Available at: https://digitalcommons.calpoly.edu/theses/2009
Date of Award
MS in Mechanical Engineering
Fresh water collection techniques have gained significant attention due to global dwindling of fresh water resources and recent scares such as the 2011-2017 California drought. This project explores the economic viability of actively harvesting water from fog, and techniques to maximize water collection. Vapor compression and thermoelectric cooling based dehumidifier prototypes are tested in a series of experiments to assess water collection capability in foggy environments, and what parameters can increase that capability. This testing shows an approximate maximum collection rate of 1.25 L/kWh for the vapor compression prototype, and 0.32 L/kWh for the thermoelectric cooling prototype; compared to 315 L/kWh for desalination or 12 L/m2/day for passive meshes. Exploration of parameters on the thermoelectric cooling prototype show a potential increase in water collection rate of 29% with the addition of a Teflon coating to the collection surface, 15% by clearing the collection surface, and 89% by tilting certain collection surfaces by 60-75°. In combination, these parameters could push active atmospheric water harvesting into economic viability where significant infrastructure investment is not feasible.