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Abstract: There is a large value in making Pulp and Paper mills more energy efficient. ABB has developed an energy assessment service where opportunities to save energy in the paper machine are identified. The energy assessment is done by quantifying energy flows, benchmarking energy users, data mining and steam sensitivity analysis and by experiments and additional measurements at the paper machine. Energy quantification helped in identifying main energy consumer, benchmarking was useful to assess the gap between operating performance and best performance whereas data mining and steam sensitivity analysis helped in studying the impact of key operating variables on performance of paper machines. After the assessment an action plan was presented to the mill for energy efficiency improvement together with a return on investment. [Copyright &y& Elsevier]

Abstract: The systematic, transparent and accurate on-line energy information of the production process is quite the basis of mill energy management and conservation. An Energy Management System (EMS) was built according to the characteristics of the energy usage in a typical newsprint paper mill. The EMS first realized the process data acquisition and integration, second fulfilled the on-line energy information calculation from the integrated data. A water and steam properties query component based on IAPWS-IF97 was developed and plugged into the EMS to facilitate the energy calculation of water and steam. The practical performance in the paper mill showed that the integrated energy information of the whole mill was gained and the on-line energy supervisory was achieved. In the end a systematic, transparent and accurate energy usage profile is obtained and it would provide the valuable fundamental energy data for the further energy analysis and optimization in the EMS. [Copyright &y& Elsevier]

Network-on-Chip (NoC) is the state of the art on-chip interconnection network for packet based communication. NoCs can offer low packet latency, high bandwidth, high throughput with minimum area, better energy efficiency and fault tolerance. Routers are the basic building blocks of the NoCs. In this paper, we present the design of a Congestion Aware Router for NoC which is then implemented using Vivado HLS. The router is then used to develop a scalable NoC based on mesh topology. Using the NoC as a test bed we carry out simulations and estimate performance metrics like latency, waiting time and total packets handled for various configurations of NoC. Provisions to alter parameters like buffer depth, packet size, packet injection interval and traffic are also added. Further, we propose a simple mechanism for detecting congestion at the router. The congestion metric is then used to adapt the XY dimension order routing into a Congestion Aware minimal adaptive X/Y routing strategy with very low hardware overhead. The proposed routing method is compared against conventional XY DOR, GCA routing and RCS based routing algorithms for different parameter variations. The results show that the proposed routing method can reduce packet latency for different traffic patterns at medium packet injection rates. • A Vivado HLS implementation of NoC Simulator. • Performance metrics like latency, waiting time and total packets are estimated. • Effect of traffic pattern, size of the mesh and packet size is carried out. • Proposed routing algorithm has been compared with GCA and RCS algorithms. • HLS NoC simulator results are compared against state-of-the-art Booksim simulator. [ABSTRACT FROM AUTHOR]

Robot comprehensive performance optimization is a high dimensional non-convex problem, which is of great significance in the practice of robotic intelligent manufacturing. Existing methods still face many challenges in performance evaluation, local optima, and planning efficiency. In this paper, a novel method based on accelerated gradient descent and directed-mutagenesis genetic algorithm (AGD-DGA) is proposed for efficient robotic motion planning and comprehensive performance optimization. Firstly, the time, energy consumption, and impact (T-E-I) are taken as the optimization objectives. In particular, the power loss sub-model is constructed, which is rarely considered in the previous research on motion optimization, and it is combined with the driving power sub-model to improve the evaluation accuracy. Next, a novel directed-mutagenesis genetic algorithm (DGA) is proposed to address the local optima problem. Compared with existing methods based on random sampling, the DGA further improves the success rate and efficiency by updating the probability model based on the adaptive Gaussian process. Moreover, a hierarchical weight updating mechanism is established to overcome the impact of additional performance indicators on the success rate of collision-free path planning. To improve planning efficiency, an incremental optimization mechanism and an adaptive fine-tuning strategy for population size are proposed to reduce unnecessary sampling, evaluation, and sorting. The simulation and experimental results in different scenarios demonstrate that the proposed AGD-DGA achieves better results than most of the mainstream algorithms in terms of optimization efficiency, success rate, and motion performance. In addition, it is also verified that the modified energy consumption model can achieve an average evaluation accuracy of more than 90% while maintaining the calculation efficiency. [ABSTRACT FROM AUTHOR]

Efficient medium access protocols are crucial in leveraging the advancement in the physical layer techniques that have been proposed for the next-generation wireless networks. However, collisions among data packets in random access protocols reduce channel efficiency and hence the throughput. In this paper, we propose a MAC protocol based on both the signal transmission diversity and Successive interference cancellation (SIC) to improve the throughput. In the proposed Medium Access Control (MAC) protocol, the receiver receives two sets of signals from the transmitters over two uncorrelated time slots. Inter slot SIC is first carried out at the receiver over two independent sets of received interfered signals. Signals are decoded by canceling those signals that have already been decoded in one set from the other set. Closed-form expressions for the packet decoding probability, system throughput, average packet transmission delay, and energy efficiency have been derived by considering order statistics of received signal power. Analytical results are validated against simulation. Maximum achievable throughput of the proposed scheme is shown to be four times that of slotted Aloha and twice that of a slotted Aloha with SIC. [ABSTRACT FROM AUTHOR]

Green roofs have been recognized as an effective way to increase urban green space and improve building micro-environment. This paper investigated the thermal and energy performance of an extensive green roof under free-floating 1 1 Free-floating here means no heating or cooling system affecting the internal conditions of the room. and air-conditioned conditions in Shanghai, a coastal city with hot and humid summer. A field experiment was conducted on two full-scale rooms of a building from 30/07/2014 to 31/08/2014. One room was covered by a green roof while the other one was covered by a common roof. The results show that solar radiation has the strongest correlation with green roof’s cooling effect, and the correlation between solar radiation and heat flux through green roof is negative in free-floating condition but positive under air-conditioned condition. Outdoor temperature is the most correlated factor of green roof’s temperatures but the least correlated one for green roof’s cooling effect. Energy balance analysis indicates that evapotranspiration and long wave radiation dissipate most of heat gain for green roof, and soil water content has a significant impact on energy balance. This paper presents the basic thermal characteristic of extensive green roof in Shanghai and also make it possible for further validation of hygrothermal transfer model of green roof system. [ABSTRACT FROM AUTHOR]

