Content uploaded by Pilar Cereceda
Author content
All content in this area was uploaded by Pilar Cereceda on May 01, 2015
Content may be subject to copyright.
A Proposed Standard Fog Collector for Use in High-Elevation Regions
Abstract
The collection of fog droplets by vegetation is an important wet
deposition process. It can, in fact, dominate the chemical and
hydrological input to certain high elevation watersheds. However,
measurements of fog deposition are rarely made and, where they do exist,
comparisons of deposition rates in different locations have been
hampered by the use of innumerable types of collection devices. A
simple, inexpensive, 1-m2 fog collector that can produce
measurements of the deposition of fog water to a vertical surface is
described here. The collector has been used successfully in five
countries to investigate the variation of fog deposition in complex
terrain and to estimate the deposition to trees and to much larger fog
collectors. It is proposed that it be employed widely as a standard to
quantify the importance of fog deposition to forested high elevation
areas and to measure the potential collection rates in denuded or desert
mountain ranges.The standard fog collector costs about the same as a
rain gauge ($100 U.S.) to construct and can be used with a variety of
recording devices. It is a flat panel made of a durable polypropylene
mesh and mounted with its base 2 m above ground. Fog collection rates
are typically 1 10 L m2 of vertical collecting surface per
day but can reach values of 30 40 L m2 day1. The
presence of drizzle or light rain with the fog, coupled with 10 m
s1 winds, has produced collection rates as high as 300 L
m2 day1. If a standard fog collector is installed
at a site with wind speed measurements and a conventional rain gauge, a
reasonable estimate can be made of the proportions of fog and rain being
deposited on the vertical mesh panel. This information is fundamental to
the understanding of acidic wet deposition at higher elevations and to
comprehensive hydrological calculations in watersheds.
... Due to the lack of standards for measurement and reporting of data [13], only the mean or maximum value was considered in many studies. In 1994, Schemenauer and Cereceda designed a Standard Fog Collector (SFC) [14], which consisted of a 1.00 x 1.00 m 2 frame stretched by a net, attached to the 2 side posts with a height of 2.00 meters, with a distance of 0.10 meters from the posts. Under the net frame, the water chute dimension L x W x D is 1.04 x 0.15 x 0.10 m 3 , whose details are shown in Figure 1. ...
... Mist collection rates range from 1 -10 l/m 2 .day, but can reach 40 l/m 2 .day in some regions [14]. ...
... Standard Fog Collector: SFC[14] ...
The production of clean water from evaporated water in fog has been very attractive in recent decades. Massive fog accumulation combined with simple concepts and technologies with respect to water production has resulted in sustainable environmental impact in producing clean, low-cost water for arid areas around the world. Mist collection systems work best in locations with repetitive fog conditions where fog is driven by wind especially coastal areas. However, the technology can also be used in mountainous areas where there is water in the Stratocumulus clouds at elevations of about 2,000-6,500 feets. The purpose of this research was to compare the fiber types that collect mist water by testing with atmospheric conditions in Khao Yai Thiang, Nakhon Ratchasima Province, which is 800 meters above sea level to produce water for the community and suitable for Thailand. The test was carried out by stretching 12 different fibers to a wooden frame measuring 0.50 x 0.50 m ² and installing it horizontally. Field tests found that three types of horizontal water droplet materials, which were the best mist water collector, are synthetic fibers: nylon net, plastic net, and polyethylene net. All three materials behave very differently. Especially, the temperature profile of the plastic net has the highest temperature in the afternoon and the lowest temperature in the night. Nylon net has a temperature close to the air temperature throughout the day but slightly lower. These materials will be used in the design of the moisture trap tower in the next experiment. In the first experiment, there was not much water and water droplets clinging to the fibers as blotted dots with tissue paper because the fog period is not long enough.
... It is composed by a mesh, two poles and tensors; its collection panel is of 40 m 2 , made by a double layer of Raschel mesh. Generally, for these experiments the Standard Fog Collector (SFC) is used, it consists of a rigid metal frame that measures 1 m × 1 m; this frame is supported by two poles at 2 m above ground level, to reach stronger winds (Schemenauer and Cereceda 1994). Klemm et al. (2012) and Schemenauer and Cereceda (1994) The three-dimensional collectors are still not widely explored. ...
