Journal Sciences News
Ultrasonics
15 March 2018
Heat transfer deterioration in helically coiled heat exchangers in trans-critical CO2 Rankine cycles
Publication date: 15 March 2018
Source:Energy, Volume 147 Author(s): Xinxin Liu, Xiaoxiao Xu, Chao Liu, Wanjin Bai, Chaobin Dang The heat transfer deterioration (HTD) of supercritical CO2 encountered in trans-critical CO2 Rankine cycle is an important issue related the safety of the whole unit. For the purpose, numerical simulations are performed to get a further insight into the mechanism of heat transfer characteristics of supercritical CO2 flow in helically coiled tube (HCT) both in horizontal and vertical orientations with parameters in a range of p
15 March 2018
Automated Building Energy Modeling and Assessment Tool (ABEMAT)
Publication date: 15 March 2018
Source:Energy, Volume 147 Author(s): Ehsan Kamel, Ali M. Memari Buildings contribute to about 40% of total annual energy consumption in the U.S. and saving a small percentage of that can lead to significant economic and environmental impacts. Building Energy Modeling (BEM) tools are important in reducing building's energy consumption. Most of the available tools only provide total energy consumption related to HVAC system, lighting, hot water, and appliances. While fine-grained data may be available in some computer tools, the process for obtaining these data is time-consuming, error-prone, and requires software-related skills. This paper explains a developed tool that contributes in automation of building energy simulation and providing fine-grained outputs by using Building Information Modeling (BIM) and modified source code of energy simulation tools such as EnergyPlus and OpenStudio. This tool, which is referred to as ABEMAT (Automated Building Energy Modeling and Assessment Tool), receives gbXML file and provides users with the amount of heat transfer through every single building envelope component such as windows, doors, and walls through an automated process. ABEMAT's and EnergyPlus advanced outputs are compared for validation; the latter being a time consuming process and error-prone, which requires software-related skills compared to ABEMAT. Results showed similar findings indicating the functionality of ABEMAT in providing fine-grained outputs.
15 March 2018
Structural features and gasification reactivity of biomass chars pyrolyzed in different atmospheres at high temperature
Publication date: 15 March 2018
Source:Energy, Volume 147 Author(s): Guangwei Wang, Jianliang Zhang, Weiwei Chang, Rongpeng Li, Yanjiang Li, Chuan Wang The purpose of this study was to investigate the gasification properties of biomass chars obtained under different conditions by using non-isotherm thermogravimetric method. The physical and chemical structure features were also systematically studied. It shows that the gasification reactivities decrease with increasing pyrolysis temperature, and the gasification reactivities for the chars obtained under different atmosphere conditions are in the order of N2 char
15 March 2018
Thermodynamic efficiency improvement of combined cycle power plant's bottom cycle based on organic working fluids
Publication date: 15 March 2018
Source:Energy, Volume 147 Author(s): Stjepko Katuli
15 March 2018
Energy characteristics assessment of olive pomace by means of FT-NIR spectroscopy
Publication date: 15 March 2018
Source:Energy, Volume 147 Author(s): A. Pizzi, G. Toscano, E. Foppa Pedretti, D. Duca, G. Rossini, C. Mengarelli, A. Ilari, A. Renzi, M. Mancini Biomass is an important renewable energy source, in particular if obtained by residues it becomes even more sustainable. In Italy, residual biomass coming from olive oil industry, i.e. olive pomace, is produced in a significant amount and is concentrated in olive oil extraction sites, making interesting a possible valorisation of these residues. The different extraction processes employed influence the pomace quality and, consequently, it is fundamental to find a rapid technique to assess its physical and chemical characteristics for a correct valorisation. The aim of the work was to develop a NIR-based methodology to obtain in a fast and cheap way information about olive pomace. Several samples (n
15 February 2018
Solving the dynamic economic dispatch by a memory-based global differential evolution and a repair technique of constraint handling
Publication date: 15 March 2018
Source:Energy, Volume 147 Author(s): Dexuan Zou, Steven Li, Xiangyong Kong, Haibin Ouyang, Zongyan Li In this paper, we propose a memory-based global differential evolution (MGDE) algorithm and a repair technique of constraint handling for the dynamic economic dispatch problems. On the one hand, MGDE modifies the mutation of DE/best/1, and uses a memory pool to provide more candidate solutions for this operation. Moreover, it adopts a randomly generated scale factor in the modified mutation to enhance its exploration capacity. In the crossover, a dynamical crossover rate is introduced to balance MGDE's global and local search capacities. On the other hand, a repair technique is designed for handling three kinds of constraints associated with generator capacity, power balance and generating unit ramp-rate. Moreover, a commonly used penalty function method is subsequently employed to handle the possible constraint violations associated with power balance and prohibited operation zones (POZs). To judge the performance of MGDE and the efficiency of the repair technique, we have solved six well-known DED problems taken from different sources. According to the experimental results, MGDE shows a superior performance in comparison with other improved DEs which also solve these problems. In the mean time, the repair technique of constraint handling has a high efficiency in eliminating or reducing the constraint violations.
