Solar Atmospheric Water Harvesting Adsorbents 2026 — PatSnap Eureka
Solar Atmospheric Water Harvesting Adsorbents 2026
Solar-powered atmospheric water harvesting using adsorbent materials captures moisture from ambient air at relative humidity as low as 10–30% without grid electricity. This dataset covers 35+ patent records across MOF, hygroscopic salt composite, hydrogel, and photothermal sorbent approaches filed from 2018 to 2026.
How Solar Adsorbent Water Harvesting Works
Solar-powered atmospheric water harvesting (SPAWH) operates on a two-phase cycle: passive adsorption of water vapor into a sorbent material at low irradiance, followed by solar-thermal desorption that releases concentrated vapor for condensation into liquid water. The approach functions at relative humidity as low as 10–30%, making it viable where conventional freshwater infrastructure is absent.
Five adsorbent material classes are represented across this dataset: metal-organic frameworks (MOFs), hygroscopic salt composites such as LiCl and CaCl₂, hydrogels and hygroscopic polymers, conventional desiccants like silica gel and zeolites, and emerging composite sorbents combining photothermal agents with hygroscopic matrices. Solar integration architectures span direct photothermal sorbent heating, evacuated tube solar air heaters, flat-plate collectors, PV-powered systems, and polygeneration configurations.
MOF-type MIL-101(Cr) achieves 3.10 L/m²/day at 10–40% RH, while Zr-MOF-808 reaches 8.60 L/m²/day above 50% RH. Hygroscopic polymer films execute 14–24 sorption-desorption cycles per day in arid conditions. A honeycomb hydrogel structure (PCLG) achieves 1.8 g/cm³ volumetric water uptake at 30°C and 30% RH, yielding 2.9 L/m²/day outdoors.
In this dataset, innovation is concentrated among academic institutions and one commercial firm. SVNIT Surat is the single most prolific assignee in retrieved records with 5 filings from 2023–2025, followed by the University of California Regents with 4 active US patents from 2018–2020. India and the United States account for the largest share of records in this dataset, with India showing notably high filing velocity in 2023–2026.
Filing Trends and Technology Cluster Distribution
Patent filing activity across this dataset shows three distinct phases from 2018 to 2026, with the highest record density appearing in 2021–2023. Technology cluster analysis reveals MOF-based and evacuated-tube system architectures as the most patented approaches in retrieved records.
Patent Records by Technology Cluster (Dataset Snapshot)
MOF-based adsorbent systems and evacuated-tube solar architectures account for the largest share of patent records in this dataset, reflecting concentrated IP activity from UC Regents, MIT, and SVNIT Surat respectively.
↗ Click bars to explorePatent Filing Activity by Phase (Dataset Snapshot, 2018–2026)
Filing activity in this dataset shows that the 2021–2023 development phase contains the highest record density, with 25+ literature records and 10+ patent filings, followed by a shift toward integrated systems in the 2024–2026 phase.
↗ Click bars to exploreKey Deployment Contexts for Solar AWH Adsorbent Systems
Across this dataset, SPAWH adsorbent systems are targeted at four distinct deployment contexts: off-grid drinking water supply in arid regions, polygeneration for desert communities, industrial power plant water recovery, and smart building-integrated water generation.
Arid Region Off-Grid Water Supply
Multiple literature sources in this dataset confirm SPAWH can meet daily drinking water requirements across tropical regions, with estimated potential coverage for approximately 1 billion people. India, Egypt, Pakistan, Saudi Arabia, and the UAE are specifically analyzed target geographies. A geospatial analysis for Pakistan using Monte Carlo simulation integrated adsorbent performance with national climatic data to project AWH potential in L/m²/day.
Off-Grid Potable WaterDesert Community Polygeneration Systems
Shanghai Jiao Tong University’s CN patents (2022, 2023) cover solar-driven adsorption-based cold-heat-electricity-water cogeneration systems explicitly targeting desert inhabitants. Uravu Labs Private Limited’s 2023 IL filing covers a 24×7 solar thermal desiccant AWG system with thermal storage decoupled from the solar unit. These multi-output approaches improve overall system economics where demand for water, power, heating, and cooling is simultaneously acute.
