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Volume 40

2016

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2016 International Conference on New Energy and Future Energy System (NEFES 2016) 19–22 August 2016, Beijing, China

Preface

011001
The following article is Open access

Preface

The 2016 International Conference on New Energy and Future Energy System (NEFES 2016) will be held from August 19 to 22, 2016 in Beijing, the capital of China.

The 2016 International Conference on New Energy and Future Energy System (NEFES 2016) is organized to provide a platform for researchers and practitioners in both industry and academia to develop ideas and thoughts, share their latest achievements and discuss the possiblities and challenges in terms of new energy and future energy systems. NEFES 2016 aims to cover various fields of new energy materials and resources, and their networking and computing issues. The key focus of the conference will be on the areas of "New Energy", "InterGrid" and "New Energy Material".

This proceedings of the NEFES 2016 conference contain 87 specially selected manuscripts submitted to the conference. We have organized the peer review and plagiarism check for each article to ensure the paper quality.

We would like to take this opportunity to thank all authors who contributed to this conference, and particularly those of all accepted papers for their high quality and successful contributions. Special thanks go to all reviewers for their careful and critical reading of the manuscripts and useful comments and suggestions. We do hope that these proceedings will be beneficial for readers in their future research endeavours and careers. We also gratefully acknowledge the efforts and dedication of many individuals, especially IOP colleagues, including Anete Ashton and all the Editorial Board members in IOP Publishing for their support in producing the proceedings of this event.

011002
The following article is Open access

All papers published in this volume of IOP Conference Series: Earth and Environmental Science have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

Papers

012001
The following article is Open access

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This study presents an improved thermal network model of the IGBT module that considers the effects of base plate solder fatigue on the junction temperature of the said module used in wind power converters. First, the coupling thermal structure 3D finite element model of the IGBT module is established based on the structure and material parameters of the module used in the wind power converters of a doubly fed induction generator. The junction temperature of the module is also investigated at different thermal desquamating degrees of the base plate solder. Second, the thermal resistance parameters are determined at different desquamating degrees, and the improved thermal network model that considers the effects of base plate solder fatigue is established. Finally, the two results of the calculation of the junction temperature are compared in different fatigue stages through the improved thermal network model and the 3D finite element model, which testify to the effectiveness of the improved thermal network model.

012002
The following article is Open access

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The high-temperature oxygen ignition technology of pulverized coal, which can replace the oil gun and achieve oil-free pulverized coal ignition by mixing the high- temperature oxygen and the pulverized coal stream directly, was proposed and a relevant ignition experimental system was built. The ignition characteristics of pulverized coal under high-temperature oxygen condition were investigated: the ignition process was described and analyzed, the influence of relevant parameters on the pulverized coal stream ignition were obtained and analyzed. The results showed: when the oxygen heating temperature is over 750 °C, the pulverized coal stream could be ignited successfully by high-temperature oxygen; increasing the pulverized coal concentration, primary air temperature and oxygen volume flow rate or decreasing the primary air velocity is helpful for the ignition and combustion of the pulverized coal stream.

012003
The following article is Open access

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This paper presents an active and reactive power dynamic optimization model for active distribution network (ADN), whose control variables include the output of distributed generations (DGs), charge or discharge power of energy storage system (ESS) and reactive power from capacitor banks. To solve the high-dimension nonlinear optimization model, a new heuristic swarm intelligent method, namely wolf pack algorithm (WPA) with better global convergence and computational robustness, is adapted so that the network loss minimization can be achieved. In this paper, the IEEE33-bus system is used to show the effectiveness of WPA technique compared with other techniques. Numerical tests on the modified IEEE 33-bus system show that WPA for active and reactive multi-period optimization of ADN is exact and effective.

012004
The following article is Open access

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The public enjoy an important role in the development of China's new energy industry. However, the role has not attracted sufficient attention. By the way of field investigation, the paper acquired the first hand data of the public cognition on the China's new energy industry. Survey data showed that the public enjoyed awareness of China's new energy industry to some extent. And the public had optimistic expectations on the future development of new energy industry. Moreover, there were obvious differences in the degree of public's familiarity with different new energy varieties. The education level and age of the individual public had a significant impact on his awareness of China's new energy industry. To raise public participation in China's new energy industry, it entailed highlighting the status of the public in China's new energy industry, increasing the publicity of the new energy industry with different measures for different types of public group.

012005
The following article is Open access

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An economic-energy-industrial-environmental optimization (EEIEO) model is proposed for identification of optimal economic, industry, energy and environment strategies. The EEIEO model is applied to a real case of Beijing-Tianjin-Hebei (BTH) region, which is the important economic growth pole of northern China. The EEIEO model could fully consider the interaction between industrial, energy, urbanization and environment sector, and generate the optimized economic development, industrial restructuring, energy consumption and environment management schemes. This is first attempt to introduce economic, energy, industrial, urbanization and environmental sectors into an optimization framework, while sustainable energy and environment development pathways are explored through EEIEO model. The results suggest that: (i) the GDP of BTH region would increase about 73.80% over the planning horizon; (ii) the contribution of tertiary industry for BTH region's economic development would gradually increase from 54.00% in 2015 to 65.00% in 2030; (iii) the consumption of coal would decrease by 36%, and the natural gas would obviously increase by 97.70% over the planning horizon; and (iv) the SO2, smoke and dust emissions and CO2 would reduce by 30.20%, 35.30% and 4.50% from 2015 to 2030, respectively.

012006
The following article is Open access

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To evaluate the optical performance of a CPC based concentrating photovoltaic system, it is essential to find the angular dependence of optical efficiency of compound parabolic concentrator (CPC-θe) where the incident angle of solar rays on solar cells is restricted within θe for the radiation over its acceptance angle. In this work, a mathematical procedure was developed to calculate the optical efficiency of CPC-θe for radiation incident at any angle based radiation transfer within CPC-θe. Calculations show that, given the acceptance half-angle (θa), the annual radiation of full CPC-θe increases with the increase of θe and the CPC without restriction of exit angle (CPC-90) annually collects the most radiation due to large geometry (Ct); whereas for truncated CPCs with identical θa and Ct, the annual radiation collected by CPC-θe is almost identical to that by CPC-90, even slightly higher. Calculations also indicate that the annual radiation on the absorber of CPC-θe at the angle larger than θe decrease with the increase of θe but always less than that of CPC-90, and this implies that the CPC-θe based PV system is more efficient than CPC-90 based PV system because the radiation on solar cells incident at large angle is poorly converted into electricity.

012007
The following article is Open access

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Energy consumption of building accounts for more than 37.3% of total energy consumption while the proportion of energy-saving buildings is just 5% in China. In this paper, in order to save potential energy, an office building in Southern China was selected as a test example for energy consumption characteristics. The base building model was developed by TRNSYS software and validated against the recorded data from the field work in six days out of August-September in 2013. Sensitivity analysis was conducted for energy performance of building envelope retrofitting; five envelope parameters were analyzed for assessing the thermal responses. Results indicated that the key sensitivity factors were obtained for the heat-transfer coefficient of exterior walls (U-wall), infiltration rate and shading coefficient (SC), of which the sum sensitivity factor was about 89.32%. In addition, the results were evaluated in terms of energy and economic analysis. The analysis of sensitivity validated against some important results of previous studies. On the other hand, the cost-effective method improved the efficiency of investment management in building energy.

012008
The following article is Open access

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The oxidation stability of the domestic and import PAO aviation lubricating base oil was studied by the method of pressurized differential scanning calorimetry testing the initial oxidation temperature. The effects of anti-oxidants were investigated, and the best ratio of antioxidants was determined.

012009
The following article is Open access

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Electric and unmanned is a new trend in the development of automobile, cable charging pile can not meet the demand of unmanned electric vehicle. Wireless charging system for electric vehicle has a high level of automation, which can be realized by unmanned operation, and the wireless charging technology has been paid more and more attention. This paper first analyses the differences in S-S (series-series) and S-P (series-parallel) type resonant wireless power supply system, combined with the load characteristics of electric vehicle, S-S type resonant structure was used in this system. This paper analyses the coupling coefficient of several common coil structure changes with the moving distance of Maxwell Ansys software, the performance of disc type coil structure is better. Then the simulation model is established by Simulink toolbox in Matlab, to analyse the power and efficiency characteristics of the whole system. Finally, the experiment platform is set up to verify the feasibility of the whole system and optimize the system. Based on the theoretical and simulation analysis, the higher charging efficiency is obtained by optimizing the magnetic coupling mechanism.

