• Energy Research
• 7. Clean energy close
• CN close
• GB close
• ES close
• CA close

A two-dimensional two-phase mass transport model has been developed to predict methanol and water crossover in a semi-passive direct methanol fuel cell with an air-breathing cathode. The mass transport in the catalyst layer and the discontinuity in liquid saturation at the interface between the diffusion layer and catalyst layer are particularly considered. The modeling results agree well with the experimental data of a home-assembled cell. Further studies on the typical two-phase flow and mass transport distributions including species, pressure and liquid saturation in the membrane electrode assembly are investigated. Finally, the methanol crossover flux, the net water transport coefficient, the water crossover flux, and the total water flux at the cathode as well as their contributors are predicted with the present model. The numerical results indicate that diffusion predominates the methanol crossover at low current densities, while electro-osmosis is the dominator at high current densities. The total water flux at the cathode is originated primarily from the water generated by the oxidation reaction of the permeated methanol at low current densities, while the water crossover flux is the main source of the total water flux at high current densities.

The transformation and environmental characteristics of natural radionuclides in a coal‐fired power plant were investigated. The coal, bottom ash, fly ash, and soil samples were collected. The activity concentrations of natural radionuclides (226Ra, 232Th, and 40K) were determined by a high‐purity germanium gamma ray spectrometer. The radiological hazard factors include radium equivalent activity, external hazard index, air absorbed dose rates, and annual effective dose that were used to evaluate the potential environmental and health risk. The results show that these natural radionuclides are enriched in bottom ash and fly ash during coal combustion. The activity concentrations of these radionuclides at the southeast and northwest soil samples are generally higher than those of the southwest and northeast. 226Ra is mainly enriched at the distance of 200 m, while 232Th is primarily higher in the power plant. Based on the radiological risk assessment, the environmental effect of natural radionuclides caused by coal‐fired power plant is considered to be negligible because the radium equivalent activity and external hazard index values of the measured samples are below the acceptance limitations of 370 Bq kg−1 and 1. The bottom ash and fly ash could be used as construction materials under high management and regularization. © 2015 American Institute of Chemical Engineers Environ Prog, 34: 1080–1084, 2015

Abstract Building energy prediction is a key factor to assess the energy performance of commercial buildings, identify operation issues and propose better operating strategies based on the forecast information. Different models have been used to forecast energy demand in buildings, including whole building energy simulation, regression analysis, and black-box models (e.g., artificial neural networks). This paper presents a different approach to predict the energy demand of commercial buildings using case-based reasoning (CBR). The proposed approach is evaluated using monitored data in a real office building located in Varennes, Quebec. The energy demand is predicted at every hour for the following 3 h using weather forecasts. The results show that during occupancy, 7:00–18:00, the coefficient of variance of the root-mean-square-error (CV-RMSE) is below 13.2%, the normalized mean bias error (NMBE) is below 5.8% and the root-mean-square-error (RMSE) is below 14 kW. When the statistical criteria are calculated for all hours of the day, the CV-RMSE is 12.1%, the NMBE is 1.0% and the RMSE is 11 kW. The case study demonstrates that CBR can be used for energy demand prediction and could be implemented in building operation systems.

A PID decoupling control method is designed on the basis of diagonal recurrent neural network(DRNN) for the currents flowing over the transistors which are large fluctuations, and is not balanced by three-phase current, And 12 PID controller are used in parallel as the decoupling controller to realize decoupling and control. The practice proven the system can improve the smelting quality and reduce the waste. It can also extend the life of the transformer for the rectifier.

Carbon capture, utilization, and storage (CCUS) is a gas injection technology that enables the storage of CO2 underground. The aims are twofold, on one hand to reduce the emissions of CO2 into the atmosphere and on the other hand to increase oil/gas/heat recovery. Different types of CCUS technologies and related engineering projects have a long history of research and operation in the USA. However, in China they have a short development period ca. 10 years. Unlike CO2 capture and CO2-EOR technologies that are already operating on a commercial scale in China, research into other CCUS technologies is still in its infancy or at the pilot-scale. This paper first reviews the status and development of the different types of CCUS technologies and related engineering projects worldwide. Then it focuses on their developments in China in the last decade. The main research projects, international cooperation, and pilot-scale engineering projects in China are summarized and compared. Finally, the paper examines the challenges and prospects to be experienced through the industrialization of CCUS engineering projects in China. It can be concluded that the CCUS technologies have still large potential in China. It can only be unlocked by overcoming the technical and social challenges.

