No abstract available

No abstract available

[en] Highlights: • The thermal behaviors of a Li-ion battery stack have been investigated by modeling. • Parametric studies have been performed focusing on three different cooling materials. • Effects of discharge rate, ambient temperature and Reynolds number are examined. • General guidelines are proposed for the thermal management of a Li-ion battery stack. - Abstract: Thermal management is critically important to maintain the performance and prolong the lifetime of a lithium-ion (Li-ion) battery. In this paper, a two-dimensional and transient model has been developed for the thermal management of a 20-flat-plate-battery stack, followed by comprehensive numerical simulations to study the influences of ambient temperature, Reynolds number, and discharge rate on the temperature distribution in the stack with different cooling materials. The simulation results indicate that liquid cooling is generally more effective in reducing temperature compared to phase-change material, while the latter can lead to more homogeneous temperature distribution. Fast and deep discharge should be avoided, which generally yields high temperature beyond the acceptable range regardless of cooling materials. At low or even subzero ambient temperatures, air cooling is preferred over liquid cooling because heat needs to be retained rather than removed. Such difference becomes small when the ambient temperature increases to a mild level. The effects of Reynolds number are apparent in liquid cooling but negligible in air cooling. Choosing appropriate cooling material and strategy is particularly important in low ambient temperature and fast discharge cases. These findings improve the understanding of battery stack thermal behaviors and provide the general guidelines for thermal management system. The present model can also be used in developing control system to optimize battery stack thermal behaviors

[en] Highlights: • The wave energy resource and hot spots along an energetic region are determined. • The slot cone generator power matrix is crossed with the energy resource available. • Capacity factor, equivalent hours and capture factor are computed. • The optimum location for the shoreline wave energy converter is determined. - Abstract: This work deals with the assessment of the optimal location—in terms of the electric energy production—for a shoreline Wave Energy Converter (WEC). The methodology is presented through a case study in which the wave energy conversion technology and the location selected correspond to the Seawave Slot-Cone Generator (SSG) and a coastal strip in Galicia (NW Spain), respectively. This region represents one of the European areas with the greatest wave energy resource and where pilot plants for wave energy conversion are still undeveloped. To carry out the assessment, we consider the wave data recorded at an offshore buoy and the power matrix of the SSG. The wave conditions offshore—representing the 90% of the total energy for an average year—are propagated through a third generation wave model toward the coast. On the basis of the results, five hotspots or areas with high wave energy levels are highlighted. After crossing the power matrix of the WEC with the wave conditions, we map the expected energy production and the percentage of the total energy captured along the coastline. Among the five hot spots in the area, one is proposed as the optimum for the SSG location. Finally, we discuss the energy supply capacity of the WEC to satisfy the energy consumption needs of nearby communities

[en] Highlights: • Energy flow model was represented as the functionals of technology options. • Relationships among available technologies can be visualized by developed model. • Technology roadmapping can be incorporated into the model as technical scenario. • Combination of technologies can increase their contribution to the environment. - Abstract: The design of energy systems has become an issue all over the world. A single optimal system cannot be suggested because the availability of infrastructure and resources and the acceptability of the system should be discussed locally, involving all related stakeholders in the energy system. In particular, researchers and engineers of technologies related to energy systems should be able to perform the forecasting and roadmapping of future energy systems and indicate quantitative results of scenario analyses. We report an energy flow model developed for analysing scenarios of future Japanese energy systems implementing a variety of feasible technology options. The model was modularized and represented as functionals of appropriate technology options, which enables the aggregation and disaggregation of energy systems by defining functionals for single technologies, packages integrating multi-technologies, and mini-systems such as regions implementing industrial symbiosis. Based on the model, the combinations of technologies on both energy supply and demand sides can be addressed considering not only the societal scenarios such as resource prices, economic growth and population change but also the technical scenarios including the development and penetration of energy-related technologies such as distributed solid oxide fuel cells in residential sectors and new-generation vehicles, and the replacement and shift of current technologies such as heat pumps for air conditioning and centralized power generation. The developed model consists of two main modules; namely, a power generation dispatching module for the Japanese electricity grid and a demand-side energy flow module based on a sectorial energy balance table. Both modules are divided and implemented as submodules represented as functionals of supply- and demand-side technology options. Using the developed model, three case studies were performed. Required data were collected through workshops involving researchers and engineers in the energy technology field in Japan. The functionals of technologies were defined on the basis of the availability of data and understanding of the current and future energy systems. Through case studies, it was demonstrated that the potential of energy technologies can be analysed by the developed model considering the mutual relationships of technologies. The contribution of technologies to, e.g., the reduction in greenhouse gas emissions should be carefully examined by quantitative analyses of interdependencies of the technology options

