Model for developing an eco-driving strategy of a passenger vehicle based on the least fuel consumption

Additional consumption of fuel in an intense traffic condition is inevitable. Excess fuel consumption may be avoided, if an optimal driving strategy is implemented subject to the surrounding condition of a vehicle and existing constraints. Development of an optimal driving strategy has been the subject of eco-driving. A model of optimal driving strategy has been developed and it has been applied for assessment of eco-driving rules. The model may be categorized as an optimal control and the objective function is minimization of fuel consumption in a given route. Vehicle speed and gear ratio are identified as control variables. The effect of working load has been considered according three engine running processes of Idle, part-load and wide open throttle. The model has then been applied to identify the optimal driving strategy of a vehicle in different traffic congestion based on eco-driving rules.     

电动汽车的能耗效率分析及提高能耗经济性的研究

通过对比电动汽车和内燃机汽油车的热效率及能耗,得出电动汽车的热效率及能耗明显优于内燃机汽油车的结论,并推断出降低电动汽车的运行能耗、提高其经济性是推动电动汽车产业化的关键因素之一。从整车动力系统、电池以及充电设备等几个方面分析了提高电动汽车能耗经济的途径,指出了今后需要重点研究的关键性问题。     

计算机显示器能效标识制度与能效测试

在计算机显示器能效标准和能效测试的基础上,通过分类统计的方法,分析了被测显示器的能效等级和能效指标的分布,讨论了计算机显示器的能效水平和制约因素,说明能效标识制度的实施促进了计算机显示器的节能进程,并对其节能技术创新具有一定的指导意义。     

Improving the PEMFC energy efficiency by optimizing the fueling rates based on extremum seeking algorithm

In this paper, the energy efficiency of the Proton Exchange Membrane Fuel Cell (PEMFC) systems based on the fueling rates is systematically investigated. The PEMFC system under dynamic load must be operated close to the Maximum Efficiency Point (MEP) to obtain the highest energy efficiency. This is a difficult task because the MEP is dependent on the PEMFC parameters and the control PEMFC variables, besides the load profile. Thus, the MEP must be tracked dynamically with a safe search speed and funded accurately during the stationary regimes. Consequently, a real-time control is recommended to be used. The Extremum Seeking (ES) control scheme is proposed here to evaluate the FC net power at the MEP under different fueling rates and load profiles. Some interesting conclusions are obtained based on the comparative method proposed using as reference a base control technique or a PEMFC stack: 1) the MEP is different based on the control of the fuel or air flow rate; 2) the energy efficiency increases if both fueling flow rates are controlled; 3) the energy efficiency is less sensitive to power losses if the MEP is tracked by the ES controller based on air flow rate; 4) the strategy of load following control considering the fuel flow rate as an input variable is recommended based on the observation that the MEP is more sensitive to this in comparison to the air flow rate; 5) the design of an appropriate MEP tracking controller should equally focus on safe operation and the increase of the performances such as the search speed and tracking accuracy under dynamic load. All these remarks are based on an extensive numerical simulation, which are highlighted in this paper by the main results shown.     

我国高校能源消耗模型构建与能效策略研究

以构建能源消耗模型为切入点,剖析我国高校的用能现状、特点及发展趋势,对我国高校的节能潜力进行量化分析,提出我国高校开展能效管理的策略。     

基于综合燃油消耗率的混合动力汽车能量管理策略研究

通过对单轴并联式混合动力汽车综合燃油消耗率的建模计算,以综合燃油消耗率(Integrated Specific Fuel Consumption,ISFC)最低为目标确定了该混合动力系统各工作模式的工作范围,并制定了相应的整车能量管理策略。在此基础上,利用Matlab/Simulink仿真平台,建立了混合动力系统能量管理策略的仿真模型,结果表明采用控制策略使该混合动力汽车的燃油经济性比传统汽车和采用基线控制策略的相同混合动力汽车有显著提高。     