The statement that in the full world, increasing the ultimate efficiency, expressed as service / throughput , is the necessary condition for humanity to achieve high levels of well-being within ecological limits is honoured as Daly's Proposition in this paper. The purpose of this paper is to make Daly's Proposition effective guidance for policymaking related to sustainable development. For this aim, this paper puts forward the indicator Ecological Well-being Performance, which is composed of the Human Development Index and the Ecological Footprint, to measure the ultimate efficiency. Furthermore, by means of matrix analysis and factor decomposition analysis, the respective pathways for countries at different stages of development to make the sustainable development transition were discussed. The G20 countries were taken as the cases to conduct the research. The empirical results show that improvements in well-being and increases in throughput level are not necessarily positively related. The relationship between the two depends on how countries control throughput levels and improve the Ecological Well-being Performance, which also explains different performances on the sustainable development transition. In a simple way, this contribution provides new methods and criteria to track and evaluate national performance on sustainable development by referring to Daly's original theories. [ABSTRACT FROM AUTHOR]

Numerous reports over the past few years have noted that wireless data consumption continues to increase at incredible rates. Such growth rates tend to be felt most acutely in the cellular space where smartphones and tablets continue to increase in capability and popularity. Unfortunately, there exists limited public data with regards to fine-grained user performance, particularly with regards to the transition between 3G and LTE and the interplay between 3G, LTE, and WiFi. The focus of this paper is to offer insight into these particular transition points as gleaned from nearly two hundred well-instrumented smartphone users. Specifically, we note the considerable impact that the quality of smartphone WiFi plays in addition to noting that consumption across WiFi and cellular tends to stay remarkably consistent once sufficient cellular speeds are achieved. We conclude our paper with a variety of research and data challenges that we pose to the wireless networking community. [ABSTRACT FROM AUTHOR]

Abstract: Energy consumption has been the focus of many studies on Wireless Sensor Networks (WSN). It is well recognized that energy is a strictly limited resource in WSNs. This limitation constrains the operation of the sensor nodes and somehow compromises the long term network performance as well as network activities. Indeed, the purpose of all application scenarios is to have sensor nodes deployed, unattended, for several months or years. This paper presents the lifetime maximization problem in “many-to-one” and “mostly-off” wireless sensor networks. In such network pattern, all sensor nodes generate and send packets to a single sink via multi-hop transmissions. We noticed, in our previous experimental studies, that since the entire sensor data has to be forwarded to a base station via multi-hop routing, the traffic pattern is highly non-uniform, putting a high burden on the sensor nodes close to the base station. In this paper, we propose some strategies that balance the energy consumption of these nodes and ensure maximum network lifetime by balancing the traffic load as equally as possible. First, we formalize the network lifetime maximization problem then we derive an optimal load balancing solution. Subsequently, we propose a heuristic to approximate the optimal solution and we compare both optimal and heuristic solutions with most common strategies such as shortest-path and equiproportional routing. We conclude that through the results of this work, combining load balancing with transmission power control outperforms the traditional routing schemes in terms of network lifetime maximization. [Copyright &y& Elsevier]

Abstract: A Microgrid (MG) Energy Management System (EMS) is a vital supervisory control to make decisions regarding the best use of the electric power generation resources and storage devices within this MG. This paper presents an operational architecture for Real Time Operation (RTO) of an islanded MG. This architecture considers two different parts including Central Control Unit (CCU) and MG Testbed. CCU implements an EMS based on Local Energy Market (LEM) to control a MG. In order to reach this objective, this unit executes Day Ahead Scheduling (DAS) and Real Time Scheduling (RTS). Regarding DAS, a Modified Conventional EMS (MCEMS) based on LEM (MCEMS −LEM ) algorithm has been proposed to find out hourly power set-points of Distributed Energy Resources (DERs) and customers. LEM is also presented in MCEMS −LEM to obtain the best purchasing price in Day-Ahead Market (DAM), as well as to maximize the utilization of existing DER. With regard to RTS, it must update and feedback the power set-points of DER by considering the results of DAS. The presented architecture is flexible and could be used for different configurations of MGs also in different scenarios. Simulations and experimental evaluations have been carried out using real data to test the performance and accuracy of the MG testbed. This paper aims to operate the MG in islanded mode, ensuring uninterruptable power supply services and reducing the global cost of generated power. Results demonstrate the effectiveness of the proposed algorithm and show a reduction in the generated power cost by almost 8.5%. [Copyright &y& Elsevier]

Abstract: Reducing the energy consumption of air-conditioning systems is becoming increasingly important. This paper focuses on the air-conditioning system in Terminal 3 in Xi’an Xianyang International Airport, the first airport terminal to adopt radiant cooling in China. In the large spaces of this airport terminal, a temperature and humidity independent control (THIC) system has been adopted instead of a conventional nozzle air supply method, which significantly reduces the energy consumption of the air supply. The radiant floor is the main mechanism for indoor temperature control, while a liquid desiccant outdoor air processor combined with displacement ventilation is responsible for humidity control. Ice storage is adopted to reduce operating costs, and the supplied chilled water temperature can be as low as 3°C. This paper examines the performance of the THIC system in detail. The indoor environment is determined through measurements to be comfortable, and the on-site performances of key components in both the airport terminal and the cooling plant are investigated. The outdoor air processor supplies air of appropriate temperature and humidity ratio; two kinds of radiant floors are used for temperature control, both with measured cooling capacities of about 30–40W/m2; and the energy efficiency ratio (EER) of the cooling plant is 2.62. [Copyright &y& Elsevier]

Abstract: One of the most promising technologies for stationary power applications is the Molten Carbonate Fuel Cell (MCFC). This is due to its high efficiency, low emissions and the medium–high operating temperature. This high temperature allows for hybridization with other power generation technologies where the bottoming cycle recovers part of the heat in the fuel cell exhaust stream, hence resulting in highly efficient hybrid systems. The current MCFC hybrid system designs use microturbines as bottoming cycle. This paper presents the integration of a MCFC with a bottoming Humid Air Turbine (HAT) instead of the conventional microturbine. The HAT cycle, even if still under development, provides a relatively simple and inexpensive solution to increase the power output of the microturbine. An indirect integration between the MCFC and the HAT cycle is chosen aiming to simplify the layout and operation of the new system and considering that the necessary modifications to be performed in the microturbine are relatively simple (and therefore the additional equipment is expected to be relatively economical). The results presented in this paper show the potential of this MCFC–HAT combination with an increase of the net power output of 6 percentage points and an efficiency increase of 3 percentage points from the high efficiency conventional hybrid system (MCFC–MGT). An economic analysis as function of the MCFC investment cost is presented showing a break-even-cost of 2092 €/kW improving the estimated for the MCFC–MGT. [Copyright &y& Elsevier]

