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... With the different kinds of fuel now available, modern spark ignition engines have to be adapted, owing not only to the difference between the characteristic heat of combustion of the different fuels, but also to the response of the flame to stretch. As the burning rate is a function of the laminar burning speed which is a function of the flame stretch, this parameter has to be taken into account ...
catalysts; diffusivity; electrochemistry; electrodes; energy conversion; equations; fuel cells; mass transfer; metals; model validation; models; oxygen
Abstract:
... A 3D multi-physics, multi-component and not isothermal model is developed to analyze the effects of catalyst structures on the performance of a gas diffusion electrode (GDE) cell toward the oxygen reduction reaction using dry oxygen as a reactant. The model includes Stokes–Brinkman, Maxwell–Stefan, and modified Butler–Volmer equations for simulating the performance of the GDE cell, solved by Comso ...
... Thermal energy storage (TES) systems allow concentrated solar power (CSP) producers to participate in a day-ahead market. Therefore, the optimal power scheduling problem can be posed, whose objective is the maximization of profits derived from electricity sales. The daily generation schedule has to be offered in advance, usually the previous day before a certain time, thus an electricity price and ...
algorithms; climate; energy efficiency; lighting; shade; solar radiation
Abstract:
... In this paper we address the problem of designing new energy-efficient static daylight devices that will surround the external windows of a residential building in Madrid. Shading devices can in fact largely influence solar gains in a building and improve thermal and lighting comforts by selectively intercepting the solar radiation and by reducing the undesirable glare. A proper shading device can ...
boiling; carbon dioxide; control methods; cooling systems; energy use and consumption; greenhouse gas emissions; model uncertainty; models; spark ignition engines
Abstract:
... Optimal thermal management of modern internal combustion engines (ICE) is one of the key factors for reducing fuel consumption and CO2 emissions. These are measured by using standardized driving cycles, like the New European Driving Cycle (NEDC), during which the engine does not reach thermal steady state; engine efficiency and emissions are therefore penalized. Several techniques for improving IC ...
buildings; carbon; case studies; emissions; energy; energy costs; heat; mathematical models; stakeholders
Abstract:
... This paper presents a model which simultaneously optimises the selection and operation of technologies for distributed energy systems in buildings. The Technology Selection and Operation (TSO) model enables a new approach for the optimal selection and operation of energy system technologies that encompasses whole life costing, carbon emissions as well as real-time energy prices and demands; thus, ...
electric vehicles; electricity costs; fossil fuels; planning; wind power
Abstract:
... Electric vehicle (EV) is a promising, environmental friendly technique for its potential to reduce the using of fossil fuels. Massive EVs pose both opportunities and challenges for power systems, especially with the growing amount of wind-power integration. This paper investigates the problem of collaborative optimization scheduling of generators, EVs and wind power. A novel bi-layer optimization ...
... The paper proposes a bi-level optimisation framework for Electric Vehicle (EV) fleet charging based on a realistic EV fleet model including a transport demand sub-model. The EV fleet is described by an aggregate battery model, which is parameterised by using recorded driving cycle data of a delivery vehicle fleet. The EV fleet model is used within the inner level of the bi-level optimisation frame ...
energy; income; models; power plants; prediction; uncertainty; wind power; China
Abstract:
... To reduce the uncertain influence of wind power and solar photovoltaic power on virtual power plant (VPP) operation, robust optimization theory (ROT) is introduced to build a stochastic scheduling model for VPP considering the uncertainty, price-based demand response (PBDR) and incentive-based demand response (IBDR). First, the VPP components are described including the wind power plant (WPP), pho ...
bibliometric analysis; energy; fossil fuels; fuel combustion; prices; researchers; wind power; Europe; United States
Abstract:
... With the increasing negative effects of fossil fuel combustion, many countries have paid more attention on supporting environmentally friendly energy generation, particularly renewable and sustainable energy sources (RES). However, renewables still cannot economically compete with fossil-fuels and are facing new challenges. Appropriate electricity pricing mechanism plays a vital role on mitigating ...
