The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform
Sandra Beauchet - One of the best experts on this subject based on the ideXlab platform.
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Comparative environmental life cycle assessment of several powertrain types for cars and buses in France for two driving cycles: “worldwide harmonized light vehicle test procedure” cycle and urban cycle
The International Journal of Life Cycle Assessment, 2020Co-Authors: Anne Bouter, Emmanuel Hache, Cyprien Ternel, Sandra BeauchetAbstract:Purpose Environmental assessments in the transportation sector are often lacking in transparency and completeness. In this article, the environmental trade-offs in road passenger transportation between conventional vehicles and electrified vehicles are compared, using life cycle assessment (LCA) methodology. Hence, the relevance of a massive electrification approach can be questioned. Assessing a set of current midsize passenger cars and buses allows for investigation of potential environmental issues. This is the first detailed LCA concerning several hybridization levels for cars and buses, and it is based on real consumption data for two traffic conditions. Methods We focused on the ISO standards (ISO 2006a , b ) and analyzed the energy carriers’ life cycle and the vehicle’s life cycle. The functional unit is clearly defined as the transportation of one passenger over 1 km in specific driving conditions from a point A to a point B, without prejudice toward the path taken. Vehicle specifications were derived based on the available manufacturers’ data, literature, and French Institute of Petroleum (IFPEN) experts. For the use stage, two driving cycles were assessed: the “worldwide harmonized light vehicles test procedure” (WLTP) cycle and an urban cycle. France was selected as the study area, and a sensitivity analysis was performed based on a European electricity charging mix for electrified vehicles. Results and discussion Battery electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) exhibit the highest climate change (CC) mitigation potential, provided that the electricity mix has low carbon and that the PHEV is used with a Fully-Charged Battery. With these conditions, PHEVs can perform even better than EVs. In that regard, PHEVs using only a thermic engine perform the worst in regard to CC indicator. It is also worth mentioning that electric buses are the best solution in urban traffic conditions for decreasing greenhouse gas emissions. Among powertrains, the electrified powertrains are even more important when performing in urban cycles. For other environmental indicators, such as particulate matter emissions, EVs perform worse than conventional thermic vehicles. Conclusions The results underline the importance of considering vehicles’ life cycles for LCA in the transportation sector and the need for multicriteria environmental analysis. Therefore, electrification of the transportation sector should not be driven by a single CC indicator, as this may generate potential environmental drawbacks. It is also crucial to adapt public policies to the local context because the results are highly sensitive to the electricity charging mix.
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Comparative environmental life cycle assessment of several powertrain types for cars and buses in France for two driving cycles: “worldwide harmonized light vehicle test procedure” cycle and urban cycle
International Journal of Life Cycle Assessment, 2020Co-Authors: Anne Bouter, Emmanuel Hache, Cyprien Ternel, Sandra BeauchetAbstract:Environmental assessments in the transportation sector are often lacking in transparency and completeness. In this article, the environmental trade-offs in road passenger transportation between conventional vehicles and electrified vehicles are compared, using life cycle assessment (LCA) methodology. Hence, the relevance of a massive electrification approach can be questioned. Assessing a set of current midsize passenger cars and buses allows for investigation of potential environmental issues. This is the first detailed LCA concerning several hybridization levels for cars and buses, and it is based on real consumption data for two traffic conditions. We focused on the ISO standards (ISO 2006a, b) and analyzed the energy carriers’ life cycle and the vehicle’s life cycle. The functional unit is clearly defined as the transportation of one passenger over 1 km in specific driving conditions from a point A to a point B, without prejudice toward the path taken. Vehicle specifications were derived based on the available manufacturers’ data, literature, and French Institute of Petroleum (IFPEN) experts. For the use stage, two driving cycles were assessed: the “worldwide harmonized light vehicles test procedure” (WLTP) cycle and an urban cycle. France was selected as the study area, and a sensitivity analysis was performed based on a European electricity charging mix for electrified vehicles. Battery electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) exhibit the highest climate change (CC) mitigation potential, provided that the electricity mix has low carbon and that the PHEV is used with a Fully-Charged Battery. With these conditions, PHEVs can perform even better than EVs. In that regard, PHEVs using only a thermic engine perform the worst in regard to CC indicator. It is also worth mentioning that electric buses are the best solution in urban traffic conditions for decreasing greenhouse gas emissions. Among powertrains, the electrified powertrains are even more important when performing in urban cycles. For other environmental indicators, such as particulate matter emissions, EVs perform worse than conventional thermic vehicles. The results underline the importance of considering vehicles’ life cycles for LCA in the transportation sector and the need for multicriteria environmental analysis. Therefore, electrification of the transportation sector should not be driven by a single CC indicator, as this may generate potential environmental drawbacks. It is also crucial to adapt public policies to the local context because the results are highly sensitive to the electricity charging mix.