Abstract: This paper presents the development of a micro-power pack using automotive alternators powered by a micro-gas turbine (MGT) to recharge battery packs, in particular for electric vehicles (EVs). The thermodynamic efficiency for the MGT with the power turbine is estimated from a simple Brayton cycle analysis. The rotordynamic and power generation performance of the MGT driven alternator was measured during a series of experiments under electrical no-loading and loading conditions, and with belt-pulley and flexible bellows couplings. The flexible coupling showed superior rotordynamic and power generation performance than the belt coupling due to the enhanced alignment of the alternator rotor and the reduced mechanical frictions. Furthermore, the micro-power pack showed dramatic increases in the mass and volumetric power densities by ∼4 times and ∼5 times, respectively, compared with those of a commercial diesel generator with similar power level. As a result, this paper assures the feasibility of the light-weight micro-power pack using a MGT and automotive alternators for EVs. [Copyright &y& Elsevier]

Abstract: Even enterprises with very advanced management systems seldom monitor efficiency of energy usage and materials flows within their processes and have, therefore, difficulty to effectively manage their resource efficiency. This paper is built upon experiences from a pilot implementation of a new tool for promotion of energy management and cleaner production, developed within the Energy Management and Performance Related Savings Scheme project to promote an effective energy management system in industrial enterprises. The combination of soft managerial approaches (Monitoring and Targeting technical services) with financing provided on a no cure, no pay basis provided by Energy Service Companies, is the foundation for this new tool for promotion of energy management and cleaner production on no cure, no pay basis. It enabled us to test the introduction of cleaner production projects with no technical or financial risks for enterprises or for the need of financing from the side of the enterprises. Consequently, it removed some of the important barriers for implementing cleaner production. This paper distinguishes between auditing and accounting approaches in the promotion of cleaner production and argues that auditing approaches are not sufficient for completion of the learning needed for integration of cleaner production into the practice of an enterprise. [Copyright &y& Elsevier]

Abstract: This paper is based on the analysis of the solar combisystem installed in a 4-storey apartment building in Sigulda, Latvia. The combisystem consists of: 42m2 of flat plate solar collectors, a 2.35m3 accumulation tank and a 100kW pellet boiler as the auxiliary heater. This paper focuses on the optimisation of the thermal performance of the pellet boiler. During laboratory tests on the 25kW pellet boiler, the influence of the supply ratio of the combustion air, the chemical and heat losses in the flue gases on the performance of the boiler was established. The results demonstrate the optimum thermal performance, CO emissions, chemical and heat losses, which are related to the amount of free oxygen (O2) in the flue gases. The results of the laboratory tests were then applied to optimise the operation of the 100kW pellet boiler. The flue gas measurements for the 100kW boiler were performed in order to identify the O2 concentration, CO emissions and flue gas temperature. The results showed that what is required to optimise performance is to reduce the amount of air supplied to the boiler’s combustion chamber. Changes were made to the boiler’s control algorithms to achieve the desired result. Additionally, boiler performance was improved by changing the location of the air intake point. Decreasing temperatures in the heat accumulation tank were achieved by making modifications to the boiler’s control algorithms. [Copyright &y& Elsevier]

Abstract: In this paper an attempt has been made to assess the performance of an office building located in London (one of the case study buildings in CIBSE TM36: 2005) in relation to energy consumption, carbon emissions and potential for adaptability to the 2050s climate. Overheating is a particular issue in office buildings due to internal heat gains from computers and other electrical equipmen t. In addition, buildings in London are affected by the urban heat island, which is likely to intensify with warmer summer temperatures, reducing the capacity for night-time cooling of buildings. This paper proposes various passive design strategies which aim to address both mitigation (by reducing carbon emissions) and adaptation (by improving human comfort and reducing energy consumption). [Copyright &y& Elsevier]

Abstract: Urban neighborhoods could represent an optimal scale for the implementation of innovative energy strategies. However, barriers at the economic, regulatory and administrative level are still present. In this framework, it is important to operate on three levels of the energy system: by reducing energy demand; by optimizing generation and management system, and by integrating local renewable energy sources. In recent years, as a result of an important agreement with the Italian Ministry of Environment, Lombardy Region has supported numerous measures for energy efficiency and renewable resources integration among its territory. The funding supported different actions such as improvements of the buildings envelope, substitution of old gas boilers for heat generation with more efficient components, integration of solar thermal systems in buildings, hydrogen and more sustainable mobility, and district heating plants, which present contribution concerns. About district heating the incentives were provided within two different calls: one aimed at the creation of plants and district heating networks and another for the extension of existing systems. Main aim of the research is to evaluate effects, effectiveness, pros and cons of the several calls for funding; to that end a methodology was developed in order to collect the data and elaborate representative energy, environmental and economic indicators. The most important characteristics, conditions and technical features of the considered plants are described in the present paper trying to provide information on the effectiveness of the supporting measures taken in order to orient future choices and to identify the most promising strategies and technologies for improving energy and environmental performances of communities. In particular present paper is related to 10 district heating plants: 6 are based on biomass and located in mountain areas, 3 are based on natural gas and located in urban areas, while the last is connected to the urban waste to energy plant. One of the important lesson is learned is that district heating (fuelled by biomass, fossil, waste and CHP or not) represents an innovative field of knowledge far from standard: in general each plant has to be evaluated on the basis of specify characteristics and it is very hard to find out average performances from the environmental and economic point of view. The results obtained during the monitoring campaign could help in providing information on the effectiveness of the supporting measures adopted and also to orient future choices by Lombardy Region and, in particular, to identify the most promising technologies for improving energy and environmental performances of communities and to develop a model for the optimization of energy use in the built environment. [Copyright &y& Elsevier]

Abstract: This paper presents an in-depth performance evaluation of three different optimization algorithms, in particular genetic algorithm (GA), particle swarm optimization (PSO), and firefly (FF) algorithm for power demand forecasting in a deregulated electricity market and smart grid environments. In this framework, this paper proposes a hybrid intelligent algorithm for power demand forecasts using the combination of wavelet transform (WT) and fuzzy ARTMAP (FA) network that is optimized by using FF optimization algorithm. The effectiveness and accuracy of the proposed hybrid WT+FF+FA model is trained and tested utilizing the data obtained from ISO-NE electricity market. [Copyright &y& Elsevier]

