Systematic and conceptual errors in standards and protocols for thermal performance of biomass stoves

Testing of biomass stove performance is mainly based on the use of water boiling or heating as a surrogate for cooking tasks. Boiling of water is prescribed as a simulation of common cooking tasks and is used for comparison of the performance of stoves under different operating conditions. Tests are designed to evaluate biomass stoves by providing quantitative and qualitative information about their thermal and emission performance. In some developing countries, notably China, India, Mongolia, and South Africa, water boiling or heating tests focus on the overall thermal performance as a fuel consumption proxy, again with narrowly defined operating conditions. During the past few years, several newly developed performance evaluation standards and protocols for cooking and space heating stoves based on solid biofuels have been developed. National standards differ significantly from one country to the other because of inhomogeneous local conditions, widely varying cooking habits, the level of industrialisation and cultural preferences. All those stove testing standards and protocols have been tried and found to be prone to systematic and conceptual errors, virtually none of them having been professionally and scientifically reviewed. The current paper reviews several different approaches to a widespread need for results of stove performance tests to be comparable and identifies a number of calculations and conceptual errors that materially affect the outcome of stove tests. Recently, research and development work promoting the dissemination of improved biomass stoves has attracted global participation. It is essenial that, as far as possible, all conceptual and systematic errors should be identified, corrected and avoided during the process of the development of acceptable international standards and protocols.