Energy Efficiency Study of Household Natural Gas Burner Using Pot-Bottom Shield and Modified Pot Arrangement

Abstract

In Bangladesh, natural gas (NG) consumption for cooking is a significant portion of total NG consumption. The study aims to design and evaluate practically applicable pot-bottom shield and finned-pot in different pot-shield arrangements for better thermal and emission performances of a conventional household radial flow NG burner to lessen the household cooking energy consumption. Eleven sets of perforated hollow cylindrical pot-bottom shields having different height were fabricated from thin metal sheet with a provision of secondary combustion air. One of the two identical flat bottom pots was converted to spot welded finned pot. The thermal and emission performances of the NG burner were then evaluated following the standard water boiling test (WBT) protocol with four different pot arrangements, namely ordinary flat bottom pot without shield and with shield and spot welded finned pot without shield and with shield at eleven different loading heights (from 2.5 cm to 7.5 cm) and six different NG supply pressures (4, 6, 10, 14, 18 and 20 mbar) keeping the burner primary air opening fixed at 50%. It was found that a simple inclusion of a pot-bottom shield can dramatically improve the thermal efficiency of a natural gas cooking system for the both type of pots.  A 20% improved thermal efficiency was evaluated for the NG burner with ordinary pot and pot-bottom shield arrangement at 6 mbar pressure and 3 cm loading height corresponded to the highest efficiency of the burner at base setting (burner with ordinary pot at 6 mbar NG pressure and 4 cm loading height). It was also found that the operation of the burner at its highest thermal efficiency was still within the safe operation limit in terms of CO emission in comparison to international standards.

Keywords: NG Burner, Loading height, Pot-Bottom Shield, WBT, Finned Pot, CO/CO2 emission