012010
The following article is Open access

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In order to improve the coupling coefficient of EV wireless power chargers, it's important to optimize the magnetic couplers. To improve the coupling coefficient, the relationship between coupling coefficient and efficiency is derived, and the expression of coupling coefficient based on magnetic circuit is deduced, which provide the basis for optimizing the couplers. By 3D FEM simulation, the optimal core structure and coils are designed for unipolar circular couplers. Experiments are designed to verify the correctness of the optimization results, and compared with previous coupler, the transmission efficiency is improved and weight is reduced.

012011
The following article is Open access

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Currently, there are many means by which to classify solar domestic hot water systems, which are often categorized according to their scope of supply, solar collector positions, and type of heat storage tank. However, the lack of systematic and scientific classification as well as the general disregard of the thermal performance of the auxiliary heat source is important to DHW systems. Thus, the primary focus of this paper is to determine a classification system for solar domestic hot water systems based on the positions of the solar collector and auxiliary heating device, both respectively and in combination. Field-testing data regarding many central solar DHW systems demonstrates that the position of the auxiliary heat source clearly reflects the operational energy consumption. The consumption of collective auxiliary heating hot water system is much higher than individual auxiliary heating hot water system. In addition, costs are significantly reduced by the separation of the heat storage tank and the auxiliary heating device.

012012
The following article is Open access

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The present work endeavors to explore the asymmetric effect of coal price on the China's macro economy by applying nonlinear autoregressive distributed lag (NARDL) model for the period of January 2005 to June 2015. The obtained results indicate that the coal price has a strong asymmetric effect on China's macro economy in the long-run. Namely one percent increase in coal price leads to 0.6194 percent of the China's macro economy increase; and while the coal price is reduces by 1 percent, the China's macro economy will decrease by 0.008 percent. These data indicate that when coal price rises, the effect on China's macro economy is far greater than the price decline. In the short-run, coal price fluctuation has a positive effect on the China's macro economy.

012013
The following article is Open access

The traditional limiting conditions have the biggest refrigeration quantity condition and the biggest refrigeration coefficient condition, there is a special operating mode during these conditions, enabling to both have the big refrigeration quantity and the small power loss, this operating mode is "Optimum condition". This article first carried on the theoretical analysis to the semiconductor's optimum condition, inferred optimum electric current's theoretical formula; Carried on the experiment again to a semiconductor refrigeration box by regulating current changing operating mode, which had analyzed performance parameter's change situation under 8 kinds of condition experiments, carried on the regression analysis to the experimental data, obtained the regression equation thus discovered optimum electric current corresponding optimum condition. Carried on working under this condition, and then obtained the big refrigeration quantity and small power, which enhanced the refrigeration performance of semiconductor refrigerator. The experimental result and the theoretical analysis result tallied basically.

012014
The following article is Open access

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There is limited research of commercial buildings' energy use data conducted based on practical analysis in China nowadays. Some energy consumption quota tools like Energy Star in U.S or VDI 3807 in Germany have limitation in China's building sector. This study introduces an innovative methodology of applying energy use quota model and empirical management to commercial buildings, which was in accordance of more than one hundred opened shopping centers of a real estate group in China. On the basis of statistical benchmarking, a new concept of "Modified coefficient", which considers weather, occupancy, business layout, operation schedule and HVAC efficiency, is originally introduced in this paper. Our study shows that the average energy use quota increases from north to south. The average energy use quota of sample buildings is 159 kWh/(m2.a) of severe cold climate zone, 179 kWh/(m2.a) of cold zone, 188 kWh/(m2.a) of hot summer and cold winter zone, and 200 kWh/(m2.a) of hot summer and warm winter zone. The energy use quota model has been validated in the property management for year 2016, providing a new method of commercial building energy management to the industry. As a key result, there is 180 million energy saving potential based on energy quota management in 2016, equals to 6.2% saving rate of actual energy use in 2015.

012015
The following article is Open access

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Experiments were carried out in an atmospheric two-stage fixed bed reactor to investigate the catalytic cracking of pinewood pyrolysis vapour over three single catalysts, HZSM-5, NaY and MCM-41. The pinewood was pyrolyzed in the first stage reactor at a heating rate of 10 °C min-1 from room temperature to 700 °C, and the resultant vapour was cracked through the second reactor at a temperature of 500, 600 or 700 °C with and without catalyst. Both the gases and liquid compounds were thoroughly determined. It was found that all three catalysts had significant catalytic effects on the vapour cracking especially in the range of 500-600 °C. However, three catalysts showed dissimilarity to each other with respect to the distributions of products. Among three catalysts, HZSM-5 displayed the highest selectivity for the formation of olefins and light aromatics, with the least deposit of coke, though NaY showed the strongest capability of deoxygenation. The HZSM-5 cracking at 600 °C was preferred to balance the yield and quality of bio-products. MCM-41 behaved as a worse catalyst in the deoxygenation, and its resultant liquid product contained more heavy aromatics.

012016
The following article is Open access

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With the energy crisis and the increasing environmental pollutionmore and more efforts have been made about wind power development. In this paper, a new type of vertical axis named the fish-bionic wind wheel was proposed, and the outline of wind wheel was constructed by curve of Fourier fitting and polynomial equations. This paper attempted to research the relationship between the setting angle and the wind turbine characteristics by computational fluid dynamics (CFD) simulation. The results showed that the setting angle of the fish-bionic wind wheel has some significant effects on the efficiency of the wind turbine, Within the range of wind speed from 13m/s to 15m/s, wind wheel achieves the maximum efficiency when the setting angle is at 37 degree. The conclusion will work as a guideline for the improvement of wind turbine design.

012017
The following article is Open access

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A soluble boron-free small modular pressurized water reactor (SMPWR) uses burnable absorbers (BA) instead of soluble boron to reduce excess reactivity. As a consequence, the fuel cycle length can be shortened by the residual penalty of BA. This paper performs cutback sensitivity tests to extend the cycle length. The influence of the height of the cutback, of the 235U enrichment rate, and of the BA material on the power peaking factor (Fq), the axial offset (AO) and the fuel cycle length is analyzed with the reactor core design system, CASMO-4E/SIMULATE-3 code system.

012018
The following article is Open access

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Solar irradiance and daylight illuminance are important for solar energy and daylighting designs. Recently, the International Commission of Illuminance (CIE) adopted a range of sky conditions to represent the possible sky distributions which are crucial to the estimation of solar irradiance and daylight illuminance on vertical building facades. The important issue would be whether the sky conditions are correctly identified by the accessible variables. Previously, a number of climatic parameters including sky luminance distributions, vertical solar irradiance and sky illuminance were proposed for the CIE sky classification. However, such data are not always available. This paper proposes an approach based on the readily accessible data that systematically recorded by the local meteorological station for many years. The performance was evaluated using measured vertical solar irradiance and illuminance. The results show that the proposed approach is reliable for sky classification.

012019
The following article is Open access

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Alternately injecting the slug of the gel and polymer/surfactant compound system is a new way to further enhance oil recovery after polymer flooding. The displacement system needs to produce an ultra low interfacial tension to oil and to enlarge swept volume significantly. Based on experimental analysis, the influence factors of Cr3+ gel system viscosity and the compatibility of gel with two types of surfactant compared with composite ion gel system has been studied. The experimental result shows that it has well stability, and the compatibility of gel with RMA-1 type surfactant is very well. It can produce an ultra low interfacial tension to oil so that enhanced oil recovery has been reached more than 10 percent by using the gel system to displace residual oil after polymer flooding in artificial large flat- panel model.

012020
The following article is Open access

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At present the waterflood efficiency is lower in most low permeable heterogeneous reservoirs, and the effect is poor using common polymer as profile control and displacement agent. As a new agent for profile control and displacement, the flow behavior of the nanomicron microsphere is evaluated in laboratory in this paper. The experimental result shows that it has well injectivity and flowability when flowing through the low permeability core. Because the nano-micron microsphere has a behavior of gradual expansion, it can be able to decrease permeability of porous medium very well. Especially in the process of subsequent water injection, the injection pressure increases firstly and then appears a small fluctuation declining, which shows that nano-micron microsphere solution has better antiscour performance and ability of gradual controlling and sealing.