15 February 2018
Co-firing of coal/biomass blends in a pilot plant facility: A comparative study between Opuntia ficus-indica and Pinus radiata
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Rub
15 February 2018
Control strategy and experimental analysis of a direct-expansion solar-assisted heat pump water heater with R134a
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Xiangqiang Kong, Kailin Jiang, Shandong Dong, Ying Li, Jianbo Li A direct-expansion solar-assisted heat pump (DX-SAHP) system was designed and built in Qingdao China, which was used to supply domestic hot water. The system mainly consisted of a bare solar collector/evaporator with area of 1.56
15 February 2018
Thermodynamic analysis of a modified system for a 1000
15 February 2018
Multi-generation system incorporated with PEM electrolyzer and dual ORC based on biomass gasification waste heat recovery: Exergetic, economic and environmental impact optimizations
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Fateme Ahmadi Boyaghchi, Mansoure Chavoshi, Vajiheh Sabeti In this paper, a multi-generation system comprising a dual organic Rankine cycle equipped with an ejector refrigeration loop, a biomass gasification process and a proton exchange membrane electrolyzer is developed to produce the syngas, power, refrigeration effect, heating load, hydrogen and oxygen. R245fa-R134a, R236fa-R1234yf and R600-R290 are applied as three organic working fluid groups inside the dual organic Rankine cycle. The system concerned is modeled using the exergy, exergoeconomic and exergoenvironmental analyses. An elitist non-dominated sorting genetic algorithm is individually used to optimize the thermodynamic, economic and environmental performances of the system for each working fluid group. The LINMAP and TOPSIS decision makers are applied to select the optimum performances of the system and electrolyzer. The optimization results show that the hydrogen cost and environmental impact per unit exergy are improved within 49.18% and 34.58%, respectively through the LINMAP method for R236fa-R1234yf. In addition, the maximum improvement in the total cost rate of the system is calculated within 39.5% for R245fa-R134a through the TOPSIS procedure and the highest increment in the environmental impact rate belongs to R236fa-R1234yf by about 34.69% using the LINMAP decision maker.
15 February 2018
Exergoenvironmental model of Organic Rankine Cycle system including the manufacture and leakage of working fluid
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Yang Ding, Chao Liu, Cheng Zhang, Xiaoxiao Xu, Qibin Li, Lianfei Mao An exergoenvironmental model of the Organic Rankine Cycle (ORC) system is established in this paper. The manufacture and leakage of working fluid are important in a life cycle assessment (LCA). The environmental impact of the working fluid is allocated to each component of the ORC system according to the exergy destruction of the corresponding component. R134a, R227ea, R152a, and R245fa are selected as the working fluids. In addition, the components in the ORC are manufactured with material steel or copper. The environmental impacts of the working fluids and components are analyzed, and the exergoenvironmental impact factors of the components are discussed. The results showed that the environmental impact of the working fluid cannot be neglected. The environmental impacts of R134a, R227ea, R152a, and R245fa are 13.76%, 26.04%, 2.62%, and 14.77% in the environmental impacts of overall system, respectively. The environmental impact caused by working fluid leakage is 67.52%, 75.62%, 35.71%, and 68.34% in the environmental impacts of the working fluid, respectively. The ORC system with R245fa has a minimal exergoenvironmental impact (steel: 70.06 mPts/h, copper: 83 mPts/h).
15 February 2018
The increasing impact of weather on electricity supply and demand
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Iain Staffell, Stefan Pfenninger Wind and solar power have experienced rapid cost declines and are being deployed at scale. However, their output variability remains a key problem for managing electricity systems, and the implications of multi-day to multi-year variability are still poorly understood. As other energy-using sectors are electrified, the shape and variability of electricity demand will also change. We develop an open framework for quantifying the impacts of weather on electricity supply and demand using the Renewables.ninja and DESSTINEE models. We demonstrate this using a case study of Britain using National Grid's Two Degrees scenario forwards to 2030. We find the British electricity system is rapidly moving into unprecedented territory, with peak demand rising above 70
15 February 2018
Urban water networks as an alternative source for district heating and emergency heat-wave cooling
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Xiaofeng Guo, Martin Hendel Urban water networks can contribute to the energy transition of cities by serving as an alternative source for heating and cooling. Indeed, the thermal energy potential of the urban water cycle is considerable. Paris is taken as an example to present an assessment of the field performance of a district-scale waste water heat recovery system and to explore potential techniques for emergency cold recovery from drinking or non-potable water networks in response to heat-waves. The heat recovery case study was found to provide significant greenhouse gas emission reductions (up to 75%) and limited primary energy savings (around 30%). These limited savings are found to be mainly due to the performance of the heat pump system. Three emergency cold recovery techniques are presented as a response to heat-waves: subway station cooling, ice production for individual cooling, and “heat-wave shelter” cooling in association with pavement-watering. The cold generation potential of each approach is assessed with a special consideration for mains water temperature sanitary limitations. Finally, technical obstacles and perspectives are discussed.