Abstract: As the number of buses increase substantially in multi-core SoC designs, the bus planning problem has become the dominant factor in determining the performance and power consumption of SoC designs. To cope with the bus planning problem, it is desirable to consider this issue in early floorplanning stage. Recently, the bus-driven floorplanning problem has attracted much attention in the literature. However, current algorithms adopt an over-simplified formulation which ignores the orientation of the bus pin, the chip performance may be deteriorated. In this paper, we propose the bus-driven floorplanning algorithm that fully considers the impact of the bus pin. By fully utilizing the position and orientation of the bus pin, bus bendings are not restricted to occur at the module of the same bus, then more flexible bus shape is obtained. With more flexibility on the bus shape, the size of the solution space is increased and a better bus-driven floorplanning solution can be obtained. In conference version, compared with the bus-driven floorplanner , experimental results show that our algorithm performs better in runtime by 3.5×, bus wirelength by 1.4×, and deadspace by 1.2×, respectively. In this paper, we improve the algorithm in to obtain better driver-load delay variation among all bus bits. [Copyright &y& Elsevier]

Abstract: Energy efficient medium access control (MAC) protocol designs for wireless sensor networks (WSNs) have already generated interests among researches due to ever increasing range of applications of WSNs. Nodes in a WSN typically operate unattended with a limited power source, energy efficient operations of the sensor nodes especially at the MAC level is very important because majority of energy expenditure take place at the radio level. MAC protocols in WSNs for diverse applications with different objectives have been proposed by researchers. In this paper, we investigate three energy-efficient synchronous MAC protocols for WSNs emphasizing their strength and weakness. Our analysis as well as simulation studies reveal the suitability of these protocols in deployed sensor fields. As a result of our investigation, we found out some open research issues in energy-efficient MAC layer design which we highlighted toward the end of this paper. [Copyright &y& Elsevier]

Abstract: In this paper, the ways of employing energy storage devices in hybrid powered orthoses have been discussed. Since these devices have many unrivalled advantages, they are environmentally safe, they store kinetic energy as potential energy and release it when it is needed and they do not need external power supply. In this paper an energy storage device (linear extension spring) has been implemented in FES-cycling, the efficiency has been calculated for different spring positions and different spring constants. It was clear that FES-cycling efficiency increases when the spring constant increases, then the pedal, spring and the overall powers were calculated, and it appears that by leaning the spring position the overall power will be always positive, and the spring absorbs the exceeded pedal energy and releases it when the pedal power is negative. This study highlights the importance of using energy storage devices to improve FES-cycling performance, which has been proven that such improvement is highly related to the mechanical design of the bicycle. [Copyright &y& Elsevier]

Abstract: This paper reviews crucial role of building performance simulation (BPS) – dynamic analysis of the inextricable linkage of building''s energy demand for HVAC and other building''s technical systems sustainable energy supply and renewable energy sources (RES) availability to reach building''s zero energy status. Reviewed are BPS advances in buildings energy efficiency optimization, solar, geothermal and other renewable energy sources integrated implementation, as well as hybridization and mixed distributed energy generation, co- and tri-generation for building''s greening and sustainable neighborhoods, settlements, as well as “high performance” Zero Energy Cities Planning. As an introduction, outlined is the intrinsic harmony of the traditional village houses balanced use of renewable materials and energy sources and presented are feasibility study results on the sustainable Zero Energy ECO Settlement at the Mediterranean Sea proceeded by the description of the site''s sustainability''s constrains assessment. Architectural design and building''s dynamic behavior and energy efficiency optimization resulting in minimization of thermal and lighting loads, precede to the multidisciplinary engineering investigation and preliminary design of sustainable Zero Energy Buildings confirming feasibility of settlement''s sustainable energy and water supply by the reliable implementation of solar PV and wind technologies, including PV powered sea water desalination. Further, interwoven with presentation of a few case studies, paper outlines advances in BPS and Co-simulation. Reviewed are optimization of mixed, natural and mechanical ventilation via CFD integrated with architectural modeling; BPS and Co-simulation approach to the “total building performance optimization” encompassing multifunctional facades, day-lighting, IE&AQ and HVAC systems operation offering an enormous potential for energy saving by residential/municipal RES integrated renovation. Stressed has been that it is impossible to reach sustainability without harmonious interdisciplinary interacting, without balance between materiality and spirituality, science and art, technology development and cultural and other human values improvement, without ethics of sustainability. [Copyright &y& Elsevier]

Abstract: Knocking combustion in spark-ignition (SI) engines is an abnormal combustion phenomenon which can constrain the engine performance and thermal efficiency. It can also result in severe permanent engine damage under certain operating conditions. This paper systematically reviews the engine knock phenomenon, including the mechanisms, influencing factors, consequences and detection methods etc. It introduces the visualization researches, simulations and some judging indexes of engine knock. Three mathematical models which can predict the engine knock, and various kinds of methods of suppressing knock are summarized. Finally, this paper puts forward some new suggestions on the weakness in the researches of knocking combustion. [Copyright &y& Elsevier]

Abstract: The article described the dilatancy technology of district heating system with high-temperature heat pump (HTHP). For the exploitation of low-temperature return network sources, a high-temperature heat pump with a heat exchanger was planned. As the core technology of the dilatancy district heating system, HTHP units and heat exchanging systems had been described detailedly through theoretical and experimental analysis. The model was proved to be in good agreement with the experiment data. It could be used for engineering design. In this paper the district heating system in Datong was taken as a case study. The main characteristics of the dilatancy district heating system had been presented in the form of diagrams. The principal advantage of dilatancy technology in the district heating system lies in increasing the temperature difference, reducing the diameters and the initial investment of primary side network. This paper shows clearly the analysis of the dilatancy technology for characterising and improving the performance of district heating systems. [Copyright &y& Elsevier]

Abstract: Prefect fore-separation technology is the precondition and key to realize garbage synthesis treatment and increase resource utilization ratio. To the lower purity quotient and efficiency of plastic and paper separation, main factors influencing performance of horizontal flow separation are analyzed in detail, and reasonable processing and design parameter are studyed in this paper. Horizontal flow separator of urban garbage that structure is reasonable and parameter can be adjusted is designed. Technology reference and support is provided to production of urban garbage treatment factory. [Copyright &y& Elsevier]

