A laboratory based comparative study of Indian biomass cookstove testing protocol and Water Boiling Test

• The thermal efficiency and air emission were used as cookstove performance indicators.
• CO emissions were higher in Bureau of Indian Standards (BIS) test compared to Water Boiling Test (WBT).
• PM emissions were ~55% lower in BIS test compared to WBT in PN cookstove.
• The effect of fuel feeding styles on cookstove performance was significant in BIS protocol.

The study was carried out to compare the cookstove performance using Water Boiling Test (WBT) and the Indian Standard on Solid Biomass Chulha Specification developed by the Bureau of Indian Standards (BIS) for testing cookstove. Additionally, the testing guidelines pertaining to feeding interval and ignition material were also tested in the BIS and WBT, respectively. Two cookstoves manufactured by Phillips, Philips Natural Draft (PN) and Philips Forced Draft (PF) were selected for assessing their performance. The thermal efficiency (TE), emission factors (EFs) of carbon monoxide (CO) and particulate matter (PM) were used as performance indicators to compare the cookstove performance. It was observed that both the cookstoves gave comparable TE with no significant difference (p > 0.05) using both protocols; whereas, CO EFs were ~ 39% and ~ 47% higher in BIS test due to dominance of smoldering conditions compared to WBT in PF and PN cookstoves, respectively. On the contrary, PM emissions were found to be ~ 55% lower in BIS test compared to WBT in PN cookstove, which could be due to the oven dried wood recommended in the BIS test. Inclusion of emissions of ignition phase was found to increase the total PM and CO emissions during cold start by 45–70% when mustard stalks were used as kindling material compared to wood chips and kerosene. Average CO emissions were found to increase by ~ 68% and ~ 48% in PF and PN cookstoves, respectively, with 15 minute fuel feeding interval in BIS test. The result shows that change in combustion conditions during the two different test protocols did not affect the energy parameters; however, the effect on CO and PM emissions was significant. It can be concluded that multiple testing methods might yield different information of cookstove performance leading to difficulty in assessing the actual performance of cookstoves.