012021
The following article is Open access

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In order to study the output mechanism and influencing factors of pulverized coal under different components of coal petrography and different coal structures during the process of drainage, the physical simulation experiments were conducted under the state of single-phase water flow displacement. The results of this experiment for different coal petrography show the weight of pulverized coal output is normally 11# coal > 5# coal > 3# coal with different displacement velocities, and the increasing ratio of pulverized coal output is 5# coal > 11# coal with the different confining stress in the constant displacement velocity. For different coal structures the pulverized coal output weight of fragmented coal is much larger than the primary structure of coal. The particle size distribution curve shows 3#, 5# and 11# primary structure of coal have a double-peak, and the grain size of primary pulverized coal is relatively small and the secondary pulverized coal is relatively large. However, the grain size distribution of fragmented coal is a double-peak distribution, and the distribution scope is relatively concentrated and the average grain size is small. Therefore, the characteristics of pulverized coal were found to be related to its coal different coal petrography components and coal structure.

012022
The following article is Open access

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The power loss and the changes of internal I-V output characteristics of photovoltaic (PV) module in the typical fault condition were analyzed. We proposed an on-line real time fault diagnosis method for PV module, which takes into account the power loss and the internal I-V characteristics. Taking into account the changes of temperature and irradiation, the running status of the PV module were simulated in real time. Firstly, by comparing the simulated power with the measured power, it could determine whether the abnormal power loss has occurred. Then based on the change of output voltage, it could decide if short-circuit fault has occurred and estimate the number of short circuited cells roughly. Further, the value of fill factor (FF) can be utilized to determine whether aging fault has occurred and to acquire the remaining service life of the module. The results of simulation and experiment show that this method can effectively detect the partial shadow short-circuit fault and aging fault. It proves the feasibility and accuracy of the fault diagnosis method.

012023
The following article is Open access

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This paper presents two different operation modes of Solar-Ground Source Heat Pump System (SGSHP(S)). With the simulation tool TRNSYS, two different SGSHP system models were built to taking simulation. After making analysis and compare of different simulation results, series operation mode was believed to be better than parallel in the target building.

012024
The following article is Open access

In work the new method of definition of isolation's parameters in a three-phase symmetric electrical network with isolated neutral which is based on measurement of modules sizes of a linear voltage, voltages of phases C and A concerning to ground, after connection of active additional conductivity between phase A of electrical network and ground is shown and the analysis of a blunder of the developed method is made. The analysis of a blunder has shown, that the developed method provides satisfactory accuracy at definition of isolation's parameters, and also simplicity and the safety of operations in working electro installations of up to above 1000 V voltage.

012025
The following article is Open access

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With the rapid development of wind power generation, the related research of wind power control and integration issues has attracted much attention, and the focus of the research are shifting away from the ideal power grid environment to the actual power grid environment. As the main stream wind turbine generator, a doubly-fed induction generator (DFIG) is connected to the power grid directly by its stator, so it is particularly sensitive to the power grid. This paper studies the improvement of DFIG control technology in the power grid harmonic environment. Based on the DFIG dynamic model considering the power grid harmonic environment, this paper introduces the shortcomings of the common control strategy of DFIG, and puts forward the enhanced method. The decoupling control of the system is realized by compensating the coupling between the rotor harmonic voltage and harmonic current, improving the control performance. In addition, the simulation experiments on PSCAD/EMTDC are carried out to verify the correctness and effectiveness of the improved scheme.

012026
The following article is Open access

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Polygeneration means simultaneous production of two or more energy products in a single integrated process. Polygeneration is an energy-efficient technology and plays an important role in transition into future low-carbon energy systems. It can find wide applications in utilities, different types of industrial sectors and building sectors. This paper mainly focus on polygeneration applications in building sectors. The scales of polygeneration systems in building sectors range from the micro-level for a single home building to the large- level for residential districts. Also the development of polygeneration microgrid is related to building applications. The paper aims at giving a comprehensive review for optimization techniques for designing, synthesizing and operating different types of polygeneration systems for building applications.

012027
The following article is Open access

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The static ice refrigeration air conditioning system (SIRACS) driven by distributed photovoltaic energy system (DPES) was proposed and the test experiment have been investigated in this paper. Results revealed that system energy utilization efficiency is low because energy losses were high in ice making process of ice slide maker. So the immersed evaporator and co-integrated exchanger were suggested in system structure optimization analysis and the system COP was improved nearly 40%. At the same time, we have researched that ice thickness and ice super-cooled temperature changed along with time and the relationship between system COP and ice thickness was obtained.

012028
The following article is Open access

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Traditional uninterrupted power supply (UPS) is difficult to meet the output voltage quality and grid-side power quality requirements at the same time, and usually has some disadvantage, such as multi-stage conversion, complex structure, or harmonic current pollution to the utility grid and so on. A three-phase three-level paralleled line-interactive UPS with LCL filter is presented in this paper. It can achieve the output voltage quality and grid-side power quality control simultaneously with only single-conversion power stage, but the multi-objective control strategy design is difficult. Based on the detailed analysis of the circuit structure and operation mechanism, a new cascaded control strategy for the power, voltage, and current is proposed. An outer current control loop based on the resonant control theory is designed to ensure the grid-side power quality. An inner voltage control loop based on the capacitance voltage and capacitance current feedback is designed to ensure the output voltage quality and avoid the resonance peak of the LCL filter. Improved repetitive controller is added to reduce the distortion of the output voltage. The setting of the controller parameters is detailed discussed. A 100kVA UPS prototype is built and experiments under the unbalanced resistive load and nonlinear load are carried out. Theoretical analysis and experimental results show the effectiveness of the control strategy. The paralleled line-interactive UPS can not only remain constant three-phase balanced output voltage, but also has the comprehensive power quality management functions with three-phase balanced grid active power input, low THD of output voltage and grid current, and reactive power compensation. The UPS is a green friendly load to the utility.

012029
The following article is Open access

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The wireless charging time of mobile phone will increase greatly if the metal objects mix in the magnetic field coupling area. In addition, the fire may be caused as for the high temperature of metal objects. The paper proposed an improved detecting method based on balance coil for mobile phone wireless charging system according to comparing the advantages and disadvantages of traditional metal detection methods. The circuit model was established, and hardware and software were optimized. At last, experimental results verified the theoretical analysis.

012030
The following article is Open access

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As the solar photovoltaic (PV) power is applied extensively, more attentions are paid to the maintenance and fault diagnosis of PV power plants. Based on analysis of the structure of PV power station, the global partitioned gradually approximation method is proposed as a fault diagnosis algorithm to determine and locate the fault of PV panels. The PV array is divided into 16x16 blocks and numbered. On the basis of modularly processing of the PV array, the current values of each block are analyzed. The mean current value of each block is used for calculating the fault weigh factor. The fault threshold is defined to determine the fault, and the shade is considered to reduce the probability of misjudgments. A fault diagnosis system is designed and implemented with LabVIEW. And it has some functions including the data realtime display, online check, statistics, real-time prediction and fault diagnosis. Through the data from PV plants, the algorithm is verified. The results show that the fault diagnosis results are accurate, and the system works well. The validity and the possibility of the system are verified by the results as well. The developed system will be benefit for the maintenance and management of large scale PV array.

012031
The following article is Open access

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In this study, a wastewater heat pump system was proposed and its thermal performance was analyzed. The proposed system includes two evaporators: an air-source evaporator and a water-source evaporator. The air-source evaporator absorbs heat from the moist hot air which exhaust from the drying oven. The water-source evaporator absorbs heat from the waste water, while the waste water recovers heat from the mechanical energy, which was produced by cutting and polishing in stone production. The thermodynamic model was developed to evaluate the performance of the proposed system. The energetic analysis was carried out to investigate the influences of the temperature of fresh air. The results show significantly higher energy efficiency, compact-sized and energy-saving compared with the system which uses air as the heat source. Among the seven of alternative refrigerants (R152a, R123, R1234yf, R1234ze, R600a, R22 and R600) investigated, R123 was suggested to be used in this heat pump for its high heating efficiency, inflammable, very low ODP(Ozone Depletion Potential) and GWP(Global warming potential).

012032
The following article is Open access

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In order to further promote integrated optimization operation of distributed new energy/ energy storage/ active load, this paper studies the integrated photovoltaic-energy storage (PV-ES) system which is connected with the distribution network, and analyzes typical structure and configuration selection for integrated PV-ES generation system. By combining practical grid- connected characteristics requirements and technology standard specification of photovoltaic generation system, this paper takes full account of energy storage system, and then proposes several new grid-connected performance indexes such as paralleled current sharing characteristic, parallel response consistency, adjusting characteristic, virtual moment of inertia characteristic, on- grid/off-grid switch characteristic, and so on. A comprehensive and feasible grid-connected performance index system is then established to support grid-connected performance testing on integrated PV-ES system.