[en] Highlights: • Cycled carbide slag from calcium looping cycles is used to remove HCl. • The optimum temperature for HCl removal of cycled carbide slag is 700 °C. • The presence of CO₂ restrains HCl removal of cycled carbide slag. • CO₂ capture conditions have important effects on HCl removal of cycled carbide slag. • HCl removal capacity of carbide slag drops with cycle number rising from 1 to 50. - Abstract: The carbide slag is an industrial waste from chlor-alkali plants, which can be used to capture CO₂ in the calcium looping cycles, i.e. carbonation/calcination cycles. In this work, the cycled carbide slag from the calcium looping cycles for CO₂ capture was proposed to remove HCl in the flue gas from the biomass-fired and RDFs-fired boilers. The effects of chlorination temperature, HCl concentration, particle size, presence of CO₂, presence of O₂, cycle number and CO₂ capture conditions in calcium looping cycles on the HCl removal behavior of the carbide slag experienced carbonation/calcination cycles were investigated in a triple fixed-bed reactor. The chlorination product of the cycled carbide slag from the calcium looping after absorbing HCl is not CaCl₂ but CaClOH. The optimum temperature for HCl removal of the cycled carbide slag from the carbonation/calcination cycles is 700 °C. The chlorination conversion of the cycled carbide slag increases with increasing the HCl concentration. The cycled carbide slag with larger particle size exhibits a lower chlorination conversion. The presence of CO₂ decreases the chlorination conversions of the cycled carbide slag and the presence of O₂ has a trifling impact. The chlorination conversion of the carbide slag experienced 1 carbonation/calcination cycle is higher than that of the uncycled calcined sorbent. As the number of carbonation/calcination cycles increases from 1 to 50, the chlorination conversion of carbide slag drops gradually. The high calcination temperature and high CO₂ concentration in the calcination of calcium looping decrease the chlorination conversions of the cycled carbide slag. Increasing the calcination time in the calcium looping is adverse to HCl removal and extending the carbonation time slightly improves the chlorination conversions. The microstructure of the cycled carbide slag shows an important effect on HCl removal capacity

[en] Highlights: • An off-line local control is proposed for real-time HEV energy management. • Powertrain efficiencies are studied to produce a unified objective function. • Penalty function is designed to ensure charge sustaining operation. • Implementation by storing optimal power share in a two-dimensional control map. • Proposed control improved fuel economy by up to 20% compared to conventional control. - Abstract: The proposed supervisory control system (SCS) uses a control map to maximize the powertrain efficiency of a hybrid electric vehicle (HEV) in real-time. The paper presents the methodology and structure of the control, including a novel, comprehensive and unified expression for the overall powertrain efficiency that considers the engine-generator set and the battery in depth as well as the power electronics. A control map is then produced with instructions for the optimal power share between the engine branch and battery branch of the vehicle such that the powertrain efficiency is maximized. This map is computed off-line and can thereafter be operated in real-time at very low computational cost. A charge sustaining factor is also developed and introduced to ensure the SCS operates the vehicle within desired SOC bounds. This SCS is then tested and benchmarked against two conventional control strategies in a high-fidelity vehicle model, representing a series HEV. Extensive simulation results are presented for repeated cycles of a diverse range of standard driving cycles, showing significant improvements in fuel economy (up to 20%) and less aggressive use of the battery