15 February 2018
Impact of human interventions on tidal stream power: The case of C
15 February 2018
Performance analysis of an evaporation process of plate heat exchangers installed in a Kalina power plant
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Hanna Mergner, Karlheinz Schaber In geothermal power generation, ammonia-water (NH3 H2O) mixtures are considered as working fluids in order to improve efficiency from low enthalpy heat sources. During the evaporation process, the NH3 H2O working pair as zeotropic working fluid has the advantage to evaporate not isothermal temperature but over a temperature glide to adapt better to the heat source temperature profile. By today, there is a lack of performance data from operational generation units available in literature that can be used for scientific works based on computational calculations to compare with. In this paper the data logs from the evaporation process of the geothermal power plant are analyzed in order to review the evaporator's performance. Data had been gathered for a period of 5 years and three key performance parameters were defined: pressure drop, vapor fraction and heat transmission capacity. The main parameters that influence the performance are the temperatures, pressures and flow rates. It turned out, that the NH3 mass fraction plays only a minor role within the evaporation process.
15 February 2018
Thermo-economic analysis of a novel cascade integrated solar combined cycle system
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Yuanyuan Li, Yamin Xiong Integrated solar combined cycle (ISCC) systems have been demonstrated to be more promising than solar-only power generation systems in terms of higher solar heat conversion efficiency and lower cost. In most ISCC projects, concentrating solar fields (e.g., parabolic trough solar fields with heat transfer (HTF) technology or direct steam generation (DSG) technology) are integrated for solar heat production with a temperature up to 400
15 February 2018
Simulation and optimization of humidification-dehumidification evaporation system
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Yang Li, Xin Huang, Hao Peng, Xiang Ling, ShanDong Tu In this paper, a theoretical and experimental investigation on HDH evaporation system performance was performed. A fixed size HDH system was constructed, and for the purpose to obtain the optimal operating parameters, a mathematical model was proposed to investigate the effect of the operating parameters on the evaporation rate and specific steam consumption (SSC). The evaporation rate is proportional to three operating parameters. SSC decrease with the increase of heat recovery ratio (HRR) in regenerator. Moreover, the operating parameters of the system were optimized to obtain minimum SSC using the GlobalSearch algorithm. The minimum SSC is 0.338–0.398
15 February 2018
An investigation into the effect of manifold geometry on uniformity of temperature distribution in a PEMFC stack
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Amir Amirfazli, Saeed Asghari, Mohammad Sarraf Thermal management is one of the most significant issues in reliability and durability enhancement of proton exchange membrane fuel cell (PEMFC). In this study, an experimentally validated analytical-numerical model of the stack is used to investigate the effect of manifold and cooling flow field channel dimensions on stack temperature uniformity. Moreover, a concept design for cooling manifold has been introduced with the purpose of increasing the total active area of the stack as well as achieving a more uniform distribution of the coolant flow rate between the cells. The U and Z stack configurations with various manifold cross sectional area and cooling flow field channel dimensions are compared with each other. The results indicate that decreasing the flow field channel dimension increase the stack temperature uniformity while increasing the manifold cross sectional area does not essentially increase the stack temperature uniformity. The introduced concept can be a feasible design for the limiting space application of fuel cell since more active area can be achieved with the same stack dimensions and temperature uniformity. However, the direction of the flow (stack configuration) would be the key issue to be considered in selection of the incremental direction of the manifold cross sectional area.
15 February 2018
Cooperative game of electricity retailers in China's spot electricity market
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Xu Peng, Xiaoma Tao Chinese electricity market has undergone twice reforms since 2002. However, the current electricity market is still partially irrational in electricity pricing mechanism. Furthermore, the utilization of renewable energy is inefficient in western regions. From the perspective of market participants, electricity retailers are new entrants in deregulated electricity market. In this spot electricity market, they are faced with various challenges and opportunities. Thus, this paper introduces an inter-regional power transaction model based on bottom-up modeling. There are mainly three parts in this paper:
15 February 2018
A coordinated energy security model taking strategic petroleum reserve and alternative fuels into consideration
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Dan Gao, Zheng Li, Pei Liu, Jiazhu Zhao, Yuning Zhang, Canbing Li Strategic petroleum reserve (SPR) and alternative fuels are both important for energy security. In this paper, a quantitative energy security model is proposed to calculate the optimized scales of SPR and alternative fuels (e.g., coal-converted methanol). The coordinated model mainly focuses on cost-benefit analysis, including the economic costs of SPR and alternative fuels, and the benefits for ensuring energy security. Demonstrating examples in China have been analyzed, and it shows that SPR and alternative fuels have coordinated effects in ensuring energy security, while alternative fuel is a supplementary method for reducing the negative effects of the raise of oil price and related economic losses. By the end of 2030, the net present value (NPV) will be considerably large with 150–200 million tons of SPR and 50–100 million tons of alternative fuels in China. Quantitative sensitivity analysis have been introduced for optimum scales and net present value (NPV) of SPR and alternative fuels, demonstrating that GDP/oil price elastic coefficient, domestic production of oil and investment of alternative fuels are key parameters for energy security. This model provides a quantitative method for the evaluations of the national energy security strategy.
