Liter-scale atmospheric water harvesting for dry climates driven by low temperature solar heat

This experimental study demonstrates a thermodynamic cycle based on isothermal regeneration to enhance the exploitation of sorbents and low temperature energy sources, such as solar energy, for atmospheric water harvesting in dry climates. An experimental setup based on silica gel has been designed to produced liquid water with low regeneration temperatures for dry climates with dew points in the range of 2 to 8 °C and ambient temperatures between 20 and 35 °C. Experimental results demonstrate daily water production from 1.5 to 3.3 L day−1 per square meter of solar field, with a maximum regeneration temperature of 57 °C, and ambient temperatures up to 35 °C. The thermal energy required to activate the cycle is between 1 and 3 kWh per liter of condensed water. •Atmospheric water harvesting with standard quality silicagel and low temperature regeneration.•Isothermal regeneration enhances performance of silica gel for dry climates.•Water vapor condensation at ambient temperature (20–35 °C) without any refrigeration.•Experimental tests in a replicated dry environment with ambient dew points between 2 and 8 °C.•Daily production of 1.5–3.3 L day−1 per square meter of solar field.