Gareth McKINLEY, et al.
Related : Air Wells / Dew Ponds / Fog Collectors : Aakash
Amrat Air Water Harvester ** Air Water
Harvester ** Air Wells ** Air Wells (
Solar Adsorption ) ** Air Well Patents (#1) ** Air Wells
Patents (#2) ** AUGUSTIN : Watercone ** BLEECHER :
CHATTRE : Fog-Collector ** Dew Pond Construction ** Dew & Fog
Harvesters ELLSWORTH : AirWell ** ESTEVES : Fog
Collector ** Fog
Collectors ** HENG / LUO : Fog Collector * HOFF :
WaterBoxx ** JAGTOYEN : Auto Exhaust Water Recovery System
** KLAPHAKE :
Air Wells ** KOHAVI
: Air Well ** McKINLEY : Fog Fence **
/ GIL : Fog Collector ** PARENT : Air Well
** QINETIQ : Dew
Collector ** RETEZAR : Fontus Air Well RICHARDS :
AquaMagic Water Generator SHER : Air Well
THEILOW : Air
Well ** VITTORI
: WarkaWater Airwell ** WHISSON : Air Well *
March 22, 2016
Could Harvesting Fog Help Solve the
World’s Water Crisis?
…As Dar Si Hmad has reckoned with the cultural implications of fog
harvesting, the technology itself has evolved. While the basic
science at its heart is not new—Bartolomé de las Casas mentions it
in his sixteenth-century magnum opus, “History of the Indies”—the
advancement of the harvesting equipment, in recent years, has been
significant. “By changing the size of the holes, and the size of
the fibres, and thinking about the coating on those fibres, we’ve
improved the fog-collecting efficiency by about five hundred per
cent,” Gareth McKinley, a professor of teaching innovation at
M.I.T.’s School of Engineering, has said. The nets in Morocco,
their designers say, are more durable and easier for locals to
repair than similar nets built in the nineteen-nineties and early
two-thousands in Eritrea, Chile, and Yemen...
Voyage of the Mimi - Season 1 Episode
Making Dew Water Water Everywhere - 1984
Aqualonis GmbH Peter Trautwein CEO
Tel + 49(0)89-48 08 81-24
Fax + 49(0)89-48 08 81-11
Obtaining drinking water with fog
In dry mountainous and coastal regions with high fog
concentration, the CloudFisher collects water from fog and
provides hundreds of thousands of people with a secure supply of
The CloudFisher is the first standard fog collector that can
withstand high wind speeds. It is quick and easy to install, and
requires no energy and only minimal maintenance. All the materials
are food-safe. The CloudFisher can supply people with high-quality
drinking water that meets WHO standards, and can also provide
water for agriculture and forestry. It is mainly deployed in
mountainous and coastal regions where rainfall is scarce but
clouds and fog are plentiful.
Aqualonis GmbH has developed the CloudFisher Pro and CloudFisher
mini for the Water Foundation Aqualonis GmbH, based in Munich, was
founded to implement this technology worldwide. As a licensee of
the WaterFoundation, the company markets and sells the CloudFisher
products. Aqualonis develops, plans, builds and maintains fog
water collection systems for non-profit and commercial projects
alike. It is thus distinct from the WaterFoundation, a strictly
non-profit organization that cannot engage in or accept liability
for activities involving a commercial aspect.
The amounts yielded per fog-day differ according to region and
season. They vary between 6 and 22 litres per square metre of net
CloudFisher Pro for villages, schools, industry,
agriculture and forestry
52.8 sqm total net surface
6 liter/sqm 316.8 liter
22 liter/sqm 1161,6 Liter
CloudFisher mini test collector and domestic user
16.5 sqm total net surface
6 liter/sqm 99 liter
22 liter/sqm 363 Liter
Each fog project starts with the collection of meteorological data
on wind speeds and directions, relative humidity and temperature,
precipitation and amounts of accumulated water. These findings are
used to decide whether the location is appropriate for a fog water
production system. How can the CloudFisher mini help with this?
LIQUID COLLECTING PERMEABLE STRUCTURES
[ PDF ]
Inventor(s): PARK KYOO-CHUL [US]; CHHATRE
SHREERANG S [US]; MCKINLEY GARETH H [US]; COHEN ROBERT E [US] +
Applicant(s): MASSACHUSETTS INST
TECHNOLOGY [US] +
A structure for collecting liquid droplets from an aerosol can
have a structure and properties that are selected for efficient
liquid collection. In particular, the strand radius and spacing of
a mesh, and a material for coating the mesh, can be selected to
provide efficient collection of water droplets from fog.
 This application claims priority to U.S. Provisional
Application 61/751,039, filed Jan. 10, 2013, which is incorporated
by reference in its entirety.
 The present invention relates to a liquid collecting
 According to WHO statistics, less than 0.007% of all water
on the earth is readily accessible for human consumption. About a
billion people lack access to safe drinking water. More than 3.5
million people die every year due to water-related diseases. Water
insecurity is one of the leading causes for school dropouts,
especially among girls, and more than 200 million working hours
are spent (almost exclusively by women) daily for the collection
of domestic water.