15 February 2018
Multi-objective optimization framework for the selection of configuration and equipment sizing of solar thermal combisystems
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Anthony Rey, Radu Zmeureanu Solar combisystems supplying thermal energy for both domestic hot water and space heating can reduce primary energy consumption for residential buildings. As their overall performance depends on their design, this paper presents the development and use of a multi-objective optimization framework for the selection of configuration and equipment sizing of a residential solar combisystem in Montreal, Quebec, Canada. A generic solar combisystem model, which enables different configurations to be chosen, is first developed, and then coupled with a micro-time variant multi-objective particle swarm optimization, which was developed and used to find the non-dominated combisystem design alternatives. The life cycle cost (LCC), energy use (LCE), and exergy destroyed (LCX) of the solar combisystem are used as objective functions to find the best feasible designs. For the minimum LCC, only one flat-plate collector is required to store energy within one thermal storage tank, whereas seven evacuated-tube collectors and two thermal storage tanks are used for the minimum LCE value. The micro-time variant multi-objective particle swarm optimization (micro-TVMOPSO) algorithm used found a non-dominated solution that reduced the LLC by 29% compared with the initial design solution, with the increase of LCE by 72%. Since the LCC and LCE objective functions are conflicting, another non-dominated solution increased the LCC by 36% and reduced the LCE by 27%. The proposed multi-objective optimization framework can therefore be used to get the most out of solar thermal combisystems given specific economic and environmental conditions.
15 February 2018
Assisted power management of a stand-alone renewable multi-source system
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Achraf Abdelkafi, Abdelkarim Masmoudi, Lotfi Krichen The work presented in this paper deals with an assisted management of a standalone multi-source power system. The proposed structure consists of a wind turbine (WT) and a photovoltaic generator (PV) used as renewable sources, a super-capacitor (SC) as an energy storage system and a diesel generator (DG) as an emergency power supply. The aim of this work was to develop an assisted management strategy in order to control the power flow in the system operation with the highest reliability. Four limits of the SC state of charge (SOC) were defined states for the power control strategy. The main advantage of the used strategy was to protect the storage system from the deep charge and discharge and then increase its lifespan. The proposed energy management concept was tested in simulation by applying all possible cases. The obtained results confirm its efficiency and harmony between production and consumption was guaranteed.
15 February 2018
Performance study and comparative analysis of traditional and double-selective-coated parabolic trough receivers
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Honglun Yang, Qiliang Wang, Xiaona Huang, Jing Li, Gang Pei Based on the simulated non-uniformity solar radiation flux distribution of the absorber by the Soltrace software using the Monte Carlo Ray-Trace Method, an innovative parabolic trough solar receiver that employs two solar selective coatings with different properties on the outer surface of the absorber is proposed. The concentration ratio and absorber temperature that influence optimal cut-off wavelengths of the solar selective coatings are quantitatively analyzed to optimize the property of the coating. The optimal cut-off wavelength increases with the concentration ratio, but drops with the increasing absorber temperature. The heat transfer process of receivers is numerically simulated to predict the thermal performance of evacuated receivers based on spectrum parameters heat transfer model. Heat loss simulation results show that: the double-selective-coated receiver can reduce heat loss and boost the collecting efficiency significantly compared with PTR70 receiver. When the temperature of absorber is 500
15 February 2018
Effect of Reynolds number on supercritical helium axial compressor rotors performance in closed Brayton cycle
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Zhitao Tian, Qun Zheng, Bin Jiang Supercritical helium has been considered as an ideal working fluid in a number of design studies for closed Brayton cycle due to its thermal properties. But the low density level of supercritical helium, the characteristics of the small flow channel in the turbomachine and the variable working condition method of the system determine that the compressor may run at low Reynolds number. In this paper, the influence of Reynolds number on supercritical helium compressor rotor is investigated under different conditions by numerical simulation program. Effects of specific heat ratio on Reynolds number sensitivity of supercritical helium compressor rotor are also investigated by comparing the calculated results of different working fluids. Special attention is paid to the relationship between properties of working fluids and efficiency. Then, the equations of efficiency and total pressure ratio for different working fluids are established. The results show that the Reynolds number sensitivity of supercritical helium compressor rotor decreases with the increase of tip clearance and increases with the increase of the specific heat ratio.
