Search for: solar-power
Total 149 records
Conceptual design and techno-economic assessment of integrated solar combined cycle system with DSG technology, Article Solar Energy ; Volume 84, Issue 9 , September , 2010 , Pages 1696-1705 ; 0038092X (ISSN) ; Farhadi, F ; Tanhaemami, M ; Sharif University of Technology
Direct steam generation (DSG) in parabolic trough collectors causes an increase to competitiveness of solar thermal power plants (STPP) by substitution of oil with direct steam generation that results in lower investment and operating costs. In this study the integrated solar combined cycle system with DSG technology is introduced and techno-economic assessment of this plant is reported compared with two conventional cases. Three considered cases are: an integrated solar combined cycle system with DSG technology (ISCCS-DSG), a solar electric generating system (SEGS), and an integrated solar combined cycle system with HTF (heat transfer fluid) technology (ISCCS-HTF).This study shows that...
Visible light switchable bR/TiO2 nanostructured photoanodes for bio-inspired solar energy conversion, Article RSC Advances ; Volume 5, Issue 24 , Jan , 2015 , Pages 18642-18646 ; 20462069 (ISSN) ; Janfaza, S ; Irani, R ; Sharif University of Technology
Royal Society of Chemistry 2015
Today, regarding the limitation and environmental side effects of fossil fuel resources, solar hydrogen production is one of the main interests in the energy research area. The development of visible light sensitized semiconductors based on non-toxic components, low cost and available bio-species is an ongoing approach for H2 generation based on water splitting reactions. Here, two different morphologies of TiO2 photoanodes, nanoparticulated and nanotubular, have been modified with simply extracted bacteriorhodopsin (bR) without any linker. Achieving a significant enhancement in photoconversion efficiency of TiO2 photoanodes, η% was increased from 2.9 to 16.5 by bR addition to the TiO2...
Selecting Support Layer for Electrodeposited Efficient Cobalt Oxide/Hydroxide Nanoflakes to Split Water, Article ACS Sustainable Chemistry and Engineering ; Volume 4, Issue 6 , 2016 , Pages 3151-3159 ; 21680485 (ISSN) ; Esfandiar, A ; Qorbani, M ; Moshfegh, A. Z ; Sharif University of Technology
American Chemical Society 2016
Energy and environment crises motivated scientists to develop sustainable, renewable, and clean energy resources mainly based on solar hydrogen. For this purpose, one main challenge is the low cost flexible substrates for designing earth abundant efficient cocatalysts to reduce required water oxidation overpotential. Here, a systematic morphological and electrochemical study has been reported for cobalt oxide/hydroxide nanoflakes simply electrodeposited on four different commercially available substrates, titanium, copper sheet, steel mesh, and nickel foam. Remarkable dependence between the used substrate, morphology, and electrocatalytic properties of nanoflakes introduced flexible porous...
Article Journal of Alloys and Compounds ; Volume 693 , 2017 , Pages 871-875 ; 09258388 (ISSN) ; Sharif University of Technology
Elsevier Ltd 2017
Providing solar hydrogen as a clean energy resource is one of the human challenges for future. Controlling oxygen vacancies as well as surface morphology in metal oxide semiconductors enables developing PEC H2production in some understood ways. Here, the influence of simple change in annealing atmosphere, air and pure oxygen, on photoresponse of nanocrystalline WO3has been studied completely. Results revealed that such slight change in annealing procedure increases effective surface interface and donor density by 77 and 72%, respectively. These effects and also retarding recombination of photogenerated electro-hole pair resulted in photocurrent enhancement under solar like illumination more...
Microstructure, morphology and electrochemical properties of Co nanoflake water oxidation electrocatalyst at micro- and nanoscale, Article RSC Advances ; Volume 7, Issue 21 , 2017 , Pages 12923-12930 ; 20462069 (ISSN) ; Solaymani, S ; Ghaderi, A ; Bramowicz, M ; Kulesza, S ; Ţălu, Ş ; Pourreza, M ; Ghasemi, S ; Sharif University of Technology
Royal Society of Chemistry 2017
Nowadays, fossil fuel limitations and environmental concerns push researchers to find clean and renewable energy resources. Solar hydrogen production via water splitting reactions in electrochemical and/or photo-electrochemical systems has been accepted as a promising route and efficient electrocatalysts are involved in both. Here, cobalt nanoflakes with an oxide/hydroxide surface and a conductive metallic core are grown on commercially available steel mesh modified with carbon based nanocomposites as a support layer. The portion of reduced graphene oxide sheets was changed from 0 to 100 wt% and the correlation of this concentration with the surface morphology and electro-catalytic activity...
