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Abstract Distillation of close-boiling mixtures, such as propylene–propane and ethyl benzene–styrene systems, is an energy intensive process. Vapor recompression techniques and heat pumping-assisted columns have been adopted for such applications for their high potential of energy savings. In direct vapor recompression columns, the vapors leaving the top of the column are compressed, and in the reboiler of the same column, these vapors are condensed to provide heat for vapor generation. Internal heat integrated distillation columns or iHIDiCs are new developments employing the same concept of vapor recompression. These new column configurations can have significantly lower energy demands than common vapor recompression units. In iHIDiCs, rectifying section is operated at a higher pressure (i.e. higher temperature) than in stripping, and therefore its heat can be used to generate vapor in stripping section. So far, design of these column configurations is performed based on engineering experience, simulation or experimental studies on given cases, including dynamic control simulations. Within previous and most recent research efforts on iHIDiCs, there exist no generalized design methods or systematic approaches for design of these internal integrated distillation columns. The present paper presents a systematic design procedure for iHIDiCs. A design hierarchy for iHIDiCs is developed, which includes two phases of design, thermodynamic and hydraulics. This design procedure is applied using commercial simulation-based design methods. In thermodynamic design, temperature profiles for column sections are used as a design tool to guide designers. On the other hand, hydraulic capacities of stages for heat exchange are analyzed to determine the maximum physical space area available for heat exchange. Hence, feasibility regions for both heat integration and hydraulic design are identified.

This paper uses data from Understanding Society: the UK Household Longitudinal Study to explore the association between fuel poverty and a set of wellbeing outcomes: life-satisfaction, self-reported health measures and more objectively measured biomarker data. Over and above the conventional income–fuel cost indicators, we also use more proximal heating deprivation indicators. We create and draw upon a set of composite indicators that concomitantly capture (the lack of) affordability and thermal comfort. Depending on which fuel deprivation indicator is used, we find heterogeneous associations between fuel poverty and our wellbeing outcomes. Employing combined fuel deprivation indicators, which takes into account the income–fuel cost balance and more proximal perceptions of heating adequacy, reveals the presence of more pronounced associations with life satisfaction and fibrinogen, one of our biological health measures. The presence of these strong associations would have been less pronounced or masked when using separately each of the components of our composite fuel deprivation indicators as well as in the case of self-reported generic measures of physical health. Lifestyle and chronic health conditions play a limited role in attenuating our results, while material deprivation partially, but not fully, attenuates our associations between fuel deprivation and wellbeing. These results remain robust when bounding analysis, IV and panel data models are employed to test the potential role of various sources of endogeneity biases. Our analysis suggests that composite fuel deprivation indicators may be useful energy policy instruments for uncovering the underlining mechanism via which fuel poverty may get “under the skin”.

In this work, front contacts for graphene-based solar cells are made by means of colloidal graphite instead of gold. The performance is characterized by exploiting impedance spectroscopy and is compared to the standard gold contact technology. Impedance data are analysed through equivalent circuit representation in terms of lumped parameters, suitable to describe the complex impedance in the frequency range considered in the experiments. Using this approach, capacitance–voltage of the considered graphene–silicon solar cell is found and the barrier height forming at the graphene–silicon interface is extracted.

Abstract This paper assesses the effects of a global emissions trading scheme (GETS) for international aviation and shipping as a way of reducing emissions of both greenhouse gases (GHG) and other atmospheric emissions that lead to air pollution. A prior assessment of such integration requires the coupling of energy–environment–economy (E3) global modelling of mitigation policies with the atmospheric modelling of pollution sources, mixing and deposition. We report the methodology and results of coupling of the E3MG model and the global atmospheric model, p-TOMCAT. We assess the effects of GETS on the concentrations of atmospheric gases and on the radiative forcing, comparing a GETS scenario to a reference BASE scenario with higher use of fossil fuels. The paper assesses the outcome of GETS for atmospheric composition and radiative forcing for 2050. GETS on international shipping and aviation reduces their CO 2 and non-CO 2 emissions up to 65%. As a consequence atmospheric concentrations are modified and the radiative forcing due to international transport is reduced by different amounts as a function of the pollutant studied (15% for CO 2 , 35% for methane and up to 50% for ozone).