Abstract: This paper is dedicated to explore the dynamic performance of energy efficiency in Africa, with panel data in country level, taking energy yield, power consumption, electricity transmission and distribution losses into account, the paper employ stochastic frontier mode,highlighting a dummy variable in energy output in terms of net imports of energy and power, which minify the deviation of estimated variables. The results show that returns of scale did not appear in energy and power industry in Africa, electricity transmission and distribution losses contribute most to GDP per unit of energy. In country level, Republic of Congo and Botswana suggest an obvious energy efficiency advantage. Energy efficiency in Mozambique and Democratic Republic of Congo are not very satisfying during the studying year [Copyright &y& Elsevier]

Abstract: An optimal control strategy based on Pontryagin''s Minimum Principle (PMP) is a promising solution because it provides a simple solution for controlling Hybrid Electric Vehicles (HEVs) and guarantees the best performance under reasonable conditions . However, it needs to be very careful when applying the control strategy if inequality state constraints are active because handling the state constraints is one of the difficult issues in optimal control problems. In contrast to HEVs, Plug-in Hybrid Electric Vehicles (PHEVs) possibly consume all of the available electric energy, and so the activation of the state constraint on minimum State of Charge (SOC) is, unfortunately, a very common control problem for PHEVs. This paper describes mathematical derivations for an additional condition necessary for the inequality state constraints and solves the problem with several control options. Whereas PMP-based control allows a unique solution for HEVs , this paper shows that the control idea based on PMP produces a number of alternative solutions for PHEVs. However, battery efficiencies can be considered to evaluate the optimality of each solution, and simulation results from several control options show that maximizing a blended-mode control is the best solution to saving fuel for PHEVs. In terms of performance, the results of applying blended-mode control are very close to those obtained by applying a global optimal solution obtained from Dynamic Programming (DP). [Copyright &y& Elsevier]

Abstract: Evaluating a building’s performance usually requires a high number of sensors especially if individual rooms are analyzed. This paper introduces a simple and scalable model-based virtual sensor that allows analysis of a buildings’ heat consumption down to room level using mainly simple temperature sensors. The approach is demonstrated with different sensor models for a case study of a building that contains a hybrid HVAC system and uses fossil and renewable energy-sources. The results show that, even with simple sensor models, reasonable estimations of rooms’ heat consumption are possible and that rooms with high heat consumption are identified. Further, the paper illustrates how virtual sensors for thermal comfort can support the decision making to identify the best ways to optimize building system efficiency while reducing the building monitoring cost. [Copyright &y& Elsevier]

Abstract: The paper suggests a multi-criteria approach for the energy refurbishment of historical buildings, proposing methodologies for the performance analysis, coupling several experimental and numerical studies. The target consisted in a rigorous evaluation procedure, in order to guarantee the necessary reliability of a numerical model of the system “building envelope/technical plants”, on which testing the technical and economical convenience of energy retrofit solutions. The paper collects the long work carried out by several Institutions during the last years, on Building “Palazzo dell’Aquila Bosco-Lucarelli”, a historical building located in Benevento (Southern Italy), currently analyzed in order to define the technical adoption of possible improving actions. The carried out studies, beyond the proposition of an operational methodology, are aimed to evidence a best-practice specified for the Italian territorial context, which has several historical buildings needing restoration. Carefully applied investigations, based on various methodologies and through several instrumentations, allowed the definition of a numerical model correspondent to the real building, defined also comparing the results with the historical requests of gas and electricity. Moreover, dynamic energy simulations tested the effectiveness, singularly and coupled, of several solutions for the building energy optimization. A significant potentiality of energy and economic optimization has been demonstrated. [Copyright &y& Elsevier]

Abstract: This paper describes the design and building technology details of a three-storey single family house located in the Pyrenees, in Andorra. The house is owned by the first author, and has been occupied since 2004. A combination of active and passive solar energy systems and night-time electricity are used to supply the heating and cooling demands. The main goal of this paper is to provide detailed design information and an evaluation of performance. Data provided includes site information and climate, basic design options and decisions, energy saving strategies and energy end use data. The house has been in use since 2003. This allows adequate performance data to be presented and evaluated. Some general results and initial design problems are discussed. [Copyright &y& Elsevier]

Abstract: In this paper, an attempt is made to evaluate the exergetic performance of a solar photovoltaic thermal (PV/T) air collector. A detailed energy and exergy analysis is carried out to calculate the thermal and electrical parameters, exergy components and exergy efficiency of a typical PV/T air collector. Some corrections are done on related heat loss coefficients. An improved electrical model is used to estimate the electrical parameters of a PV/T air collector. Further, a modified equation for the exergy efficiency of a PV/T air collector is derived in terms of design and climatic parameters. A computer simulation program is also developed to calculate the thermal and electrical parameters of a PV/T air collector. The results of numerical simulation are in good agreement with the experimental measurements noted in the previous literature. Finally, parametric studies have been carried out. It is observed that the modified exergy efficiency obtained in this paper is in good agreement with the one given by the previous literature. It is also found that the thermal efficiency, electrical efficiency, overall energy efficiency and exergy efficiency of PV/T air collector is about 17.18%, 10.01%, 45% and 10.75% respectively for a sample climatic, operating and design parameters. [ABSTRACT FROM AUTHOR]

Abstract: The challenges confronting in mobile grid systems are: limited CPU power, limited memory, small screen, short battery life, and intermittent disconnection. Considering all these limitations, this paper is targeted to control energy consumption without compromising system’s performance in mobile grid. In this paper, we focus on using the mobile devices on the mobile grid environment. Mobile devices can serve two important functions in mobile grid environment either as service consumer or as valuable service providers. The proposed approach is not only to reduce energy consumption, but also to improve system performance in mobile grid environment. Utility functions are used to express grid users’ requirements, resource providers’ benefit function and system’s objectives. Dynamic programming is used to optimize the total utility function of mobile grid. A distributed controlling energy algorithm in mobile grid environment is proposed which decomposes mobile grid system optimization problem into sub-problems. In order to verify the efficiency of the proposed algorithm, in the experiment, the performance evaluation of controlling energy algorithm is conducted. [Copyright &y& Elsevier]

