Biomass-gasification-based atmospheric water harvesting in India

Biomass from crop residue remains an underutilized and inexpensive energy resource around the world. Inadequate supply chain management forces farmers to resort to field burning of crop residue, resulting in environmental, health, and economic issues. In this study, we conceptualize a novel approach for biomass utilization which jointly addresses the common and often concurrent issues of energy, environment, and water. We propose to use the thermal energy from the combustion of the producer gas obtained from biomass gasification to power an off-the-grid refrigeration system which can condense moisture from air. We conduct a detailed thermodynamic analysis of vapor-adsorption cycle-based atmospheric water harvesting (AWH) system to develop an integrated modeling framework. We use the ambient weather data to report that the biomass-powered AWH can condense 800-1200 L of water per 1000 kg of biomass. Based on the local population and biomass availability, this can meet up to 10-12% of the potable water requirements in certain states of India. We also discuss the immediate challenges underlying this waste-to-value concept. Finally, we discuss that the proposition to jointly address energy, water, and the environment issues may motivate key paradigm shifts in policies required for practical implementation of this technology.