Rachid Outbib - One of the best experts on this subject based on the ideXlab platform.
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Analysis and implementation of an adaptative PV based Battery floating charger
Solar Energy, 2012Co-Authors: Nabil Karami, Nazih Moubayed, Rachid OutbibAbstract:Abstract In a system composed of a photovoltaic (PV) cell, a converter and a resistive load, the Maximum Power Point Tracking (MPPT) techniques are applied at the output of the PV panel and not at the level of the load. In this study, the considered load is a Battery at different States Of Charge (SOC) that is Charged by the PV panel. The power consumed by the Battery is related to its SOC. Consequently, an empty Battery consumes more current than a Charged one. At full state of charge, the Battery does not call for more energy and thus it is not rewarding to extract more power from the PV panel. Besides, in a stand-alone photovoltaic system, the size of the PV panel and the Battery should be respected. Thus, the PV current at different irradiances should be compatible with the charging current required to charge the Battery at different SOC. A critical situation occurs at high irradiance when the PV panel delivers a high current at Maximum Power Point (MPP) that exceeds the tolerated charging current. The current reaches the top limit when the Battery is totally empty, caused by the big difference in potential between the converter output and the Battery voltages. In this case, the Battery starts to gas when attempts are made to charge it faster than it can absorb the energy. On the other hand, in a Fully Charged Battery, the difference in potential between the converter and the Battery is zero. In this case, there is no need to track the MPP. In this study, we will focus on the load type and suggest new methods to reach the MPP depending on the load state. In the proposed designs, the components of the stand-alone system are protected even if they are not well sized. In addition, we will focus on the development of the PV array mathematical model. The results achieved with the system, as well as the experimental results of a laboratory prototype, will be given.
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Analysis of an irradiance adaptative PV based Battery floating charger
2011 37th IEEE Photovoltaic Specialists Conference, 2011Co-Authors: Nabil Karami, Nazih Moubayed, Rachid OutbibAbstract:In a system composed of a PV cell, a converter and a resistive load, the MPPT techniques are done on the output of the PV cell and not on the load level. This study considers a Battery as load and considers its state of charge and take into consideration that empty Battery need more current than a Fully Charged one and therefore the MPPT is not useful in this case, but a smart system able to manage the Battery current based on different irradiance levels. For a fixed voltage output of the DC/DC converter, the current risks to reach its maximum when the Battery is totally empty which is caused by the big difference of potential between the converter and the Battery voltages. Whereas in a Fully Charged Battery, the difference of potential between the charger and the Battery is zero and therefore no need to search for the MPP in this case. The study treats first the modeling of an open loop DC/DC buck converter and then a modeling of the converter in a closed loop with a PID controller. Also, it proposes the use of a microcontroller with three different circuit designs and algorithms to manage the current and the voltage together depending on the Battery state of charge. The final design is called a PV based Battery floating charger that increase the lifetime of the Battery by controlling the converter output voltage with respect to the consumed current, the available PV current and the converter Mosfet tolerated current.
Marco Zorzi - One of the best experts on this subject based on the ideXlab platform.