Wireless Sensor Network (WSN) is instrumental in transferring the data gathered by Sensors mounted on the Sensors Nodes (SNs) to the Base Station (BS). Lifetime of WSN is solely depends on the energy/battery life of SNs and higher the battery life longer the lifetime of Network. The sustained operation of WSN is achieved through the efficient consumption of SNs energy. In the recent past several energy conservation mechanism were proposed and among them LEACH-WSN was the most widespread methodology [1]. Further, the work pertaining to the sustained energy conservation mechanisms which are enriched with bio inspired technique or neural computational systems such as PSO-PSO-WSN, PSO-GSO-WSN, GSO-KGMO-WSN, FCM-PSO-GSO-WSN EBC-S or RSOM-WSN are reported [2-6]. In order to conserve energy in WSN; SNs are clustered using a set of criteria and gather the data at each Cluster Head (CH) to avoid redundant transfer of data to the BS. Further, gathered data is routed to the BS efficiently using intelligent routing process. In this paper, PSO-PSO-WSN, LEACH-WSN and EBC-S are compared with PSO-GSO-WSN, GSO-KGMO-WSN, FCM-PSO-GSO-WSN and RSOM-WSN. These methods are subjected to the Performance Evaluation (PE) in terms of alive nodes, dead nodes, energy consumption, throughput and total data/packet delivered. [ABSTRACT FROM AUTHOR]

Recently, performance evaluation of coal-fired power generation with high pollution based on data envelopment analysis (DEA) method has become an advanced research hotspot in China. Instead of a single process in previous studies, we divide the production system of coal-fired power plants into the production process and pollutants abatement process, with pollutant intermediates as the link to connect the two processes in the current paper. Then we present a new two-stage network DEA model to evaluate the performance of China's coal-fired power generation by improving the link constraint that different with traditional network DEA approaches. Meanwhile, we conduct an empirical study to verify the applicability of the proposed approach and find that the proposed model is more effective than the previous models in evaluating the inefficiencies of coal-fired power generation. The empirical results also show that: the inefficiencies of the pollutants abatement process bring poor performance of the regional coal-fired power plants; and the efficiency results vary greatly among different areas of China, efficiency is best in the west area but the worst in the northeast area. Finally, some appropriate propositions are present in order to create better conditions for China's sustainable development. [ABSTRACT FROM AUTHOR]

In recent years there has been increased concern on energy efficiency of industries. Since the scheduling problems in the shop floors are directly related to the energy consumption, an appropriate way to improve energy efficiency in industrial plants is to develop effective scheduling strategies. Hence, the aim of this paper is to design an energy-efficient scheduling in a shop floor industrial environment, i.e., flexible job-shop scheduling problem (FJSP). To this end, a multi-objective optimization model is developed with three objective functions: (i) minimizing total completion time, (ii) maximizing the total availability of the system, and (iii) minimizing total energy cost of both production and maintenance operations in the FJSP. To cope with this multi-objective optimization problem, an enhanced evolutionary algorithm incorporated with the global criterion, as a multi-objective handling technique, is proposed and then performance evaluation is performed based on an extensive numerical analysis. [ABSTRACT FROM AUTHOR]

The optimization design of engine is always one of the top concerns in motorcycle industry. In this paper, effective torque and fuel consumption ratio are defined as the performance evaluation indexes of engine, while air-fuel ratio, intake valve timing angle, exhaust valve timing angel, pressure, and temperature are defined as input variables. With the application of DOE methodology, a full factorial DOE is conducted to estimate the regression model and identify the statistical significant factors. And then, with the selection of additional experimental points, RSM is introduced to construct the precise regression model between input variables and performance indexes. Based on that, an optimum solution that can satisfy both performance requirements are brought forward and testified. [ABSTRACT FROM AUTHOR]

Deep underground mining is highly energy intensive due to the need to overcome high pressure rise required by ventilation fans, high cooling load in summer due to rise in rock temperature and the auto-compression effect, and heating requirement in winter. Rising energy costs have led the mining industry to look for alternatives in energy-efficient systems to reduce the operating costs as well as to reduce the carbon footprint. This paper addresses the challenge by utilizing naturally available renewable energy source from seasonal cycle for heating and cooling of underground mines: heat in the summer is stored in the rock-pit to be used for heating in winter, and the “cold” energy in winter is captured within the rock-pit for cooling during summer. A three-dimensional unsteady local thermal non-equilibrium model is developed to evaluate thermal storage and heat transfer between ventilation air and rock-pit. The results suggest that the seasonal thermal energy storage of rock-pit is able to assist thermal management in underground mine and to reduce energy consumption for winter heating and summer cooling. The ventilation air temperature is about 15–20 °C higher/lower as compared to ambient temperature in winter/summer, respectively. Clearly, this shows potential application of large scale seasonal thermal energy storage systems in mining industry. [ABSTRACT FROM AUTHOR]

This investigation presents an estimation of the energy performance of an office building which is equipped with a heat pump system. The paper presents the simulation methodology of a multi-zone office building for temperate climate conditions of Belgrade city. Our baseline model was developed according to the guidelines of designing office spaces, accessories and communication. The parameters of the building envelope, heat pump system and indoor environmental criteria were mandatory elements of the simulation. The medium office building model is constructed according to the Serbian energy efficiency regulation, Official gazette RS no. 61/2011. The EnergyPlus simulation results outline the importance of applying simulation techniques in energy performance assessment for qualitative decision-making. Findings highlight the office building's energy performance equipped with an air-to-air heat pump system, with and without heat recovery equipment. [ABSTRACT FROM AUTHOR]

This paper addresses quality and impact issues concerning Energy Performance Certificates (EPC) by means of a dataset based upon the Swedish EPCs for single-family houses. Assuming that the quality of the certificates plays an important role for their impact, we examine to what extent various characteristics of the firms and experts issuing the certificates are influencing their assessments of energy consumption and energy conservation. Exploiting the information on biased assessments, we also investigate the relationship between the transaction price of a house and its EPC label. Doing so, we distinguish the attributes that can be observed by visiting the house and those that a buyer only can inform herself about through the EPC. Applying regression analyses we find that firm and expert characteristics matter quite a lot implying that the EPC-quality could be improved considerably by increasing the inter-rater reliability. The results also show that the price impact of the energy label is related to information that the buyers can obtain by visiting the house rather than to information uniquely provided by the EPCs. Hence, the EPCs per se are unlikely to stimulate energy conservation through the price mechanism. [ABSTRACT FROM AUTHOR]

