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This paper analyses the economics of cogeneration potential in the pulp and paper industry of Vietnam. The analysis focuses on six large existing paper mills, their planned capacity expansion and nine planned new mills up to 2010. The analysis considered five alternative fuels (coal, diesel, fuel oil, natural gas and rice husk), three different technologies (steam turbines, gas turbines and reciprocating engines) and two modes of operation (thermal match and power match) of cogeneration. It also considered the case of sale of excess power to the grid. The analysis indicates that cogeneration is a viable option in the paper and pulp industry in Vietnam and the potential is about 200 MW. IRR in most of the cases ranges between 15 and 30% and the general payback period is between 3 and 5 years. Cogeneration remains a viable option even without sale of power to the grid and under different unfavourable conditions of fuel price, investment and other factors. Copyright © 2005 John Wiley & Sons, Ltd.

Different energy and exergy concepts and methods are presented and applied to a Swedish pulp and paper mill. Flow diagrams show that the exergy content is mostly much less than the energy content o ...

In the pulp and paper industry, energy costs represents a relatively large proportion of the value of production. When investing in new equipment, considerations concerning boundary conditions, suc ...

SUMMARY The present study deals with a comprehensive thermodynamic modeling of a combined heat and power (CHP) system in a paper mill, which provides 50 MW of electric power and 100 ton h−1 saturated steam at 13 bars. This CHP plant is composed of air compressor, combustion chamber (CC), Air Preheater, Gas Turbine (GT) and a Heat Recovery Heat Exchanger. The design parameters of this cycle are compressor pressure ratio (rAC), compressor isentropic efficiency (ηAC), GT isentropic efficiency (ηGT), CC inlet temperature (T3), and turbine inlet temperature (T4). In the multi-objective optimization three objective functions, including CHP exergy efficiency, total cost rate of the system products, and CO2 emission of the whole plant, are considered. The exergoenvironmental objective function is minimized whereas power plant exergy efficiency is maximized using a Genetic algorithm. To have a good insight into this study, a sensitivity analysis of the results to the interest rate as well as fuel cost is performed. The results show that at the lower exergetic efficiency, in which the weight of exergoenvironmental objective is higher, the sensitivity of the optimal solutions to the fuel cost is much higher than the location of the Pareto Frontier with the lower weight of exergoenvironmental objective. In addition, with increasing exergy efficiency, the purchase cost of equipment in the plant is increased as the cost rate of the plant increases. Copyright © 2010 John Wiley & Sons, Ltd.

Regression analysis is used to detect and quantify the gross consequences for energy use of structural differences in the pulp and paper industries of the OECD countries. It is shown that changes in the specific energy use with time are explicable in terms of the concentration of production. Size and learning effects on paper making machines are detected and quantified.

Recent progress in nanoscience and technology offers huge opportunities for applications in the energy field and for the development of clean energy systems. Advanced materials based on nanoscience could lead to large energy savings in a whole range of end-use energy applications such as buildings or lighting systems. Major technology breakthroughs could be accomplished through nanotechnology in solar cells, fuel cells and hydrogen technology, energy storage, etc. International research in nanoscience finds increasingly new and novel directions into energy applications.

Energy efficiency measures in pulp mills can potentially reduce the consumption of biofuel, which can instead be exported and used elsewhere. In this paper a methodology is proposed for analysing the robustness of energy efficiency investments in Kraft pulp mills or other industrial process plants equipped with biofuelled combined heat and power units, given uncertain future climate policy. The outlook for biofuel and electricity prices is a key factor for deciding if energy efficiency measures are cost competitive. CO2 emission charges resulting from climate policy are internalized and thus included in electricity and biofuel prices. The proposed methodology includes a price-setting model for biofuel that assumes a constant price ratio between biofuel and electricity in the Nordic countries. Thirteen energy efficiency retrofit measures are analysed for an existing Swedish Kraft pulp mill. Special attention is paid to heatintegrated evaporation using excess process heat. Four possible energy market development paths are considered that reflect different climate policies. Pulp mill energy efficiency investments considered are shown to be robust with respect to uncertain climate policy. Copyright # 2006 John Wiley & Sons, Ltd.

Summary Current communication reports the application of kinetic models viz., modified Gompertz, modified Logistic, Ratkowsky and Andrew model to study the acidogenic hydrogen (H2) production along with volatile fatty acids (VFA) production and substrate degradation from various wastewater (dairy, distillery, chemical and designed synthetic wastewater) using mixed consortia. Influence of fermentation time was specifically evaluated by modified Gompertz and modified Logistic models on H2 and VFA production. Influence of system redox condition on process was evaluated by Ratkowsky and Andrew models. The modified Gompertz model showed best fit for H2 production as well as substrate degradation while modified Logistic model showed good acceptability with VFA production. The Andrew model describes both H2 and VFA production with respect to system redox condition relatively well. This information provides an understanding of the process behavior, which can help in the design and upscaling of the process for efficient H2 production. Copyright © 2015 John Wiley & Sons, Ltd.