Sustainable starfish like cobalt electrocatalyst grown on optimized CNT-graphene hybrid host for efficient water oxidation, Article Applied Surface Science ; Volume 524 , 15 September , 2020 ; Ghasemi, S ; Pourreza, M ; Moshfegh, A. Z ; Sharif University of Technology
Elsevier B.V 2020
Solar energy generation is one of the most efficient approach to solve emerging environment and energy challenges. In this context, solar assisted dissociation of water into oxygen and hydrogen utilizing scalable and high performance electrocatalysts plays key role since the produced hydrogen is a clean energy carrier. Here, cobalt based nanoflakes with metallic core and oxidized surface were grown on the designed carbonaceous layer for anodic oxygen evolution reaction (OER) using an electrochemical approach. Carbonaceous layers containing proper amount of carbon nanotubes (CNT) and reduced graphene oxide (rGO) species were used to optimize the system. Although higher weight percent of rGO...
Graphitic carbon nitride (g-C3N4)-based photocatalysts for solar hydrogen generation: Recent advances and future development directions, Article Journal of Materials Chemistry A ; Volume 5, Issue 45 , 2017 , Pages 23406-23433 ; 20507488 (ISSN) ; Samadi, M ; Pourjavadi, A ; Moshfegh, A. Z ; Ramakrishna, S ; Sharif University of Technology
Royal Society of Chemistry 2017
Graphitic carbon nitride (g-C3N4) is a metal-free conjugated polymer constructed from two-dimensional sheets with a bandgap energy of 2.7 eV, which makes it an applicable and efficient visible-active photocatalyst for H2 production. In the present study, the basic concepts and principles of photocatalytic water splitting have been discussed, and a guide for the selection of appropriate photocatalysts, focusing on the g-C3N4 nanomaterials, has been proposed. Our approach is mainly concentrated on evaluating two factors, namely the solar-to-hydrogen (STH) conversion and apparent quantum yield (AQY) for different photocatalysts, to provide an in-depth analysis and a framework for solar H2...
Thermal residual stresses in silicon thin film solar cells under operational cyclic thermal loading: A finite element analysis, Article Solar Energy ; Volume 135 , 2016 , Pages 366-373 ; 0038092X (ISSN) ; Dehghany, M ; Sohrabpour, S ; Naghdabadi, R ; Sharif University of Technology
Elsevier Ltd 2016
In manufacturing amorphous silicon solar cells, thin films are deposited at high temperatures (200-400 °C) on a thick substrate using sputtering and plasma enhanced chemical vapor deposition (PECVD) methods. Since the thin films and substrate have different thermal expansion coefficients, cooling the system from deposition temperature to room temperature induces thermal residual stresses in both the films and substrate. In addition, these stresses, especially those having been induced in the amorphous silicon layer can change the carrier mobility and band gap energy of the silicon and consequently affect the solar cell efficiency. In this paper, a 2D finite element model is proposed to...
Part load behavior of molten salt cavity receiver solar tower plants under storage mode operational mode, Article ASME 2016 10th International Conference on Energy Sustainability, ES 2016, collocated with the ASME 2016 Power Conference and the ASME 2016 14th International Conference on Fuel Cell Science, Engineering and Technology, 26 June 2016 through 30 June 2016 ; Volume 1 , 2016 ; 9780791850220 (ISBN) ; Shafiei Ghazani, A ; Taylor, R. A ; Saberi, P ; Sharif University of Technology
American Society of Mechanical Engineers 2016
The performance of the tower based concentrated solar thermal (CST-tower) plant is very sensitive to the operation strategy of the plant and the incident heat flux on the receiver. To date, most studies have been examined only the design mode characteristics of the cavity receivers, but this paper significantly expands the literature by considering non-design operating conditions of this important sub-component of the CST-tower plants. A feasible non-design operating conditions of the cavity receivers that was considered in this study is the storage mode of operation. Two practical dynamic control strategies were examined then to find the most efficient approach: fixed solar field mass...
Annual comparative performance and cost analysis of high temperature, sensible thermal energy storage systems integrated with a concentrated solar power plant, Article Solar Energy ; Volume 153 , 2017 , Pages 153-172 ; 0038092X (ISSN) ; Taylor, R. A ; Nithyanandam, K ; Shafiei Ghazani, A ; Sharif University of Technology
Elsevier Ltd 2017
The present study conducts a comprehensive comparative techno-economic analysis of some near-term sensible thermal energy storage (TES) alternatives to the ‘standard’ two-tank molten salt system for concentrated solar power (CSP) plants. As such, we conducted detailed, relative annual transient simulations for single-medium thermocline (SMT), dual-media thermocline (DMT), and shell-and-tube (ST) systems. To be consistent with recent literature, the DMT and ST systems use concrete with a porosity of 0.2 (e.g. where concrete occupies 80% of the system) as their low cost filler material. The systems were integrated into a validated 19.9 MWe Gemasolar CSP model, which has a solar multiple of...
