Liquid fuel utilization in SOFC hybrid systems

The interest in solid oxide fuel cell systems comes from their capability of converting the chemical energy of traditional fuels into electricity, with high efficiency and low pollutant emissions. In this paper, a study of the design space of solid oxide fuel cell and gas turbine hybrids fed by methanol and kerosene is presented for stationary power generation in isolated areas (or transportation). A 500 kW class hybrid system was analysed using WTEMP original software developed by the Thermochemical Power Group of the University of Genoa. The choice of fuel-processing strategy and the influence of the main design parameters on the thermoeconomic characteristics of hybrid systems were investigated. The low capital and fuel cost of methanol systems make them the most attractive solutions among those investigated here.     

Integrated energy systems based on cascade utilization of energy

Focusing on the traditional principle of physical energy utilization, new integration concepts for combined cooling, heating and power (CCHP) system were identified, and corresponding systems were investigated. Furthermore, the principle of cascade utilization of both chemical and physical energy in energy systems with the integration of chemical processes and thermal cycles was introduced, along with a general equation describing the interrelationship among energy levels of substance, Gibbs free energy of chemical reaction and physical energy. On the basis of this principle, a polygeneration system for power and liquid fuel (methanol) production has been presented and investigated. This system innovatively integrates a fresh gas preparation subsystem without composition adjustment process (NA) and a methanol synthesis subsystem with partial-recycle scheme (PR). Meanwhile, a multi-functional energy system (MES) that consumes coal and natural gas as fuels simultaneously, and co-generates methanol and power, has been presented. In the MES, coal and natural gas are utilized synthetically based on the method of dual-fuel reforming, which integrates methane/steam reforming and coal combustion. Compared with conventional energy systems that do not consider cascade utilization of chemical energy, both of these systems provide superior performance, whose energy saving ratio can be as high as 10%–15%. With special attention paid to chemical energy utilization, the integration features of these two systems have been revealed, and the important role that the principle of cascade utilization of both chemical and physical energy plays in system integration has been identified.     

Analysis of small-scale biogas utilization systems on Ontario cattle farms

The production of biogas through the anaerobic digestion of cattle manure and its subsequent use in the generation of electricity on larger farms in Ontario is currently economically attractive. This is a result of the Ontario Feed-In Tariff (FIT) program, which provides incentivized rates for the production of electricity from biogas. Although larger farms can take advantage of the higher rates for electricity, there are substantially more smaller farms for which individually designed and engineered biogas systems would be prohibitively expensive. By employing the concept of modular biogas plants, this analysis evaluates the economics of small-scale biogas utilization systems. Dairy farms with at least 33 animals and beef farms with at least 78 animals can operate economically attractive biogas systems. This analysis shows that approximately 9000 additional Ontario cattle farms would be able to take advantage of the FIT program, which would add 120 MW_e of renewable energy capacity to the Ontario electrical grid.     

Safety assessment of envisaged systems for automotive hydrogen supply and utilization

A novel consequence-based approach was applied to the inherent safety assessment of the envisaged hydrogen production, distribution and utilization systems, in the perspective of the widespread hydrogen utilization as a vehicle fuel. Alternative scenarios were assessed for the hydrogen system chain from large scale production to final utilization. Hydrogen transportation and delivery was included in the analysis. The inherent safety fingerprint of each system was quantified by a set of Key Performance Indicators (KPIs). Rules for KPIs aggregation were considered for the overall assessment of the system chains. The final utilization stage resulted by large the more important for the overall expected safety performance of the system. Thus, comparison was carried out with technologies proposed for the use of other low emission fuels, as LPG and natural gas. The hazards of compressed hydrogen-fueled vehicles resulted comparable, while reference innovative hydrogen technologies evidenced a potentially higher safety performance. Thus, switching to the inherently safer technologies currently under development may play an important role in the safety enhancement of hydrogen vehicles, resulting in a relevant improvement of the overall safety performance of the entire hydrogen system.     

小区给水水质优化与水资源综合利用新技术

小区给水系统的水质优化及水资源的综合利用,是保证居民用水质量、提高水资源利用率的一种重要手段,通过对现有的集中供水体制作必要的升级,可有效地提高供水水质,并根据需要满足不同用户需求,在提高供水水平的同时,降低了供水成本,通过对膜技术、中水回用技术等新技术作分析研究,以期在未来工程中应用.     

Reliability/cost implications of PV and wind energy utilization insmall isolated power systems

The application of renewable energy in electric power systems is growing rapidly due to enhanced public concerns for adverse environmental impacts and escalation in energy costs associated with the use of conventional energy sources. Photovoltaics and wind energy sources are being increasingly recognized as cost effective generation sources in small isolated power systems primarily supplied by costly diesel fuel. The utilization of these energy sources can significantly reduce the system fuel costs but can also have considerable impact on the system reliability. A realistic cost/reliability analysis requires evaluation models that can recognize the highly erratic nature of these energy sources while maintaining the chronology and interdependence of the random variables inherent in them. This paper presents a simulation method that provides objective indicators to help system planners decide on appropriate installation sites, operating policies, and selection of energy types, sizes and mixes in capacity expansion when utilizing PV and wind energy in small isolated systems     

Cost effectiveness of decentralized energy supply systems taking solar and wind utilization plants into account

In this article, results are presented of annual simulations of a decentralized (regional) plant for the power and heat supply of a residential complex. This complex consists of four houses with 40 flats all in all. The annual power consumption of the complex is 157 MWh and the heat requirement is 325 MWh. The concrete dynamics of the energy demands over the year is taken into consideration. The energy supply system is composed of a power-controlled combined heat and power (CHP) plant (55 kW), a photovoltaic plant (PV array or PV plant) array for power generation as well as a field of solar thermal collectors with a short-term accumulator for water heating and a long-term accumulator for supplying heat for domestic heating purposes. Simulation results demonstrate that synergetic effects result from the combination of a CHP plant with wind power and PV plants of varying sizes, which have an effect on the cost effectiveness of the plant as a whole with the different dynamics of energy sources (wind and solar energies) and of the consumption of power and heat being the decisive factors. The power deficits of wind power and PV plants are compensated through the application of a natural gas-operated CHP plant. In almost all variants, the demand for fossil energy carriers is distinctly less than in conventional energy supply plants.     

