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Current study aims in finding the combined effect of using rectangular fins, gravels (G) and phase change material (PCM) on the performance of pyramid solar still. Two solar stills, one of conventional type (CSS) and other of modified solar still (MSS) which uses fins and PCM inside the basin, are fabricated. Experiments are conducted at Greater Noida (28°28′N, 77°30′E) of Uttar Pradesh, India, during May 2023. The influence of solar still design modifications (CSS and MSS) and adding gravels (CSS + G and MSS + G) on the performance of solar stills is investigated in terms of productivity, energy, exergy, economic, and environmental parameters. Experimental results show an enhancement of about 84 %, 38 % and 32 % in daily productivity for MSS + G, CSS + G and MSS, respectively, than CSS. The MSS + G shows the highest improvement in energy (81.1 %) and exergy efficiency (273 %) with significant reduction in costs per liter of yield produced (29.2 %) and payback period (29 %) when compared with CSS. About 76 % rise in carbon credits earned is observed for MSS + G than CSS while mitigating the CO 2 emission of 19.14 tons. Conclusively, the innovative design (MSS + G) not only offers cost-effective yield production but also plays a crucial role in promoting environmental sustainability by reducing CO 2 emissions. • This paper develops and tests a modified solar still that uses PCM and fins. • The combined effect of fins, gravels and PCM is investigated. • The experiments conducted in Greater Noida, India, during May 2023. • MSS + G improved daily productivity by 84 %. • MSS + G reduces costs/l of water by 29 % and mitigates CO 2 emissions by 19.14 tons. [ABSTRACT FROM AUTHOR]

Abstract: An important aspect of urban water systems is the interactions that take place between different components of the system (e.g. foul water from leaky sewers entering into a drinking water distribution network). It is widely recognised that it is important to consider these interactions in order to maintain effective, efficient and safe water and sanitation services. Hence, an integrated approach to urban water management (IUWM) is necessary. This paper begins by presenting a case study in India that highlights the important interactions that takes place between different components of the urban water system. The case study highlights the need to recognise these interactions in order to provide safe and sustainable urban water services. The paper then presents ongoing research on development of integrated urban water modelling tool that allows an integrated approach to urban water services. By applying an IUWMapproach it is possible to satisfy the water and sanitation needs of a community at the lowest cost to society whilst minimising environmental and social impacts. [Copyright &y& Elsevier]

This paper justifies photovoltaic (PV)-powered electrodialysis (ED) as an energy and cost-effective means of desalinating groundwater in rural India and presents the design requirements for a village-level system. Saline groundwater, which underlies 60% of India, can negatively impact health as well as cause a water source to be discarded because of its taste. A quarter of India's population live in villages of 2000–5000 people, many of which do not have reliable access to electricity. Most village-scale, on-grid desalination plants use reverse osmosis (RO), which is economically unviable in off-grid locations. Technical and ethnographic factors are used to develop an argument for PV-ED for rural locations, including: system capacity, biological and chemical contaminant removal; water aesthetics; recovery ratio; energy source; economics of water provision; maintenance; and the energetic and cost considerations of available technologies. Within the salinity range of groundwater in India, ED requires less specific energy than RO (75% less at 1000 mg/L and 30% less at 3000 mg/L). At 2000 mg/L, this energetic scaling translates to a 50% lower PV power system cost for ED versus RO. PV-ED has the potential to greatly expand the reach of desalination units for rural India. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the experimental and theoretical work, conducted in central India at Rewa (M.P.) (24°32″N, 81°18″E) to analyse the performance of modified basin type solar still, incorporating multiple low thermal inertia porous absorbers, floated adjacent to each other on the basin water with the help of thermocol insulation. The porous absorbers were made up of ordinary blackened jute cloth. Multiple floating absorbers of smaller width ensured that the absorber surface was always wet due to capillary action and there were no dry spots. Due to low thermal inertia of the porous absorber, quicker start-up times, as well as higher operating temperatures were achieved resulting in higher distillate yield. Also, the increase in the evaporation surface area further aided the performance. In order to evaluate the improvement obtained by the modification, the performance of the modified still was compared with a conventional basin type solar still of same size, under similar operating conditions on both clear and partially clear days. The results indicate that on clear days, about 68% more distillate output was obtained by the modified still, whereas it was nearly 35% more on cloudy days. Since the basin water beneath the floating insulation remained warm enough during the off shine hours, reasonable amount of nocturnal distillate output was also obtained from the modified still. A twin reflector booster was constructed by placing two plane mirrors mutually perpendicular to each other. On applying the twin reflector booster with the modified still an increase in the yield by 79% was obtained over the modified still without booster. The basin water depth does not have any significant effect on the performance of the modified still; therefore the modification can be effectively applied on deep basin stills also. Results obtained from the thermal model have fair agreement with the experimental values. The effect of wind transfer coefficient, base heat loss coefficient and the floating insulation heat transfer coefficient has also been theoretically analysed. [Copyright &y& Elsevier]