... Generally, for these experiments the Standard Fog Collector (SFC) is used, it consists of a rigid metal frame that measures 1 m × 1 m; this frame is supported by two poles at 2 m above ground level, to reach stronger winds (Schemenauer and Cereceda 1994). Klemm et al. (2012) and Schemenauer and Cereceda (1994) The three-dimensional collectors are still not widely explored. Moreover, a threedimensional device can provide more collection rate for the same soil occupation, but the additional mesh layers permit to collect the fog droplets that already passed through the first mesh. ...
... In order to develop a fog harvesting project, firstly the climatic conditions of the site should be analysed; in fact, wind speed, wind direction, mean humidity, temperature and Liquid Water Content (LWC) (Holmes et al. 2015) are determining factors for the fog collector disposition and dimensioning. In fact, the collectors should be oriented perpendicularly towards the main wind direction, and generally more wind speed imply more water collection (Schemenauer and Cereceda 1994). Moreover, due to the vertical development and the lightness of the traditional fog collector, the possibility to integrate this device into a smart membrane façade is under consider (Caldas et al. 2018). ...
Water emergency is one of the terrible effects of climate change; it is defined as the Blue gold of twenty-first century. In this scenario, fog stands as a potential alternative water resource. Many territories are affected by fog phenomenon; here fog collectors have been developed to extract water from humid mass of air. The aim of this paper is to explore the application of this technology in building sector. The Large Fog Collector is the device commonly used for these projects; it is a textile structure, composed of a mesh, two poles and cables. The exploitation of conventional water resources implies a massive distribution system with significant energy consumption and costs. Otherwise, fog harvesting is a passive system; it relieves the stress upon freshwater resources. Nowadays, fog collectors are low tech devices, and fog harvesting projects are commonly developed in arid areas for agricultural and reforestation purposes. Nevertheless, taking advantage of the vertical development of the device, this textile structure shall be integrated in façade, to promote resilient constructions and make buildings water self-sufficient. The paper explores the design criteria for the development of a novel concept of smart water collecting façade. It can promote also shading effect, reducing the use of cooling system, energy demand, so lowering the ecological footprint. Depending on fog Liquid Water Content, the collected water can be used for the irrigation of green roofs, gardens or in an optimal scenario also for domestic use. The analysis of local weather data is crucial to extend the territories where this system can be applied; but, more important, the improvement of the device’s technology is essential to implement it in new application fields.
... Coastal areas are usually foggy but the wind speed may render inadequate to move the fog; that is, without adequate wind speed, a passive collector cannot function in practice. Therefore, before implementing a fog water collection project, one needs to evaluate local wind speed for successful operation of the system, configure the structures to minimize the loss across the system (Holmes et al. 2015), and consider dominant wind direction to determine installation direction of the collector (Schemenauer & Cereceda 1994a). ...
... The considered collector model was used as a reference to compare the results to those of other projects performed around the world and evaluate the efficiency against other types of collectors. According to the standards mentioned in Schemenauer & Cereceda (1994a), the collectors were made into 1 Â 1 m dimensions and a height of 2 m, and then deployed. In order to guide the collected water to the storage tank, a gutter, which was a segment of a polyethylene pipe, was employed at a slope of 2%. ...
In arid and semi-arid areas where available water resources are very limited, the application of unconventional sources of water like the fog is of paramount importance. In this paper, the feasibility of using a standard fog collector (SFC) to collect fog water for complementary irrigation of rainfed wheat in the Abi-beyglu area was investigated. For this purpose, collected water volume was measured on a daily basis during fog time in 2021. The water demand of the winter wheat was estimated by the FAO Penman–Monteith equation under dry and normal conditions. Then, the contribution of the collected water to supply the water demand of the wheat and the resultant increase in the yield under two different scenarios, namely complementary irrigation with 30 and 60 mm of collected water, was estimated using the AquaCrop model. Results showed that it is feasible to obtain an average water production of 3.6 L/m2/day over the studied period. Upon irrigation with 30 and 60 mm of collected water under dry and normal conditions, 26 and 34% of the water deficiency for wheat farming was supplied, leading to increased crop yields by 0.6 and 1.7 ton/ha, respectively.
... Fog harvesting is typically carried out by blowing saturated air with water droplets through a fog water collector. 4 Fog water collectors are usually constructed using permeable polyethylene (PE) or polypropylene (PP) meshes 5,6 and vary significantly in yield, ranging between 3 and 75 L·m −2 per day. 7 An efficient fog collector allows the passage of humid air through the permeable mesh collector, recovers most of the liquid from the fog stream, and quickly releases the water from the mesh for storage. ...
