From the Indian Copper Belts to Chulhas: Affordable Thermoelectric Materials for Rural India

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An estimated 840 million people in India use a solid-fuel cookstove (chulha) powered off wood or biomass. These are very inefficient and produce emissions harmful to health and the environment. Chulhas emit harmful pollutants and particulates that contribute to respiratory diseases, including chronic obstructive pulmonary disease and lung cancer. India has the largest number of people exposed to high levels of indoor air pollution (IAP), which is primarily caused by solid-fuel cookstoves. IAP was responsible for 482,000 deaths in India in 2017 alone, the largest number of deaths attributable to IAP worldwide. The cooking stoves operate at temperatures up to 600 deg. C, providing a ready supply of waste heat. A thermoelectric (TE) device is capable of converting this waste heat into useful electricity, providing a localised power source to power an auxiliary fan to improve combustion in the stove, making them cleaner, safer and more efficient and mitigating the effects of IAP. Approximately 100 million people in rural areas of India have no access to electricity. The areas which electrification has not reached are among the more remote, where off-grid electricity generation is essential. A TE device would also provide sufficient electrical power to fulfill basic needs in lighting, communication and mobile device charging. Addition of a TE device to a chulha would therefore provide a cleaner cooking environment whilst simultaneously delivering a localised electricity supply delivering a major impact on the health and well-being of rural communities.Central to the creation of a TE generator for use with a cooking stove is the development of materials that are affordable, sustainable and optimised to the working temperature (< 600 deg. C) of the stove. Proof of principle has been demonstrated with commercially-available bismuth telluride modules. However tellurium is scarce and bismuth telluride and the corresponding modules expensive. In this project we seek to develop materials that meet the criteria of performance and cost that are optimised for use in the traditional cooking stoves. In particular, we will create new sulphide TE materials for electricity generation that are derived from minerals such as chalcopyrite, bornite and chalcocite, to which India has access to potentially cheap and abundant reserves in the Indian copper belts, including the Khetri, Singhbuhum, and Malanjkhand copper belts. In this way the project seeks to apply the natural resources of India to the solution of a problem affecting a substantial number of the most disadvantaged sector of the population. The project will benefit from the combined computational and experimental expertise of three leading TE laboratories in the UK and India. By applying a variety of materials design strategies and synthetic approaches, we seek to create new high performance n- and p-type semiconductors that can be incorporated into a TE device for electrical power generation in the temperature range 200 < T/deg. C < 400, using the waste heat from a cooking stove.