History
Contenido
A partir de principios del siglo , una serie de inventores experimentaron con colectores de gran masa. Destacaremos al ingeniero ruso Friedrich Zibold") (a veces se pone como Friedrich Siebold[10]), el bioclimatólogo francés Leon Chaptal"), el investigador alemán-australiano Wolf Klaphake") y el belga Achille Knapen").
Zibold manifold
In 1900, near the Byzantine city of Feodosia, 13 large piles of stones were discovered by Zibold, who was a forester and the engineer in charge of this area.[12] Each stone pile covered just over 900 m² and was 10 m high. The finds were associated with the remains of 75 mm diameter terracotta pipes, which apparently led to wells and fountains in the city. Zibold concluded that the stone piles were condensers that supplied Feodosia with water; and it is estimated that each aerial well could produce more than 55,400 L per day.[10].
To verify his hypothesis Zibold built a condenser with stone piles at an altitude of 288 m on Mount Tepe-Oba, near Feodosia; It was surrounded by a 1 m high and 20 m wide wall, around a bowl-shaped collection area with drainage. Zibold used sea stones of 10 to 40 cm in diameter stacked up to 6m high with a truncated conical shape of 8 m in diameter at the top. The shape of the stone pile allows for good airflow with only minimal thermal contact between the stones.[13].
The Zibold condenser began operating in 1912 with a maximum daily output estimated to have been 360 L (Zibold did not publish results).[10] The base developed leaks that forced the experiment to end in 1915 and the site was partially dismantled before being abandoned. Although the site was rediscovered in 1993 and cleared. Zibold's condenser was approximately the same size as the ancient stone piles that had been found, and although the yield was much lower than the yield Zibold had calculated for the original structures, the experiment provided inspiration for later developers.
Chaptal collector
Inspired by Zibold's work, Chaptal built a small aerial well near Montpellier in 1929. Chaptal's condenser is a 3 m² and 2.5 m high concrete "Pyramid (geometry)" pyramidal structure, filled with 8 m³ of pieces of limestone approximately 7.5 cm in diameter. The ventilation holes are small surrounding the top and bottom of the pyramid, and can be closed or opened as required to control air flow. The structure is left to cool at night, and during the day it is exposed to hot, humid air. Subsequently, the dew formed on the limestone pieces is collected in a tank below ground level. The amount of water obtained varies between 1 and 2.5 L per day depending on atmospheric conditions.[14].
Chaptal did not consider his experiment a success. When he retired in 1946, he left the condenser out of service, possibly because he did not want to leave an incorrect installation that could mislead those who might later continue studies of the aerial wells.[3].
Klaphake collectors
Wolf Klaphake") was a successful chemist who worked in Berlin between the 1920s and 1930s. During that time, he tested various forms of aerial wells in Yugoslavia and the Island of Vis "Vis (island)") in the Adriatic Sea. His work was inspired by Zibold[15] and by Maimonides, a well-known Jewish scholar who wrote in Arabic about 1,000 years ago and who mentions the use of water condensers in Palestine.[13].
Klaphake experimented with a very simple design: part of a mountainside was cleared and covered with an impermeable surface, accompanied by pillars or ridges. The sides of the structure were closed, although the top and bottom edges were left open. At night the slope cooled and the moisture of the day condensed and slid down the smoothed surface. The system worked, however it was expensive, and Klaphake eventually adopted a more compact design based on a masonry structure. It was a sugar loaf-shaped building (Sugar Loaf (food)), about 15 m high, with walls at least 2 m thick, with holes at the top and bottom. The outer wall was made of concrete to achieve a high thermal capacity, the inner surface was made of sandstone due to its porosity.[16] According to Klaphake:.
Presumably traces of the Klaphake capacitors have been identified.[17].