Abstract: Fresh water crisis is evident in many parts of India, varying in scale and intensity at different times of the year. About seven states are underlain by brackish ground water affecting 42million people. 25% population of India resides along the coast having easy access to seawater. Hence, these saline water resources can be exploited to meet their water requirements. Desalination technologies create new sources of fresh water from seawater or brackish water, but they do require energy. This paper addresses the socio-economic and technical feasibility of powering membrane desalination technologies with photovoltaic (PV) systems in regions which have mixed advantage of high solar potential and disadvantage of presence of saline water. A database of Indian population dependence on saline water, its regional solar potential and present state of desalination have been compiled. Technical aspects of reverse osmosis (RO) and electrodialysis (ED) membrane desalination processes powered by PV are addressed and desalinated water cost, obtained through PV-RO and PV-ED processes, are compared with diesel powered RO and ED processes respectively for a plant capacity of 50m3/day over a 20year working life of the plant. The technology will augment fresh water requirements of India and contribute to its sustainable development. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, an attempt has been made to evaluate the internal heat transfer coefficient of single and double slope passive solar stills in summer as well as winter climatic conditions for three different water depths (0.01, 0.02 and 0.03 m) by various thermal models. The experimental validation of distillate yield using different thermal models was carried out for composite climate of New Delhi, India (latitude 28°35′N, longitude 77°12′E). By comparing theoretical values of hourly yield with experimental data it has been observed that Dunkle''s model gives better agreement between theoretical and experimental results. Further, Dunkle''s model has been used to evaluate the internal heat transfer coefficient for both single and double slope passive solar stills. With the increase in water depth from 0.01 m to 0.03 m there was a marginal variation in the values of convective heat transfer coefficients. It was also observed that on annual basis output of a single slope single slope solar still is better (499.41 l/m2) as compared with a double slope solar still (464.68 l/m2). [Copyright &y& Elsevier]

Abstract: This work was carried out under the specific collaboration agreement between the Bhabha Atomic Research Centre (BARC) from India and the Commissariat à l''Energie Atomique (CEA) from France. This paper summarises first results of review and research on the possible extraction of uranium from the concentrated brine rejected by integrated nuclear desalination systems, which both partners are currently developing in the two organisations. Three innovative and efficient methods of uranium extraction have been proposed: 1) Resin grafted with calixarene: this method has the advantage of very high selectivity. Its performances, especially for large-scale extraction, still need further R&D and optimisation; 2) Magnetic separations: yet another method with high selectivity, easy separation and affording high degree of material recovery. The method, however, is in developmental stage; 3) Canal system with Braid adsorbents: high selectivity. Appears to be feasible in conjunction with existing technology. It would nonetheless require large amounts of adsorbents and adequate infrastructure. [Copyright &y& Elsevier]

This study provides experimental validation of a previously published optimal design theory for photovoltaic (PV)-powered electrodialysis reversal (EDR) desalination systems. The prior work describes the co-optimization of PV and EDR subsystems, and flexible operation to accommodate daily and annual solar irradiance variability, significantly reducing water cost. This study presents the fabrication of a PV-EDR pilot system designed using the co-optimization theory and field testing results from the rural village of Chelluru, India. Testing in the field enabled observation and evaluation of real-world factors on system performance, resulting in updates to the previous theory to include unaccounted factors that affect costs, including: filling and draining of water tanks, salt and water accumulation in tanks from prior batches, unexpected energy losses due to locally purchased converters, and scaling in the ED stack. Therefore, water cost in the PV-EDR pilot system was updated from previous estimates based on field performance. The estimated capital cost and lifetime cost of the Chelluru system are 34% and 45% lower, respectively, than the corresponding costs if the PV-EDR system was designed using conventional design practice. The theory and experimental insights presented in this paper will enable desalination engineers to better design and optimize PV-EDR systems. • This study validated previous published optimal design theory of PV-EDR systems. • A pilot-scale co-optimized PV-EDR system was built and tested in rural India. • Testing in the field enabled accounting real-world factors in future PV-EDR design. • 34% and 45% reductions of LCOW and capital cost are achieved by the pilot system. [ABSTRACT FROM AUTHOR]