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Lithium-ion batteries are fast becoming the battery of choice in applications such as electric/hybrid electric vehicles (EV/HEV) and renewable energy systems. This increasing usage demands an improved reliability of the battery systems, which in turn heavily relies on the control and optimization algorithms. Of particular importance is ensuring that each lithium-ion cell within a battery pack remains strictly within an acceptable charge range to avoid untimely degradation of the battery pack. Unfortunately, current battery models make the design of charge equalization circuitry difficult due to their limitations. The aim of this paper is to develop a component-wise control-oriented physics-based battery pack model to facilitate implementation of advanced model-based control and optimization algorithms. In the first stage some existing results are used to obtain a simplified electrochemical ODE model of an individual lithium-ion cell. Then, the cell model is used as the building block of the complete battery pack model. Different charge/discharge scenarios are presented to illustrate the potential of the modeling approach in facilitating the implementation of advanced control and optimization algorithms in improved power equalization and hence prolonging the battery pack lifetime.

Cogeneration of heat and electricity is an important pillar of energy and climate policy. To plan the production and distribution system of combined heat and power (CHP) systems for residential heating, suitable methods for decision support are needed. For a comprehensive feasibility analysis, the integration of the location and capacity planning of the power plants, the choice of customers, and the network planning of the heating network into one optimization model are necessary. Thus, we develop an optimization model for electricity generation and heat supply. This mixed integer linear program (MILP) is based on graph theory for network flow problems. We apply the network location model for the optimization of district heating systems in the City of Osorno in Chile, which exhibits the “checkerboard layout” typically found in many South American cities. The network location model can support the strategic planning of investments in renewable energy projects because it permits the analysis of changing energy prices, calculation of break-even prices for heat and electricity, and estimation of greenhouse gas emission savings.

Pervasive computing and business process modeling are increasingly joining forces, as mobile human users shall be seamlessly integrated into business processes. In respective scenarios, humans use mobile devices and wireless technology to interact with workflows running in a powerful back-end infrastructure. However, the frequent interaction between humans and workflows causes a high communication overhead and, thus, high energy consumption on mobile devices. This impacts the usability and efficiency of the business process due to rapidly drained batteries and the resulting short life-times of the devices and applications. We present an approach based on a minimum-cut algorithm for reducing costly data transmissions during workflow execution by distributing parts of a workflow to the users' devices. Our motivation is to reduce the energy consumption on the mobile devices and, thus, avoid draining batteries in the field. We prove that our algorithm finds the optimal solution for a given network and workflow, decreasing the energy consumed on mobile devices by 32-37% compared to an approach where the entire workflow is executed in the infrastructure. Thus, in typical domains like logistics and health care, one third of the energy can be saved. This either means that devices have to be charged less frequently, leading to less distraction in the business process, or that mobile device specifications can be lowered. Significant cost reductions result in both cases.

After a halt of four years, the n TOF spallation neutron facility at CERN has resumed operation in November 2008 with a new spallation target characterized by an improved safety and engineering design, resulting in a more robust overall performance and e cient cooling. The rst measurement during the 2009 run has aimed at the full characterization of the neutron beam. Several detectors, such as calibrated ssion chambers, the n TOF Silicon Monitor, a Mi- croMegas detector with 10B and 235U samples, as well as liquid and solid scintillators have been used in order to characterize the properties of the neutron uence. The spatial pro le of the beam has been studied with a specially designed \X-Y

Most of the Catalonian population and urban areas are located along the Mediterranean coastal zone and for this analysis three largest Catalonia’s cities are chosen: Barcelona, Terrassa and Tarragona. Each city is a geographical representative of a different climate type according to the re-analysed Köppen-Geiger climate classification. The objective of this research is to demonstrate the effects of regional climate variations on the potential of natural ventilation (NV) application in building design. The first part of the article presents the availability of NV corresponding to yearly climate conditions applying the methodology “Climate Potential for Natural Ventilation” (CPNV). In continuation, the second analysis is calculated with building energy simulation software and displays possible refrigeration energy savings in three geographical locations. Mixed-mode (or hybrid-mode) and night-ventilation techniques are applied for the cooling process of a hypothetical low-rise office building model. Peer Reviewed

Abstract Nanofluids have been introduced for the enhancement in the heat transfer phenomena in the last few years. In this paper a corrugated bottom triangular solar collector has been studied introducing water based nanofluids inside the enclosure. The corrugated bottom is kept at a constant high temperature whereas the side walls of the triangular enclosure are kept at a low temperature. Three types of nanoparticles are taken into consideration: Cu, Al2O3, and TiO2. The effect of solid volume fraction (ϕ) of the nanoparticle of nanofluid has been studied numerically by Galerkin weighted residual method of finite element for a wide range of Grashof number (Gr) 104–106. Calculations are carried out for ϕ = 0, 0.05, 0.08, and 0.1 and dimensionless time, τ = 0.1, 0.5, and 1. For the specified conditions streamlines and isotherm contours are obtained and detailed results of the interaction between different parameters are studied using overall Nusselt number. It has been found that both Grashof number and solid volume fraction have significant influence on streamlines and isotherms in the enclosure. It is also found that heat transfer increased by 24.28% from the heated surface as volume fraction ϕ increases from 0% to 10% at Gr = 106 and τ = 1 for copper water nanofluid.

Abstract This paper contributes to the existing literature as well as policy debates by examining energy intensity and its determinants in China's regional economies. The analysis is based on a comprehensive database of China's regional energy balance constructed for this project. Through its focus on regional China, this study extends the existing literature, which mainly covers nationwide studies. It is found in this paper that energy intensity declined substantially in China. The main contributing factor is the improvement in energy efficiency. Changes in the economic structure have so far affected energy intensity modestly. Thus there is considerable scope to reduce energy intensity through the structural transformation of the Chinese economy in the future.