PolygenerationPower Plant Dry Cooling Water Recovery
Stanford University (Leland Stanford Junior University) filed a WO patent in 2021 targeting water harvesting specifically for dry cooling tower-operated power plants using rapid adsorption-desorption cycling. This application addresses water consumption in water-stressed power generation infrastructure without dependence on conventional freshwater sources. The filing represents the dataset’s sole application of SPAWH technology explicitly to industrial power generation.
Industrial Water RecoverySmart Building-Integrated Water Generation
A 2026 IN filing from Nitte (Deemed to be University) covers a solar-powered nanocoated window panel integrating MOF nanocoatings, photothermal graphene oxide layers, and transparent PV films for architectural-scale water harvesting. Multiple 2025 IN filings cover IoT-monitored solar AWH systems with real-time humidity and temperature sensing, purification modules, and AI-driven cycle optimization. These filings signal a new application paradigm of distributed water generation embedded in urban building envelopes.
Smart ArchitectureLeading Assignees in Solar AWH Adsorbents — Dataset Snapshot
In this dataset, SVNIT Surat is the most prolific assignee with 5 filings in retrieved records (2023–2025), while the Regents of the University of California hold 4 active US patents from 2018–2020 covering MOF-based sorption devices. Academic institutions account for the majority of filings in retrieved records, with Water Harvesting Inc. being the primary commercial assignee.
Top Assignees by Filing Count — SPAWH Adsorbent Patents (Dataset Snapshot, in Retrieved Records)
↗ Click bars to exploreSVNIT Surat
SVNIT Surat is the single most prolific assignee in this dataset with 5 active IN filings spanning 2023–2025, covering evacuated tube solar air heater-based AWH systems, desiccant wheel configurations, double-ended vacuum tube collector systems with Jute/CaCl₂ composite desiccant, and complete SDAWH system architectures for arid climates. One system using a 4.86 m² collector with 12 kg desiccant achieves 5,850 mL/day at $0.086/L water cost and 13.93% overall efficiency. All filings are active IN patents targeting domestic arid-region deployment.
India — INRegents of the University of California
The Regents of the University of California hold 4 active US patents filed from 2018 to 2020, all covering MOF-based sorption-based atmospheric water harvesting devices driven by low-grade solar energy. These foundational filings established the use of porous MOF adsorbents with S-shaped water adsorption isotherms enabling operation at 10–40% RH. The patents represent the earliest concentrated IP cluster in this dataset for the core sorbent-solar desorption mechanism.
United StatesNext-Generation Approaches in Solar AWH Adsorbent Patents
The most recent filings in this dataset (2024–2026) reveal five emerging directions: hygroscopic hydrogel sorbents, architectural integration, AI and IoT-enabled autonomous systems, multi-output polygeneration, and fully renewable-energy-autonomous sorption-condensation hybrids.
Hygroscopic Hydrogels Replacing MOF Beds
MIT’s 2026 WO filing on a solar-driven hygroscopic hydrogel device signals that polymer hydrogel architectures are emerging as a primary sorbent platform, offering lower cost and better volumetric water uptake compared to pure MOF beds. This aligns with 2022–2023 literature on super-hygroscopic polymer films (SHPFs) achieving 14–24 sorption-desorption cycles per day in arid conditions. The honeycomb hydrogel structure (PCLG) achieves 1.8 g/cm³ volumetric uptake at 30°C and 30% RH, yielding 2.9 L/m²/day outdoors.
AI and IoT Integration for Adaptive Cycling
Multiple 2025 IN filings incorporate AI-based environmental sensing, adaptive navigation to high-humidity microclimates, MPPT solar optimization, and machine learning-driven cycle management. Adaptive cycling strategies demonstrated in this dataset achieve a 169% increase in water production in desert climates (17–32% RH) by adjusting adsorption/desorption phase durations to real-time weather conditions. A 2025 IN filing (Aquabot) combines biomimetic condensation surfaces with AI-powered solar-driven harvesting and autonomous repositioning.