The global water supply worsens yearly with climate change; therefore, the need for sustainable water resources is growing. One of them is fog water collectors with variable surface wettability, with multifunctional designs for utilization worldwide and to address regions with low humidity levels. Therefore, we created fiber meshes with a photoresponsive switchable surface. This study uses electrospun polyvinylidene fluoride (PVDF) meshes, whose wettability is controlled by adding TiO2. The fog water collection performance is studied at high and low humidity levels. With TiO2-PVDF, the electrospun mesh can be converted from hydrophobic to hydrophilic under UV irradiation and transformed back to a hydrophobic state with heat treatment. The switchable meshes were found to be more effective at water collection after UV irradiation at lower fog rates of 200 mL·h-1. The ability to switch between hydrophobic and hydrophilic properties as needed is highly desired in fog collection applications using electrospun meshes, as it can improve overall efficiency after UV irradiation.
... Yet producing affordable, efficient and durable fog nets is a remaining challenge: easily accessible low-cost nets as the "Raschel mesh" (from grocery packing) 16,18 have low efficiency and can break in high winds 19,20 . Previous studies tested new geometries together with the use of coatings to improve drainage as on Raschel mesh 21 , grids 22 and cylinders 23 ; "fog harps" made of vertical wires have also shown good drainage and partial avoidance of clogging [24][25][26][27][28] . ...
As scarcity of water is expected to intensify with global warming, unconventional water sources such as advective fogs may become essential. In numerous arid regions, nets are used to harvest such water droplets. However, many current fog nets are either not durable or expensive, and have poor performances for short time or low intensity fog events. With a dedicated test bench, we show here that a low-cost net with kirigami design offers a higher and faster fog collecting ability than the usual fibers nets. This kirigami fog net consists of a continuous network of strips where water quickly forms a stable film, accounting for its superior capture efficiency. We rationalize this mechanism with a simplified structure composed of disconnected strips whose optimization paves the way to the shaping of original fog nets such as the kirigami one.
... Therefore, it has been a priority to search for new and modern supply systems such as the construction of massive infrastructure in the form of pipelines, dams, aqueducts and treatment plants, as well as further new technologies and applications in order to provide the needed water volumes for arid or relatively dry sites, which have been traditionally ignored or isolated from central water supply systems [24][25][26][27][28]. In this respect, one of the new applications to increase the fresh water supply has been based on the catchment of water by the presence of fog in elevated mountainous regions [29][30][31][32][33][34]. The fog-water catcher technique has been originally developed by the Inca Empire, where buckets were placed under trees, allowing them obtain water from the moisture-laden fog along the water catcher technique has been originally developed by the Inca Empire, where buckets were placed under trees, allowing them obtain water from the moisture-laden fog along the Peruvian coast, which is characterized by extremely low rainfall [35]. ...
The lack of water is a fundamental issue for survival of peasant communities located at heights above 3200 masl in the Andean highlands, such as in the case of the Galte-Yaguachi community in central Ecuador. The social balance, agricultural development as well as animal subsistence and finally the economic income is pending on the availability of hydric resources. Therefore, a three-dimensional fog collector system was constructed with Urku Yaku material in order to provide water for the close-by community. Simultaneously, we determined the quality of the collected water per square meter of the mesh, during the period of the highest annual precipitations. The installed nets yielded a gain of at least 2.63 L/m2 and a minimum of 0.65 L/m2 per day. The analyzed water quality reflected the suitability for human consumption. As water collection has been successful, an expansion of the proposed system may provide this fundamental good also to other communities with similar characteristics. Fog catcher towers will produce 26,577.84 m3/year of water, fulfilling crops’ needs, and the economic analysis proves it is worth the investment, as demonstrated by a benefit cost ratio of 1.90.
Agricultural production in the Atacama Desert is restricted by extreme aridity and poor soil quality. Between 18°S and 30°S, low stratocumulus clouds regularly cover the southeastern Pacific Ocean reaching the Coastal Cordillera. Thus, marine fog is constantly present in the coastal areas of the desert. Fog can be harvested using fog collectors. However, limited information is available with regards to the variability of fog presence throughout the year and along the coast of the desert. Combining fog water harvest with hydroponic production under greenhouse facilities presents an alternative for sustainable and local fresh food production. In this article, we analyze
the potential of fog water collection in two sites (Alto Patache and Falda Verde) distant by about 1000 km within the Atacama Desert. Additionally, in both locations, the environmental conditions within greenhouse structures, the potential energy requirement for environmental conditioning (including the energy production from photovoltaic panels) and the water requirements of vegetable crops under greenhouse conditions were modeled. The annual average of fog water collection
registered was 2.9 and 3.3 L per day per m2 in Alto Patache and Falda Verde, respectively. During the most demanding season for crop evapotranspiration, 2.13 m2 of fog collectors can supply the water required for 1 m2 of greenhouse crops. The energy required for water and air pumps in the hydroponic systems can be supplied with photovoltaic systems including eight PV modules and a battery storage capacity of 9.4 kWh. In conclusion, the present study sheds light on the possibilities of massive water collection from fog to be used in local and sustainable food production in the Atacama Desert.