Article International Journal of Ambient Energy ; 17 February , 2020 ; Roshandel, R ; Sharif University of Technology
Taylor and Francis Ltd 2020
The combination of concentrating photovoltaic (CPV) and organic Rankine cycle (ORC) systems not only leads to a reduction of photovoltaic (PV) operating temperature, but also leads to an additional electric power production. Increase in the temperature of the PV decreases its operating efficiency, while increases the ORC efficiency. Therefore, there is an optimum temperature in which the total electricity produced by the combined system will be maximum. In this study, a modified CPV/ORC system is simulated and the optimum operating temperature of the PV panel is determined for different PV efficiencies. The most striking result is that increase in the PV nominal efficiency will result in the...
Efficient dye-sensitized solar cells based on TiO2 nanoparticles and skein-like nanotubes: effect of arrangement modes of the layers and TiCl4 treatment, Article Journal of the Taiwan Institute of Chemical Engineers ; Volume 61 , 2016 , Pages 138-146 ; 18761070 (ISSN) ; Andaji Garmaroudi, Z ; Mohammadi, M. R ; Madaah Hosseini, H. R ; Sharif University of Technology
Herein, we report a double-layer photoanode electrode composed of TiO2 nanoparticles active layer and a mixture of nanoparticles and newly proposed skein-like nanotubes (NTs) top layer. Such structure performs well in solar light harvesting due to first, the top layer exhibits superior light scattering and second, the active layer with high dye-loading can make better use of the back-scattered light. The results reveal that 30-40 nm nanoparticles have anatase structure, whereas 5-7 μm skein-like NTs show a mixture of anatase and rutile phases. Photovoltaic measurements demonstrate that by tuning mass ratio between nanoparticles and skein-like NTs, the cells based on single-layer photoanode...
A novel concentrating photovoltaic/thermal solar system combined with thermoelectric module in an integrated design, Article Renewable Energy ; Volume 113 , 2017 , Pages 822-834 ; 09601481 (ISSN) ; Shafii, M. B ; Jafari mosleh, H ; Sharif University of Technology
Elsevier Ltd 2017
The use of solar energy concentration systems for achieving performance enhancements in the Photovoltaic/thermal hybrid solar systems and reduction of initial costs is an idea that has been studied for years. In this article a new structure for parabolic trough photovoltaic/thermal collector is proposed and its thermal and electrical performances are experimentally investigated. The receiver of this concentrator contains a triangular channel with an outer surface covered with photovoltaic cells and thermoelectric modules with a specific arrangement so that in addition to absorbing heat, a larger portion of the solar radiation is directly converted to electricity. Hence, the performance of...
Article Thin Solid Films ; Volume 616 , 2016 , Pages 754-759 ; 00406090 (ISSN) ; Alizadeh, A. H ; Moshaii, A ; Gharibzadeh, S ; Alizadeh, A ; Mohammadpour, R ; Fathi, D ; Sharif University of Technology
We report on fabrication of halide perovskite solar cells using a two-step spin-spray coating rout. The applied method is one of the most straight forward procedures for fabricating uniform stoichiometry and crystalline perovskite cells. To fabricate a high quality perovskite layer, various concentrations of methyl-ammonium iodide (CH3NH3I) were sprayed on a spin coated PbI2 layer using a simple airbrush gun. The characterization results indicate that the size of cuboid perovskite morphology depends on the concentration of methylammonium iodide in the spray procedure. The photovoltaic performance of the fabricated solar cells has been measured and a high dependency on the cuboid sizes was...
Dye-sensitized solar cells based on a single layer deposition of TiO 2 from a new formulation paste and their photovoltaic performance, Article Solar Energy ; Volume 86, Issue 9 , 2012 , Pages 2654-2664 ; 0038092X (ISSN) ; Louca, R. R. M ; Fray, D. J ; Welland, M. E ; Sharif University of Technology
A new strategy for enhancing the efficiency and reducing the production cost of TiO 2 solar cells by design of a new formulated TiO 2 paste with tailored crystal structure and morphology is reported. The conventional three- or four-fold layer deposition process was eliminated and replaced by a single layer deposition of TiO 2 compound. Different TiO 2 pastes with various crystal structures, morphologies and crystallite sizes were prepared by an aqueous particulate sol-gel process. Based on simultaneous differential thermal (SDT) analysis the minimum annealing temperature to obtain organic-free TiO 2 paste was determined at 400°C, being one of the lowest crystallization temperatures of TiO 2...
