Person: Sharan, Girja
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Girja Sharan
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Publication Metadata only Harvesting dew with radiation cooled condensers to supplement drinking water supply in semi-arid coastal northwest India(08-05-2011) Sharan, Girja; DA-IICT, GandhinagarThis paper describes the development of dew harvest systems for use in semi-arid coastal region of north-west India, chronically short of drinking water. These were developed to ameliorate drinking water problem, especially of people living near the coast where groundwater is of poor quality and surface sources scarce. Although dew is much smaller in magnitude (20-30 mm) than the rains (300 mm) it is a more reliable source. Dew occurs over a season of seven months (October to April), rain over four (June - September). Dew nights number ~ 100, rainy days 15-20. There is much greater year to year variation in rainfall than in the dew amount. A R&D program of over four years led to development of three types of systems - condenser-on-roof (CoR), condenser-on-ground (CoG) and Roof-as-Condenser (RaC). The CoR, CoGs employ condenser made of plastic film insulated on the underside. CoRs are constructed over the roof of buildings, CoGs on open ground. The RaCs use metal roof of buildings itself as condenser. The CoR and CoGs give higher output, require higher investment. The RaCs give lower output; require only a small investment in collection and storage. Examples of working installation are presented. Rain and dew seasons in the region are complementary. Although engineered specifically to harvest dew, these also harvest rain, providing varying amounts of potable water through the year. Benefits to the region, learning accrued and partnerships created in the course of work are also briefly discussed.Publication Metadata only A very large dew and rain ridge collector in the Kutch area (Gujarat, India)(Elsevier, 21-07-2011) Sharan, Girja; Clus, O; Singha, S; Muselli, M; Beysens, D; DA-IICT, GandhinagarThe world�s largest dew and rain collecting system, comprised of ridge-and-trough modules, was constructed in March 2006 at Panandhro in the semi-arid area of Kutch (NW India). The main goals were (i) to collect dew on a scale that could be beneficial to the local population (ii) to determine the efficiency of this new module shape, (iii) to determine whether results obtained from small measurement condensers can be projected to large condensers, (iv) to apply a computational fluid dynamic simulation to improve the condenser set-up. Preliminary studies performed with four standard plane condensers of 1�m2�surface area, inclined 30� from horizontal, identified Panandhro as a promising site. The cumulated dew water during 192�days was 12.6�mm with a maximum of 0.556�mm/night. A large dew condenser (850�m2�net total surface) was designed with 10 ridge-and-trough modules. The ridges are trapezoidal, 33�m long, 0.5�m wide at the top, 2.2�m wide at the base and sloping 30� from horizontal. The depth of the troughs between the ridges is 0.5�m. A 2.5�cm thick polystyrene foam rests on the surface as insulation with a radiative foil on top (similar to that developed by OPUR, see�www.opur.fr).Publication Metadata only Dew plant for bottling water(Elsevier, 01-07-2017) Sharan, Girja; Roy, Anil; Royon, Laurent; Mongruel, Anne; Beysens, Daniel; DA-IICT, GandhinagarIn a context of�climate change�and increasing need of fresh water in the world, rain and dew water can have a significant impact as new sources of water, especially in arid and semi-arid areas. The aim of the paper is to demonstrate that atmospheric moisture can be harvested and processed into safe�drinking water�comparable in quality and price to�reverse osmosis�processed water available in the market. The paper describes the construction and functioning of a water production plant in northwest India (Kothara). Rain and dew are collected; for dew special attention has to be taken. In particular, special condenser architecture (ridges) is designed using�Computational Fluid Dynamics simulation�and improved condensing surfaces are operated. Dew yields are estimated from the meteo data and using simulation. From the figures an economic model is derived; it comes out that water passively harvested from atmospheric moisture may be cheaper than that from�reverse osmosis�and does not pollute the environment, supporting the importance of dew and rain resources to provide supplementary supply of potable water in arid and semi-arid environment.Publication Metadata only Cropping in semi-arid northwest India in greenhouse with ground coupling shading and natural ventilation for environmental control(11-05-2010) Sharan, Girja; Madhavan, T; DA-IICT, GandhinagarResearch is ongoing to develop greenhouse technology with controls economical on water and energy, to improve farming in water-scarce, hot, semi-arid region of north-west India. A greenhouse under investigation, is coupled to earth-tube�heat� exchanger (ETHE) and has provisions for shading, natural ventilation and mist nozzles. In a recent round tomatoes were grown. A regime of natural ventilation and top shading kept the greenhouse temperature close to the ambient in cooler months, although a difference of up to 3 �C was anticipated. Evaporation and later transpiration may have aided cooling. Mist was not used. This became less effective in warmer period as cooling load increased and dense foliage appeared to hinder ventilation. Forced ventilation via ETHE and top shading was then implemented. Inside temperature occasionally rose 2- 3 �C above the ambient. But cropping could be done through spring and early summer. Heating was affectively achieved with ETHE in cold nights of December and January keeping the inside temperatures well above 12�C. Yield was 68 t / ha nearly twice the open fields, water used 266 mm nearly half of the open-fields. This appears to�Publication Metadata only Controlled Environment Agriculture in Semi-arid North-West India(01-06-2009) Sharan, Girja; DA-IICT, Gandhinagar