There are several processes in a Kraft pulp mill where there is a need for sodium hydroxide, e.g. in the digester and the bleaching plant. The objective of this study is to perform a preliminary evaluation, intended to select the best alternative for producing sodium hydroxide on a Kraft pulp mill site. The first step of the evaluation consists of screening available processes for producing sodium hydroxide needed in the mill. The first step of the evaluation shows that the two best options for increasing the production of sodium hydroxide for internal use in a mill are the conventional lime cycle process or direct causticization with titanates. The second step of the evaluation compares the lime cycle and the titanate process using first and second law analyses to determine the energy requirement and the exergy efficiencies of both processes. Such analyses show a higher energy requirement and a lower exergy efficiency in the titanate process than in the lime cycle process without any heat integration. However, the titanate process shows better performance in terms of energy requirement and exergy efficiency than the lime cycle, if heat is integrated into both processes. The titanate process requires, in the best case, only 80% of the energy required for a fully heat-integrated lime cycle process. Copyright © 2009 John Wiley & Sons, Ltd.

In this study we present an energy and exergy modelling of industrial final macaroni (pasta) drying process for its system analysis, performance evaluation and optimization. Using actual system data, a performance assessment of the industrial macaroni drying process through energy and exergy efficiencies and system exergy destructions is conducted. The heat losses to the surroundings and exergy destructions in the overall system are quantified and illustrated using energy and exergy flow diagrams. The total energy rate input to system is 316.25 kW. The evaporation rate is 72 kg h−1 (0.02 kg s−1) and energy consumption rate is found as 4.38 kW for 1 kg water evaporation from product. Humidity product rate is 792 kg h−1 (0.22 kg s−1) and energy consumption rate is found about 0.4 kW for 1 kg short cut pasta product. The energy efficiencies of the pasta drying process and the overall system are found to be as 7.55–77.09% and 68.63%. The exergy efficiency of pasta drying process is obtained to be as 72.98–82.15%. For the actual system that is presented the system exergy efficiency vary between 41.90 and 70.94%. Copyright © 2006 John Wiley & Sons, Ltd.

Summary The consumption of fossil fuel has resulted in global warming, environmental pollution, and many other crucial problems. Replacing fossil fuel with renewable energy has become an important issue over the recent decades. As a renewable clean energy, wind power is a relatively well-developed and promising energy method for current technology development in China. Under the background of growing demand for electricity and enhancing awareness for environmental, the “Internet+ wind power” concept has emerged based on both the wind power's characteristics that renewable and non-polluting, and the rapid development of the Internet in China. Through querying an amount of literature and information, this paper reveals the resource endowment and policy environment about wind power and energy Internet at first. Then, the PEST-SWOT strategy analysis model is used to analyze the internalities (strengths and weaknesses) and the externalities (opportunities and threats) of “Internet+ wind power”. According to these results, the paper puts forward some measures (development and utilization, business mode) for wind power accommodation. Then some policy recommendations have been proposed. The government should provide favorable conditions for wind power grid with the “Internet+” technology innovation.

Summary Mass roll-out of plug-in hybrid electric vehicles (PHEVs) and significant penetration of renewable energy sources in distribution system play a major role in delivering low carbon environment. However, placing and utilizing these units randomly result in overloading, increased power loss, and reduced voltage profile. This paper responds to these technical challenges by using a strategic placement method for locating the distributed generation (DG) and the charging station (CS) of PHEVs in a multi-zone distribution system. For simultaneously scheduling of these units in each zone, the smart energy management framework is proposed in this paper. Apart from usual energy management constraints, this paper also incorporates the real-time constraints involving the capacity of PHEV batteries, the mobility pattern, and the power level of the charging infrastructure. The simulation studies are carried out for each hour of a day. To cope with this time constraint execution, particle swarm optimization algorithm-based approach is used. The proposed framework is tested in IEEE 33 and IEEE 69 bus radial distribution system. The obtained results imply that the presented energy management framework provides maximum profits for the vehicle owner, and meanwhile it fulfills preferences of the user in each zone simultaneously.

Summary This paper presents a techno-economic analysis of photovoltaic mini-grid systems (PMs), using a group of remote houses in 3 locations in Nigeria, as case studies. It uses a worst-case users' load demand approach for the design and analysis of the proposed energy system, according to international technical standards. It presents detailed capacity, yield and losses, battery state of charge (SoC), reliability, users' load demand increase (Ldi), and life cycle economic analyses by using the Hybrid Optimisation for Electric Renewables (HOMER) simulation tool. The effect of 25% Ldi is also considered in the paper. The study can be used to develop a practical energy model to address the poor energy situation in those locations when they are implemented. Results indicate that PMs of 68, 76, and 61 kW can meet the users' demand of ~63 500 kWh/year with an availability of 99.2% for the locations, respectively. By including a 30-kVA diesel generator to the PMs' model, an availability of 100% was obtained, demonstrating that the issue of loss of energy supply for several days in the year due to users' Ldi and the cloudy days is being addressed. The results further show that although the hybrid energy systems have relatively higher initial capital, total life cycle and replacement costs, and the cost of energy, they achieve a higher reliability compared with the proposed PMs. The research can be useful for planning solar PV infrastructure for remote locations around the world.