[en] Highlights: • Thermal modeling of the HPHEX for the high-temperature. • Radiation heat transfer analysis in the high-temperature HPHEX. • Prediction of the temperature distribution by adopting nodal approach. • Design and analysis of the HPHEX for the high-temperature. - Abstract: The heat transfer of an air-to-air heat pipe heat exchanger (HPHEX) with counter flow and a high-temperature range was modeled. The HPHEX was constructed from sodium-stainless steel (STS) heat pipes (HPs) using a staggered configuration. The thermal numerical model was developed by the nodal approach, and the junction temperature and thermal resistance of the HP and heat transfer fluid of each row were defined. Surface-to-surface radiant heat transfer was applied to each row of the liquid metal HPHEX. The cold-side inlet air temperature was determined by iteration to converge to the minimum operating temperature of the sodium HP. The cold-side inlet velocity and position of the common wall were considered as the main variables in evaluating the performance of the liquid metal HPHEX, and their effects on the temperature distribution, effectiveness, heat transfer rate of each row were investigated. The proposed row-by-row heat transfer model is useful for understanding the temperature distribution of each row and can be used to predict the cold-side inlet temperature of a liquid metal HPHEX with counter flow. The recovery heat and effectiveness of the heat exchanger were calculated for various configurations and operating conditions. The simulation results agreed with experimental data to within 5% error for normal operation of the heat pipes, and within 11% error when the minimum temperature was lower than could allow normal operation of the sodium heat pipes

[en] Highlights: • The development phase of China’s oil industry is detailed. • Risk to oil industry in China is identified along the supply chain. • Policy aimed at improving oil security is examined. - Abstract: Oil security has become a major issue in China. This paper analyzes China’s oil security from the supply chain perspective, as the country faces challenges from an increasing reliance on imported oil, a fast-growing economy, the Malacca dilemma, and volatile international oil prices. To clarify the issue of oil security, we first review the development phase of China’s oil industry and previous research related to its energy security. Then a framework from the supply chain perspective is constructed to identify the current risk from three aspects: energy flow, financial and environmental. Finally, policies aimed at improving the country’s energy security are examined and potential problems presented. From this analysis, we conclude that the potential risk arising from China’s oil system is inherently interconnected. There is still great potential for the country to improve oil security by strengthening its strategic oil reserves, improving energy efficiency, and developing its domestic oil tanker fleet

[en] Highlights: • The interactive mechanism between system and PHEVs is presented. • The charging load self-management without sacrificing user requirements is proposed. • The charging load self-management is coupled to system operation risk analysis. • The charging load self-management can reduce the extra risk brought by PHEVs. • The charging load self-management can shift charging power to the time with low risk. - Abstract: Many jurisdictions around the world are supporting the adoption of electric vehicles through incentives and the deployment of a charging infrastructure to reduce greenhouse gas emissions. Plug-in hybrid electric vehicles (PHEVs), with offer mature technology and stable performance, are expected to gain an increasingly larger share of the consumer market. The aggregated effect on power grid due to large-scale penetration of PHEVs needs to be analyzed. Nighttime-charging which typically characterizes PHEVs is helpful in filling the nocturnal load valley, but random charging of large PHEV fleets at night may result in new load peaks and valleys. Active response strategy is a potentially effective solution to mitigate the additional risks brought by the integration of PHEVs. This paper proposes a power system operation risk analysis framework in which charging load self-management is used to control system operation risk. We describe an interactive mechanism between the system and PHEVs in conjunction with a smart charging model is to simulate the time series power consumption of PHEVs. The charging load is managed with adjusting the state transition boundaries and without violating the users’ desired charging constraints. The load curtailment caused by voltage or power flow violation after outages is determined by controlling charging power. At the same time, the system risk is maintained under an acceptable level through charging load self-management. The proposed method is implemented using the Roy Billinton Test System (RBTS) and several PHEV penetration levels are examined. The results show that charging load self-management can effectively balance the extra risk introduced by integration of PHEVs during the charging horizon