With increasing concern for building energy efficiency, domestic hot water (DHW) supply systems, which have significant energy-saving potential, have drawn more attention from both practitioners and academia. In this study, we conducted a field study on seven centralized hot water supply systems in Beijing, measuring the water temperature and flow rate in primary or secondary pipes and collecting the operating records of hot water usage, gas consumption, and electricity consumption. In addition, we discuss the main problems existing in the current centralized DHW system. Based on measured data, this paper further analyzes energy losses from each link in the hot water supply system. A mathematical model is then proposed for simulating the energy consumption of hot water supply systems under various conditions such as various boiler efficiency, thermal insulation thickness, water pipe network structure, and hot water usage. The model is also used to explore the main factors that lead to low performance of centralized DHW systems in China. Finally, we analyze the applicability of diverse heat sources (e.g., electricity, gas, and heat pumps) in centralized DHW systems in China. [ABSTRACT FROM AUTHOR]

Information broadcasting in MANETs is an essential building block for cooperative operations, group discussions, and common announcements (e.g., filling routing tables). The flooding is the simplest broadcasting scheme used in MANETs. In this scheme, source nodes broadcast at once packets to all neighbors. Broadcasting through flooding causes increased messages redundancy, collision, and wastage of bandwidth and energy. Several approaches have been proposed to solve these issues and could be classified into two main categories: static schemes and adaptive schemes. In this paper, we introduce an adaptive scheme for information broadcasting in MANETs. This scheme allows nodes to select an appropriate action, either to rebroadcast or to discard receiving messages. The decision is based on the amount and timestamps of received messages. Simulations have been conducted and results show that the proposed scheme reduces the number of packet transmissions, has better latency and SRB, good reachability, and low energy consumption. [ABSTRACT FROM AUTHOR]

In response to strong growth in energy intensive wastewater treatment, public agencies and industry began to explore and implement measures to ensure achievement of the targets indicated in the 2020 Climate and Energy Package. However, in the absence of fundamental and globally recognized approach evaluating wastewater treatment plant (WWTP) energy performance, these policies could be economically wasteful. This paper gives an overview of the literature of WWTP energy-use performance and of the state of the art methods for energy benchmarking. The literature review revealed three main benchmarking approaches: normalization, statistical techniques and programming techniques, and advantages and disadvantages were identified for each one. While these methods can be used for comparison, the diagnosis of the energy performance remains an unsolved issue. Besides, a large dataset of WWTP energy consumption data, together with the methods for synthesizing the information, are presented and discussed. It was found that no single key performance indicators (KPIs) used to characterize the energy performance could be used universally. The assessment of a large data sample provided some evidence about the effect of the plant size, dilution factor and flowrate. The technology choice, plant layout and country of location were seen as important elements that contributed to the large variability observed. [ABSTRACT FROM AUTHOR]

With the rapid development of large data center, the required power consumption increases sharply. The thermal management of that accounts for about 33% of energy consumption. Single phase liquid convection heat transfer of microchannel heat sink has been thought as one of the most promising methods. For energy efficient cooling, optimized microchannel structures is one important approach. Hence, the novel offset zigzag microchannnel is proposed and optimized for inlet Reynolds number ranging from 200–800 in this paper. The heat sink is composed of 30 parallel channels, and basic structure parameters of rectangular channel are width of 0.1 mm, depth of 0.3 mm, length of 5 mm and pitch of 0.2 mm. The numerical model considers entrance effect, viscous heating and the temperature-dependent thermal-physical properties. In order to study the influence of geometry on flow and heat transfer characteristics, two non-dimensional variables are defined, such as the length ratio of zigzag length to channel length ( α ) and the length ratio of zigzag expansion to zigzag length ( γ ). Results indicate the zigzag channel can effectively prevent the rise of heat surface temperature along the flow direction and increase the minimum temperature, which improves the temperature distribution uniformity. Under Re in = 650 and α = 0.04, the minimum temperature increases from 309.9 K to 310.1 K and maximum temperature decreases from 324.02 K to 318.91 K. For 0.04 ⩽ α < 0.1 and α < 0.04 of Re in < 500, the thermal characteristic is enhanced and the flow resistance also is reduced. Compared with rectangle channel, the maximum temperature and pressure drop of zigzag channel with α = 0.04 of Re in = 650 are also reduced from 324.02 K to 318.76 K and 29.81 kPa to 26.75 kPa, respectively. It can be interpreted that with the decrease of α , the porosity and convection heat transfer areas are increased and turbulence intensity of fluid flow is enhanced. The smaller γ is more favorable for the enhancement of heat transfer except for γ = 0 due to the fluid stagnation at the bottom of zigzag cavity. However, compared with rectangular microchannel, heat transfer is enhanced for all cases and flow resistance is decreased besides γ = 0.1 of Re in > 500. For γ = 0 of Re in = 650, the maximum temperature and pressure drop are reduced from 324.02 K to 318.01 K and 298.81 kPa to 27.91 kPa, respectively. The overall thermal performance is measured with total thermal resistance vs pumping power. The best performance of offset zigzag microchannel is found at α = 0.04 and γ = 0.1. For Re in = 800, the maximum temperature of heat surface is decreased 5.65 K, the minimum increased 0.36 K, and pumping power is decreased 1.4%. And thermal resistance is reduced by 17.4% at the P p = 0.167 W. [ABSTRACT FROM AUTHOR]

Nowadays cities tend to become “Smarter”, usually disregarding the issues of energy efficiency and sustainability. Therefore, optimizing energy use in a city remains a challenge and respective decision support systems are important to guide local authorities toward that direction. This paper provides a holistic approach presenting a Smart City Energy Assessment Framework (SCEAF) along with a specific web based decision support tool, the so-called e-SCEAF , which can provide local authorities with fruitful results for assessing the energy behavior and performance of their city. The tool merges heterogeneous information, such as clearly quantifiable energy related indicators, the related city policy context performance and the integration of smart infrastructure. This multi-source information fusion is based on the 2-tuple linguistic representation model of Herrera and Martínez. This particular model has been widely used in decision problems and was mainly selected due to the fact that it provides linguistic results that are accurate and easy to understand by the cities’ local authorities. The performance, usefulness and effectiveness of the SCEAF framework and the e-SCEAF tool are tested on a real life application in three different cities, Savona (Italy), Sant Cugat del Vallès (Spain) and Zaanstad (The Netherlands). In this respect, the role of fusion methods and algorithms for merging multiple information will be evaluated in a “real life environment”. [ABSTRACT FROM AUTHOR]