012033
The following article is Open access

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Based on the discussion about topology structure of integrated distributed photovoltaic (PV) power generation system and energy storage (ES) in single or mixed type, this paper focuses on analyzing grid-connected performance of integrated distributed photovoltaic and energy storage (PV-ES) systems, and proposes a comprehensive evaluation index system. Then a multi-level fuzzy comprehensive evaluation method based on grey correlation degree is proposed, and the calculations for weight matrix and fuzzy matrix are presented step by step. Finally, a distributed integrated PV-ES power generation system connected to a 380 V low voltage distribution network is taken as the example, and some suggestions are made based on the evaluation results.

012034
The following article is Open access

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An monitoring system for three-stage wireless charging was designed. The vehicle terminal contained the core board which was used for battery information collection and charging control and the power measurement and charging control core board was provided at the transmitting terminal which communicated with receiver by Bluetooth. A touch-screen display unit was designed based on MCGS (Monitor and Control Generated System) to simulate charging behavior and to debug the system conveniently. The practical application shown that the system could be stable and reliable, and had a favorable application foreground.

012035
The following article is Open access

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To increase the test efficiency of thermal performance of solar collector, a vehicle- mounted test system with high automation, simple operation, good mobility and stability is proposed in this paper. By refitting a medium bus, design of mechanical system and test loop, and using PC control technology, we implemented the vehicle-mounted system and realized effective integration between vehicle and test equipment. A number of tests have been done, and the results show that the vehicle-mounted test system has good parameters and performance and can be widely used to provide door-to-door testing services in the field of solar thermal application.

012036
The following article is Open access

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The paper presents an analysis on small systems for converting biomass/wastes into power using Micro Gas Turbines (MGT) fed with gaseous bio-fuels produced by air- gasification. The MGT is designed for burning various fossil liquid and gas fuels, having catalogue data related to natural gas use. Fuel switch changes their performances. The present work is focused on adapting the MGT for burning alternative low quality gas fuel produced by biomass air gasification. The heating values of these gas fuels are 3 to 5 times lower than the methane ones, leading to different air demand for the stoichiometric burning. Validated numerical computation procedures were used to model the MGT thermodynamic process. Our purpose was to analyze the influence of fuel change on thermodynamic cycle performances.

012037
The following article is Open access

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Micro-siting aims to determine every wind turbine's position to reduce velocity deficits caused by the wake effect. The Novel CMO (cell membrane optimization) approach is proposed to overcome this weakness. It plays a vital role to utilize more wind resources while the type of wind turbine and the area to build a wind farm have been determined. The work is based on the Jensen wake model, and the hypothetical situations are the same as those used by the former researchers. There are three wind cases: constant speed with one direction, constant speed with variable directions and variable speeds with variable directions. The area of wind farm is assumed to be a plane 2km×2km square. The numbers of the wind turbines is 26, 19 and 15 in three cases respectively. Compared with Gene Algorithm introduced by G. Mosetti, CMO's results are acceptable and the velocity deficit is smaller, which results from that CMO's variables is continuous and can make the most of the area the wind turbines can be placed. Moreover, it performs well to avoid the local optimal solutions by dividing the searching particles into different types which move according to different rules.

012038
The following article is Open access

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Transmission line icing prediction is the premise of ensuring the safe operation of the network as well as the very important basis for the prevention of freezing disasters. In order to improve the prediction accuracy of icing, a transmission line icing prediction model based on discrete wavelet transform (DWT) feature extraction was built. In this method, a group of high and low frequency signals were obtained by DWT decomposition, and were fitted and predicted by using partial least squares regression model (PLS) and wavelet least square support vector model (w-LSSVM). Finally, the final result of the icing prediction was obtained by adding the predicted values of the high and low frequency signals. The results showed that the method is effective and feasible in the prediction of transmission line icing.

012039
The following article is Open access

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This paper describes the design and development of a solar powered mobile laboratory (SPML) system. The SPML provides a mobile platform that schools, universities, and communities can use to give students and staff access to laboratory environments where dedicated laboratories are not available. The lab includes equipment like 3D printers, computers, and soldering stations. The primary power source of the system is solar PV which allows the laboratory to be operated in places where the grid power is not readily available or not sufficient to power all the equipment. The main system components include PV panels, junction box, battery, charge controller, and inverter. Not only is it used to teach students and staff how to use the lab equipment, but it is also a great tool to educate the public about solar PV technologies.

012040
The following article is Open access

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Mono-Crystalline solar cell module is experimentally conducted in Khartoum, Sudan to study the difference between maximum empirical value of peak Watt and maximum value of thermal power produced in field under highly sufficient solar conditions. Field measurements are recorded for incident solar radiation, produced voltage, current and temperature at several time intervals during sun shine period. The thermal power system has been calculated using fundamental principles of heat transfer. The study shows that solar power for considered module could not attain the empirical peak power irrespective to maximum value of direct incident solar radiation and maximum temperature gained. A loss of about 6% of power can be considered as the difference between field measurements and the manufacturer's indicated empirical value. Solar cell exhibits 94% efficiency in comparison with manufacturer's provided data, and is 3'% more efficient in thermal energy production than in electrical power extraction for hot-dry climate conditions.

012041
The following article is Open access

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The annular linear induction electromagnetic pump (ALIP) with the flowrate of 900 L/min and the developed pressure of 4 bar has been designed by electric equivalent circuit analysis. It was fabricated by the consideration of materials compatible to the sodium environment of high temperature. Basic characteristic test of the ALIP was carried out in advance for its installation to the integral effect TEst Loop for safety simuLation and Assessment (STELLA) loop to confirm the sodium-thermo-hydraulic components. The test showed that the magnetic field had been linearly increased when the input current was increased, where input current and voltage had represented linear relation each other. The generated electromagnetic force was proportionate to the square of the applied current. The velocity of the aluminium pipe was proportionally increased when the input current was increased. It was verified that the basic characteristic of the ALIP showed a good accordance with the theoretical calculation.

012042
The following article is Open access

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The hydrogasification of pine wood (PW) and rice husk (RH) was carried out in a two-stage fixed-bed reactor to investigate the effects of hydrogen pressure and hydrocracking temperature on the yields of gas and tar compositions. The elevation in hydrogen pressure promoted the conversion of two biomasses, leading to the improvement in gaseous hydrocarbons but resulted in a decrease in the yield of BTX (benzene, toluene and xylene). The increased severity of hydrocracking boosted the yield of methane, ethane and BTX mainly at the expense of heavy compounds in tar for PW under 1 MPa. The co-hydrogasification of biomass and DWG swelling coal chiefly showed a synergistic effect on the yields of BTX and PCX (phenol, cresol and xylenol) at 500 °C hydrocracking temperature under 5 MPa.

012043
The following article is Open access

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The conversion efficiency of wind energy is the focus of researches and concerns as one of the renewable energy. The present methods of enhancing the conversion efficiency are mostly improving the wind rotor structure, optimizing the generator parameters and energy storage controller and so on. Because the conversion process involves in energy conversion of multi-energy fields such as wind energy, mechanical energy and electrical energy, the coupling effect between them will influence the overall conversion efficiency. In this paper, using system integration analysis technology, a testing system based on multi-energy field coupling (MEFC) of vertical axis wind power system is proposed. When the maximum efficiency of wind rotor is satisfied, it can match to the generator function parameters according to the output performance of wind rotor. The voltage controller can transform the unstable electric power to the battery on the basis of optimizing the parameters such as charging times, charging voltage. Through the communication connection and regulation of the upper computer system (UCS), it can make the coupling parameters configure to an optimal state, and it improves the overall conversion efficiency. This method can test the whole wind turbine (WT) performance systematically and evaluate the design parameters effectively. It not only provides a testing method for system structure design and parameter optimization of wind rotor, generator and voltage controller, but also provides a new testing method for the whole performance optimization of vertical axis wind energy conversion system (WECS).

