区间数-灰靶决策模型在低碳电网规划评价中的应用

低碳电网规划作为电力工业的一个重要环节,为深入分析和评价低碳电网规划,建立了低碳电网规划评价的综合指标体系,引入区间数理论处理电网规划面临的不确性问题,结合灰色系统理论中的灰靶决策方法构建区间型多指标灰靶决策模型,并以保定地区电网规划为例进行方案评价比选。结果表明,该方法有效合理,准确度和可信度较高。     

理想等效热降法和常规等效热降法的一致性分析

首先分析了常规等效热降法与热平衡方法之间的一致性,指出常规热平衡方法得到的单位质量蒸汽在汽轮机内的膨胀功与等效热降法得到的新蒸汽等效热降之间相差单位质量给水所消耗的给水泵的压缩功。然后,对理想等效热降法与常规等效热降法之间在分析热力系统热经济性方面的一致性进行了分析。最后,提出了采用等效热降法进行汽轮机热经济性诊断应该注意的问题。     

广东省经济发展与能源电力消费影响关系分析

采用协整及相关性理论分析了广东省现有经济发展模式下能源、电力消费与经济发展的关系,建立了能源与经济、电力与经济之间的关系模型,并在此基础上提出了缓解广东省能源供需矛盾的建议。     

Design optimization of grid-connected PV-Hydrogen for energy prosumers considering sector-coupling paradigm: Case study of a university building in Algeria

Integrating sector coupling technologies into Hydrogen (H₂) based hybrid renewable energy systems (HRES) is becoming a promising way to create energy prosumers, despite the very little research work being done in this largely unexplored field. In this paper, a sector coupling strategy (building and transportation) is developed and applied to a grid-connected PV/battery/H₂ HRES, to maximise self-sufficiency for a University campus and to produce power and H₂ for driving electric tram in Ouargla, Algeria. A multi-objective size optimization problem is solved as a single objective problem using the ε-constraint method, in which the cost of energy (COE) is defined as the main objective function to be minimized, while both loss of power supply probability (LPSP) and non-renewable usage (NRU) are defined as constraints. Particle swarm optimization and HOMER software are then employed for simulation and optimization purposes. Prior to the two scenarios investigated, a sensitivity study is performed to determine the effects of H₂ demand by tram and NRU on the techno-economic feasibility of the proposed system, followed by a new reliability factor introduced in the optimization, namely loss of H₂ supply probability (LHSP). The results of the first scenario show that by setting NRU^max = 100%, the system without H₂ provides the best solution with COE of 0.016 $/kWh that reaches grid parity and has 13% NRU. However, by setting NRU^max = 1% in the second scenario, an optimized configuration consisting of grid/PV/Electrolyzer/Fuel cell/Storage tank is obtained, which has 0% NRU and COE of 0.1 $/kWh. In the second scenario, it is also observed that an increased number of trams (i.e. increased H₂ demands) causes a significant reduction in LHSP, COE, NRU and CO₂ emissions. It is thus concluded that the grid/PV combination is the optimal choice for the studied system when considering economic aspects. However, taking into account the growing requirements of future energy systems, grid-connected PV with H₂ will be the best solution.     

米勒循环及低压废气再循环技术对汽油机性能的影响研究

在某2.0L涡轮增压商用车缸内直喷汽油机概念设计阶段,运用GT-Power软件进行了一维热力学计算分析,并着重研究了米勒循环技术与低压废气再循环(exhaust gas recirculation,EGR)技术对燃油经济性的影响。仿真结果显示,长米勒循环和短米勒循环都存在使燃油经济性达到最佳的可变气门正时角度。在中高转速范围内,因为质量流量和流速过高导致长米勒循环的缸内空气无法顺利回流,米勒效应减弱,所以短米勒循环的燃油经济性更好;另外长米勒循环具有两次泵气过程,致使其泵气损失也大于短米勒循环。在低转速范围内,短米勒循环的增压压力需求更大,导致其泵气损失大于长米勒循环,所以长米勒循环的燃油经济性更好。对于试验用汽油机来说,短米勒循环具有明显的优势。低压EGR技术能够使缸内最高温度降低,减轻爆震倾向,因此燃烧重心可以适当提前,从而改善燃油经济性。另外,EGR和新鲜空气总量的增加也使最高燃烧压力增大,有利于燃油经济性的提高。不同工况下,缸内最高温度均随EGR率的增加而降低,因此在一定范围内EGR率越高燃油经济性越好,涡前排温越低,但EGR冷却器需要的散热功率也增大。在发动机燃烧开发阶段,推荐采用短米勒循环技术并结合8%的EGR率。为了验证仿真结果的准确性,开展了性能试验,试验结果与仿真结果在趋势上有很好的一致性。     