This paper presents a novel methodology for improving efficiency and power consumption of networks-on-chip (NoCs). The proposed approach applies queue length considerations of a modified version of RED algorithm. Moreover, a stochastic learning-automata-based algorithm has been used to optimize the threshold values required in RED algorithm. Furthermore, a new architecture has been provided for dynamic flow control of virtual channels. The proposed method contributes to reduction in queue blockages and power consumption in addition to determining an appropriate size for virtual channels. The proposed algorithm was evaluated under various synthetic traffic patterns for different injection rates and trace-driven SPLASH-2 benchmark suite. The experimental results demonstrate that the algorithm reduces latency and power consumption by 23% and 52%, respectively, compared to the conventional NoC. Further, compared to Express Virtual Channels (EVC) scheme, it showed 13% and 36% improvement in latency and power consumption, respectively. [ABSTRACT FROM AUTHOR]

When frost forms and accumulates over the outdoor coil’s surface in an air source heat pump (ASHP) unit, system operating performance will be dramatically deteriorated. Reverse cycle defrosting is the most widely used standard defrosting method. A previous related study reported that downwards flowing of melted frost due to gravity over a vertical multi-circuit outdoor coil would decrease the reverse cycle defrosting performance. If the outdoor coil can be changed to horizontally installed, the flow path of melted frost over coil surface can be shortened, and the flow directions of refrigerant and melted frost changed from opposite to orthogonal. Consequently, a better defrosting performance is expected. In this paper, therefore, an experimental study on defrosting performance for an ASHP unit with a horizontally installed multi-circuit outdoor coil was conducted. Experimental results show that, when a vertical outdoor coil was changed to horizontally installed, the defrosting efficiency increased 9.8%, however, with the same defrosting duration at 186 s. Furthermore, when the outdoor air fan was reversed to blowing the melted frost during defrosting, the total mass of the retained water collected decreased 222 g. However, the defrosting efficiency was not increased, but decreased 6.6% because of the heat transfer enhanced between hot coil and cold ambient air. [ABSTRACT FROM AUTHOR]

The increase in energy demand has led to expansion of renewable energy sources and their integration into a more diverse energy mix. Consequently the operation of thermal power plants, which are spearheaded by the gas turbine technology, has been affected. Gas turbines are now required to operate more flexible in grid supporting modes that include part-load and transient operations. Therefore, condition based maintenance should encapsulate this recent shift in the gas turbine’s role by taking into account dynamic operating conditions for diagnostic and prognostic purposes. In this paper, a novel scheme for performance-based prognostics of industrial gas turbines operating under dynamic conditions is proposed and developed. The concept of performance adaptation is introduced and implemented through a dynamic engine model that is developed in Matlab/Simulink environment for diagnosing and prognosing the health of gas turbine components. Our proposed scheme is tested under variable ambient conditions corresponding to dynamic operational modes of the gas turbine for estimating and predicting multiple component degradations. The diagnosis task developed is based on an adaptive method and is performed in a sliding window-based manner. A regression-based method is then implemented to locally represent the diagnostic information for subsequently forecasting the performance behavior of the engine. The accuracy of the proposed prognosis scheme is evaluated through the Probability Density Function (PDF) and the Remaining Useful Life (RUL) metrics. The results demonstrate a promising prospect of our proposed methodology for detecting and predicting accurately and efficiently the performance of gas turbine components as they degrade over time. [ABSTRACT FROM AUTHOR]

Existing calculated benchmarking methods and main energy performance assessment schemes often lack the practical ability to manage the energy performance of a vast number of widespread telecommunication base stations (TBSs). Therefore, on the basis of a TBS survey, this paper puts forward the dynamic simulation and sensitivity analysis method to allow the new rule “one energy benchmark for a group of similar TBSs” rather than the traditional rule “one benchmark for one assessed building”. The new method reasonably limits the number of benchmarks and a feasible benchmark system is established for managing numerous TBSs. The results indicate that, first, more than one million TBSs distributed in a large area of China can be divided into 448 typical scenarios. Second, the benchmarks for reasonable energy use of these scenarios can be organized into four simple benchmarking charts. Third, the attempt to establish further challenging energy benchmarks shows that the most energy-saving measure in TBSs, i.e., ventilation cooling, can fully eliminate the negative impact of poor configurations of envelops and cooling coefficients of performance (COP). Finally, establishing telecom industrial standards for locating the reasonable TBS energy consumption level even in giant countries appears feasible. [ABSTRACT FROM AUTHOR]

The regenerative liquid ring (RLR) pump is a type of rotodynamic machine which has the ability to develop high heads at relatively low flow rates in only one impeller stage. Although the exact principle of operation of this type of pump has been a phenomenon not fully understood, it has nevertheless been widely applied for over a century in areas of liquid pumping. Despite the low efficiency, RLR pumps have several advantages over other turbomachines with similar tip speed due to relatively low manufacturing costs, simplicity, high reliability, enhanced priming behaviour and can in many applications offer a more efficient alternative. Efficiency improvements are key to reducing energy consumption and ultimately combatting the global climate change. This paper offers an extensive review into the development, performance challenges and design improvements of RLR pumps in order to provide some useful insight on future research and next steps, with a particular focus on improving efficiency throughout the pump life cycle. [ABSTRACT FROM AUTHOR]

This paper evaluated the performance of the building integrated solar thermal shading (BISTS) system on building energy consumption and daylight levels through energy and daylighting modeling and simulations. A medium office reference building in Los Angeles defined by the DOE was used in the case studies. The horizontal BISTS louvers on the south windows and vertical BISTS louvers on the east and west windows were modeled and simulated. The final BISTS configuration was achieved by considering the balance between primary energy savings and daylight provision. The results revealed that 1) the BISTS system could effectively improve the daylight condition for a single perimeter room by increasing the useful daylight level and reducing the excessive level. 2) The savings for the building energy consumption were not significant. The final design with the BISTS layouts on three façades could result in 5.3% of total primary energy saving. 3) 90° of slat angle should be avoided for both the horizontal and vertical BISTS louvers. Smaller angles – between 0° and 60° – are preferred. [ABSTRACT FROM AUTHOR]