012044
The following article is Open access

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The transient stability of interconnected network with supplementary time-delay controller for generator excitations and static var compensator (SVC) has been investigated in this paper. Firstly, a delay-dependent stability criterion based on Hamilton function method is derived, and the criterion is in term of matrix inequalities. Secondly, a nonlinear time-delay Hamilton function model of interconnected network with SVCs is constructed. Thirdly, the wide-area time-delay supplementary controller (WATSC) for the interconnected network is designed and converted into the form of Hamiltonian system. The delay-dependent stability of the closed-loop power system is analysed. The gains of the WATSC are determined by using the theoretical analysis results. It is effective for the designed WATSC installed in the 16- machine, 68-bus power system for damping the inter-area modes. Then simulation results show that the method of the controller is effective.

012045
The following article is Open access

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Phase change materials are of great interest in energy storage and energy management applications due to their high latent heat and excellent cycling stability. In this paper, the thermal characteristics of phase change materials (PCM) for thermal management of cylindrical 18650 lithium-ion battery (LIB) were experimentally investigated. A commercial paraffin wax with a melting temperaturerange between 47 - 53.8oC was used in this study. A metal cylinder with a heater was used to emulate the heat generation from a battery, which was surrounded with the paraffin PCM and containted in a metal housing. The experiment was conducted in an environmental test chamber with controlled ambient temperatures and power inputs. Both the battery temperature and the housing wall temperature were measured during steady-state heating and cyclic heating conditions. Since PCM has low thermal conductivity, thermal enhancement techniques were investigated by adding metal foams (MFs) or combining metallic foam and fins into the PCM to enhance the thermal conductivity. The battery temperatures were measured for all the cases and the results were analyzed and discussed.

012046
The following article is Open access

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Solid-fluid phase change materials have been of increasing interest in various applications due to their high latent heat with minimum volume change. In this work, numerical analysis of phase change materials is carried out for the purpose of thermal control of the cylindrical power battery cells for applications in electric vehicles. Uniform heat density is applied at the battery cell, which is surrounded by phase change material (PCM) of paraffin wax type and contained in a metal housing. A two-dimensional geometry model is considered due to the model symmetry. The effects of power densities, heat transfer coefficients and onset melting temperatures are examined for the battery temperature evolution. Temperature plateaus can be observed from the present numerical analysis for the pure PCM cases, with the temperature level depending on the power densities, heat transfer coefficients, and melting temperatures. In addition, the copper foam of high thermal conductivity is inserted into the copper foam to enhance the heat transfer. In the modeling, the local thermal non-equilibrium between the metal foam and the PCM is taken into account and the temperatures for the metal foam and PCM are obtained respectively.

012047
The following article is Open access

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The liquid product obtained from biomass pyrolysis is very valuable that it could be used for extraction of chemicals as well as for liquid fuel. The desire goal is to obtain the most bio-oil with desired higher heating value (HHV), high physicochemical stability. The yields and chemical composition of products from biomass pyrolysis are closely related to the feedstock, pyrolysis parameters and catalysts. Current researches mainly concentrated on the co-pyrolysis of different biomass and introduce of novel catalysts as well as the combined effect of catalysts and pyrolysis parameters. This review starts with the chemical composition of biomass and the fundamental parameters and focuses on the influence of catalysts on bio-oil. What is more, the pyrolysis facilities at commercial scales were also involved. The classic researches and the current literature about the yield and composition of products (mainly liquid products) are summarized.

012048
The following article is Open access

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Nowadays biodiesel has become more attractive because it is made from renewable resources. The main ingredients of industrial biodiesel are rap oil, sun oil, fat acid, olive oil cooked. In this study we verify that, the proportion of these components sets the qualitative composition and energy efficiency of the final product. Essential we link the raw materials (rap oil, sun oil, fat acid, olive oil cooked) used in the manufacture of industrial biodiesel the proportion of mixes, with the variation of physicochemical properties of biodiesel produced. According to the quantitative analysis we notice that the physiochemical properties which alter the value for example humidity, acidity, while a large number of physicochemical properties do not change their value depending on the ratio of raw materials in each mixture. The analysis of these changes seems that the presence of fat acids is negative for the quality of the mixture. From the analysis of the cost of the final mixtures that lower cost is achieved in the mixture was 10 and the highest cost was in the mixture 3. Based on a study of the cost of the mixtures can determine a basic relation between the quality and the cost of the final product.

012049
The following article is Open access

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Currently the BIOCAT drilling fluid system adopted in oil field results in wellbore collapsing frequently, borehole enlargement rate over 100%. In order to settle these problems, the Impermeable anti-collapsing inhibitive Polymer Drilling Fluids System is developed by optimizing the inhibitors with high anti-collapsing inhibitive instead of BIOCAT inhibitor, adding impermeable agent SMT3, sealing materials such as graphite, calcium carbonate, etc. Laboratory experiments results show that the developed drilling fluid system has stronger inhibitive and anti-collapse capacity. The swelling increment decreases by over 10% and recovery rate increases by 60%-70%, also, it can efficiently prolong the borehole wall stable period by over 100%. 24 wells applications with the Impermeable anti-collapsing inhibitive Polymer Drilling Fluids System achieved good results, comparing to adjacent wells with BIOCAT drilling fluid system, wellbore collapsing decreasing significantly and borehole diameter enlargement of unstable hole section in wells decreased from 100% to 10%, well drilling time decreased by 15%, drilling cost decreased by 10%. It shows that the developed Impermeable anti-collapsing inhibitive Polymer Drilling Fluids System KPAM-NH4PAN can provide strong and long-term inhibition, close to oil-based drilling fluid. so it is suggested that it be used in subsequent drilling operations to enhance the wellbore stability in an oilfield.

012050
The following article is Open access

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This paper puts forward a kind of managerial method based on the combination of PPF (passive power filter) and APF (active power filter) for the problem of three-phase current balance in three-phase four-wire system. This method uses two special reactors to filter zero- sequence current and uses APF to filter negative-sequence fundamental current, positive- sequence and negative-sequence harmonic current. It is more effective, reliable and economic. This paper proves feasibility of the method by the simulation results.

012051
The following article is Open access

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As to the heat pump technology applying in the HVAC engineering, the relationship between energy saving rate (ESR) and electricity cost saving rate (ECSR) of heat pump should be a positive correlation in theory. But in the actual energy price system, due to the fluctuating energy price comparison, the relationship between them is of less coordination. Moreover, despite the high ESR, the economic benefit of ECSR is lost. In this paper, via the case analysis under the condition of average technical and economic parameters in North China, the critical point rate of economic benefit of ECSR in energy price comparison among prices of residential electricity, steam-coal, and residential natural gas is found, which is about 2:3:8. Also, a viewpoint as well as method is suggested to promote the wide usage of heat pump, balance energy supply structure, save energy consumption, and reduce emissions by optimizing the energy price comparison, which is feasible and desirable to raise the price comparison between residential electricity and natural gas, and reduce the price comparison between residential electricity and steam-coal in a certain extent.

012052
The following article is Open access

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An assessment of the economic, energy consumption, and greenhouse gas (GHG) emission dimensions of forest-based biomass harvest stage in the state of Michigan, U.S. through gathering data from literature, database, and other relevant sources, was performed. The assessment differentiates harvesting systems (cut-to-length harvesting, whole tree harvesting, and motor-manual harvesting), harvest types (30%, 70%, and 100% cut) and forest types (hardwoods, softwoods, mixed hardwood/softwood, and softwood plantations) that characterize Michigan's logging industry. Machine rate methods were employed to determine unit harvesting cost. A life cycle inventory was applied to calculating energy demand and GHG emissions of different harvesting scenarios, considering energy and material inputs (diesel, machinery, etc.) and outputs (emissions) for each process (cutting, forwarding/skidding, etc.). A sensitivity analysis was performed for selected input variables for the harvesting operation in order to explore their relative importance. The results indicated that productivity had the largest impact on harvesting cost followed by machinery purchase price, yearly scheduled hours, and expected utilization. Productivity and fuel use, as well as fuel factors, are the most influential environmental impacts of harvesting operations.

012053
The following article is Open access

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There is usually considerable energy consumption in data centers. Load forecasting to data centers is in favor of formulating regional load density indexes and of great benefit to getting regional spatial load forecasting more accurately. The building structure and the other influential factors, i.e. equipment, geographic and climatic conditions, are considered for the data centers, and a method to forecast the load of the data centers based on power usage effectiveness is proposed. The cooling capacity of a data center and the index of the power usage effectiveness are used to forecast the power load of the data center in the method. The cooling capacity is obtained by calculating the heat load of the data center. The index is estimated using the group decision-making method of mixed language information. An example is given to prove the applicability and accuracy of this method.