In 1935, Wolf Klaphake and his wife Maria emigrated to Australia. Probably the decision to emigrate was mainly the result of Maria's encounters with the Nazi authorities;[18][19] Her decision to settle in Australia (rather than, for example, Britain) was influenced by Wolf's desire to develop a dew condenser "Dew (physical phenomenon)").[19] Being a dry continent, Australia would probably need other sources of fresh water, and the Prime Minister of South Australia, whom she had met in London, had expressed interest. Klaphake made a specific proposal for a condenser in the small town of Cook&action=edit&redlink=1 "Cook (South Australia) (not yet drafted)"), where there was no drinking water supply. At Cook, the railway company had previously installed a large coal-fired active condenser,[20] but it was prohibitively expensive to maintain, as it was cheaper to transport water. However, the Australian government rejected Klaphake's proposal, and lost interest in the project.[21][15].
Knapen air well
Knapen, who had previously worked on systems for removing moisture from buildings,[22][23][24] was in turn inspired by Chaptal's work and set about constructing an ambitious large air well (aerial well) on a 180 m hill in Trans-en-Provence in France.[2][25] Starting in 1930, Knapen's dew tower took him 18 months for its construction and it is still standing, although in a dilapidated state. At the time of its construction, the condenser attracted some public interest.[26].
The tower has 14 m high walls made of massive masonry with a thickness of 3 m in which there are a series of openings for air to enter. Inside there is a huge concrete column. At night, the entire structure is cooled and during the day warm moist air enters the structure through the high openings, cools, and exits through the lower openings.[27] Knapen's intention was that water should condense in the cold internal column. In accordance with the Chaptal's finding that the condensation surface must be hard and the surface tension must be low enough so that the condensed water can drip, the external surface of the central column was studded with projecting slate plates "Slate (rock)", placed almost vertically to encourage dripping downwards to a collection tank at the bottom of the structure. Unfortunately, the aerial well never managed to achieve the expected performance and produced a few liters of water each. day.[28].
International Organization for the use of dew
By the end of the century, the details of how dew condenses are much better understood; the key idea is that it is best done by low-mass collectors that quickly lose heat through radiation. A number of researchers worked on this method.[29] In the early 1960s, dew condensers made of polyethylene sheets supported by a simple frame resembling a Canadian-style tent were used in Israel for watering plants. The seedlings supplied by the dew and very light rain from these collectors survived much better than the control group planted without these aids (they all dried out during the summer).[30] In 1986, in New Mexico, condensers made of a special foil produced enough water to supply young trees.[4].
In 1992, a group of French academics attended a conference in Ukraine on dew condensation, where physicist Daniel Beysens introduced them to the story of how ancient Feodosia was supplied with water from dew condensers. They were intrigued enough that in 1993 they went to see it for themselves. They concluded that the mounds identified by Zibold as dew condensers were in fact ancient burial mounds (a part of the necropolis of ancient Feodosia) and that the tubes were of medieval origin and not associated with the mounds. They found the remains of the capacitor that Zibold built, and examined it closely. Apparently the Zibold condenser had performed reasonably well, but in reality its exact results are not entirely clear, and it is possible that the collector was intercepting fog, thereby significantly increasing performance.[10] If the Zibold condenser worked at all, this was probably due to the fact that some stones near the surface of the mound were able to lose heat at night while thermally insulated from the ground; However, they could never have produced the performance that Zibold had anticipated.[3][31].
Filled with enthusiasm, the group returned to France to set up the "International Organization for Dew Utilization" (OPUR), with the specific objective of making dew available as an alternative source of water.[32].
OPUR began a condensation study under laboratory conditions; They developed a special hydrophobic film and experimented with test facilities, including a 30 m² collector in Corsica.[33] Fundamental ideas included the idea that the mass of the condensation surface should be as low as possible so that it cannot easily retain heat, that it should be protected from unwanted thermal radiation by a layer of insulation, and that it should be hydrophobic, in order to shed condensed moisture easily.[34]
By the time they were ready for their first practical installation, they learned that one of their members, Girja Sharan, had obtained a grant to build a dew condenser in Kothara, India. In April 2001, Sharan had noticed some substantial condensation on the roof of a cottage at Toran Beach Resort in the arid coastal region of Kutch, where he was staying briefly. The following year, he investigated the phenomenon more closely and interviewed local people. Funded by the Gujarat Energy Development Agency and the World Bank, Sharan and his team went on to develop passive radiant condensers for use in the arid coastal region of Kutch.[35] Sales began in 2006.[36]