MOF Adsorbents vs. Hygroscopic Salt/Hydrogel Composites
Click any row to explore further.
| Dimension | MOF Adsorbents | Hygroscopic Salt / Hydrogel Composites |
|---|---|---|
| Water Yield | MIL-101(Cr): 3.10 L/m²/day at 10–40% RH; Zr-MOF-808: 8.60 L/m²/day above 50% RH | PCLG honeycomb hydrogel: 2.9 L/m²/day outdoors; LiCl@ACFF: 2.1 g/g at 25°C, 70% RH |
| Operating RH Range | 10–40% RH (S-shaped isotherm with steep uptake at low humidity) | Effective from low to moderate RH; salt composites active from ~30% RH upward |
| Desorption Temperature | 60–85°C (moderate solar thermal input sufficient) | Below 80°C for LiCl@ACFF; compatible with low-grade solar heat |
| Cycling Speed | Single-cycle standard; adaptive cycling achieves 169% more output in desert (17–32% RH) | Hygroscopic polymer films: 14–24 sorption-desorption cycles per day in arid conditions |
| Key Challenge | High material cost; concentrated IP cluster around UC Regents, MIT, Water Harvesting Inc. | Salt leakage during deliquescence; addressed by encapsulation enabling up to 80 wt% loading |
| IP Landscape | Dense IP cluster: 4 UC Regents US patents (2018–2020), MIT WO (2018, 2026), Water Harvesting Inc. (2022–2023) | Comparatively less encumbered in this dataset; KAUST holds 2 US filings for hydrogel photothermal materials |
| Scalability | Scalable systems demonstrated; architectural MOF nanocoating integration shown in 2026 IN filing | Super-hygroscopic polymer films described as scalable; honeycomb hydrogel suitable for outdoor deployment |
| Representative Assignees | UC Regents (US), MIT (US/WO), Water Harvesting Inc. (US) | MIT (WO 2026), KAUST (US), SVNIT Surat (IN), Shanghai Jiao Tong University (CN) |
FAQ: Solar Atmospheric Water Harvesting Adsorbent Patents
Five adsorbent material classes are represented: metal-organic frameworks (MOFs), hygroscopic salt composites (e.g., LiCl, CaCl₂), hydrogels and hygroscopic polymers, conventional desiccants (silica gel, zeolites), and emerging composite sorbents combining photothermal agents with hygroscopic matrices.
SVNIT Surat (Sardar Vallabhbhai National Institute of Technology, Surat) is the single most prolific assignee in this dataset with 5 active IN filings from 2023–2025, covering evacuated tube solar air heater systems, desiccant wheel configurations, and SPAWG system architectures.
MOF-type MIL-101(Cr) achieves 3.10 L/m²/day at 10–40% RH, while Zr-MOF-808 reaches 8.60 L/m²/day above 50% RH, according to technical reviews cited in this dataset.
Adaptive cycling strategies that adjust adsorption/desorption phase durations to real-time weather conditions achieve a 169% increase in water production in desert climates operating at 17–32% RH, based on literature in this dataset.
One system described in SVNIT Surat’s 2024 IN patent uses a 4.86 m² double-ended vacuum tube collector with Jute/CaCl₂ composite desiccant (12 kg) and yields 5,850 mL/day at a water cost of $0.086/L with 13.93% overall efficiency.
India is the most active patent-filing jurisdiction in this dataset with at least 15 patent records, followed by the United States with approximately 12 records. China has 3 filings (all from Shanghai Jiao Tong University), and there are 5 WO international filings including MIT, Stanford, and Water Harvesting Inc.
Data and insights on this page are based on a limited patent and literature dataset and are for reference only. Figures may not represent the complete technology landscape.