012054
The following article is Open access

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As a new means of transport, electric vehicle (EV) is of great significance to alleviate the energy crisis. EV charging station planning has a far-reaching significance for the development of EV industry. This paper analyzes the impact factors of EV charging station planning, and then uses the analytic hierarchy process (AHP) to carry on the further analysis to the influencing factors, finally it gets the weight of each influence factor, and provides the basis for the evaluation scheme of the planning of charging stations for EV.

012055
The following article is Open access

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We present a framework that seeks to improve the objectivity of renewable energy policy decisions in Nigeria. It consists of expert ranking of resource abundance, resource efficiency and resource environmental comfort in the choice of renewable energy options for large scale power generation. The rankings are converted to a more objective function called Resource Appraisal Function (RAF) using dependence operators derived from logical relationships amongst the various criteria. The preferred option is that with the highest average RAF coupled with the least RAF variance. The method can be extended to more options, more criteria, and more opinions and can be adapted for similar decisions in education, environment and health sectors.

012056
The following article is Open access

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China's modern coal chemical industry has grown into a certain scale after over a decade of development, and remarkable progress has been made in key technologies. But as oil price collapsed since 2015, the economic benefit of the industry also slumped, with loud controversies in China over the necessity of modern coal chemical industry. The research believes that the modern coal chemical industry plays a positive role in the clean and sustainable exploitation of coal in China. It makes profit when oil price is no lower than $60/bbl, and outperforms petrochemical in terms of cost effectiveness when the price is between $60/bbl and 80$/bbl. Given the low oil price and challenges posed by environmental protection and water restraints, we suggest that the state announce a guideline quickly, with adjusted tax policies and an encouragement to technological innovation, so that the modern coal chemical industry in China can grow sound and stable.

012057
The following article is Open access

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The maximum power point tracking control is the key link to improve the energy conversion efficiency of wave energy converters (WEC). This paper presents a novel variable step size Perturb and Observe maximum power point tracking algorithm with a power classification standard for control of a buoy-rope-drum WEC. The algorithm and simulation model of the buoy-rope-drum WEC are presented in details, as well as simulation experiment results. The results show that the algorithm tracks the maximum power point of the WEC fast and accurately.

012058
The following article is Open access

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Industrial washing oil as solvent, pyrolysis gas produced from Bai Yinhua lignite during thermal extraction was studied by gas chromatography. The effects of temperature and solvent coal ration on coal pyrolysis gas were investigated. The results showed that: Pyrolysis gas produced mainly in CO, CO2, O2, H2, CH4, and so on, in which the total amount of oxygen containing compounds nearly 40%, significant effects of deoxidation was achieved. The increase of heat extraction temperature can significantly increase the degree of bond breaking and the gas formation rate, the gas yield and the rate of oxygen increase significantly, while the gas yield increases with the decrease of the solvent coal ration.

012059
The following article is Open access

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The nanosized tremella-like NiO was synthesized by a simple hydrothermal method at low temperature. A novelty modified (CH3)4N)2S/((CH3)4N)2Sn electrolyte was introduced in solar cell successfully and NiS as the counter electrode. Moreover, PbS sensitized p-type NiO was synthesized by chemical bath deposition (CBD) in an precursor solution to ensure the nanosized tremella-like NiO films obtain a better uniformity and high penetration. At the same time, a series of comparative experiments were designed for studying the influence of mesoporous NiO film thickness on the photoelectron characteristic of the cells. The result indicated that when there were three layers of screen printing and the thickness of NiO film was approximately 3 pm, the maximum power conversion efficiency of 0.87% was achieved, with 512 mV of Voc, 0.33% of ff and 5.14 mA cm-2 of Jsc.

012060
The following article is Open access

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With the development of residential energy conservation technology, the air tightness requirement of the window is higher and higher. So in winter the cold penetration wind cannot satisfy the requirement of indoor personnel to fresh air. The common ventilation mode includes natural ventilation, natural inlet and mechanical exhaust, wall type ventilator with heat exchange, ventilation unit with heat exchange. Looking for energy saving, comfortable way of ventilation, the application effect of the way of ventilation is evaluated in air distribution and comfort performance and the initial investment by FLUENT software. The conclusion is that the mode of ventilation unit with heat exchange has higher superiority compared with the others.

012061
The following article is Open access

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At this stage of the development of China's highway, the quantity and size of traffic signs are growing with the guiding information increasing. In this paper, a calculation method is provided for special sign board with reducing wind load measures to save construction materials and cost. The empirical model widely used in China is introduced for normal sign structure design. After that, this paper shows a computational fluid dynamics method, which can calculate both normal and special sign structures. These two methods are compared and analyzed with examples to ensure the applicability and feasibility of CFD method.

012062
The following article is Open access

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To improve the starting performance of the straight-bladed vertical axis wind turbine (SB-VAWT) at low wind speed, and the output characteristics at high wind speed, a flexible, scalable auxiliary vane mechanism was designed and installed into the rotor of SB-VAWT in this study. This new vertical axis wind turbine is a kind of lift-to-drag combination wind turbine. The flexible blade expanded, and the driving force of the wind turbines comes mainly from drag at low rotational speed. On the other hand, the flexible blade is retracted at higher speed, and the driving force is primarily from a lift. To research the effects of the flexible, scalable auxiliary module on the performance of SB-VAWT and to find its best parameters, the computational fluid dynamics (CFD) numerical calculation was carried out. The calculation result shows that the flexible, scalable blades can automatic expand and retract with the rotational speed. The moment coefficient at low tip speed ratio increased substantially. Meanwhile, the moment coefficient has also been improved at high tip speed ratios in certain ranges.

012063
The following article is Open access

Degradation analysis of photovoltaic (PV) modules based on real operational data is essential to the future development of the PV industry. Weather conditions and system drifting often lead to large uncontrollable fluctuations in operational data, which present great challenges for calculating degradation rates of PV modules. In this paper, we propose a new numerical two-step approach to overcome these difficulties. In particular, we will show that our method is able to eliminate effects of seasonal patterns and systematic sensor drifting in evaluating degradation rates of PV modules. The method is applied to the six-year operational data of a solar PV system installed at CA United States. We demonstrate that our approach can greatly improve the degradation calculations, compared with other widely used methods.

012064
The following article is Open access

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Traditional AVC strategy is mainly used in wind farm and only concerns about grid connection point, which is not suitable for distributed wind power system. Therefore, this paper comes up with an improved AVC strategy applied in distributed wind power system. The strategy takes all nodes of distribution network into consideration and chooses the node having the most serious voltage deviation as control point to calculate the reactive power reference. In addition, distribution principles can be divided into two conditions: when wind generators access to network on single node, the reactive power reference is distributed according to reactive power capacity; when wind generators access to network on multi-node, the reference is distributed according to sensitivity. Simulation results show the correctness and reliability of the strategy. Compared with traditional control strategy, the strategy described in this paper can make full use of generators reactive power output ability according to the distribution network voltage condition and improve the distribution network voltage level effectively.

012065
The following article is Open access

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In this paper, based on the principle of the capillary plane radiation air conditioning system, taking the slope roof as an example, the application of the capillary plane radiation airconditioning system is studied and analysed. Then the numerical solution of differential equations is obtained by the technology of CFD. Finally, we analyze the distribution of indoor temperature of the slope roof and the predicted mean votes (PMV) using Airpak simulation software by establishing a physical model. The results show that the PMV of different sections ranges from 0 to 2.5, which meets the requirement of the comfort. These provide a theoretical basis for application and promotion of capillary plane in the slope roof.

012066
The following article is Open access

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The grid side converter is an important part of the excitation system of doubly-fed asynchronous generator used in wind power system. As a three-phase voltage source PWM converter, it can not only transfer slip power in the form of active power, but also adjust the reactive power of the grid. This paper proposed a control approach for improving its performance. In this control approach, the dc voltage is regulated by a sliding mode variable structure control scheme and current by a variable structure controller based on the input output linearization. The theoretical bases of the sliding mode variable structure control were introduced, and the stability proof was presented. Switching function of the system has been deduced, sliding mode voltage controller model has been established, and the output of the outer voltage loop is the instruction of the inner current loop. Affine nonlinear model of two input two output equations on d-q axis for current has been established its meeting conditions of exact linearization were proved. In order to improve the anti-jamming capability of the system, a variable structure control was added in the current controller, the control law was deduced. The dual-loop control with sliding mode control in outer voltage loop and linearization variable structure control in inner current loop was proposed. Simulation results demonstrate the effectiveness of the proposed control strategy even during the dc reference voltage and system load variation.

