Can you pull drinking water out of thin air using nothing but sunshine? That was the question behind our project under the TÜBİTAK SME R&D Start-up Support Programme (1507), project no. 7230226, which ran from January 2023 to June 2024. At Innorma R&D, Solimpeks' R&D start-up based at the InnoPark technology zone, we developed a standalone prototype that harvests atmospheric moisture using solar energy, building on several years of work in energy-efficient cooling systems and solar collectors.
How does the solar atmospheric water harvester work?
The system runs a day-night cycle. A desiccant adsorbs moisture from the air overnight; during the day, a solar air heater (HGK) warms incoming air to release that moisture from the desiccant unit (DNT), and an air-cooled condenser (HSY) turns the vapour into liquid water. Regeneration temperatures reach up to 90°C.
We tested three desiccant routes:
| Prototype | Desiccant | Geometry | | --- | --- | --- | | A | Granular silica gel | Cylindrical unit | | B | ACFF-LiCl composite (developed in-house) | Sinusoidal honeycomb | | C | MOF-303 | Sinusoidal honeycomb |
Climate-chamber runs confirmed water production, with yields varying with humidity and temperature — results that guided the optimisation work in the rest of the project.
What did the four work packages cover?
WP1 — concept and simulation. Schematics for the prototypes and test units, EES mathematical models for heat and mass transfer, air flows of 0.03–0.07 kg/s, SolidWorks for 3D design, and ANSYS CFD to refine geometries — cylindrical for A, sinusoidal honeycomb for B and C. Boundary conditions: 1000 W/m² irradiation, 30°C ambient, targeting 50% thermal efficiency in the solar air collector.
WP2 — procurement and build. Lithium chloride, silica, and MOF sourced (with backups against delays); the solar air collector built with perforated absorbers; desiccant units in granular-cylinder and layered-composite variants; the condenser as a cross-flow exchanger. Desiccant samples showed up to 18% weight-gain uptake in carbon felt.
WP3 — validation and optimisation. Comparing simulations to early tests, we optimised the desiccant unit at 300 mm width with 58 layers at a 4 mm pitch for low pressure drop, iterating on fin designs and LiCl ratios for better kinetics without corrosion.
WP4 — the proving ground. Climate-chamber runs at 15–35°C and 45–60% relative humidity, logged via PT1000 sensors and dataloggers — adsorption overnight, desorption and condensation by day — plus outdoor monitoring. Fixes along the way included sealed leakages, separate fan controls, and better damper seals.
What hurdles did we hit, and what did we gain?
Sourcing MOF-303 was pricey and tricky; after a literature review showed promise at low humidity, we settled on 2 kg. Simulations overstated efficiencies — tests at 50% RH and 26°C yielded less than the models, pointing to wind losses or uneven flow. Desiccant clumping and seal leaks meant redesigns such as perforated diffusers. We kept the build lean, putting the budget into the essential instrumentation.
The payoffs were tangible. The optimised solar air collector hit its 50% efficiency target, and the composite desiccants adsorbed 1.2 g/g at 70% RH. Yields were highest in humid test conditions, pointing to Türkiye's coasts and the Middle East as promising applications — and we built lasting know-how in CFD validation and composite recipes. One late-night debate on layer spacing stands out: 3 mm clogged in prototypes, and moving to 4 mm boosted flow by 20%. Actively powered systems suit grid-connected sites in very humid locations; the passive solar approach is designed for off-grid use, where it shines.
Who needs water from air?
People in remote rural areas where water or power is a hassle to reach — farmers running greenhouses, communities cut off from supply lines — plus disaster zones, where quick access to clean water saves lives, and households facing steep costs for bottled or delivered water. Commercially, water-stressed regions such as the Middle East and Africa combine abundant sun with limited fresh sources. The market has grown quickly, and patent activity — led by the US and China — has risen sharply since 2000, leaving room for our own twist.
This TÜBİTAK-supported venture ended successfully in June 2024, affirming our role in water technology: small solar-powered setups can harvest water from thin air. We are scouting pilots — reach out if you would like to collaborate.
Further reading
- A 2024 study on solar-driven sorbent systems for water from air, testing composites in arid setups
- 2025 research on MOF-derived porous carbon sorbents for atmospheric water harvesting in arid conditions
- A 2024 long-term performance evaluation of vapour-compression atmospheric water generators in arid climates