Sustainable hydrogen roadmap: A holistic review and decision-making methodology for production,utilisation and exportation using Qatar as a case study

Hydrogen is seen as a promising and inevitable energy carrier in the transition towards a carbon-free energy era. This study reviews the potential for carbon-free hydrogen production, utilisation and exportation from the State of Qatar. The study aims to introduce a roadmap for current and future exploration of carbon-free hydrogen production and exportation from Qatar, for which an assessment of several available alternatives for the production of hydrogen in Qatar is performed. These alternatives include the use of natural gas as a feedstock for hydrogen production through steam methane reforming (SMR), solar integrated steam methane reforming with carbon capture, as well as the possibilities for hydrogen production from electrolysis using renewables and ammonia as another intermediate. The potential of each alternative is reviewed based on selected technical, economic and environmental criteria. The findings of this review study indicate that the production and exportation of blue ammonia currently present the best pathway for Qatar, while green hydrogen is expected to become as competitive as blue ammonia in the mid-future. It is widely accepted that as the technologies associated with clean hydrogen production improve, and the cost of renewable energy falls, green hydrogen will become quite competitive in the region.     

超超临界机组参数和热力系统的优化分析

概要叙述了国外超超临界技术的现状和发展趋势，研究了各种因素对超超临界机组参数和热力系统选择的影响，指出发展国产化大容量超超临界参数机组十分必要，提出了我国发展超超临界技术的可选方案，并对其经济性作了初步分析。表3参4     

甲醇/柴油双燃料发动机的性能

在一台柴油机基础上，采用气道口电控喷射甲醇，缸内柴油引燃甲醇的方式，开发了电控甲醇／柴油双燃料样机，并通过发动机台架实验，研究了柴油／甲醇双燃料燃烧模式在燃烧特性、燃油经济性及排放性能方面的特点．与原发动机相比，双燃料模式的最高爆发压力下降，压力升高率上升，排烟和NOx大幅度下降，但THC和CO排放均升高．该方法能使甲醇喷射量得到精确控制以便燃烧达到最佳状态，是甲醇／柴油双燃料发动机可行的技术方案．     

车用汽油机的节油潜力及高效汽油机的可行性

本文通过对未来30年的主要交通能源和乘用车动力主流产品的分析,指出研发汽油机节油技术的重要性。车用汽油机还有很大节油潜力,尤其是均质压燃汽油机克服了点燃燃烧对发动机空燃比和压缩比的限制,能够提高汽车平均燃油效率达25%以上。均质压燃的燃烧时间能在各种情况下得到可靠控制,因而能够在车辆上应用。目前国内车用发动机技术研发现状不容乐观。要避免在10年内陷入困境,应建立车用发动机创新研究的体制。     

谈谈物流管理与社会和谐

现代物流已成为新世纪发展的重要产业和新的经济增长点。如何认识现代物流管理在构建社会和谐中的作用和意义,这对提高物流管理整体运行效益,凸显现代物流管理的地位和价值,以及对全面实施和提升现代企业管理和创建和谐社会有着极其重要的现实意义。物流管理既是经济活动的管理形式,同时又具有管理的社会性。一个健康、规范、有序的物流管理,不仅在经济活动中为社会创造巨大财富,而且其社会性的良好体现会促进社会各层面的广泛和谐。