012067
The following article is Open access

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A light ray tracing model and a heat transfer model were built to analyse the heat flux distribution and heat transfer in a 1m cavity receiver tube with Parabolic Trough Collectors as the concentrator. The numerical methods were used to simulate the thermal stress and deformation of the receiver tube. The temperature fields of the receiver tube and the thermal stress distribution in the steel tube at the cross section and along the fluid flowing direction were presented. It is obtained from this study that non-uniform heat flux distribution is absorbed at the receiver tube outer surface due to the structure of the cavity receiver tube. Temperature fields in the steel receiver tube at the inlet and the outlet match well with the incident solar radiation. An eccentric circle temperature gradient is observed at cross section of the outlet fluid. The equivalent stress is a complex result of solar heating flux, energy transfer inside the PTC and the fluid and steel characteristics. Highest deformation is 3.1mm at 0.82m. On increasing the fluid mass flow rate, higher fluid mass flow rate results in higher equivalent stress along the absorber tube.

012068
The following article is Open access

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In Sichuan basin the Lower Palaeozoic source rock has reached high to over-mature stage, but it is still considered that it has obvious genetic link with some gas reservoirs which were formed later. Therefore, the accumulation process between ancient high to over-mature source rock and the late formation of gas reservoirs has become one of the key factors to recognize the law of natural gas accumulation in Sichuan Basin. Based on some characteristics of Carboniferous gas reservoir in eastern basin, such as the gas compositions, stable carbon isotope, it is found that the gas reservoir is oil-cracking gas. The result reveals that the formation and evolution of present gas reservoir is that an ancient oil pool experienced the processes of forming, accumulating, destructing, and thermal maturating and cracking into gas reservoir.

012069
The following article is Open access

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Gaseous fuels have always been established as an assuring way to lessen emissions in Spark Ignition engines. In particular, LPG resolved to be an affirmative fuel for SI engines because of their efficient combustion properties, lower emissions and higher knock resistance. This paper investigates performance, emission and combustion characteristics of a microcontroller based electronic LPG gaseous phase port injection system. Experiments were carried out in a single cylinder diesel engine altered to behave as SI engine with LPG as fuel at a compression ratio of 10.5:1. The engine was regulated at 1500 rpm at a throttle position of 20% at diverse equivalence ratios. The test results were compared with that of the carburetion system. The results showed that there was an increase in brake power output and brake thermal efficiency with LPG gas phase injection. There was an appreciable extension in the lean limit of operation and maximum brake power output under lean conditions. LPG injection technique significantly reduces hydrocarbon and carbon monoxide emissions. Also, it extremely enhances the rate of combustion and helps in extending the lean limit of LPG. There was a minimal increase of NOx emissions over the lean operating range due to higher temperature. On the whole it is concluded that port injection of LPG is best suitable in terms of performance and emission for LPG fuelled lean burn SI engine.

012070
The following article is Open access

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The hydrothermal treatment (HT) is an effective method to remove chlorine from chlorinated wastes under mild conditions. However, the alkali was required to improve the dechlorination efficiency. Meanwhile, the alkalis contents removed was necessary to realize the clean and highly efficient utilization of coal. This work was trying to investigate the feasibility of simultaneously removal alkalis and chlorine by co-hydrothermal treatment of PVC and high-alkali coal. The effect of operating conditions including the HT temperature, the holding time and particle sizes of coal on the dechlorination efficiency (DE) of PVC during the HT process was experimentally studied in this work. The results show that the DE increased with the rise of: 1) particle sizes (0.054~0.22mm), 2) holding time (30~90 min) and 3) temperature (240~300 °C). In detail, under 300 °C and 60min of holding time, the 85.18% of DE with first PS was lower than the 93.93% of DE with second PS and 100% of DE with third PS. The organic chlorine mainly transferred into chloridion in aqueous solution in HT process. All the results indicate that it is a prospective way to simultaneously removal alkalis and chlorine by co-hydrothermal treatment of chlorinated wastes and high-alkali coal.

012071
The following article is Open access

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Double-fed induction generator (DFIG) is sensitive to the disturbances of grid, so the security and stability of the grid and the DFIG itself are under threat with the rapid increase of DFIG. Therefore, it is important to study dynamic response of the DFIG when voltage drop failure is happened in power system. In this paper, firstly, mathematical models and the control strategy about mechanical and electrical response processes is respectively introduced. Then through the analysis of response process, it is concluded that the dynamic response characteristics are related to voltage drop level, operating status of DFIG and control strategy adapted to rotor side. Last, the correctness of conclusion is validated by the simulation about mechanical and electrical response processes in different voltage levels drop and different DFIG output levels under DIgSILENT/PowerFactory software platform.

012072
The following article is Open access

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Waste cooking oil (WCO) and its model compounds (oleic acid and methyl laurate) are catalytically pyrolyzed in a fixed-bed reactor over La modified ZSM-5 catalysts (La/ZSM-5) aiming for production of C2-C4 light olefins. The LaO content in catalysts was set at 0, 2, 6, 10 and 14 wt%. The gas and liquid products are analyzed. The La/ZSM-5 catalyst with 6% LaO showed higher selectivity to light olefins when WCO and methyl laurate were pyrolyzed, and olefin content was 26% for WCO and 21% for methyl laurate. The catalyst with 10% LaO showed high selectivity to light olefins (28.5%) when oleic acid was pyrolyzed. The liquid products from WCO and model compounds mainly contain esters and aromatic hydrocarbons. More esters were observed in liquid products from methyl laurate and WCO pyrolysis, indicating that it is more difficult to pyrolyze esters and WCO than oleic acid. The coked catalysts were analyzed by temperature-programmed oxidation. The result shows that graphite is the main component of coke. The conversion of WCO to light olefins potentially provides an alternative and sustainable route for production of the key petrochemicals.

012073
The following article is Open access

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Thermal performance of vortex tube is noticeably influenced by its geometrical and operational parameters. In this study effect of various geometrical (L/D ratio: 15, 16, 17, 18; exit valve angle; 300, 450, 600, 750, 900; cold end orifice diameter: 5, 6 and 7mm, tube divergence angle: 00, 20, 30, 40) and operational parameters (inlet pressure: 2 to 6 bars) on the performance of vortex tube have been investigated experimentally. Multiple Attribute Decision Making (MADM) techniques are applied to determine the optimum combination of the vortex tube. Performance of vortex tube was analysed with optimum temperature difference on cold end, COP for cooling. The MADM (Multiple Attribute Decision Making) methods, namely WSM (Weighted Sum Method), WPM (Weighted Power Method), TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) and AHP (Analytical Hierarchy Process) are applied. Experimental best performing combinations are obtained for Length to Diameter ratios 15, 16, 17 with exit valve angle as 450,750 and 900 at orifice diameter 5mm for inlet pressure of 5 and 6 bar pressure. Best COP, efficiency and cold end temperature difference are 0.245, 40.6% and 38.3K respectively for the combination of 15 L/D, 450 valve angle, 5mm orifice diameter and 2 bar pressure by MADM techniques.

012074
The following article is Open access

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With the fast increase of world energy consumption in recent years, new and sustainable energy sources are becoming more and more important. Methane Hydrate is one promising candidate for the future energy supply of humankind, due to its vast existence in permafrost regions and near-coast seabed. This study is focused on the effective low emission utilization of methane hydrate from deep seabed. The Nankai Trough of Japan is taken as the target region in this study for methane hydrate extraction and utilization system design. Low emission system and power generation system with CCS (Carbon Capture and Sequestration) processes are proposed and analyzed for production rate and electricity generation efficiency problem study. It is found that the gas production price can reach the current domestic natural gas supply price level if the production rate can be improved. The optimized system is estimated to have power efficiency about 35%. In addition, current development and analysis from micro-to-macro scale methane hydrate production and dissociation dynamics are also discussed into detail in this study.