15 February 2018
Catalytic cracking of biomass tar over char supported nickel catalyst
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Mian Hu, Mahmood Laghari, Baihui Cui, Bo Xiao, Beiping Zhang, Dabin Guo Catalytic cracking of biomass tar was investigated using steam gasification obtained char supported nickel catalyst in a lab-scale fixed bed reactor to determine the effects of catalytic cracking temperature, Ni loading and gas residence time on product distribution and gas composition. Results showed that the optimum catalytic cracking parameters were at 800
15 February 2018
Performance, combustion and emission characteristics of diesel engine fuelled with papaya and watermelon seed oil bio-diesel/diesel blends
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): M.A. Asokan, S. Senthur prabu, Shikhar Kamesh, Wasiuddin Khan In this paper, we have produced bio diesel from papaya and watermelon seed oil by trans-esterification process using methanol and KOH (catalyst) and a new biodiesel i.e. WP is produced which is a mixture of papaya seed oil biodiesel and watermelon seed oil biodiesel in 1:1 ratio is prepared. The blends (B0, B20, B30, B40, and B100) of WP with diesel and watermelon 100% and papaya 100% are used for further testing. The performance, combustion and emission test were conducted on single cylinder 4-stroke diesel engine using different blends of these biodiesels and the results showed that B20 is superior blend among other biodiesel blends. Further the performance and combustion characteristics of B20 is very close to diesel while the emission characteristics of B20 is better than that of diesel as the emission of CO, HC and smoke is 27.27%, 23.8%, 8.3% less for B20 than diesel respectively. Thus we concluded that B20 is the most suitable blend of WP for substitute of diesel which will reduce diesel consumption by 20%.
15 February 2018
A framework for real-time monitoring of energy efficiency of marine vessels
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Hongtao Chi, Giulia Pedrielli, Szu Hui Ng, Thomas Kister, St
15 February 2018
Transient response of the flexible blade of horizontal-axis wind turbines in wind gusts and rapid yaw changes
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Abbas Ebrahimi, Mahmood Sekandari In this paper, the aeroelastic analysis of a large scale wind turbine rotor is performed with the aim of studying transient performance of turbine in extreme wind conditions, such as wind gusts and rapid yaw changes. The effect of the presence and/or lack of blade pitch control system on output power, rotor thrust, and blade deformation in sudden change of wind speed are investigated. The NREL 5
15 February 2018
Wind resource assessment offshore the Atlantic Iberian coast with the WRF model
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): N. Salva
15 February 2018
Novel classification of pure working fluids for Organic Rankine Cycle
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): G
15 February 2018
Hierarchical control strategy with battery aging consideration for hybrid electric vehicle regenerative braking control
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Jian Wu, Xiangyu Wang, Liang Li, Cun'an Qin, Yongchang Du Regenerative braking is a key technology for hybrid electric vehicles (HEVs) to improve fuel economy, and it is a multi-objective control problem, which should ensure vehicle braking safety, recover more energy, and protect components from aging. As is known, battery is the most sensitive component in hybrid powertrain, so a large recover current can cause damage to the battery and reduce its life. However, the damage to is usually ignored in regenerative braking. Therefore, this paper proposed a hierarchical control strategy with battery aging consideration to solve the problem. In the up-level controller, the control targets are to recover more energy and minimize aging of the battery in general braking mode, and ensuring the vehicle braking safety in emergency braking mode at the same time. The low-level controller receives the commands of the up-level controller, and controls the pneumatic braking system and the electric motor (EM). The constraints of maximum EM torque and maximum battery charging power are set to protect the EM and the battery. Simulation tests are designed to indicate the effects of regenerative braking on battery aging and the control effectiveness of the proposed method, and controller-in-the-loop tests are carried out to verify the real-time calculation performance.
15 February 2018
Influence of the steam generator on the exergetic and exergoeconomic analysis of solar tower plants
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): J. G
15 February 2018
Understanding the thermodynamic and kinetic performances of the substituted phosphorus ylides as a new class of compounds in carbon dioxide activation
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Hossein Sabet-Sarvestani, Mohammad Izadyar, Hossein Eshghi, Nazanin Noroozi-Shad The investigation of thermodynamic and kinetic behavior of the carbon dioxide activation in the presence of the phosphorus ylides (P-ylides) is the main purpose of this study. Different substituents on the carbon atom of the P-ylides have different effects on the P-ylides performances in the carbon dioxide activation. The accessibility of the lone pair electrons on the carbon atom has a remarkable effect on the thermodynamic features of the reaction. A greater involvement of this carbon atom with the orbitals of the substituted groups decreases its reactivity in the CO2 fixation and Gibbs energy increment. A similarity in the energy levels of the involved orbitals of the carbon dioxide and P-ylides is another factor that affects the thermodynamics of the reaction. The proximity of the energy levels corresponding to the lone pair electrons on the carbon atom of the P-ylides and
15 February 2018
A thorough investigation on hybrid application of biomass gasifier and PV resources to meet energy needs for a northern rural off-grid region of Bangladesh: A potential solution to replicate in rural off-grid areas or not?