Water scarcity is the most common concept associated with the desert. The Atacama Desert is worldly known as the aridest desert on Earth. However, some populations are established in this area, requiring water for living that promotes the search of alternative water sources, as fog catchers taking in advance the regional fog event known as Camanchaca. During 2015, the construction of fog trap units was carried out on a hill in the Falda Verde sector in Chañaral (North Chile). In the design of these new fog trap units it was considered to improve the anchoring system and the distribution and angles of the clamping tensioners in order that the structure could withstand the maximum wind speeds that have been registered in the area, while recording the water accumulated by these units during a period of 12 months determined an average catchment of 22 liters of water/m2 per month.
Atmospheric water harvesting is a sustainable solution to global water shortage, which requires high efficiency, high durability, low cost, and environmentally friendly water collectors. In this paper, we report a novel water collector design based on a nature-inspired hybrid superhydrophilic/superhydrophobic aluminum surface. The surface is fabricated by combining laser and chemical treatments. We achieve a 163° contrast in contact angles between the superhydrophilic pattern and the superhydrophobic background. Such a unique superhydrophilic/superhydrophobic combination presents a self-pumped mechanism, providing the hybrid collector with highly efficient water harvesting performance. Based on simulations and experimental measurements, the water harvesting rate of the repeating units of the pattern was optimized, and the corresponding hybrid collector achieves a water harvesting rate of 0.85 kg m-2 h-1. Additionally, our hybrid collector also exhibits good stability, flexibility, as well as thermal conductivity and hence shows great potential for practical application.
The lack of equitable distribution of resources, including water, is one of the most influential causes of conflicts and divisions; in fact, the so-called “water wars” are on a constant increase. The aim of this paper is to give an alternative solution to hydric issues, through a new strategy, that is fog water collection. Many territories worldwide are affected by the fog phenomenon, those are defined as “fog oasis.” Fog harvesting is documented to be an efficient system to collect water from fog, as confirmed by projects developed in many locations. In order to promote fog harvesting as a possible solution to restrain social, political, and environmental divisions caused by water issues, the authors are going to analyze some case studies in Africa. They were chosen based on local factors, including fog formation, and existing fog harvesting projects, in order to serve as a model for any other fog oasis. In Morocco, many villages are facing high levels of emigration, due to many factors, like water scarcity. The border between Ethiopia and Eritrea is the scenario of the Tigray war, which contributes to scarce water availability. The fog collector device is proposed as an architectural system that can be developed and integrated into a divided city, in order to heal and transform the hydric situation.KeywordsFog harvestingSustainable urban ecologyWater self-sufficiency
A small, carefully cleaned fog-water collector was used at the site (elevation 780 m) to study the incoming fog (cloud). The ion and trace-element concentrations met Chilean and the World Health Organization's (WHO) drinking-water standards. The pH values, however, were at times extremely low. Samples from 1987 and 1988 were consistent with those from the larger dataset in 1989. The lowest observed pH was 3.46. The acidity was associated with high concentrations (89%) of excess sulfate in the 15 fog-water samples (based on Cl- as the seawater tracer element). The NO3-/SO+4 equivalents ratio for the fog samples was 0.18, showing the dominance of SO4= in determining the acidity of the fog samples. -from Authors
A ground-based, cloud water collection system capable of intercepting significant volumes of water from clouds has been in operation at a mountain field station in the Adirondack Mountains of New York State for three summer seasons. An analysis of cloud water pH for August-September 1977 and 1979 strongly suggest that acid input to the ecosystem due to clouds at Whiteface Mountain may be significantly more important than that due to the much-discussed phenomenon of acid precipitation. The mean pH of nonprecipitating clouds was 3.55 during 1977 and 3.50 during 1979; approximately 90% of all observations were found in the pH interval between 2.66 and 4.66. In the event that precipitation is intercepted concurrently with cloud droplets, a minimum dilution of the cloud water acidity by a factor of 60-80% can be expected. Other aspects of the collection and pH analysis of cloud water at Whiteface Mountain are also discussed.