012075
The following article is Open access

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The current research aims to investigate the relation of indoor weather to energy consumption of air conditioned classroom by design and construct the indoor weather and energy monitoring systems. In this research, a combined temperature and humidity sensor in conjunction with a microcontroller was constructed for the indoor weather monitoring system. The wire sensor network for the temperature-humidity sensor nodes is the Controller Area Network (CAN). Another part is using a nonintrusive method where a wireless current transformer sending the signal to the data collection box then transmitted by the radio frequency to the computer where the Ethernet application software was installed for the energy monitoring system. The results show that the setting air temperature, outdoor ambient temperature and operating time impact to the energy consumption of the air conditioned classroom.

012076
The following article is Open access

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A major share of China's total carbon dioxide (CO2) emissions is from the electric power sector. To solve this problem, Chinese government has implemented many renewable energy policies in the electric power sector. In China, the most popular renewable energy policies are Feed-in tariff (FIT) and renewable portfolio standard (RPS). This paper first introduces the current development of renewable electricity generation. Second the design plan and implement of FIT and RPS in China's thermal electricity generation sector are summarized in this paper. Third this paper establishes a complementary mode of FIT and RPS which can provide a stable environment to make the FIT and RPS work together. Finally, based on the above analysis, this paper proposes relative suggestions for the implementation of FIT and RPS in China making recommendation for the development of electricity generation from renewable energy.

012077
The following article is Open access

In order to effectively guide the narrow channel sand body oil fields to exploit, according to the sand body distribution characteristics and geological genesis of narrow channel sand body oil fields, the type of single sand body is clarified. By means of identification of logging curves and correlation of well-tie profile, the internal structure of single sand body is recognized. and then the remaining oil genesis, distribution characteristics and the potential areas for polymer flooding are clarified by combining numerical simulation technology and dynamic analysis technology, and the remaining oil potential tapping method is designed by taking into consideration various factors including the characteristics of the remaining oil, reservoir property and product dynamic character. The result shows that the single sand body is divided into five types including multiphase channel superposition, distributary channel, single channel, sheet sand and lenticular sand. Potential remaining oil mainly are distributed in thick oil layers of multiphase channel superposition type and distributary channel type in which channel sands were developed and sedimentary environment are stable inner front facies and lake regressive inner front facies. The remaining oil is developed by optimizing the parameters of polymer flooding and combining many different measures. The study provides technical support for the efficient exploration for polymer flooding.

012078
The following article is Open access

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According to the limitations of the LVRT technology of traditional photovoltaic inverter existed, this paper proposes a low voltage ride through (LVRT) control method based on model current predictive control (MCPC). This method can effectively improve the photovoltaic inverter output characteristics and response speed. The MCPC method of photovoltaic grid-connected inverter designed, the sum of the absolute value of the predictive current and the given current error is adopted as the cost function with the model predictive control method. According to the MCPC, the optimal space voltage vector is selected. Photovoltaic inverter has achieved automatically switches of priority active or reactive power control of two control modes according to the different operating states, which effectively improve the inverter capability of LVRT. The simulation and experimental results proves that the proposed method is correct and effective.

012079
The following article is Open access

In modern smart green buildings, sensors can detect various physical status of a building such as temperature, humidity, motion, and light, which can be used for smart living services. This paper presents an energy-efficient vertical transportation by making use of indoor sensor technologies. Specifically, sensors detect elevator users before they push the call button, and then inform to the elevator control system through building networks. By using this information, our system generates a reservation call and controls the moving time and direction of each elevator efficiently. Simulation experiments with a variety of traffic situations show that our elevator control system exhibits significantly better performance than the conventional system that does not use sensor information with respect to passengers' waiting time and energy consumption.

012080
The following article is Open access

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The decision on photovoltaic project depends on the level of climate environments. Changes in temperature and insolation affect photovoltaic output. It is important for investors to consider future climate conditions for determining investments on photovoltaic projects. We propose a real options-based framework to assess economic feasibility of photovoltaic project under climate change. The framework supports investors to evaluate climate change impact on photovoltaic projects under future climate uncertainty.

012081
The following article is Open access

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This paper focused on the influence of using position of thermal insulation materials in exterior walls on the indoor thermal comfort and building energy consumption of residential building in Chongqing. In this study, four (4) typical residential building models in Chongqing were established, which have different usage of thermal insulation layer position in exterior walls. Indoor thermal comfort hours, cooling and heating energy consumption of each model were obtained by using a simulation tool, Energyplus. Based on the simulation data, the influence of thermal insulation position on indoor thermal comfort and building energy consumption in each season was analyzed. The results showed that building with internal insulation had the highest indoor thermal comfort hours and least cooling and heating energy consumption in summer and winter. In transitional season, the highest indoor thermal comfort hours are obtained when thermal insulation is located on the exterior side.

012082
The following article is Open access

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The triangular-lattice Blume-Capel magnetic system is investigated using efficient Wang-Landau Monte Carlo algorithm. From extensive Wang-Landau Monte Carlo simulations with massive large-scale computing, the microcanonical entropy as a function of energy variables, the most fundamental quantity in statistical thermodynamics, for the triangular- lattice Blume-Capel ferromagnet and antiferromagnet at the same time is evaluated for the first time. The important properties of the microcanonical entropy as a function of energy variables are discussed for the triangular-lattice Blume-Capel magnetic system.

012083
The following article is Open access

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The Pubei oilfield belongs to the reservoir with low permeability and poor physical property. It has entered the late period of high water cut stage, so it needs polymer flooding to produce remaining oil. In order to pursue benefits and avoid risk, it is necessary to select potential block of polymer flooding by optimum parameters. In the paper, the limit of permeability for selecting potential block of polymer flooding is calculated by using both reservoir engineering method and economic analysis theory.

012084
The following article is Open access

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There are two type of airflow form in tobacco barn, one is air rising, the other is air falling. They are different in the structure layout and working principle, which affect the tobacco barn in the distribution of temperature field and velocity distribution. In order to compare the temperature and air distribution of the two, thereby obtain a tobacco barn whose temperature field and velocity distribution are more uniform. Taking the air source heat pump tobacco barn as the investigated subject and establishing relevant mathematical model, the thermodynamics of the two type of curing barn was analysed and compared based on Fluent. Provide a reasonable evidence for chamber arrangement and selection of outlet for air source heat pump tobacco barn.

012085
The following article is Open access

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Based on the design theory of the wind turbine, a turbine applied to solar chimney power plant with a vertical collector is designed, and the performance of the wind turbine is conducted by wind tunnel test. The results point out that the experimental performance is consistent with the designed performance. Then the number of blades and tip speed ratio are conducted, as well as we obtained the optimum blade number and tip speed ratio of turbine for the system.

012086
The following article is Open access

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The reconfiguration on underground geology system is one of the key techniques for secondary development in Daqing oil field. The geological modeling is the unique method to characterize new knowledge system of reservoir. The development history of maturing field is long. The structure of maturing field is complex and the distribution of oil remaining is highly scattered. The difficulty of adjustment and potential tapping is great. In viewing of demand for secondary development, the strategies and methods of geological modeling are proposed. According to the characteristics that many faults crosscut each other, the clue of fractional simulation—key horizon controlling—overall structural modeling is carried out to accurately and effectively build fine structural models. In order to approximate the real microfacies simulation effect, microfacies modeling technology of multiple iterations and geology tendency under vertical and lateral geology tendency constraint is used. And the attribute models could approximate the real parametric distribution. Moreover, in viewing of the key and potential reservoir sand, the countermeasure on configuration modeling by different stochastic simulation methods and step simulation is proposed to rapidly build geologic models. The geologic models are scientific and feasible. The above-mentioned countermeasures and methods have been used in secondary development of Daqing oilfield and the effect was well. This new technology presents directive sense.

012087
The following article is Open access

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This paper examines the influence of attitude towards energy conservation at home, the attitude in the campus, subjective norm, and self-efficacy on energy conservation behavioural intention among students in a private university using the Theory of Planned Behaviour (TPB). Data was collected from about 194 students using a questionnaire developed from current literature on TPB. Data analysis using Smart PLS version 3.2.4 found that attitude towards energy conservation at home has an indirect significant influence on attitude towards energy conservation behavioural intention via the mediating effect of attitude towards energy conservation in the campus. Self-efficacy and subjective norm are also positively related to energy conservation intention. The study also indicates the suitability of the TPB in predicting behavioural intention through attitudes, subjective norms, and self-efficacy. Results suggest that energy education is vital in creating a positive attitude towards energy conservation while facilities managers in institutions need to formulate appropriate policies and regulations to inculcate the right attitude and behaviour towards energy saving.