Efficiencies and emissions comparison and optimization of commercially available domestic LPG cooking stoves in Pakistan

Abstract

LPG is considered as one of the most convenient and clean fuels for domestic cook stoves and is a popular choice, particularly in urban areas. Considering the limited fossil fuel resources, increasing emissions with ever increasing LPG demands, it is important to improve thermal efficiency and reduce emissions of the existing LPG cooking stoves by incorporating design modifications. This study reports design modification, in the form of loading height optimization, and consequent evaluation of thermal performance and emissions of two of the most widely used LPG fuelled medium scale cooking stoves, Sa and Sb, in Pakistan. Using two standard pots Pa and Pb, Water Boiling Test (WBT) 4.3.2 is adopted to evaluate the thermal efficiencies and a specifically designed emission collection hood is used for the assessment of CO emissions. In the first part of the study, variation in the performance of stoves is evaluated with varying loading heights at fixed thermal power input. Once, the loading height was optimized, in the second part, the efficiencies of the stoves were evaluated with varying thermal inputs at fixed/optimum loading height. Averaging for both pots, thermal efficiency of stove Sa was increased by around 20% and that of stove Sb by 13% during high power phase of WBT after loading height optimization. The numbers were comparable for low power phase. Both stoves showed a decline in thermal efficiencies with increase in thermal power input. At optimum loading heights, lowest CO emissions were observed.