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Improved cookstoves, which are designed to address the health and environmental damage caused by inefficient biomass cooking and heating, are generally engineered to prioritize technical emissions and efficiency improvements over practical user cooking needs. As a result, improved stoves are often only used alongside traditional technologies, or are rejected by cooks entirely, and may fall short in efforts to address health and environmental problems even if they are technically capable of doing so. A testing protocol for cookstove usability was developed by the authors to help stove designers and implementers evaluate user needs for a given stove technology and cooking culture, and balance them with technical design criteria more effectively. The protocol is based on established usability practices and includes ethnographic testing methods to increase validity in cross-cultural testing applications. This paper discusses evaluative trials of the protocol in 10 rural and urban households and 2 institutional kitchens near Lira, Uganda, 4 rural households in Antigua, Guatemala, and 11 stove designs in a US laboratory, as well as preliminary results from a usability study on 20 rural households near Gulu, Uganda by an international NGO. These trials, along with feedback from test administrators in Uganda and Guatemala, demonstrated that the protocol is a viable tool for increasing the understanding of cookstove usability, though more work is needed to improve its validity and connect the results to effective stove design and selection decisions, as well as health and environmental impact. As a result of this research, various improvements were made to the protocol, and opportunities for further validation, expansion, and improvement were identified. In addition, methods used by the protocol elicited related data from participants regarding their attitudes towards improved cookstoves and the relative importance of reducing air pollution and fuel use in the larger context of their lives. Finally, this research highlights the value of an interdisciplinary approach, in this case based in anthropology and engineering, to increase the accessibility of user input in international development more broadly.

While filtration, chlorination, and UV drinking water treatments are commonplace, globally an estimated 1.2 billion people continue to boil their drinking water over inefficient biomass fires instead because it allows them to use available resources paired with a time-tested and trusted method. Although boiling water is culturally well-established, there is vast potential to improve human health, environmental impact, and efficiency by leveraging the fact that a significant reduction in pathogenic microorganisms occurs at temperatures well below boiling through a process known as pasteurization. This paper presents the evaluation of a community-scale, biomass-powered, flow-through water pasteurization system that was designed to heat water to the temperature required for pasteurization to occur before recuperating heat while cooling treated water down to a safe-to-handle temperature. The system is then compared to other common thermal treatment methods including batch-boiling over open fires and improved cookstoves. Results from computational modeling and empirical analysis show that the water pasteurizer significantly increases the overall water treatment capacity (from 7.9 to 411 L/h, adjusted for one hour of treatment via household boiling and operation of the water pasteurizer at steady-state, respectively) and uses far less biomass fuel (from 22 to 5.5 g/L, adjusted for treatment of 1 L of water via household boiling and operation of the water pasteurizer at steady-state, respectively). Notable comparisons to the batch-boiling of water over institutional-sized traditional and improved cookstoves are also demonstrated. Further, the results of fecal indicator reduction through the system (8 log and 6 log reduction of E. coli and bacteriophage MS2, respectively) suggest compliance with US-EPA (6 log and 4 log reduction of E. coli and bacteriophage MS2, respectively) and WHO requirements (effluent concentrations below the detection limit, specified as E. coli CFU/100 mL and E. coli and bacteriophage for water treatment processes. It is recommended that engineers continue to explore the use of heat transfer and microorganism reduction theory to design technologies that increase the capacity and efficiency for thermal water purification that uses locally-available biomass resources.

While improved cookstoves have been designed and distributed for decades with the goal of addressing the human health and environmental issues caused by traditional biomass cooking methods, they often have not achieved the intended impact. One of the main reasons for this shortcoming is that engineers often focus on technical attributes of cookstove designs, such as improved fuel and combustion efficiency, but neglect usability. If a stove design does not meet a cook’s needs and preferences, the stove will likely be used only as a supplement to a traditional stove, or not used at all. To help close this gap, a testing protocol for cookstove usability was developed. The proposed protocol is based on established usability practices from fields such as software and consumer product design, and includes usability criteria taken from existing cookstove research and interviews with subject experts. The protocol includes objective and subjective testing methods, is designed to elicit user perceptions of and the relative importance of each usability criterion in a given context, and incorporates ethnographic methods to improve validity in cross-cultural applications and in diverse testing scenarios. This protocol may be useful to stove designers as a way to better understand users and validate or improve designs, to implementers as a method to assist with the selection of the most appropriate stove for a project, and to researchers as a tool to assess cookstoves and cookstove programs. Preliminary field and laboratory work to test the validity of the protocol demonstrated a mixture of meaningful and uncertain results, indicating that while it is a reasonable tool to assess cookstove usability, the protocol requires interpretation of qualitative data and assessment of uncertainty to be most effective.