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A technoeconomic evaluation has been conducted by the US Department of Energy, for four conceptual photoelectrochemical (PEC) H2production systems namely, single-bed particle system, dual-bed particle system, PEC planar array system and PEC tracking solar concentrator system. The present work extends the analysis to capture solar energy in the vicinity of Indian oil refineries and generate H2at estimated costs of 42, 84, 281 and 85 in ₹/kg H2for the four systems, respectively. This includes the capital and operating costs involved if the PEC H2production plant is set up around these refineries. Employing PEC H2production systems obviate the CO2generated by conventional processes like steam reforming, and thereby earning carbon credits. Inclusion of such credits is found to increase the annual earnings of the four conceptual systems by 0.7–8% depending on the selling price of H2. The sensitivity analysis of various economic factors like payback time, H2price, carbon credit, efficiency of the system, etc., is performed which is useful in judging economics of the venture depending on the market variations in prices or rise in efficiency of the system or variable economic constraints of the investor. [ABSTRACT FROM PUBLISHER]

The conventional solar still is limited to a daily yield of approximately 2–3.5 kg/m2/day. To increase the yield, this study investigates experimentally the combined effects of latent and sensible energy storage together with magnetization. Paraffin and novel high-thermal conductivity nanomaterial (graphite plate) were used as latent and sensible heat storage materials, respectively. There was an overall increase of 62% and 235% in the daytime and night-time yield, respectively, giving a total yield of 5.5 kg/m2/day compared to 3.4 kg/m2/day for a conventional still. Enviro-economic parameters like emissions, CO 2 mitigation and carbon credit (CC) earned were also investigated. Energy matrices analysis and water quality checks were performed to estimate the energy-payback time, life cycle conversion efficiency (LCCE) and purity of desalinated water. The cost per liter of freshwater was found to be 3.7% cheaper than for a conventional still and 69% cheaper than bottled water in India. Over a 30 year period, 40.3 Tonnes of CO 2 will be mitigated contributing a CC and LCCE of $402 and 0.52, respectively. The proposed modified still is recommended as a substitute for conventional stills and stills with simple energy storage. [Display omitted] [ABSTRACT FROM AUTHOR]