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Md Shahinur Islam, Ruma Akhter, Mohammad Ashifur Rahman Rural electrification is a critical global challenge specifically in developing countries and Bangladesh is no exception. Most of the people live in the rural areas of the country and having no access to grid electricity hindering the development of these areas and the overall progress of the country's economy severely. In this regard, renewable energy based hybrid mini-grid can be a viable solution to ensure access to electricity for all. This paper presents a case study of supplying electricity through hybrid mini-grid to the rural unelectrified areas of the northern region of Bangladesh, and provides an analysis of its business creation, operation and related challenges. The study involves modelling of three alternative configurations for electricity generation with the different combination of solar energy, biomass generator, diesel generator and battery storage resources. Hybrid Optimization Model for Electric Renewable (HOMER) software is used to carry out the techno-economic analysis and identify the optimal off-grid system configuration. The analysis exposed that the per unit cost of electricity from the optimum off-grid supply configuration is much higher than the regulated tariff for grid connected residential consumers and cannot reach grid parity even with the full capital subsidy. However, the cost of off-grid supply is economical than the diesel-only supply option or the cost of owning a solar home system. The analysis further considered different electricity selling tariff to obtain a practical and reasonable payback period to make the proposed hybrid mini-grid system economically worthwhile. From the emission analysis, it is found that the proposed hybrid system would produce 75% lower CO2 than the existing methods of fulfilling energy needs in the study area.
15 February 2018
Selective catalytic reduction in a rotary air heater (RAH-SCR)
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Robert Wejkowski, Wac
15 February 2018
Feasibility assessment of a novel refrigeration FCC gas plant driven by self waste heat
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Siyao Liu, Chengtian Cui, Jie He, Jinsheng Sun Fluid catalytic cracking (FCC), an important post-processing, converts wet gas and crude gasoline into dry gas, LPG and stabilized gasoline in its gas plant. On-site dry gas from the absorber contains residual LPG at absorption temperatures higher than requirement because of very limited refrigeration capacity of cooling water (CW). Whereas this LPG lost co-exists with that of waste heat sources in the same unit, potentially capable of generating deeper chilling energy than CW to decrease absorption temperature. This context triggers heat integration for refrigerated FCC gas plant scheme through self waste heat recovery, also beneficiary from improved product yield. The target requirement helps screen out two candidates from a variety of possible methods: organic Rankine cycle with compression refrigeration (ORC-CR) and absorption refrigeration (AR). Feasibility of these two pathways was simulatively assessed, by Aspen Plus™, to demonstrate the superiority of AR over ORC-CR in efficiency at the optimum cooling temperature of 15
15 February 2018
Design, construction, testing and performance of split power solar source using mirror photovoltaic glass for electric vehicles
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): R. Maruthi Prasad, A. Krishnamoorthy Solar photovoltaic panels are prominently integrated into electric vehicle rooftop to charge the battery bank. In this paper, the performance of the conventional solar power source architecture employed in electric vehicles is analyzed using PVsyst real-time simulator. The limitations with solar photovoltaic panels and conventional solar power source are addressed through a novel mirror photovoltaic glass and split power solar source architecture. The design, manufacturing and structural merits of split power solar source are presented. The operational behavior of split power solar source is validated using Matlab. The performance of the mirror photovoltaic glass is analyzed at standard test conditions and various combinations of irradiation and temperatures using climate chamber solar simulator. The performance of mirror photovoltaic glass at on-site conditions is analyzed by comparing with climate chamber solar simulator results. Further, the analysis is validated through a convection analysis carried out using ANSYS. Subsequently, the performance of the split power solar source is studied using PVsyst real-time simulator. The split power source architecture is obtained as the best feasible solar power source design for an electric vehicle in terms of material requirement, replacement cost, withstanding capability, space utilization, power loss, tracking mechanism feasibility and performance through the comparative study.
15 February 2018
The causality link between energy electricity consumption, CO2 emissions, R&D stocks and economic growth in Mediterranean countries (MCs)
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Bassem Kahouli This study examined the four-way linkages between electricity consumption, CO2 emissions, R&D stocks and economic growth for the MCs over the 1990–2016 periods, by implementing several estimators: SUR, 3SLS and GMM. The specification of these econometric techniques is that the four sets of equations (electricity, CO2, R&D and growth models) are estimated jointly through the system of equations. These techniques make it possible to estimate all the parameters of the models at the same time and solve the problem of endogeneity. Under conditional homoskedasticity, GMM reduces to 3SLS if the set of instrumental variables is common to all equations. If we further assume that all the regressors are predetermined, then 3SLS reduces to SUR. Empirical results confirm the existence of strong feedback effects between electricity, CO2 emissions, R&D stocks and economic growth (especially in SUR estimator). However, the results support the occurrence of unidirectional causality between electricity and R&D stocks (in 3SLS) while the other relationships exist. On the one hand, here is unidirectional causality among R&D stocks and economic growth as well as unidirectional causality between R&D stocks and CO2 emissions, on the other hand (GMM estimator). The study consolidates the policy insights to control the environment from degradation by using energy-efficient technologies. It is important for policymakers in formulating a conclusive, economic, energy and environmental policies to meet the bourgeoning energy demand in MCs. They should concentrate on allocating funds to adopt environmentally friendly technologies and encourage using more energy-efficient technologies for production purposes and thus preserving the environment from degradation.