 The water crisis is worsened in arid parts of the world due
to abuse of groundwater, water-intensive crop cultivation, rapid
industrialization, and changing lifestyle. In some dry regions,
the appearance of fog in the early morning is common. Fog is a
completely untapped water resource. Fog harvesting provides an
opportunity to “produce” water locally for rural communities,
which will reduce the stress on groundwater. Consider a country
like Chile, where a persistent advection fog is occurs due to the
long and mountainous coastline. By one estimate, 10 billion m
<3 >of fog water per year is available in Chile. Currently,
water consumption in northern Chile is 391 million m <3 >per
year, i.e., only 4% of the total water content in the fog. Water
collection from fog harvesting thus has enormous potential to
locally satisfy the need for a pure and dependable supply of water
in arid locations.
 Highly efficient permeable structures for collection of
liquid droplets or small particles are described. The surface
wetting properties and topography of the material can guide the
design of the permeable structures. For example, the fog
harvesting ability of woven meshes can be increased greatly by
judiciously choosing the physico-chemical properties of the mesh
surfaces. A working model for the interaction of liquid with the
permeable structures allows design of highly efficient liquid
collecting structures for a variety of possible conditions.
 The permeable structures can be used for applications
including fog harvesting; elimination of mist in engines and
turbines; or elimination of small droplets or colloidal particles
in the chemical process industries. These mist eliminators
decrease pressure drops across unit operations, such as
distillation columns, and therefore save energy required for
pumping. Filters based on the permeable structures can selectively
capture hazardous colloidal emissions based on size...
BRIEF DESCRIPTION OF THE DRAWINGS
 FIG. 1 is a series of microscope images of various
permeable structures with different wire radii (R) and spacing
 FIGS. 2A-2C are a diagrams depicting fog flow through a
woven mesh surface, and a contour plot of the fog harvesting
efficiency. FIG. 2A is an illustration indicating the stream
surfaces of fog laden wind and their divergence after passing
through a woven mesh surface. FIG. 2B is an enlarged drawing
focusing on the interaction between incoming fog droplets and a
horizontal mesh element. FIG. 2C is a contour plot of the fog
harvesting efficiency (η) s a function of the ratio of radius of
the fog droplets to the radius of the wire (R*=r fog/R) and the
spacing ratio of the woven mesh (D*=(R+D)/R).
 FIGS. 3A-3E represent two factors that reduce collection
efficiency, and the surface modification design space that depicts
the relative resistance to re-entrainment and drainage. Two
factors that inhibit fog harvesting and reduce collection
efficiency are ( FIG. 3A) re-entrainment of collected droplets in
the wind and ( FIG. 3B) blockage of the mesh. FIG. 3C shows a plot
that identifies the range of droplet sizes where the forces of
adhesion dominate the drag forces, and establishes a criterion for
a threshold droplet size for re-entrainment. FIG. 3D shows a plot
that represents a second constraint arises from comparing the
weight of the droplet with the surface pinning force arising from
contact angle hysteresis. The threshold size where gravity
dominates hysteretic pinning can be decreased by minimizing
CAH=cos θ rec−cos θ adv. FIG. 3E shows a graph depicting the
design space constructed from two dimensionless parameters related
to work of adhesion (abscissa) and contact angle hysteresis
(ordinate) depicts the relative resistance to re-entrainment and
drainage. Measured values for droplets of water (V ″10 μL)
deposited on several different coatings are shown in the plot.
Wetting characteristics corresponding to a higher work of adhesion
and lower contact angle hysteresis are ideal for the maximum fog
 FIG. 4 is a contour map of the predicted aerodynamic
capture efficiency of fog droplets of radius r fog using a mesh
with a wire radius R and a spacing ratio D*, assuming a wind
velocity of 2 m/s. The efficiency is expected to increase with
decreasing R (increasing R*) and at an intermediate value of D*.
 FIG. 5 illustrates clogging and bridging problems
associated with draining of collected liquid and a how a coating
having a low contact angle hysteresis and a high receding contact
angle can address these problems.
 FIGS. 6A-6B show contour plots of fog harvesting efficiency
of woven mesh surfaces with either ( FIG. 6A) a polypropylene (PP)
coating, or ( FIG. 6B) a POSS-PEMA coating.
 FIG. 7 illustrates a fabrication process of
liquid-collecting permeable surfaces with different wettability by
dip-coating and spray-coating.
 FIG. 8 is a schematic depiction of an artificial fog
harvesting experimental setup. The experiments were carried out in
a humidity chamber at T=26° C., and a relative humidity of 100% to
eliminate the effects of condensation and evaporation of water.
 FIGS. 9A-9D illustrate results of fog harvesting
experiments with woven wire meshes of different dimensions and
surface coatings. FIGS. 9A-9C show design chart based on spacing
ratio D* and dimensionless width R*. FIG. 9D displays the
experimentally observed collection efficiency for the 5 dip-coated
wire meshes along with coated and uncoated Raschel mesh.
 FIG. 10 is shows predicted fog harvesting efficiency for a
double layered Raschel mesh (blue) and for a woven mesh with R=127
μm and D*=3.5 (red) under different conditions of fog droplet size
and wind velocity. Velocities and fog droplet radii were: (1) 0.5
m/s and 3 μm; (2) 0.5 m/s and 6 μm; (3) 2 m/s and 3 μm (conditions
used in lab experiments); (4) 2 m/s and 6 μm; (5) 8 m/s and 3 μm;
and (6) 8 m/s and 6 μm (Chilean fog conditions).
 FIG. 11 is a schematic diagram depicting a water droplet on
a cylindrical mesh filament.
 FIG. 12 is a micrograph depicting a coated mesh.
 FIG. 13 is a diagram and graph depicting contact angles of
water droplets on surfaces...
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