Alginate Biopolymeric Coated Heat Exchanger for Atmospheric Water Harvesting

We present a new type of sorbent material involving an aluminum heat exchanger coated with a hydrophilic alginate biopolymer hydrogel for atmospheric water harvesting (AWH). The hydrogel-coated heat exchanger is tested in a prototype driving cycle, collecting water over several days of continuous operation. The thermal cycle performance of the coating is tested in dry climates with relative humidity in the range of 30–50%. The new sorbent demonstrates regeneration temperatures between 60 and 80 °C, allowing efficient thermal cycles. The system allowed for a water yield of 2.48–3.3 L/kgHydrogel/day. The compactness of the coated heat exchanger, together with the performed daily water productivity, makes it compatible with applications integrating AWH technologies in the building sector.