15 February 2018
Atmospheric extinction levels of solar radiation at Plataforma Solar de Almer
15 February 2018
Industrial sectors' energy rebound effect: An empirical study of Yangtze River Delta urban agglomeration
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Xiaoling Ouyang, Beiying Gao, Kerui Du, Gang Du As the most prosperous area and one of China's major economic centers, Yangtze River Delta urban agglomeration (YRDUA) shows the largest concentration of adjacent metropolitan areas in the world. Its energy conservation and emissions reduction efforts are critical for developing a low carbon economy in China. Based on panel data of 14 cities from 2003 to 2013, this study estimates the rebound effect's magnitude in YRDUA's industrial sectors using dynamic ordinary least squares (DOLS) and seemingly unrelated regression (SUR) methods. The empirical results are as follows: (1) Significant substitute relationships exist between energy and capital factors and between energy and labor factors. (2) The own-price elasticity of labor is the most elastic, followed by those of energy and capital. (3) The rebound effect is approximately 40.04%. Evidence suggests that promoting financial development, conducting structural reform in the supply side, and establishing reasonable controls of industrial growth and scale expansion are conducive for energy conservation and pollution alleviation of YRDUA's industrial sectors.
15 February 2018
Spatial and geographic heterogeneity of wind turbine farms for temporally decoupled power output
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Nathaniel S. Pearre, Lukas G. Swan Many regions with good wind resources and aggressive renewable energy portfolio targets have achieved installed wind turbine capacity that is difficult for electricity system operators to manage. The purpose of this paper is to compare the measured output of wind farms at various locations throughout Nova Scotia, looking specifically at factors that either facilitate or hamper integration of additional capacity into the existing grid system. Special emphasis is placed on the effects of aggregating wind farms that are separated by distance and geography, and consequently experience different wind conditions at different times. The results are presented using metrics that have significance to electricity grid system operators, and new metrics that are accessible, readily interpretable, and actionable in locating new wind farms. The principle findings are that over a distance of 540
15 February 2018
Effect of ambient temperature on the puffing characteristics of single butanol-hexadecane droplet
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Yu Zhang, Ronghua Huang, Yuhan Huang, Sheng Huang, Yinjie Ma, Shijie Xu, Pei Zhou Puffing characteristics of BUT50 (50% n-butanol and 50% n-hexadecane by mass) were investigated using the droplet suspension technology under 638, 688 and 738
15 February 2018
A flexible active distribution system expansion planning model: A risk-based approach
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): M. Moradijoz, M. Parsa Moghaddam, M.R. Haghifam This paper presents an active distribution network expansion planning framework, which concurrently uses the renewable distributed generations and energy storage systems as capacity expansion options. In order to enhance the network reliability, the model takes into account the island mode operation of the renewable resources and energy storage systems. The proposed planning framework, which is modeled as a probabilistic bi-level optimization problem quantifies and controls the economic risk level associated with the stochastic nature of these resources. The master level is devoted to the here-and-now decisions in the planning phase, whereas the slave level, which is formulated as a two-stage model, is related to the wait-and-see decisions in the operational phase. At the first stage of the slave level, the network operational behaviour is determined by performing an optimal power flow modeled as a mixed-integer linear programming problem. At the second stage of the slave problem, the network reliability is optimized considering island mode operation and taking into account energy-limited nature of storage systems. The effectiveness of the proposed active distribution network planning model is demonstrated through several case studies. Simulation results demonstrate that the proposed approach can result in a flexible low-risk plan for the expansion of the network.
15 February 2018
Study on ammonia/water hybrid absorption/compression heat pump cycle to produce high temperature process water
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Chung Woo Jung, Joo Young Song, Yong Tae Kang The objectives of this paper are to analyze the heat transfer characteristics during the ammonia water absorption process for the hybrid absorption/compression heat pump system application. The hybrid absorption/compression heat pump cycle aims at obtaining the high temperature process water. The parametric analysis on the effects of each key parameter, which are system high-pressure, ammonia weak solution concentration, ammonia weak solution and vapor flow rates is carried out. It is found that the increases in the high pressure and ammonia weak solution flow rate have positive effects on the absorber heat transfer rate, whereas the increase in the weak solution concentration does negative effect. It is also found that the weak solution concentration acts as the most important parameter to obtain the high temperature process water. As the weak solution concentration increases, the absorber heat transfer rate decreases, but the system COP tends to increase. It is concluded that the concentration of the weak solution should be maintained at approximately 0.40–0.45, the flow rate of the weak solution be lower than 0.03
15 February 2018
Value of performance baseline in voluntary carbon trading under uncertainty
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Xiaoyu Liu, Qingbin Cui Voluntary carbon trading has long been criticized for producing a large number of non-additional offsets. The reason for this production lies primarily in the use of a project-based baseline that misrepresents the business-as-usual (BAU) emissions of individual projects. Performance baseline however, as an alternative baseline approach, does not rely on evaluating individual BAU emissions. Instead, it uses a pre-defined emission threshold for a class of project activities. This paper compares the effects of the two baseline approaches on sectoral emission mitigation and compliance costs by modeling dynamic emission abatement behaviors. In the context of the U.S. commercial building sector, the modeling results indicate that while both baseline approaches are capable of reducing sectoral emissions, the use of performance baseline is especially advantageous under private cost information and uncertain market environments. The performance baseline should be stratified by region to ensure the equity in offset allocation in sectors that are highly diversified in emission magnitudes.