Article Evolutionary Ecology ; Volume 25, Issue 4 , 2011 , Pages 871-876 ; 02697653 (ISSN) ; Zohoor, H ; Sharif University of Technology
Using hybrid energy storage system is a method for increasing the storage capability of solar thermal energy. If multiple energy storage devices with complementary performance characteristics are used together, the resulting system will be a 'Hybrid Energy Storage System'. In other words, a Hybrid Energy Storage System (HESS) has several media available for storage at any time. In this way, increase in storable energy is obtained without increasing collectors' area. When there are more than one storage mediums, the system should be able to choose the best medium for storing energy according to the conditions. In the previous works, an optimizer program was used to find the proper medium...
Article Solar Energy ; Volume 170 , 2018 , Pages 969-973 ; 0038092X (ISSN) ; Ahmadpour, M ; Mosavi, A ; Alharbi, N ; Gorji, N. E ; Sharif University of Technology
Elsevier Ltd 2018
We proposed two different time-dependent modeling approaches for variation of device characteristics of perovskite solar cells under stress conditions. The first approach follows Sah-Noyce-Shockley (SNS) model based on Shockley–Read–Hall recombination/generation across the depletion width of pn junction and the second approach is based on thermionic emission model for Schottky diodes. The connecting point of these approaches to time variation is the time-dependent defect generation in depletion width (W) of the junction. We have fitted the two models with experimental data reported in the literature to perovskite solar cell and found out that each model has a superior explanation for...
Comparing different scenarios for thermal enhanced oil recovery in fractured reservoirs using hybrid solar-gas steam generators, a simulation study, Article Society of Petroleum Engineers - SPE Europec Featured at 78th EAGE Conference and Exhibition, 30 May 2016 through 2 June 2016 ; 2016 ; 9781613994573 (ISBN) ; Bashtani, F ; Tahmasebi, A ; Ayatollahi, S ; Al Wahaibi, Y. M ; Sharif University of Technology
Society of Petroleum Engineers 2016
The application of the renewable energy sources, especially solar energy, for thermal enhanced oil recovery methods as an economical and environmental valuable technique has received many attractions recently. Concentrated Solar Power systems are capable of producing substantial quantities of steam by means of focused sunlight as the heat source for steam generation. This paper aims to investigate viability of using this innovative technology in fractured reservoirs to generate steam instead of using conventional steam generators. A synthetic fractured reservoir with properties similar to those of giant carbonate oil reserves in the Middle East was designed by using commercial thermal...
Design and construction of a charge controller for stand-alone PV/battery hybrid system by using a new control strategy and power management, Article Solar Energy ; Volume 149 , 2017 , Pages 132-144 ; 0038092X (ISSN) ; Forooghi, M ; Ghadimi, A. A ; Abolmasoumi, A. H ; Riahi, M. R ; Sharif University of Technology
Elsevier Ltd 2017
In this paper, a new control strategy and power management for a stand-alone PV/battery hybrid power system has been suggested. The solar cell arrays provide energy in the steady-state and the battery provides energy in transient states. Here, a charge controller system based on the MPP tracking technology, suitable for using in the islanded micro grid that contains a solar panel and a battery is designed. The charge controller includes a unidirectional DC-DC converter as an interface circuit between the solar panel and the DC bus, a bidirectional DC-DC converter as an interface circuit between the battery and the DC bus with a control system and power management in different states of...
Practical battery size optimization of a PV system by considering individual customer damage function, Article Renewable and Sustainable Energy Reviews ; Volume 67 , 2017 , Pages 36-50 ; 13640321 (ISSN) ; Rayati, M ; Sheikhi, A ; Ranjbar, A. M ; Sharif University of Technology
Today, energy crises attracted many researchers’ attention to renewable energy technologies especially photovoltaic (PV) systems. The main challenge of PV systems is unpredictable nature of solar power generation. To overcome this challenge, a storage system is integrated which reduces demand reliance on electricity grid and uses excess energy that solar panels produce. As investment cost of the storage system is considerable, finding an optimal technology, size, and configuration are crucial. In this paper, the optimal battery system is excluded from existing PV plant installing in a commercial building located in Mashhad/Iran. Here, the sizing procedure is based on a financial evaluation...