Summary This paper presents a degradation testing of a lithium-ion battery developed using real world drive cycles obtained from an electric vehicle (EV). For this, a data logger was installed in the EV, and real world drive cycle data were collected. The EV battery system consists of 3 lithium-ion battery packs with a total of 20 battery modules in series. Each module contains 6 series by 49 parallel lithium-ion cells. The vehicle was driven in the province of Ontario, Canada, and several drive cycles were recorded over a 3-month period. However, only 4 drive cycles with statistical analysis are reported in this paper. The reported drive cycles consist of different modes: acceleration, constant speed, and deceleration in both highway and city driving at −6°C, 2°C, 10°C, and 23°C ambient temperatures with all accessories on. Additionally, individual cell characterization was conducted using a C/25 (0.8A) charge-discharge cycle and hybrid pulse power characterization (HPPC). The Thevenin battery model was constructed in MATLAB along with an empirical degradation model and validated in terms of voltage and SOC for all drive cycles reported. The presented model closely estimated the profiles observed in the experimental data. Data collected from the drive cycles showed that a 4.6% capacity fade occurred over the 3 months of driving. The empirical degradation model was fitted to these data, and an extrapolation estimated that 20% capacity fade would occur after 900 daily drive cycles.

Summary Triboelectric nanogenerator (TENG) is a newly proposed technology for effectively converting mechanical energy into electricity. Triboelectric nanogenerator has shown a great potential for harvesting the clean and abundant energy of ocean waves. Recently, a duck-shaped TENG device has been proposed as a lightweight, cost-effective, highly stable, and efficient system for scavenging the existing energy in water waves. In this paper, a detailed investigation on the performance of the duck-shaped TENG is presented. Then, a comparative analysis between the TENG device and an equivalent electromagnetic generator (EMG) for wave energy harvesting is performed. The electric output characteristics of both techniques under various mechanical and electrical conditions are obtained. The analysis demonstrates that at a low operating frequency of 2.5 Hz, the TENG and EMG achieve the peak power density of 213.1 and 144.4 W/m3, respectively. The present paper provides guidance for design and optimization of hybrid TENG and EMG technology toward scavenging the blue energy.

Summary Storing energy allows both the efficiency and availability of renewable energy to be increased, thus dissociating actual from expected generation and from consumption demands. Compressed air energy storage (hereinafter ‘CAES’) enables the efficient and cost-effective storage of large amounts of energy, achieving a capacity of over 100 MWh. There are several geological structures that can be used as CAES, among which the use and construction of salt domes are particularly noteworthy. However, there is a high exploration risk associated with subsurface exploration. To this end, it is advisable to establish a detailed schedule to select and characterize structures, with the purpose of minimizing the aforementioned risk. Multi-criteria algorithms can be used to establish a hierarchy of the alternatives and to identify the structures with the greatest potential with an objective approach. The analytic hierarchy process method is used in this paper as the selection algorithm, which is based on identifying and assessing criteria and weighting each criterion. In accordance with the analytic hierarchy process method, the goal was divided into a series of different level criteria, defining a breakdown structure of the problem to select salt domes. This paper defines a structure hierarchization method that allows the objective establishment of the areas with the highest potential for CAES, considering both technical and socioeconomic factors. Therefore, a supporting decision-making method may be established to reduce the exploration risk associated with underground structures. Copyright © 2017 John Wiley & Sons, Ltd.

Summary There is a constant growth in energy consumption and consequently energy generation around the world. During the recent decades, renewable energy sources took heed of scientists and policy makers as a remedy for substituting traditional sources. Wind and photovoltaic (PV) are the least reliable sources because of their dependence on wind speed and irradiance and therefore their intermittent nature. Energy storage systems are usually coupled with these sources to increase the reliability of the hybrid system. Environmental effects are one of the biggest concerns associated with the renewable energy sources. This study summarizes the last and most important environmental and economic analysis of a grid-connected hybrid network consisting of wind turbine, PV panels, and energy storage systems. Focusing on environmental aspects, this paper reviews land efficiency, shaded analysis of wind turbines and PV panels, greenhouse gas emission, wastes of wind turbine and PV panels' components, fossil fuel consumption, wildlife, sensitive ecosystems, health benefits, and so on. A cost analysis of the energy generated by a hybrid system has been discussed. Furthermore, this study reviews the latest technologies for materials that have been used for solar PV manufacturing. This paper can help to make a right decision considering all aspects of installing a hybrid system. Copyright © 2017 John Wiley & Sons, Ltd.

Summary This paper aims to research the thermal power of lithium-ion cell with different operating conditions. A 55-Ah lithium-ion cell is selected as the research object. Experiment and simulation are chosen as the methods to research the temperature distribution and thermal power of the cell under different conditions. Combining with the thermal power of cells, this paper also researches the heat dissipation performance of battery pack under different operation conditions. The results indicated that average thermal power of a 55-Ah lithium-ion cell decreases along with the increase of ambient temperature and the decrease of state of charge and charge and discharge rates. The results achieved through simulation and experiment are consistent, so simulation could be used to research the temperature distribution of cell during charge and discharge. As considering the longitudinal battery pack with steady analysis, high temperature area is in the centre, and the temperature of air inlet is relatively low. The airflow mostly passes the top of battery pack but not through both sides. As considering the longitudinal battery pack with transient analysis, the temperature rise of battery pack is evidently higher than the inner temperature difference by studying three operating conditions (sustained deceleration, sustained acceleration and pulsed discharge). The curves of temperature rise and inner temperature difference rise along with sustained acceleration of the electric vehicle; therefore, even if the electric vehicle begins to decelerate, the fan must still work until the temperature of battery pack decreases. Then, the references are given for researching thermal characteristic during charge and discharge of the cell and the heat dissipation analysis of battery pack. Copyright © 2017 John Wiley & Sons, Ltd.

