Compact rapid cycling fuel-fired atmospheric water harvesting device for all-day water production

Abstract

Atmospheric water harvesting (AWH) has emerged as a vital technology in alleviating the significant water struggles around the globe. Advances in sorption-based AWH (SAWH) primarily focus on novel materials, often overlooking system-level considerations. We introduce the first-of-its-kind compact rapid cycling fuel-fired (CRCF) AWH device. The CRCF device packages aluminum fumarate MOF into a compact adsorbent heat exchanger (AHX), which uses fuel combustion and an ambiently cooled condenser. The CRCF prototype was designed to maximize volumetric production density ($P_v$$P_v$), defined as the daily water production per unit volume of the AHX ($k{g}_{water}{\left(m^3\right)}_{AHX}^{-1}da{y}^{-1}$$k{g}_{water}{\left(m^3\right)}_{AHX}^{-1}da{y}^{-1}$). Fuel enables continuous daily cycling and reduces the system footprint relative to a purely solar-driven system. A computational model is used to optimize the adsorption truncation and the thickness of sorbent fins (τ) for maximum water productivity (P) or $P_v$$P_v$ demonstrating the potential of CRCF. A daily water productivity of 3.19 $k{g}_{water}k{g}_{MOF}^{-1}da{y}^{-1}$$k{g}_{water}k{g}_{MOF}^{-1}da{y}^{-1}$ or a $P_v$$P_v$ of 718 ($k{g}_{water}{\left(m^3\right)}_{AHX}^{-1}da{y}^{-1}$$k{g}_{water}{\left(m^3\right)}_{AHX}^{-1}da{y}^{-1}$) can be achieved representing an improvement of 1.5× and 2.1× in P and $P_v$$P_v$ relative to state-of-the-art metal organic framework-based multi-cycle SAWH devices operating without refrigeration.