The aerodynamic characteristics of advanced low-pressure turbines (LPTs) could be affected by the interaction between the transitional and turbulent flow and the dynamic behaviour of the blades. Consequently, analysing the details of the interactions between the transient flow, blade vibrations and the flutter occurrence over the blades of LPTs are essential in order to enhance the aerodynamic efficiency of the modern LPTs. The distinctive feature of the present analysis is performing high-fidelity simulations based on a DNS approach employing a 3D blade model to investigate the flutter instabilities in a T106A turbine at various inter blade phase angles (IBPAs) at different Reynolds numbers. The impacts of the flutter on the transient flow structure are examined by using a direct numerical simulation method. The results show that at IBPA=0∘, persistent patterns of vortex generation are detected with fluid flow mixing in the downward areas. For IBPA=180∘, however, the recirculation generated by the upper blades proceeds toward the lower ones and interferes with the shedding from the trailing edge which impact the wake structure in the downstream regions significantly. A three-dimensional frequency domain model based on the harmonic balance method is also proposed in this study to investigate the capabilities and limitations of frequency domain methods in predicting aeroelasticity and details of flow structures in LPTs.

Abstract Eradicating poverty and mitigating greenhouse gas (GHG) emissions are core issues of global sustainable development goals (SDGs), and China is struggling in realizing these targets. The poverty reduction that leads to popualtion structure and lifestyle changes would have an impact on GHG emission changes. However, few studies have assessed the historical and future impacts of the poverty allevation on China's emissions. Here by linking Chinese Multi-Regional Input Output (MRIO) database to the global MRIO database EXIOBASE, and using provincial household consumption data, we identified the distribution of Chinese household greenhouse gas footprints (HGFs) by income groups in 2015 at the national and provinical levels. Moreover, we focused on the historical impact of poverty alleviation on HGFs during 2010–2015, and developed four scenarios to project future HGFs changes due to poverty alleviation by 2030. We find that eradicating extreme poverty in the secanrio S2, i.e., bringing people to an income above $1.9 daily, does not cause a large emission impact with current technological level. However, lifting people from a higher poverty line of $5.5 per day in the sceanrio S4 results in a 1.6% increase in emissions compared with the scenario S1 without any poverty reduction goals. Furthermore, realizing a higher poverty reduction target will result in an increase of emissions contribution from internatioanl supply chains due to the differences in consumption patterns among different income groups. Our study highlights the conflict between the high poverty alleviaition goal and emission reduciton in China, and reminds us of the need to make more technological efforts for avoiding the large emissions embodied in international supply chains.

The automobile industry, as a representative in pursuing the goals of “emission peak” and “carbon neutrality”, has made low carbon a new industrial practice. With regard to low carbon, the lightweight design proves to be an effective approach to reducing carbon emissions from automobiles. Given the state of research, in which the existing lightweight design schemes of automobiles seldom consider the impact of the lightweight quality on carbon emissions during the whole life cycle of the automobiles, this paper proposes a more comprehensive lightweight design method for automobiles in regard to carbon emissions. First, the finite element method was adopted to analyze the stress, strain and safety factors of the automobile parts based on their stress, so as to identify the positions where the lightweight design was applicable. Subsequently, a lightweight scheme was designed accordingly. Next, the finite element method was re-applied to the parts whose weights had been reduced. In this way, the feasibility of the lightweight scheme was verified. In addition, a method of calculating the carbon emissions produced by changes in the mass, manufacturing processes, application and recycling of automobile parts after the application of the lightweight design was also presented. The method can be used for evaluating the low carbon benefits of the lightweight design scheme. To prove the feasibility of the method, the ZS061750-152101 wheel hub designed and manufactured by Anhui Axle Co., Ltd. was taken as an example for the case analysis. The lightweight design changes three structures of the wheel hub, reducing its weight by 1.4 kg in total. For a single wheel hub, the carbon emissions are reduced by 51.22 kg altogether. That is to say, if the lightweight scheme were to be applied to all the wheels produced by Anhui Axle Co., Ltd. (about 500,000 per year), the carbon emissions from the wheel production, application and recycling could be cut by 2.56 × 107 kg, marking a favorable emission reduction effect. The proposed method can not only provide insight into the lightweight design of automobiles and other equipment against the background of low carbon but also provide a channel for calculating the carbon emission changes in the whole process after the application of the lightweight design.

Under a two-part tariff, the user-side installation of photovoltaic and energy storage systems can simultaneously lower the electricity charge and demand charge. How to plan the energy storage capacity and location against the backdrop of a fully installed photovoltaic system is a critical element in determining the economic benefits of users. In view of this, we propose an optimal configuration of user-side energy storage for a multi-transformer-integrated industrial park microgrid. First, the objective function of user-side energy storage planning is built with the income and cost of energy storage in the whole life cycle as the core elements. This is conducted by taking into consideration the time-of-use electricity price, demand price, on-grid electricity price, and energy storage operation and maintenance costs. Then, considering the load characteristics and bidirectional energy interaction of different nodes, a user-side decentralized energy storage configuration model is developed for a multi-transformer-integrated industrial park microgrid. Finally, combined with the engineering practice constraints, the configuration model is solved by mixed integer linear programming. The simulation test demonstrates how the proposed model can successfully increase the economic benefits of an industrial park. Electricity and demand costs are reduced by 11.90% and 19.35%, respectively, and the photovoltaic accommodation level is increased by 4.2%, compared to those without the installation of energy storage system.