Summary Estimating the dynamic status parameters of a battery, such as its state of health (SoH) and remaining useful life (RUL), is still a very difficult and complex task. In this paper we perform a structured review of the most relevant state of the art models, algorithms and commercial devices employed in the estimation of the SoH/RUL battery performance figures, in the context of embedded applications. The models and estimation techniques are thoroughly classified and, for each taxonomy class, a presentation of the working principles is made. A comprehensive set of metrics is then introduced for the evaluation of the SoH/RUL estimation techniques from the perspective of their implementation and operation efficiency in embedded systems. These algorithms are then analyzed and discussed in a comparative manner, with concrete figures and results. The capability and the performance of the different types of off-the-shelf fuel gauges to estimate the battery SoH/RUL parameters are also evaluated in this paper. Copyright © 2016 John Wiley & Sons, Ltd.

Summary This paper reviews the recent hybrid photovoltaic thermal (PV/T) structural/geometrical topologies to highlight the state of the art on this form of collector approaches and designs for both liquid and air-based systems. The review focuses on the development of the typical flat-plate collector – as an essential part in the PV/T system – in terms of new concept and novel configurations and specifically on the design of these collectors that use air or liquid as a heat transfer medium and their ability to extract useful heat from the back surface of the PV panel. Different mechanisms of fluid flow either natural or forced are considered. Many different design configurations for hybrid PV/T collectors have been cataloged and evaluated. It is shown that at least 30 distinct configurations have been introduced in the literature in the last 5 years. The paper concludes with identifying the major factors that affect the performance of typical PV/T systems and lead to effective enhancement of the heat removal mechanisms thus improving the electrical and thermal solar conversion efficiencies. This paper should serve as a significant form of reference for any future development in the design of the PV/T concept. Copyright © 2016 John Wiley & Sons, Ltd.

Summary In this paper, a hybrid algorithm consisting of particle swarm optimization and pattern search algorithm is proposed to evaluate and optimize the design and operation of microgrids (MGs) in combined gas and power networks. Key performance indicators (KPIs) are modeled and proposed to evaluate and assess MGs. The paper begins by proposing a comprehensive study to define KPIs, which are used to evaluate the following MG parameters: economical efficiency, reliability, environmental conservation, and power quality. Multi-objective evaluation functions are then developed by building a relationship matrix of MG and KPI components. The results are then displayed as optimized power generation percentages for each technology with values for four KPI categories: cost, quality, reliability and environmental friendliness. Two case studies are examined in this paper; both the province of Ontario and Toronto regional zone under all system parameters with varying percentage of generation via gas technology. Results indicated that the optimal scenario for both Ontario and Toronto was achieved at hybrid PSO–patern search percentage generation via gas technology with improved cost KPI and other KPIs remaining approximately constant. Copyright © 2016 John Wiley & Sons, Ltd.

Summary Dynamics modeling is of fundamental importance to Li-ion battery design and manufacturing. Accurate dynamics models established can be used to optimize the operation strategy, manage the life cycle, and thus ensure the economic and safe operation of the batteries. The Li-ion dynamics model examined in this paper has integrated both empirical and electrochemical aspects, and it has been specifically validated for electric vehicle applications using experimental data. Previously, the model parameter estimation was done by manually picking three key points from the discharge curve obtained from the datasheet. The approach is quite subjective and error prone. The resulted model may deviate greatly from the experimental curve. To address this issue, this paper proposes to use particle swarm optimization to more objectively estimate the model parameters. Results from case studies show that the proposed approach provides more accurate estimation of the true parameters, and thus the new approach can more precisely capture the battery dynamics. In addition, this approach is generic because it is independent of specific battery chemistries and applicable to many different types of Li-ion batteries. Copyright © 2016 John Wiley & Sons, Ltd.

Summary Previous study shows the ITM (oxygen ion transfer membrane)-integrated MCFC (molten carbonate fuel cell) hybrid system with CO2 recovery can maintain high efficiency; however, the oxygen partial pressure on the ITM permeate side is usually 1 atm, which requires a very high pressure ratio of the ITM air compressor in order to separate the oxygen; using the sweep gas can solve this problem. In this paper the ITM-integrated MCFC hybrid systems with CO2 recovery using different sweep gases are studied. With the Aspen plus software, two systems with different sweep gases are established, and their performances are compared with the benchmark system without sweep gas; the effects of key parameters on the optimum system performance are also investigated. Results show that compared with the benchmark system, the efficiencies of the systems with sweep gases are increased and the pressure ratios of the air compressors are decreased; the system using pure CO2 as sweep gas can improve the system efficiency by 1.25%, which is superior to the system using the mixture gas of CO2 and H2O as sweep gas. Achievements from this paper will provide a valuable reference for CO2 recovery from the MCFC hybrid power system with lower energy consumption. Copyright © 2016 John Wiley & Sons, Ltd.

Summary The application of renewable sources such as solar photovoltaic (PV) to charge electric vehicle (EV) is an interesting option that offers numerous technical and economic opportunities. By combining the emission-free EV with the low carbon PV power generation, the problems related to the greenhouse gases due to the internal combustion engines can be reduced. Over the years, numerous papers, including several review work, have been published on EV charging using the grid electricity. However, there seems to be an absence of a review paper on EV charging using the PV as one of the energy sources. With growing interest in this topic, this review summarizes and updates some of the important aspects of the PV-EV charging. For the benefit of a wider audience, it provides the background on the EV fundamentals, batteries and a brief overview on the PV systems. Two types of PV-EV charging, namely the PV-grid and the PV-standalone, are comprehensively covered. Moreover, a case study is carried out in comparison to the grid-only charging to critically analyse the technical and the economical feasibilities of both types using Matlab simulation. At the end, recommendations and future directions are presented. It is envisaged that the material gathered in this paper will be a valuable source of information for the researchers working on this topic. Copyright © 2015 John Wiley & Sons, Ltd.