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Transmission Policies for Energy Harvesting Sensors with Time-Correlated Energy Supply
IEEE Transactions on Communications, 2013Co-Authors: Nicolo Michelusi, Kostas Stamatiou, Marco ZorziAbstract:This paper considers a wireless sensor powered by an energy harvesting device, which reports data of varying importance to its receiver. Modeling the ambient energy supply by a two-state Markov chain ("GOOD" and "BAD"), assuming a finite Battery capacity constraint, and associating data transmission with a given energy cost, we propose low-complexity transmission policies, that achieve near-optimal performance in terms of the average long-term importance of the reported data. In particular, we derive the performance of the Balanced Policy (BP), which adapts the transmission probability to the harvesting state, such that energy harvesting and consumption are balanced. Our analysis demonstrates that the performance of the BP largely depends on the power-to-depletion, defined as the power that a Fully Charged Battery can supply on average over a BAD period. Numerical results show that the optimal BP achieves near-optimal performance and that a BP which avoids energy overflow further reduces the gap with respect to the globally optimal policy. A heuristic BP, based on the analysis of a system with a deterministic and periodic energy supply, is also proposed, and the parallels between the deterministic system and its stochastic counterpart are discussed.
Zhang Changhua - One of the best experts on this subject based on the ideXlab platform.
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A Battery Swapping Requirement Adequacy Model for Electric Vehicles and Its Simulation Research
Power system technology, 2012Co-Authors: Zhang ChanghuaAbstract:Energy shortage,air pollution and greenhouse gas over-emission are serious issues that the whole world is faced with now.After the large-scale application of electric vehicles(EV),it is a problem to be solved that in different time intervals how many Fully Charged batteries,which are just enough to meet the demand on EV Battery swapping,should be reserved in a Battery swapping station.For this reason,a concept of swapping Battery adequacy of EV is given,and a mathematical model based on certain assumed conditions,such as the EV owners’ driving custom,Battery capacity and charging management strategy,is proposed,and the conditions at the moment when the requirement of Fully Charged Battery swapping arises are analyzed,then from this the Battery swapping requirements,i.e.,the corresponding amounts of Fully Charged batteries to be reserved in the Battery swapping station in different time intervals,are obtained.The proposed method is simulated by Monte Carlo method,and the amount of Fully Charged batteries to be reserved in the Battery swapping station to meet the requirement of Battery swapping adequacy in different time intervals is achieved.Moreover,it is pointed out that both the proposed model and method can be further applied to calculate the amount of batteries for the vehicle to grid(V2G) and research the impacts of such factors as charging time,capacity of Battery and charging management strategy on the Battery swapping adequacy.
Furkan Ahmad - One of the best experts on this subject based on the ideXlab platform.
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Low cost residential microgrid system based home to grid (H2G) back up power management
Sustainable Cities and Society, 2018Co-Authors: Syed Muhammad Amrr, Mohammad Saad Alam, M. S. Jamil Asghar, Furkan AhmadAbstract:Abstract Load shedding is a common scenario in developing countries to mitigate the high-power demand. Normally, a low power backup supply is used for essential home-loads only, viz. essential lighting and fan loads. However, there always is a need of essential backup power supply for household applications during load shedding hours. Currently, rooftop, grid-connected, solar photovoltaic (PV) based inverters are being extensively used for home based backup power supply. These inverters have unidirectional power flow i.e. from generation side (PV source as well as utility grid supply) towards the home-load side. However, during a Fully Charged Battery condition, as charging is done by the utility grid too, the power of solar PV modules gets underutilized as the solar energy is only partially used for charging the Battery. The proposed supervisory switching control system, in conjunction with a conventional, low-cost home based inverter/UPS, adds up improved control features which ensure the reliability of the power supply and/or complete utilization of solar energy while operating in economy mode. In economy mode, only solar energy is utilized to meet the load demand during sunshine hours and thereafter. In case of repeated and prolong load shedding, the proposed controller selects a reliable mode of operation where batteries are allowed to be Charged both from utility grid as well as solar PV modules. Thus, two modes of control offer maximum harnessing of solar energy as well as better standby power supply, respectively. The proposed controller has been successFully implemented with the residential microgrid (existing home based inverter system for backup power supply). The proposed system also works as home-to-grid (H2G) system to meet load demand and peak load of utility grid during the sunshine hours by islanding the residential microgrid (home-loads System.)