This paper introduces the concept of payment probability as an important component of carbon risk (the financial risk associated with CO2 emissions under uncertain climate policy). In modeling power plant investment decisions, most existing literature uses the expected carbon price (e.g., the price of traded permits or carbon tax) as a proxy for carbon risk. In contrast, this paper identifies expected carbon payment as a more accurate measure of carbon risk as perceived by industry practitioners. This measure of carbon risk incorporates both expected price and the probability that this price would actually be faced in the case of a particular investment. This concept helps explain both the surge of activity in 2005–2006 and the subsequent decline in interest in coal-fired power plant development in the U.S. The data for this case study comes from an extensive online survey of 700 U.S. energy professionals completed in 2006, as well as interviews conducted with industry representatives from 2007 to 2009. By analyzing industry views on policy uncertainty and future carbon legislation, we gain a better understanding of investor attitudes toward carbon risk. This understanding will help policy makers design better incentives for investing in low-carbon technologies.

AbstractTurbocharging technique is more and more widely employed on compression ignition and spark ignition internal combustion engines, as well, to improve performance and reduce total displacement. Experimental studies, developed on dedicated test facilities, can supply a lot of information to optimize the engine-turbocharger matching, especially if tests can be extended to the typical engine operating conditions (unsteady flow). A specialized components test rig (particularly suited to study automotive turbochargers) has been operating since several years at the University of Genoa. The test facility allows to develop studies under steady or unsteady flow conditions both on single components and subassemblies of engine intake and exhaust circuit.In the paper the results of an experimental campaign developed on a turbocharger waste-gated turbine for gasoline engine application are presented. Preliminarily, the measurement of the turbine steady flow performance map is carried out. In a second step the same component is tested under unsteady flow conditions. Instantaneous inlet and outlet static pressure, mass flow rate and turbocharger rotational speed are measured, together with average inlet and outlet temperatures.A numerical procedure, recently developed at the University of Naples, is then utilized to predict the steady turbine performance map, following a 1D approach. The model geometrically schematizes the component basing on few linear and angular dimensions directly measured on the hardware. Then, the 1D steady flow equations are solved within the stationary and rotating channels constituting the device. All the main flow losses are properly taken into account in the model. The procedure is able to provide the sole “wheel-map” and the overall turbine map. After a tuning, the overall turbine map is compared with the experimental one, showing a very good agreement.Moreover, in order to improve the accuracy of a 1D engine simulation model, the classical map-based approach is suitably corrected with a sequence of pipes that schematizes each component of the device (inlet/outlet ducts, volute and wheel) included upstream and downstream the turbine to account for the wave propagation and accumulation phenomena inside the machine. In this case, the previously computed “wheel-map” is utilized. The turbine pipes dimensions, are automatically provided by the geometrical module of the proposed procedure to correctly reproduce the device volume and the flow path length.

AbstractFloating photovoltaic system for reservoirs is a recent innovative technology that is highly advantageous in reducing evaporation while generating solar power. In addition, the integration of floating photovoltaic systems with the existing hydroelectric power plants will increase renewable power production. The present study aims to assess the electrical performance of floating photovoltaic systems in major reservoirs with existing hydroelectric power plants in India. The reservoirs with large water surface area were selected for the study, and a model floating photovoltaic system with a 5-MW capacity was designed for the selected reservoirs. The numerical analysis showed that installing floating photovoltaic systems will result in an annual energy yield of 160 GWh. Further, the systems also save 1.40 million cubic meters of water per day and also help in generating additional energy of 514.80 MWh/day from the saved water through its integration with hydroelectric power plants. A single-axis tracking mechanism to the floating photovoltaic systems will increase the annual energy generation by 11%. The detailed cost analysis and carbon emission analysis were also carried out. The results indicate that the tracking mechanisms increase the total installation cost of the systems. The annual carbon emission reduction from the floating photovoltaic systems accounts for about 3.30 million tons of CO2. The obtained results highlight the suitability of this innovative technology for installation in Indian reservoirs and its effectiveness in reducing evaporation and carbon emission. Graphic abstract

The Bono Social de Electricidad (BSE) is a government programme, introduced in 2009, to reduce energy poverty in Spain. The BSE is a discount on the price of electricity, available to vulnerable households who applied. Applying differences-in-differences and propensity score matching to household data between 2008 and 2011, we find no statistically significant impact of the intention to treat on two indicators of energy poverty, viz. the ability to keep the house adequately warm, and the presence of damp walls, rotting windows and leaking roofs. This may be because eligible households did not apply. A third indicator, delays in paying electricity bills, showed a statistically significant deterioration. That is, the BSE has not reduced energy poverty, if anything it has made it worse. This is not because eligible households transferred income to relatives hit harder by the financial crises, but it may be because the BSE discount did not fully compensate for the cold of 2010.