An energy efficiency plan for the Iranian building sub-sector

The objective of this paper is to develop a 25-year least cost plan for energy management in the Iranian building sub-sector. For this purpose, an energy flow optimization from the point where the final energy is delivered to consumers, until the useful energy and energy services point is investigated. This will help to select the most economically feasible technologies as well as energy carriers considering all technical and social constraints. Based on the optimization results, absorption cooling for the regions where natural gas network is available, grades A and B evaporative coolers and air conditioners for those areas where there is no gas service, gas fired heating systems, wall insulation, double-glazed windows, equipments and appliances with highest energy labelling grade and compact and non-compact fluorescent lamps are among the selections. The results of the sensitivity analysis indicates that if the cost of natural gas network development to the regions where there is no gas will result in the tripling rate of the actual cost of the natural gas, in those areas, the priority should be still given to the consumption of gas. The proposed energy efficiency plan results in 27%, 54% and 10% saving in energy consumption, energy cost and investment cost, respectively.     

Potential for reducing GHG emissions and energy consumption from implementing the aluminum intensive vehicle fleet in China

The automobile industry in China has rapidly developed in recent years which resulted in an increase in gasoline usage and greenhouse gas (GHG) emissions. Focus on climate change has also accelerated to grow pressure on reducing vehicle weight and improving fuel efficiency. Aluminum (Al) as a light metal has demonstrated a great potential for weight savings in applications such as engine blocks, cylinder heads, wheels, hoods, tailgates etc. However, primary Al production requires intensive energy and the cost of Al is more than traditional steel, which may affect the total benefits realized from using Al in automobiles. Therefore, it is very essential to conduct a study to quantify the life cycle GHG emissions and energy consumption if the plan is to achieve fleet-wide Al intensive vehicles.     

Model projections for household energy use in India

Energy use in developing countries is heterogeneous across households. Present day global energy models are mostly too aggregate to account for this heterogeneity. Here, a bottom-up model for residential energy use that starts from key dynamic concepts on energy use in developing countries is presented and applied to India. Energy use and fuel choice is determined for five end-use functions (cooking, water heating, space heating, lighting and appliances) and for five different income quintiles in rural and urban areas. The paper specifically explores the consequences of different assumptions for income distribution and rural electrification on residential sector energy use and CO₂ emissions, finding that results are clearly sensitive to variations in these parameters. As a result of population and economic growth, total Indian residential energy use is expected to increase by around 65–75% in 2050 compared to 2005, but residential carbon emissions may increase by up to 9–10 times the 2005 level. While a more equal income distribution and rural electrification enhance the transition to commercial fuels and reduce poverty, there is a trade-off in terms of higher CO₂ emissions via increased electricity use.     

An energy demand model for a fleet of plug-in fuel cell vehicles and commercial building interfaced with a clean energy hub

This paper presents an energy demand model for a fleet of plug-in fuel cell vehicles and a medium-sized commercial/office building interfaced with a clean energy hub. The approach taken is to model the architecture and daily operation of every individual vehicle in the fleet. A simplified architecture model was developed, with daily operation divided into two periods: charging and travelling. During the charging period, the vehicle charges its batteries and refills its compressed hydrogen tanks. During the travelling period, the vehicle depletes the batteries and hydrogen tanks based on distance travelled. Daily travel distance is generated by a stochastic model. The modeling of the clean energy hub is also presented. The clean energy hub functions as an interface between electricity supply and the energy demand (i.e. hydrogen and electricity) of the vehicle fleet and the commercial building. Finally, a sample case is presented to demonstrate the use of the models.     

Fuel conservation and GHG (Greenhouse gas) emissions mitigation scenarios for China’s passenger vehicle fleet

