The process involves pumping sea water up to a Gortex covered reservoir, where the water is subject to evaporation. The evaporated water then hits the top canopy and condenses, filling the four pockets around the raft with fresh drinking water. The Gortex cover over the reservoir allows the vapor molecules to escape, but holds in the larger liquid molecules, preventing the pockets of fresh water from becoming contaminated by the sea water.
This produces enough water for up to five passengers to stay sufficiently hydrated.
Read more about the project which was entered for a James Dyson Award.