Analysis of different condensing surfaces for dew harvesting

Due to water shortages in several places in the world, alternative water sources such as atmospheric water and greywater have been studied. Dew water harvesting by passive radiative cooling is an unconventional water source that is easy to use, install, and shows great potential in several places in the world. This paper aims to experimentally evaluate the dew yield through passive radiative cooling in Vicosa city, Minas Gerais, Brazil by using standard white plastic for dew harvesting, developed by the International Organization for Dew Utilization (OPUR), polypropylene plastic, black plastic, packaging tape, and anodized aluminum as condensing surfaces during two different periods. The polypropylene plastic and packing tape materials used in this present research have not been researched before in the literature. However, they have demonstrated potential for harvesting dew. As a result, the average water collected was, respectively, 0.151, 0.135, 0.140, 0.127, and 0.046, mm/night using the OPUR standard plastic, polypropylene plastic, black plastic, and packaging tape, and anodized aluminum as condensing surfaces. Although relatively small water volumes were harvested, this water should not be neglected since it can supplement the water demand for irrigation, human and animal consumption, among other uses in drought periods.