Passenger vehicles are the main consumers of gasoline in China. We established a bottom-up model which focuses on the simulation of energy consumptions and greenhouse gas (GHG) emissions growth by China’s passenger vehicle fleet. The fuel conservation and GHG emissions mitigation effects of five measures including constraining vehicle registration, reducing vehicle travel, strengthening fuel consumption rate (FCR) limits, vehicle downsizing and promoting electric vehicle (EV) penetration were evaluated. Based on the combination of these measures, the fuel conservation and GHG emissions mitigation scenarios for China’s passenger vehicle fleet were analyzed. Under reference scenario with no measures implemented, the fuel consumptions and life cycle GHG emissions will reach 520 million tons of oil equivalent (Mtoe) and 2.15 billion tons in 2050, about 8.1 times the level in 2010. However, substantial fuel conservation can be achieved by implementing the measures. By implementing all five measures together, the fuel consumption will reach 138 Mtoe in 2030 and decrease to 126 Mtoe in 2050, which is only 37.1% and 24.3% of the consumption under reference scenario. Similar potential lies in GHG mitigation. The results and scenarios provided references for the Chinese government’s policy-making.     

Evaluation of the effectiveness of an energy efficiency program for new home construction in eastern North Carolina

This paper reports on the evaluation of the effectiveness of an energy efficiency program in eastern North Carolina. This subject program is focused on improved construction methods for residential housing. The program incorporates proven energy saving technologies, construction procedures, onsite inspections, and design construction methodologies in new residential construction. The analysis compared the energy usage associated with the houses built in conjunction with the energy efficiency program (test group) with similar new residential construction unrelated to the program (control group). Several statistical methods were employed to establish differences between the energy efficiency program participants and the control group. The analysis provides significant support for the effectiveness of this energy efficiency program and supports the suitability of similar efforts for inclusion in plans for renewable energy offsets and energy efficiency standards.     

EUE (energy use efficiency) of cropping systems for a sustainable agriculture

Energy efficiency of agriculture needs improvement to reduce the dependency on non-renewable energy sources. We estimated the energy flows of a wheat-maize-soybean-maize rotation of three different cropping systems: (i) low-input integrated farming (LI), (ii) integrated farming following European Regulations (IFS), and (iii) conventional farming (CONV). Balancing N fertilization with actual crop requirements and adopting minimum tillage proved the most efficient techniques to reduce energy inputs, contributing 64.7% and 11.2% respectively to the total reduction. Large differences among crops in energy efficiency (maize: 2.2 MJ kg⁻¹ grain; wheat: 2.6 MJ kg⁻¹ grain; soybean: 4.1 MJ kg⁻¹ grain) suggest that crop rotation and crop management can be equally important in determining cropping system energy efficiency. Integrated farming techniques improved energy efficiency by reducing energy inputs without affecting energy outputs. Compared with CONV, energy use efficiency increased 31.4% and 32.7% in IFS and LI, respectively, while obtaining similar net energy values. Including SOM evolution in the energy analysis greatly enhanced the energy performance of IFS and, even more dramatically, LI compared to CONV. Improved energy efficiency suggests the adoption of alternative farming systems to reduce greenhouse gas emissions from agriculture. However, a thorough evaluation should include net global warming potential assessment.     

From waste to electricity through integrated plasma gasification/fuel cell (IPGFC) system

The waste management is become a very crucial issue in many countries, due to the ever- increasing amount of waste material, both domiciliary and industrial, generated.The main strategies for the waste management are the increase of material recovery (MR), which can reduce the landfill disposal, the improvement of energy recovery (ER) from waste and the minimization of the environmental impact.These two last objectives can be achieved by introducing a novel technology for waste treatment based on a plasma torch gasification system integrated with a high efficiency energy conversion system, such as combined cycle power plant or high-temperature fuel cells.This work aims to evaluate the performance of an Integrated Plasma Gasification/Fuel Cell system (IPGFC) in order to establish its energy suitability and environmental feature.The performance analysis of this system has been carried out by using a numerical model properly defined and implemented in Aspen Plus™ code environment. The model is based on the combination of a thermochemical model of the plasma gasification unit, previously developed by the authors (the so-called EquiPlasmaJet model), and an electrochemical model for the SOFC fuel cell stack simulation.The EPJ model has been employed to predict the syngas composition and the energy balance of an RDF (Refuse Derived Fuel) plasma arc gasifier (that uses air as plasma gas), whereas the SOFC electrochemical model, that is a system-level model, has allowed to forecast the stack performance in terms of electrical power and efficiency.Results point out that the IPGFC system is able to produce a net power of 4.2 MW per kg of RDF with an electric efficiency of about 33%. This efficiency is high in comparison with those reached by conventional technologies based on RDF incineration (20%).     