15 February 2018
Repeated batch methanol production from a simulated biogas mixture using immobilized Methylocystis bryophila
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Sanjay K.S. Patel, Sanath Kondaveeti, Sachin V. Otari, Ravi T. Pagolu, Seong Hun Jeong, Sun Chang Kim, Byung-Kwan Cho, Yun Chan Kang, Jung-Kul Lee In this study, biological methanol production under repeated batch conditions by immobilized Methylocystis bryophila, using simulated biogas of methane (CH4) and carbon dioxide (CO2) as a feed is demonstrated for the first time. The composition of the simulated gas mixtures significantly influenced methanol production by M. bryophila, and in all cases, higher concentrations were achieved than with pure CH4 alone. Under optimum conditions, maximum methanol concentrations of 4.88
15 February 2018
A study of the relationship between coulombic efficiency and capacity degradation of commercial lithium-ion batteries
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Fangfang Yang, Dong Wang, Yang Zhao, Kwok-Leung Tsui, Suk Joo Bae High coulombic efficiency (CE) usually indicates a long battery cycle life. However, the relationship between long-term CE evolution and battery degradation is not fully understood yet. This paper explores the behavior of long-term CE and clarifies its relationship with capacity degradation. Cycle life tests are conducted on two types of mainstream commercial lithium-ion batteries. An incremental capacity (IC) analysis is then employed to identify battery aging mechanisms. Experimental observations along with in-depth discussions are presented regarding battery degradation, aging mechanisms, and CE evolution. From the experimental results, two typical degradation patterns are recognized. From the IC analysis, we observed that, in addition to a loss of lithium inventory, a loss of active material accelerates battery degradation and brings down CE values. From an electrochemical perspective, this paper establishes the relationship between CE evolution and capacity degradation. This relationship can help develop battery degradation models, estimate battery health states, and provide early failure warnings for a battery management system.
15 February 2018
NOx model development and validation with diesel and hydrogen/diesel dual-fuel system on diesel engine
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Madan Kumar, Taku Tsujimura, Yasumasa Suzuki In this paper, a common NOx model for hydrogen and diesel fueled combustion engines is developed and experimentally validated on a diesel engine with diesel and hydrogen/diesel dual-fuel operation system. The model is developed based on the simple measurement with the commonly used sensors situated on the engine system. NOx model is then calibrated with NOx sensor in diesel and hydrogen/diesel dual-fuel operation experiment with different engine variables, such as engine speed, engine brake power (equivalence ratio), hydrogen energy share ratio, injection timing and exhaust gas re-circulation (EGR). From results, it is observed that the model performed well in diesel engine with diesel fuel operation, injection timing and EGR with a single calibration factor on wider range of operating conditions. Moreover, NOx model has also shown satisfactory results with hydrogen/diesel dual-fuel combustion using a single calibration factor on a fixed operating condition (speed and brake power constant) with hydrogen ratio changes. The changes in calibration factor evident different fuel combustion properties and flame temperature kernel travel in cylinder changes for diesel and hydrogen fuel. Hence, finally, it can be stated that the developed NOx model can be used for diesel as well as hydrogen/diesel dual-fuel engines with simple calibration efforts.
15 February 2018
Analysis of a displacer-coupled multi-stage thermoacoustic-Stirling engine
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): J.Y. Hu, E.C. Luo, L.M. Zhang, Y.Y. Chen, Z.H. Wu, B. Gao A new thermoacoustic-Stirling engine is introduced, composed of a compressor, regenerative assemblies, displacers and an alternator. The regenerative assemblies are coupled to displacers to successively multiply the acoustic power input by the compressor. The amplified acoustic power is converted into electric power in the alternator. This new configuration overcomes the limitations of traditional thermoacoustic or Stirling engines, including losses in long resonant tubes, response hysteresis and current inversion. The design method of the displacers and alternators is presented. Numerical simulations are carried out to investigate the characteristics of this system. Results show that the overall efficiency of this system could reach 47% with heating temperature of 900

The pattern of electricity use in residential sector: The experiences from 133 economies
Publication date: 15 February 2018
Source:Energy, Volume 145 Author(s): Hua Liao, Huai-Shu Cao While growing electricity consumption in residential sectors worldwide will draw more attention in economic and policy related decisions, the fast-growing developing world still requires enormous amounts of electric power to achieve better living conditions. This dilemma can hardly be addressed without a thorough understanding of the relationship between economic development and residential electricity demand. Based on a country-level panel data set covering 133 countries or regions over four decades, this paper aims to investigate how the historical relationship between economic development and residential electricity use evolved. Different to previous studies, we are not assuming the curve shape of the electricity use and economy in advance. A flexibly piecewise spline model is employed rather than the commonly used linear, quadratic, cubic polynomial or S shape saturation curve model. We capture an inverted-U relationship, and the turning point is at about $20,000 (purchasing power parity, 2005 constant price). This pattern is robust in the sense that it is not sensitive to eliminating any special countries or to alternative model specifications. These results are important for understanding the future trend of electricity consumption in the less developed world.
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