energy conversion Articles
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Electrical contacts to single nanowires: a scalable method allowing multiple devices on a chip. Application to a single nanowire radial p–i–n junction
Semiconductor nanowires are currently at the forefront of research in the areas of nanoelectronics and energy conversion. In all these studies, realising electrical contacts and statistically relevant measurements is a key issue. We propose a method that enables to contact hundreds of nanowires on a single wafer in an extremely fast electron beam lithography session. The method is applied to ...
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Recent developments in exergy analysis and exergoeconomics
In advanced exergy analysis, the exergy destruction within a component of an energy conversion system can be split into avoidable/unavoidable exergy destruction and endogenous/exogenous exergy destruction. A combination of these two concepts provides accurate information with respect to improving the overall system efficiency. Extended to exergoeconomics, the approach provides the costs ...
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Role of acridine orange – sodium lauryl sulphate system in photogalvanic cell for solar energy conversion
Energy conversion efficiency was studied in liquid phase photogalvanic cell consisting acridine orange as photosensitiser, NaLS as surfactant and DTPA as reductant. Values of photopotential and photocurrent generated by this system were 746.0 mV and 205.0 µA respectively. The observed power conversion photon energy efficiency was 0.83% and fill factor was determined as 0.56. This photogalvanic ...
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Exergy of solar radiation
Solar radiation reaching the ground is accompanied with radiation entropy. When the entropy production rate within any solar energy conversion device is to be calculated, the incoming radiation entropy flux has to be known. In this contribution, first it is shown how the radiation entropy flux arriving on earth is to be calculated. Secondly, the interaction between the incoming radiation and the ...
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Understanding the exergy of cold: theory and practical examples
Exergy analysis is used to evaluate the thermodynamic performance of processes, including energy conversion and supply systems. This often involves the calculation of the exergy of heat, at a temperature either above or below the environmental temperature (T0). The exergy of 'cold', i.e., heat at T Keywords: exergy of cold, cool exergy, exergy analysis, exergy factor, cool exergy potential, ...
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Thermodynamic and exergy efficiencies of magnetocaloric energy conversion utilising industrial waste heat
An investigation under which conditions industrial waste heat utilised with magnetic energy conversion machines can be a possible alternative to conventional energy conversion technologies is presented. The application of a numerical model leads to the thermodynamic efficiency, the exergy efficiency, and approximate values of the total mass and the total volume of a magnetic energy conversion ...
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Nanophotonic structures
This paper proposes a selection of topics on nanophotonic structures, which choice has been partly driven by the most outstanding achievements of Rhone-Alpes laboratories in the field. This includes high index contrast dielectric nanophotonic structures, in connection with hybrid micro-electronic/micro-photonic integration along III-V/silicon heterogeneous integration schemes, and for ...
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Understanding and improving energy conversion systems with the aid of exergy–based methods
Exergy–based methods are powerful tools for developing, evaluating and improving an energy conversion system. Conventional exergy–based analyses have limitations, which are significantly reduced by the so–called advanced analyses. The latter evaluate: (a) the interactions among components of the overall system, and (b) the real potential for improving a system component. The main objective of ...
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Decentralised energy systems: state of the art and potentials
The increasing liberalisation of the energy market as well as the ecological and business environment of public heat and power supply are leading to a re-evaluation of established and innovative energy conversion systems. A more efficient usage of fossil and regenerative primary energy resources is to be achieved by decentralised systems providing combined heat and electrical power. This paper ...
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Ocean exergy and energy conversion systems
Oceans store energy in the form of currents, waves, tides, heat and salinity that can help to alleviate worldwide demand for power and the global climate change threat. They also store a considerable amount of an isotope of hydrogen (deuterium) which takes part in the most promising fusion reactions. Exergy analysis can be applied to evaluate the work potential (extractable) of a resource. This ...
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Issues related to wind energy conversion systems
There is growing interest in the development of more sustainable electricity systems employing renewable, low-emission resources. In this context, the number of wind power generators installed in the world is increasing, and there are strong indicators that such growth should continue in the next decades. The intensity of wind power expansion depends on different factors related to technical, ...
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Why Emergy- and Exergy Analysis are non-commensurable methods for the assessment of energy conversion systems
The paper discusses a fundamental incompatibility between Emergy- ('EMA') and Exergy ('EXA') Analysis. Both approaches quantify the resource consumption of physical systems by applying space- and time integrated energy input/output methods. A detailed theoretical analysis and two specific examples show that at least one of the claims made by EMA practitioners is based on a misinterpretation of ...
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Endoreversible thermodynamics approach for optimum oven operation
This paper refers to the problem of how much heat is necessary for oven operation. An endoreversible thermodynamics approach is used here. More accurate upper bounds for the oven heat gain factor are obtained than when the traditional reversible thermodynamics approach is used. The optimum operation temperatures and the oven heat gain factor depend on three parameters incorporating both design ...
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Nanomaterials based on carbon and Ti(IV) oxides: some aspects of their electrochemistry
Some aspects of electrochemical synthesis, characterisation and applications of nanostructured carbons and Ti(IV) oxides are discussed. These themes have attracted considerable attention from addressing purely academic questions up to promising applications in energy storage and conversion.Keywords: carbon nanostructures, titanium oxide, electrochemistry, spectroelectrochemistry, solar cells, ...
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Steady-state analysis of doubly fed induction generators for wind turbines using MATLAB
A wind energy conversion system (WECS) differs from a conventional power system. The power output of a conventional power plant can be controlled whereas; the power output of a WECS depends on the wind. This nature of WECS makes it difficult for analysis, design and management. Various approaches have been developed to study the behaviour of WECS. In this paper, the steady-state characteristics ...
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Application of neural network to wind energy conversion systems
In the previous study, the energy generation of two WECS deployed at Darling site were estimated using the statistical–based technique. A total energy generation of 178.43 MWh at 50 m and 196.17 MWh at 70 m height were estimated from both WECS for the month of January 2010. In this study, the energy generations of both WECS for the same month were estimated using a developed wind power predictor. ...
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Fuel cells - the environmentally friendly energy converter and power generator
Heat engines based on fossil fuel combustion produce harmful pollutant emissions. Environmental concerns and sustainable development call for new technology for energy conversion and power generation, which is more efficient, environmentally friendly and compatible with alternative fuels and renewable energy sources and carriers. Fuel cells meet all these requirements and are being rapidly ...
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A reduced switch count UPF power conditioner for grid connected variable speed wind energy conversion system employing PM generators: a simulation study
In this paper, modelling and simulation of a grid connected variable speed wind energy conversion system (VSWECS) with reduced switch count power converter is presented. The system consists of a permanent magnet synchronous generator (PMSG), two pulse width modulated B-4 power converters and a maximum power point tracker (MPPT). Mathematical models of each element of the system are developed ...
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Chemistry Future: Priorities and Opportunities from the Sustainability Perspective
Abstract To celebrate the 10 year anniversary of ChemSusChem, we as the chairmen of the editorial board are writing this Essay to summarize important scientific contributions to our journal during the past decade in terms of sustainable science and technology. Bibliometric analysis of published papers show that biorefinery, solar energy conversion, energy-storage materials, and carbon ...
By SusChem
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Optimal design of power system stabiliser using a new cost function and PSO algorithm
In power system, the application of the power system stabiliser (PSS) has been proved to overcome the stability of power system. It is necessary to determine the appropriate PSS parameters. In this paper, a new cost function is presented for the tuning of PSS parameters. Optimisation of PSS parameters has been done by particle swarm optimisation algorithm. The power plant system that is simulated ...
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