Experimental study of exhaust‐gas energy recycling efficiency of hybrid pneumatic power system

A hybrid pneumatic power system (HPPS) comprises an internal combustion engine (ICE), an air compressor, a high‐pressure air storage tank, and a turbine, which stores the flow work instead of a battery's electrochemical energy; moreover, this system can recycle the exhaust‐gas energy and make the ICE operate at its optimal point. Therefore, it can be viewed as a promising solution to increase a system's thermal efficiency and greatly improving exhaust emissions. This paper presents experimental study results concerning the operating capabilities of the HPPS and the effect of the contraction of the cross‐sectional area (CSA) at the merging region of the energy merger pipe for the change in the compressed airflow pressure (P_air) on the exhaust‐gas energy recycling of the HPPS. The experiments were performed on an HPPS that uses an innovative energy merger pipe with a total length of 530 mm, a diameter of 34 mm, and an angle between the two pipes of 30°, and the CSA was adjusted for the change in P_air. The experimental results show that the exhaust‐gas energy recycling and the merger flow energy are significantly dependent on the CSA adjustment for the change in P_air. The optimum conditions for the best merging process can be achieved at a CSA of around 5–35% in the full range of P_air. Under these conditions, the exhaust‐gas energy recycling efficiency reached approximately 75–81%; therefore, a vehicle equipped with an HPPS can achieve efficiency that is approximately 40% higher than that of conventional vehicles. Copyright © 2009 John Wiley & Sons, Ltd.     

Thermodynamic performance assessment of ocean thermal energy conversion based hydrogen production and liquefaction process

In the proposed study, the thermodynamic performance assessment of ocean thermal energy conversion (OTEC) based hydrogen generation and liquefaction system are evaluated. In this context, the energetic and exergetic analyses of integrated system are conducted for multigeneration. This integrated process is consisted of the heat exchangers, turbine, condenser, pumps, solar collector system, hot storage tank, cold storage tank and proton exchange membrane (PEM) electrolyzer. In addition to that, the impacts of different design indicators and reference ambient parameters on the exergetic performance and exergy destruction rate of OTEC based hydrogen production system are analyzed. The energetic and exergetic efficiencies of integrated system are founded as 43.49% and 36.49%, respectively.     

Multi carrier energy systems and energy hubs: Comprehensive review,survey and recommendations

In this paper, the multi carrier energy (MCE) systems are reviewed from different point of views including mathematical models, integrated components and technologies, uncertainty management, planning objectives, environmental pollution, resilience, and robustness. The basic of MCE systems is formed by combination of cooling, heating and power (CCHP). The natural gas and electricity are the main inputs to MCE systems and the cooling, heating, and electricity are the common outputs. The regular energy converters in the MCE systems are combined heat and power (CHP), gas boiler, absorption-electrical chillers, power to gas (P2G) and fuel-cell. The generic energy storages are electrical, heating, cooling, hydrogen, carbon dioxide (CO₂) and hydro systems.     

大型公共建筑空调系统能耗监测探讨

介绍了我国节能监测（监察）的现状和不足,指出了空调系统节能监测的重要性。分析了空调系统主要能耗和节能监测中常见的问题;指出要规范节能监测标准,真正做到空调系统节能。为政府部门节能减排工作提供措施建议。     

建筑智能化系统节能综合评价

从发展方向、技术经济、投资与收益等方面分析了建筑智能化系统工程中的节能问题,提出系统优化设计的原则与技术措施,并对系统节能效益评价的内容与方法进行探讨．     

能源需求组合预测模型的构建和应用研究

随着中国经济的快速发展,能源消费不断提高。利用能源消费量的历史数据,建立了我国能源消费系统的ARMA模型和灰色预测模型的组合模型,通过组合模型和ARMA模型、灰色预测模型的具体比较分析,证明组合模型更为易行、有效,可以作为我国及地区未来能源消费量预测的有效工具。