Energy efficiency study of household natural gas burner using pot-bottom shield and modified pot arrangement. (November 2022) - Islam, Ashfarul
Abstract: 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 heights 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 (0.4, 0.6, 1.0, 1.4, 1.8 and 2.0 kPa) keeping the burner primary air opening fixed at 50%. The corresponding NG flow rates at SATP were 4.23, 4.30, 4.70, 4.84, 4.94, 5.15 L/min for 0.4, 0.6, 1.0, 1.4, 1.8, and 2.0 kPa, respectively. 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 0.6 kPa pressure and 3 cm loading height corresponded to the highest efficiency of the burner at base setting (burner with ordinary pot at 0.6 kPa 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. Highlights: The thermal and emission characteristics of the NG burner were evaluated using four different pot-bottom shield arrangements. The pot-bottom shield improved HTE, and thermal efficiency for standard flat bottom pot and spot-welded finned pot set-up. Standard flat bottom pot shield arrangement exhibited 20% improvement than the highest baseline overall thermal efficiency. The finned pot configuration was less efficient than the standard flat bottom pot configuration. Around 30 billion cubic feet of household cooking NG can be saved in Bangladesh with a simple and low-cost pot-bottom shield.