This paper reviews the feasibility of ultralong-cycle operation on a compact liquid metal-cooled fast reactor (LMR) firstly by assessing the operation of a long-life fast reactor core and secondly by evaluating material performance in respect to both long-cycle operation and compact-size fast reactor. Many kinds of reactor concepts have been proposed, and LMR and small modular reactor (SMR) are the issued leading technologies for generation four (Gen-IV) reactor system development. The breed-and-burn strategy was proposed as a core burning strategy to operate a long cycle, and it has been evaluated in this paper with two reactor concepts: constant axial shape of neutron flux, nuclide densities, and power shape during life of energy and ultralong cycle fast reactor. In addition, Super-Safe, Small, and Simple and small modular fast reactor, compact LMR concepts, have been simulated to evaluate their long-life operation strategies. For the other practical issues, the materials for fuel, coolant, and structure have been identified and some of them are selected to have their performance optimized specifically for compact LMR with a long-cycle operation. It is believed that this comprehensive review will propose a proper direction for future reactor development and will be followed by the next step research formore » a complete reactor model with the other reactor components.« less

Summary The problems of energy shortage engage us to find new resource, and varieties of renewable energy produced in different places are looking forward to be feedback to the power grids. These requirements also make power grids start to change from centralized structure with a few power plant to distributed system with many generating stations. To fit the building requirement of Smart Grid, smart units and their information networks with functions of measurement protection and control are becoming necessities. This paper tries to give a new small grid with curtains applications. Around this grid needs, paper introduces the development of Smart Units, the real-time networks and information web services: (i) The Smart Unit is multi-μPU instruments with function of measurement analysis and control, which includes intelligent algorithms of FFT Zoom-FFT Wavelet to fit signal processing, networks communication protocols with Ethernet and 3G/4G interfaces, and controlling functions to control devices like Intelligent Broker and Intelligent Capacitor; (ii) Based on Ethernet, a real-time controlling protocol named Synchronous Ticket Strategy (STS) is proposed, which is used to manage to synchronize measurement and control; and (iii) Information web services are built on cloud computing platforms, which provide parallel calculation with S transmit and user application services like power parameters GIS and data accessing. At the end some results are given from simulations of algorithms and online tests. Copyright © 2015 John Wiley & Sons, Ltd.

Summary In this paper, research has been conducted on the floating type nuclear power plant named as ABV reactor which is designed for district heating, power, and sea water desalination by OKBM facility at Russia. This reactor was tested under different thermal loads during the designing phase, and three modules have been investigated. Theoretical calculations and simulation studies have been performed on these three modules having specifications as ABV-6M with 47MWth, ABV-6 with 38MWth, and ABV-3 with 18MWth.The results obtained from these modules have been calculated mathematically and verified by simulation. We have compared the originally derived data of ABV desalination system with our theoretical and simulation analysis. The results from two desalination techniques including RO and RO + MED have been calculated and are presented in this paper with details. The results obtained from both analysis show that the efficiency of ABV nuclear reactor desalination system increases with the decrease in corresponding water cost ratio. Copyright © 2015 John Wiley & Sons, Ltd.

Summary The valorization of municipal solid waste (MSW) into liquid fuels is a multi-beneficial global option for ensuring environmental and energy sustainability. The paper critically reviewed a wide range of recent literature on the potency, progress, and challenges associated with MSW upgrading into liquid fuels. Concise details on the various upgrading technologies involved such as gasification, pyrolysis, and syngas-to-fuels (i.e., syngas to gasoline and diesel) via a Fischer–Tropsch process were documented. Emphasis was critically given to the recent literature updates. The paper explored the role of heterogeneous catalyst systems in achieving the various processes with special considerations for optimizing fuel yield. Prospective technologies such as plasma gasification and nanoscale catalyst design with potentials to revolutionize the industry were also discussed. Copyright © 2015 John Wiley & Sons, Ltd.

Summary Electricity, heating and cooling usage at the same time constitute an important part of primary energy consumption. Currently, intense efforts are being devoted to the improvement and development of new technologies to promote energy savings and to mitigate the global warming. Among these technologies, tri-generation and poly-generation systems come into prominence due to their high efficiencies, as well as low operating costs and low greenhouse gas emissions. Nevertheless, modelling and sizing these systems is a large-sized problem itself, and the higher the number of inputs, the higher the computational complexity. This paper aims to give a comprehensive review of the optimisation techniques used in tri-generation and poly-generation systems modelling and optimisation. After having reviewed more than a hundred papers, taxonomy is constructed. Self-organising map is used to cluster the reviewed studies based on the optimisation techniques. Variations of the energy resources and the outputs of implemented systems are summarised. The crowd of clusters demonstrated the widely used optimisation techniques and the gaps in research. This study will certainly pioneer the optimisation studies in the field of tri-generation/poly-generation applications. Copyright © 2015 John Wiley & Sons, Ltd.

