In February 2020, Water. Desalination + reuse (Faversham House) reported that researchers backed by US and Chinese funders had published a multistage solar desalination design. The TMSS device combined heating at the water surface, capillary feeding and reuse of the heat released by condensation across several stages. Under one-sun light, the prototype turned solar energy into vapour at a reported 385 percent, and over three quarters of the vapour was recovered as water. Salt built up by day and diffused away overnight. The paper appeared in Energy and Environmental Science.
The report showed passive solar desalination gaining performance mainly through repeated heat reuse, with off-grid and water-scarce regions in view as later users.