Abstract
Caldwell HERMES‑AWH is a modular, solar-regenerated atmospheric-water-harvesting system designed for low-to-moderate relative humidity, nominally 15–35% RH. The design addresses the major practical bottlenecks of conventional sorption-based atmospheric water harvesting: slow water-vapor diffusion into thick sorbent beds, adsorption heat that reduces uptake, poor thermal uniformity during regeneration, loss of desorbed vapor, incomplete condensation recovery, and low daily cycle count.
The system uses multiple thin structured sorbent cassettes, each carrying a 0.5–2.0 mm active sorbent layer on a thermally conductive backplane. Cassettes operate in sequential modes: ambient-air adsorption, thermal preconditioning, closed solar-thermal regeneration, vapor recovery and condensation, and cooling/reset. The system maintains a physically separate clean-water pathway from the sorbent pathway. A shared insulated vapor manifold transfers desorbed water vapor through a demister to a dedicated recovery condenser. Counterflow heat exchangers recover useful heat between regeneration and reset stages. A radiative nighttime panel may provide direct dew collection and limited thermal reset, but the principal water-capture mechanism is sorption followed by closed-loop vapor recovery.
The platform is deliberately modular: every claimed improvement has a bypassable baseline configuration. It is intended to enable honest side-by-side testing against a conventional fixed-bed solar-sorption control. The central hypothesis is that a thin structured sorbent geometry, segmented rapid cycling, conductive adsorption-heat removal, closed vapor recovery, and staged heat recuperation can raise net water yield by approximately 25–100% relative to a strong comparable low-RH solar-sorption system, with a central success target of approximately 50% improvement. These figures are engineering targets, not established results, and require independently instrumented testing.
MOF‑303 is a suitable reference sorbent because published work reports water uptake around 39 wt% at 20% RH, an adsorption inflection near 12% RH, and rapid thin-layer cycling with regeneration near 85°C; however, HERMES is deliberately sorbent-agnostic and must be tested with a safe, obtainable material before any performance claim is made.pmc.ncbi.nlm.nih+2
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Recommended Citation
Caldwell, Michael Victor Mr., "Caldwell HERMES‑AWH v1.0 High‑Flux Enthalpy‑Recycling Modular Extraction System Open-Hardware, Build-and-Test Atmospheric Water Harvester for Low-Humidity Environments", Technical Disclosure Commons, ()
https://www.tdcommons.org/dpubs_series/11536