Summary The combined use of clean technologies can lead amongst other benefits to reduced environmental impacts, improved system efficiencies, better management of land scarcity, and diminishment of the effect of power variability of intermittent clean energy sources. Nonetheless, private investors facing budgetary constraints will only opt to invest in the combination of technologies if the latter is more profitable than the investment in a single technology. The aim of the paper is to provide a systematic model for decision makers that allows them to evaluate the profitability of any random combination of technologies under budgetary constraints, and to compare this profitability with that of the individual projects in isolation. This research goes beyond the state of art in the field of financial management and more specifically in the field of the rationing of capital amongst interdependent projects, by developing a method to calculate the payoff of interdependent projects undertaken together. Moreover, this paper develops a computational model from the investor's point of view, of which the purpose is threefold: First, the model allows to directly compare the economic payoff of individual complementary technologies with the economic payoff of their integrated combination, under budgetary constraints. Second, the model calculates economic synergies labeled ‘benefits of combined technologies’ (BOCT) when combining complementary technologies. Third, the model explains the rationalization behind the presence of BOCT. The model exemplifies an ex ante cost benefit analysis developed for business and non-governmental use. A four step methodology is proposed and illustrated by means of a case study of PV solar power and battery electric vehicles (BEVs) for a small Belgian enterprise. Results show that at low electricity prices ( €0.134/kWh), investment in exclusively PV becomes most attractive. In all other cases, it is more profitable to invest in the combination of both technologies. Copyright © 2015 John Wiley & Sons, Ltd.

High-temperature steam electrolysis (HTSE) consists of the splitting of steam into hydrogen and oxygen at high temperature in solid oxide electrolyzers. Performing the electrolysis process at high temperatures offers the advantage of achieving higher efficiencies as compared to the conventional water electrolysis. Furthermore, this allows the direct use of process heat to generate steam. This paper is related to the FCH JU (Fuel Cells and Hydrogen Joint Undertaking) project ADEL (ADvanced ELectrolyser For hydrogen Production with Renewable Energy Sources), which investigates different carbon-free energy sources to be coupled to the HTSE process. Renewable energy sources are able to provide the high-temperature steam electrolysis (HTSE) process with heat and power. This paper investigates the capability of Concentrating Solar Power (CSP) technologies to provide the HTSE process with the necessary energy demand. The layout of the plant is shown in the following figure. The design of commercial-scale high-temperature steam electrolysis has been carried out. The HTSE plant is coupled to an air cooled solar tower. The configuration and the operating parameters of the solar tower are based on those of the solar tower of Julich (Germany), which is operated by DLR. This paper presents the results of process analysis performed to evaluate the hydrogen production from a HTSE plant coupled to an 80MWth air solar tower. Additionally, the dynamic behavior of the system during energy fluctuations has been analyzed. The receiver-to-hydrogen efficiency (based on the Higher Heating Value of hydrogen) is 26% at a hydrogen production rate of 680 kg/h in steady-state operation. The overall solar-to-hydrogen efficiency is calculated to be at 18%. Moreover, the analysis under transient conditions shows that a steady-state operation of the plant is only possible for 8 h.

Summary Over the past few decades, the world demand for energy has risen steadily, forcing the world communities to look for alternative sources. Photovoltaic (PV) is seen as the most promising solution for this demand. However, the PV system is popularly known to suffer from low-energy harvesting due to the change of environment conditions. An inexpensive and practical solution to extract the energy from the PV is by improving the maximum power point tracking (MPPT) controller technique. An ideal MPPT should be able to track the true maximum power operating point accurately under all circumstances and overcome all nonlinearities in the characteristic I-V curves. This paper presents an updated review of the techniques based on the perturbative MPPT methods, both using the conventional and soft computing methods. The working principles of the techniques, parameter effects, and their limitations are discussed. The focus of this review is to direct the readers to the new direction of MPPT using the artificial intelligence and evolutionary computation techniques. Besides serving as a comprehensive source of information, the paper also provides a critical review on the relative performance of the selected MPPT methods. This includes the module dependency, tracking performance, and the ability to handle the partial shading conditions. Copyright © 2015 John Wiley & Sons, Ltd.

Summary Thermal management of Li-ion cells is an important technological problem for energy conversion and storage. Effective dissipation of heat generated during the operation of a Li-ion cell is critical to ensure safety and performance. In this paper, thermal performance of a cylindrical Li-ion cell with an axial channel for coolant flow is analyzed. Analytical expressions are derived for steady-state and transient temperature fields in the cell. The analytical models are in excellent agreement with finite-element simulation results. The dependence of the temperature field on various geometrical and thermal characteristics of the cell is analyzed. It is shown that coolant flow through even a very small diameter axial channel results in significant thermal benefit. The trade-off between thermal benefit and reduction in cell volume, and hence capacity due to the axial channel, is analyzed. The effect of axial cooling on geometrical design of the cell, and transient thermal performance during a discharge process, is also analyzed. Results presented in this paper are expected to aid in the development of effective cooling techniques for Li-ion cells based on axial cooling. Copyright © 2014 John Wiley & Sons, Ltd.

