The device operates in a simple yet effective cycle. With the cup’s dome lid open, the sponge absorbs airborne moisture. When closed and exposed to sunlight, the material heats up and releases the collected water into the container below.
Hao revealed that the sponge absorbed about two milliliters of water per gram and released nearly all of it within 10 hours during lab tests carried out at 90 percent humidity. The prototype consists of nine sponge cubes, each weighing 0.8 grams, yielded 15 milliliters of water per harvesting cycle.