carbon dioxide; climate; energy; energy policy; global warming; greenhouse gas emissions; lignite; prediction; rain; solar collectors; system optimization; temperature; time series analysis; wind turbines; Greece
Abstract:
... An approach for a plan to meet the energy needs of the state of Greece in conjunction with assumed responsibilities to confront global warming is presented. Time series of climate indicators like average temperature and rain precipitation together with energy consumption and CO2 emissions are examined for stationarity and causality. Predictions of energy needs for the next 25years and CO2 emission ...
carbon dioxide; fuels; convection; mass transfer; prediction
Abstract:
... This study presents a state-of-the-art overview on heat transfer characteristics of fluids (mainly water, carbon dioxide and hydrocarbon fuels) flowing in smooth tubes and enhanced tubes at supercritical pressures and tries to obtain a fundamental understanding of the unique characteristics. Heat transfer in enhanced tubes is much better than that in smooth tubes with a larger pressure drop penalt ...
batteries; lithium; longevity; model validation; models
Abstract:
... The incremental capacity (IC) analysis method is widely used to analyze the aging origins and state of health (SOH) of lithium ion batteries. This paper analyzes the technical difficulties during the application of the IC analysis method at first. A universal capacity model based on charging curve is then proposed, which not only inherits the advantages of IC analysis method but also avoids the te ...
carbon; carbon dioxide; global warming; greenhouse gas emissions; pressure; China
Abstract:
... Given the acceleration of global warming and rising greenhouse gas emissions, all countries are facing the harsh reality of the need to reduce carbon emissions. In this study, we propose an index to quantify the pressure faced by policymakers to reduce such emissions, termed the carbon emissions reduction index. This index allows us to observe the effect of carbon emissions volume on the pressure ...
... A pulse tube cryocooler (PTC) cannot work with Carnot efficiency due basically to the expansion work that has to be dissipated thermally at the warm end of the pulse tube, this dissipation is especially phenomenal with high cooling capacity or at high temperatures which reduces the COP and limits the application of PTC above 120K. Therefore, how to recover this amount of dissipated work becomes a ...
... Microfluidic fuel cell (MFC) stacking is a prerequisite to improve its power output for practical applications. Unlike the stacking of membrane-based fuel cells, MFC stacking generally involves complex fluidic management, such as anolyte and catholyte distribution, and spent electrolyte collection, which greatly increases the system’s complexity. In addition, the operational robustness of MFC stac ...
air temperature; buildings; energy; heat; heat island; heat sums; insulating materials; methodology; models; France
Abstract:
... Efficient strategies are required to reduce space heating energy demands in buildings at city scale. Models taking into account the dynamic of the Urban Heat Island (UHI) phenomenon may be useful tools to help urban planners in this task. In this paper, we propose a new methodology to assess the energy demands for space heating in buildings at city scale: a degree-day method is applied, coupled wi ...
air; entropy; friction; heat exchangers; heat transfer; models; temperature
Abstract:
... In the design of multistream plate-fin heat exchangers (MPFHEs), surface selection and layer pattern optimization have been investigated as two independent problems and still remain at the empirical stage, which becomes an obstacle for optimizing the performance of MPFHEs. A combined method of the equipartition of entropy production and the balance of local heat load is proposed in the present res ...
algorithms; case studies; electricity; industry; markets; models; seasonal variation; New South Wales; Queensland
Abstract:
... Short-term load forecasting (STLF) plays an irreplaceable role in the efficient management of electric systems. Particularly in the electricity market and industry, accurate forecasting could provide effective future plans and economic operations for operators of utilities and power systems. Hence, a more precise and stable load-forecasting model is essentially needed in the field of electricity l ...
air; air flow; combustion; energy conversion; fuels; heat recovery; internal combustion engines; methodology; models; wastes
Abstract:
... A novel intra-cycle waste heat recovery (ICWHR) methodology, applied to an internal combustion engine is presented in this study. Through a split type thermodynamic cycle design, quasi-isothermal compression of the charge air and isobaric combustion of the air/fuel mixture can be performed separately in two chambers. Within such a design, the exhaust heat can be recovered to the intake air flow be ...