Changing conditions in biomass and energy markets require the pulp and paper industry to improve energy efficiency and find new opportunities in biorefinery implementation. Considering the expected changes in the pulp mill environment and the variety of potential technology pathways, flexibility should be a strong advantage for pulp mills. In this context, flexibility is defined as the ability of the pulp mill to respond to changing conditions. The aim of this article is to show the potential value of flexibility in the planning of pulp mill energy and biorefinery projects and to demonstrate how this value can be incorporated into models for optimal strategic planning of such investments. The paper discusses the requirements on the optimization models in order to adequately capture the value of flexibility. It is suggested that key elements of the optimization model are multiple points in time where investment decisions can be made as well as multiple scenarios representing possible energy price changes over time. The use of a systematic optimization methodology that incorporates these model features is illustrated by a case study, which includes opportunities for district heating cooperation as well as for lignin extraction and valorization. A quantitative valuation of flexibility is provided for this case study. The study also demonstrates how optimal investment decisions for a pulp mill today are influenced by expected future changes in the markets for energy and bioproducts.

SUMMARY The objective of this paper is to study the performance of a combined heat and power (CHP) system that uses two power generation units (PGU). In addition, the effect of thermal energy storage is evaluated for the proposed dual-PGU CHP configuration (D-CHP). Two scenarios are evaluated in this paper. In the first scenario, one PGU operates at base-loading condition, while the second PGU operates following the electric load. In the second scenario, one PGU operates at base-loading condition, while the second PGU operates following the thermal load. The D-CHP system is modeled for the same building in four different locations to account for variation of the electric and thermal loads due to weather data. The D-CHP system results are compared with the reference building by using conventional technology to determine the benefits of this proposed system in terms of operational cost and carbon dioxide emissions. The D-CHP system results, with and without thermal storage, are also compared with that of single-PGU CHP systems operating following the electric load (FEL), following the thermal load (FTL), and base-loaded (BL). Results indicate that the D-CHP system operating either FEL or FTL in general provides better results than a single-PGU CHP system operating FEL, FTL, or BL. The addition of thermal storage enhances the potential benefits from D-CHP system operation in terms of operational cost savings and emissions savings. Copyright © 2013 John Wiley & Sons, Ltd.

SUMMARY This paper reports the thermodynamic optimization of air conditioning systems with one or more evaporators, for one or more rooms. First, the paper shows that the minimization of the total power requirement leads to the same results as the minimization of entropy generation in the whole system, which includes the insulation between the cold space and the ambient. The results also show that there is a trade-off between the power lost by fluid friction in the distribution network and the power required by the refrigerant. This trade-off determines the optimal allocation of hardware in the installation. The optimum diameters of the refrigerant pipelines are independent of their lengths. Copyright © 2013 John Wiley & Sons, Ltd.

SUMMARY A new zero CO2 emission solid oxide fuel cell (SOFC) hybrid power system integrated with the oxygen ion transport membrane using CO2 as sweep gas is proposed in this paper. The pure oxygen is picked up from the cathode outlet gas by the oxygen ion transport membrane with CO2 as sweep gas; the oxy-fuel combustion mode in the afterburner of SOFC is employed. Because the combustion product gas only consists of CO2 and steam, CO2 is easily captured with lower energy consumption by the condensation of steam. With the aspen plus soft, this paper builds the simulation model of the overall SOFC hybrids system with CO2 capture. The exergy loss distributions of the overall system are analyzed, and the effects of the key operation parameters on the overall system performance are also investigated. The research results show that the new system still has a high efficiency after CO2 recovery. The efficiency of the new system is around 65.03%, only 1.25 percentage points lower than that of the traditional SOFC hybrid power system(66.28%)without CO2 capture. The research achievements from this paper will provide the valuable reference for further study on zero CO2 emission SOFC hybrid power system with higher efficiency. Copyright © 2013 John Wiley & Sons, Ltd.

SUMMARY Refrigeration by an active magnetic regenerative system (AMR) is potentially more attractive, as compared to conventional techniques. Indeed, devices based upon an AMR cycle are more efficient, compact, environment-friendly and can operate over a broad range of temperatures. In this paper, attention is focused to the near room-temperature range. On the other hand, however, the AMR cycle poses a variety of complex problems, in terms of fluid dynamics, heat transfer and magnetic field. In order to identify the optimal operational parameters, the design and optimization of a magnetic refrigeration system can be supported by modelling. In this paper, a dimensionless approach was adopted to simulate an AMR cycle following a Brayton regenerative cycle. In the simulation, the temperature range that has been explored is 260 – 280 K and 275 – 295 K. The heat transfer mediums are, respectively, water–glycol mixture (50% by weight) and pure water. The Gd0.8Dy0.2 alloy and pure Gd have been chosen as constituent material for the regenerator of the AMR cycle. With this model, the influence of the different parameters on cycle efficiency has been analysed. In particular, the study has been focused on the influence of the secondary fluid properties, magnetic material particle diameter, fluid blow time, secondary fluid mass flow rate, regenerator geometry and effect of axial thermal conduction. The model enables to find optimal dimensionless numbers in order to maximize the cycle performances. The results can be extended to widely different situations and therefore can be easily employed for the design and the optimization of new experimental prototypes. Copyright © 2012 John Wiley & Sons, Ltd.

