Fuel Household Stoves And Its Application

Approximately three billion people are using solid fuels such as wood,straw,and coal as their primary energy source for cooking and heating.Along with household cooking and heating stove usage,the unreasonable combustion,fuel wasting,and the indoor air quality problems caused by the unreasonable designs or operations of the stove have attracted more and more attention.The current testing methods lose detailed combustion information when evaluating the unstable and non-continuous combustion,which further makes the laboratory tests different from the field tests and hardly contributing to the stove design improvement.This study developed the real-time testing method and testing system by considering the combustion features of household cooking and heating stove to overcome the existing defects of lacking real-time combustion details.It then combined the results of influences of different testing operations on the stove performances to form the suitable testing conditions for further stove study,providing information for stove design and promotion.Firstly,this study developed the real-time testing method based on the chemical balance and verified the method by calculating the real-time Siegert constants of propane and solid biomass fuel.It designed the real-time testing system based on mass loss measurements.Detailed descriptions for dilution system,gas channel and water channel were given,and equipment met the minimum requirements of the system were chosen.It compensated water physical properties changes,background carbon dioxide and water,response times and system delay for different instruments.The uncertainties evaluation was carried out,and software system was also developed.Secondly,this study researched the influences of different testing operations on the stove performances to form the reasonable and representativeness testing conditions.The results showed that for coal cooking and heating stoves,or biomass cooking stoves with/without a chimney,different ventilation conditions,fuel qualities,moisture contents,flame heights and testing sequences had significant influences on certain or multiple test indicators.Results from different based emission factors cannot be compared directly.The particle emissions from the stove mainly come from the ignition,adding fuel for banking,adding fuel for fire recovery and adding fuel during high power phase.Finally,tests were carried out for real-time method evaluation and utilization.The result showed that the organic carbon and element carbon ratio for different biomass combustion stages were within 2.47?11.30,and particulate matters were mainly smaller than 1.1 ?m.The emission factors of 16 priority-controlled PAHs under different stages were ignition stage 807.75 g/kg,stable stage 34.58 g/kg,burn out stage 5558.78 g/kg,and after burnout stage 127.43 g/kg,respectively.The distribution of ring numbers and characteristic values were also different with stages changing.Results for application of the real-time method on Hebei stove promotion showed that improved stoves had better performances than baseline stoves on both thermal and emission indicators,with using briquette coal better than using raw coal.The heating power had no significant influences on thermal efficiency,emission performance or cooking performance.The cooking function of the stove still needs improvements.