Comparing the Mass, Energy, and Cost Effects of Lightweighting in Conventional and Electric Passenger Vehicles

In this work the effect of weight reduction using advanced lightweight materials on the mass, energy use, and cost of conventional and battery electric passenger vehicles is compared. Analytic vehicle simulation is coupled with cost assessment to find the optimal degree of weight reduction minimizing manufacturing and total costs. The results show a strong secondary weight and cost saving potential for the battery electric vehicles, but a higher sensitivity of vehicle energy use to mass reduction for the conventional vehicle. Generally, light weighting has the potential to lower vehicle costs, however, the results are very sensitive to parameters affecting lifetime fuel costs for conventional and battery costs for electric vehicles. Based on current technology cost estimates it is shown that the optimal amount of primary mass reduction minimizing total costs is similar for conventional and electric vehicles and ranges from 22% to 39%, depending on vehicle range and overall use patterns. The difference between the optimal solutions minimizing manufacturing versus total costs is higher for conventional than battery electric vehicles

Integrated environmental and economic assessment of current and future fuel cell vehicles

Light-duty vehicles contribute considerably to global greenhouse gas emissions. Fuel cell vehicles (FCVs) may play a key role in mitigating these emissions without facing the same limitations in range and refueling time as battery electric vehicles (BEVs). In this study, we assess the environmental impacts and costs of a polymer electrolyte membrane fuel cell system (FCS) for use in light-duty FCVs and integrate these results into a comparative evaluation between FCVs, BEVs, and internal combustion engine vehicles (ICEVs).Swisselectric ResearchSwiss Competence Centre for Energy and MobilitySwiss Petroleum Associatio

Heat transfer challenge and design evaluation for a multi-stage temperature swing adsorption (TSA) process

Functionalized solid amine-based temperature swing adsorption (TSA) processes have recently been proposed as a potential way to reduce the energy-penalty of post-combustion carbon capture processes (1). If TSA is to be carried out at large scale and with high energy-efficiency, continuously operated counter-current contactors are required for thermodynamic reasons. This could, generally, be achieved by using moving bed contactors. However, the heat exchange requirement of TSA is significant and heat transfer is poor in fixed and moving beds. Therefore, multi-stage fluidized bed contactors with counter-current flow of solids and gas phase and immersed heat exchange surfaces may solve the heat transfer challenge while maintaining the thermodynamic process requirements. Experiments have shown that adsorption and desorption kinetics of suitable functionalized amine sorbents are fast and equilibrium loadings are practically reached in the stages (1). Thus, heat exchange is the dominant limiting factor for a practical stage design in multi-stage fluidized bed TSA. The present work rationally develops design requirements for TSA stages based on the necessary heat exchange rates. The considered particles are Geldart Type B (diameter 200-300 µm, particle density 1000-1500 kg/m3). Scalability of the design proposal is considered and vertically orientated heat exchanger tubes are compared to horizontal tube bundles. The net movement and mixing of particles within the bubbling bed stage must be maintained in spite of the emulsified heat exchangers (possible dead zones in the area of the tube bundles). It is shown that the pressure drop of multi-stage fluidized bed TSA units for flue gas CO2 capture is practically determined by the heat exchange requirement and not by the space-time of the solids for the adsorption. Future work will employ a bubbling fluidized bed heat exchange testing device for optimization of the heat exchanger geometry with respect to heat transfer rates and particle residence time distribution in the stage. Heat exchange measurement devices have been presented recently in literature for horizontal tube bundles and Geldart Type A particles (2), but the importance of the heat exchanger issue in continuous fluidized bed TSA requires the detailed investigation for the Geldart B range, potentially considering the macroscopic particle movement relative to the heat exchangers within each individual TSA stage. Please click Additional Files below to see the full abstract

Applying optimal choices for real powertrain and lightweighting technology options to passenger vehicles under uncertainty

This paper illustrates how cost-constrained optimization based on a set of real lightweighting and powertrain efficiency options can be used to guide decision-making for automotive manufacturers. The paper provides a method for answering the question posed by Original Equipment Manufacturers (OEMs): ‘given a maximum amount additional cost which can be passed on to consumers for fuel-saving technology with uncertain manufacturing cost, to what degree should it be spent on lightweighting versus powertrain efficiency improving technology’. The optimization is formulated as a 0–1 knapsack problem, and dynamic programming is used to find the global optimum technology combination at various levels of maximum up-front technology cost. This paper builds on previous work, which showed that for continuous marginal cost functions under uncertainty, a decision heuristic to either implement lightweighting technology or efficiency technology but not both under cost constraints was preferable. This work extends that result to provide more quantitative strategies for dealing with uncertainty, and finds that, despite uncertainty, optimum lightweighting and efficiency technology selections can be made for the real discrete cases studied. It is found that while the optimum efficiency technology set is highly sensitive to the up-front cost a consumer is willing to pay for future operational savings, lightweighting options are often selected preferentially to efficiency reduction measures. In the same sense, although both technologies are very sensitive to discount rate, lightweighting technologies are less sensitive. Fully hybridized vehicles emerge as a robust option, and, surprisingly, rank highly together with fully electric powertrains

Research gaps in the neurodevelopmental assessment of children with complex congenital heart defects: a scoping review

BackgroundChildren with congenital heart defects (CHD) are at risk for a range of developmental disabilities that challenge cognition, executive functioning, self-regulation, communication, social-emotional functioning, and motor skills. Ongoing developmental surveillance is therefore key to maximizing neurodevelopmental outcome opportunities. It is crucial that the measures used cover the spectrum of neurodevelopmental domains relevant to capturing possible predictors and malleable factors of child development.ObjectivesThis work aimed to synthesize the literature on neurodevelopmental measures and the corresponding developmental domains assessed in children aged 1−8 years with complex CHD.MethodsPubMed was searched for terms relating to psycho-social, cognitive and linguistic-communicative outcomes in children with CHD. 1,380 papers with a focus on complex CHD that reported neurodevelopmental assessments were identified; ultimately, data from 78 articles that used standardized neurodevelopmental assessment tools were extracted.ResultsThirty-nine (50%) of these excluded children with syndromes, and 9 (12%) excluded children with disorders of intellectual development. 10% of the studies were longitudinal. The neurodevelopmental domains addressed by the methods used were: 53% cognition, 16% psychosocial functioning, 18% language/communication/speech production, and 13% motor development-associated constructs.ConclusionsData on social communication, expressive and receptive language, speech motor, and motor function are underrepresented. There is a lack of research into everyday use of language and into measures assessing language and communication early in life. Overall, longitudinal studies are required that include communication measures and their interrelations with other developmental domains

Lidar/radar approach to quantify the dust impact on ice nucleation in mid and high level clouds

We present the first attempt of a closure experiment regarding the relationship between ice nucleating particle concentration (INPC) and ice crystal number concentration (ICNC), solely based on active remote sensing. The approach combines aerosol and cloud observations with polarization lidar, Doppler lidar, and cloud radar. Several field campaigns were conducted on the island of Cyprus in the Eastern Mediterranean from 2015-2018 to study heterogeneous ice formation in altocumulus and cirrus layers embedded in Saharan dust. A case study observed on 10 April 2017 is discussed in this contribution. © 2019 The Authors, published by EDP Sciences