SUMMARY Currently, governments and companies aim their concern about the environmental problems and energy security. Within this context, the use of renewable hydrogen is presented as an interesting option. This paper presents the alternative to use a renewable resource abundant in the country: hydroelectricity. The public transport service in the urban area of Foz do Iguacu city, Brazil, was chosen as the scenario where a simulated replacement of the current diesel bus fleet with fuel cell buses was performed. The focus was to take advantage of the energy called Spilled Turbinable Energy (STE) verified by the ITAIPU Hydroelectric Power Plant from 2001 to 2006 in order to produce hydrogen by water electrolysis process. The paper does not contain thermodynamic analysis of the processes involved in the proposal. Based on the monthly average, the maximum value was 1,054,899 MWh and the minimum 9559 MWh. Evaluating the historic behavior of this potential energy in the considered period, from October to June, it was found that the energy demand to produce the electrolytic hydrogen needed to meet the whole demand of the public transport sector of Foz do Iguacu city, estimated in 14,454.3 MWh/month, amounts only between 1.5% to 8.5% of total spilled energy. This study presents two electrolytic hydrogen production models: the centralized and the decentralized associated with various distribution modes. The comparison between models shows that the centralized hydrogen production associated with central supply mode are economically more convenient for the city, and the hydrogen cost achieved was US$ 2.38/kg in contrast with the decentralized model associated with cryogenic liquid delivery which showed the highest cost, equal to US$ 4.61/kg. Finally, a sensitivity analysis was performed varying four parameters: equipment cost; rate of return; capital recovery time and electricity cost. Copyright © 2012 John Wiley & Sons, Ltd.

SUMMARY In order to transport and store the captured CO2 from coal-fired power plants, it is necessary to compress and liquefy CO2 first. However, the power consumption of conventional process is enormous. In this paper, a novel process for CO2 compression and liquefaction based on the analysis of the power consumption of traditional method is proposed. The new process integrates the refrigeration process driven by the lower level heat from the coal-fired power plant. This paper analyzes and compares the energy consumptions of conventional process and new process for CO2 compression and liquefaction. The research result indicates that, when CO2 needs to be compressed and liquefied and an abundant low quality heat is available, the new process has obvious superiority in lowering the energy consumption. The new process for CO2 compression and liquation integrated with the exhaust heat powered refrigeration can greatly reduce the work consumption of CO2 compression and liquefaction. The refrigeration temperature has great effects both on the coefficient of performance of refrigeration process and work consumption of compressors. The refrigeration temperature can be selected by optimization. Using refrigerator with double stages of evaporation can further reduce the amount of the extracted steam and lower the total energy consumption for CO2 compression and liquation. Recovering the cool energy of CO2 is beneficial to the reduction of the total work consumption. The achievements obtained from this paper will provide a useful reference for CO2 compression and liquefaction with the lower energy consumption. Copyright © 2012 John Wiley & Sons, Ltd.

SUMMARY As an open and demanding problem, accurate modeling of polarization curve in proton exchange membrane fuel cell has become the main issue of various researches. In recent years, because of their great potentials, metaheuristic optimization algorithms have represented good performances in identification of the unknown parameters of the proton exchange membrane fuel cell model, but there is the possibility to obtain more accurate results with more capable algorithms. In the literature, many heuristic optimization algorithms have been developed on the basis of natural phenomena. However, there are still some possibilities to devise new ones. In this paper, evolution of bird species has been regarded, and the intelligent behavior of birds during mating season has become an inspiration to devise a new heuristic optimization algorithm, named bird mating optimizer. Moreover, in this paper, the whole unknown parameters of the model, even dimensional parameters, are included in the identification process. The proposed algorithm is used to model the Ballard Mark V FC, and its performance is compared with those of the recently published paper by the authors. Simulation results reveal the superior performance of bird mating optimizer algorithm. Copyright © 2012 John Wiley & Sons, Ltd.

SUMMARY Economic, environmental and social pressures have increased the need for business organisations to control and manage their energy performance on a continual basis. Responding to these pressures follows a learning curve that is influenced by changing drivers and barriers. Consequently, different energy management factors have different development priorities over time. This paper explores the development priority of one factor, namely, energy performance measurement, in the energy-intensive industrial sector, which is the most advanced industrial sector in its energy management learning curve. In addition, the paper identifies the research and development needs of energy performance measurement that are required to further improve energy performance. The results are based on interviews carried out with managers and operators in three energy-intensive industrial sectors in Finland. Energy performance measurement is found to be the third development priority in energy management, behind resource and commitment issues. This represents a paradox as resources and commitment are prerequisites for energy performance measurement to be developed, whereas energy performance measurement influences the very same issues by enforcing changed behaviour. Several deficiencies are identified in energy performance measurement in the temporal, systemic and organisational dimensions. Research should be continued towards the implementation of energy performance measurement as a process, the integration of energy performance metrics into overall management and the development of metrics for different industrial sectors, companies and operating cultures. Copyright © 2012 John Wiley & Sons, Ltd.

SUMMARY Among various developed methods for CO2 capturing from industrial flue gases, chemical absorption system is still considered as the most efficient technique, because of its lower energy requirement and also its applicability for low concentration of CO2 in the inlet gas stream. Also, it can be used to retrofit the existed power plants, which are the major industrial CO2 emission sources, without changing their design condition. Selection of a suitable solvent is the first parameter that should be considered in the design of capture plants that use absorption technology. The most important challenge for using chemical solvents is finding the optimum operating conditions to minimize the energy requirement. Study of technical parameters can be helpful to improve the overall capture plant efficiency. In this paper, CO2 capture plant has been simulated for different solvents to compare their performance and energy requirement. To improve the plant overall efficiency, effect of the main operating factors such as amine flow rate, temperature, inlet gas temperature, and pressure has been studied in this paper. This analysis indicates the best chemical solvent for various cases of inlet flue gas. This parametric study reduces the overall energy requirement and helps design a cost-effective plant. Copyright © 2012 John Wiley & Sons, Ltd.