On capital utilization in the hydrogen economy: The quest to minimize idle capacity in renewables-rich energy systems

The hydrogen economy is currently experiencing a surge in attention, partly due to the possibility of absorbing variable renewable energy (VRE) production peaks through electrolysis. A fundamental challenge with this approach is low utilization rates of various parts of the integrated electricity-hydrogen system. To assess the importance of capacity utilization, this paper introduces a novel stylized numerical energy system model incorporating the major elements of electricity and hydrogen generation, transmission and storage, including both “green” hydrogen from electrolysis and “blue” hydrogen from natural gas reforming with CO₂ capture and storage (CCS). Concurrent optimization of all major system elements revealed that balancing VRE with electrolysis involves substantial additional costs beyond reduced electrolyzer capacity factors. Depending on the location of electrolyzers, greater capital expenditures are also required for hydrogen pipelines and storage infrastructure (to handle intermittent hydrogen production) or electricity transmission networks (to transmit VRE peaks to electrolyzers). Blue hydrogen scenarios face similar constraints. High VRE shares impose low utilization rates of CO₂ capture, transport and storage infrastructure for conventional CCS, and of hydrogen transmission and storage infrastructure for a novel process (gas switching reforming) that enables flexible power and hydrogen production. In conclusion, all major system elements must be considered to accurately reflect the costs of using hydrogen to integrate higher VRE shares.     

Development of large scale unified system for hydrogen energy carrier production and utilization: Experimental analysis and systems modeling

The world's largest class hydrogen energy carrier production, storage, and utilization system has been operated in order to obtain basic data for practical use of the system using renewable energy. In this system, an alkaline water electrolyzer is combined with hydrogenation reactors to produce methylcyclohexane (MCH). Since electrolyzer behavior directly affects hydrogenation reaction, behaviors of the 150 kW class water electrolyzer against fluctuating electricity inputs were experimentally investigated. The cell stack voltage and hydrogen flow rate changed following temporal changes of the input current, whereas the temperature response was slow due to the large heat capacity of the system. Hydrogenation reactors performance using the hydrogen from the electrolyzer are reported. Then, based on the experiment data, a numerical simulation model for the electrolyzer was developed, which predicts the experimental result using fluctuating electricity very well. Furthermore, using the simulator, the heat utilization from the hydrogenation reaction for the electrolyzer warm-up process was investigated.     

Heating requirements in greenhouse farming in southern Italy: evaluation of ground-source heat pump utilization compared to traditional heating systems

Greenhouse farming, where energy consumptions are mainly related to the greenhouses heating, is one of the sectors consuming the most energy in the agricultural industry. High costs and the uncertain availability of fossil fuels constrain the use of heating applications. Among possible solutions, the utilization of renewable heating systems such as geothermal energy through ground-source heat pump systems (GSHPs) at competitive prices has to be taken in consideration. The competitiveness of these systems depends mainly on the characteristics of the end-users, i.e., the annual heating loads. Few studies focusing on the potential of using these systems start with an analysis of the thermal requirements and end with a cost evaluation in tune with local assets, geo-climatic conditions, and landscape protection. This paper analyzes the greenhouse crop industry in the Apulia region in southern Italy, as a potential end-user of GSHP systems. Data collected from an area mainly devoted to greenhouse crop production have been used to (a) describe greenhouse farms, (b) define the heating requirements of a greenhouse model representative of the most used typology in the investigated area, and (c) examine the economic viability of greenhouse heating with GSHP systems. Both vertical and horizontal ground heat exchanger (GHE) configurations are compared with conventional fossil-fuel heating systems. In all scenarios considered, the observed payback periods appear reasonable and worthy of consideration. The results suggest that these technologies can fully satisfy the winter heating requirements in a cost-effective way and they can support the planning of measures aimed to improve the sector competitiveness.     

太阳能利用综述及提高其利用率的途径

文章综述了太阳能的优缺点、利用方式以及太阳能热水器集热器的研究开发现状,介绍了连续水平旋转太阳能集热器实现太阳跟踪,提高太阳热利用率的途径。     

趣谈风能利用

一帆风顺、风调雨顺、风和日丽、狂风暴雨、风雨同舟、微风荡漾……人们每天都在谈论风。风是我们最常见的自然现象之一。那么,风是怎样产生的呢?太阳和风     

冰岛的地热利用

尽管冰岛有一个寒冷的外表和国名，可是它仍然是地球上最温暖的地区之一。对于２５万冰岛人来说，火与硫磺并没有在人们生活中构成恐惧与问题。来访者在旅馆中淋浴时常常抱怨硫磺的气味，但他们不知道每５户冰岛家庭中就有４户享用着地热能源，这意味着室内温暖如春和随时使用的热水拧开龙头就是。在有全国一半以上人口居住的大雷克雅未克市，每家每户都有热水供应。在全国，只有远离活跃地热区的分散的家庭、村镇例外。目前开发的温泉只是可开发温泉的一小部分，但已接近满足全国的需要了。地热除了向位于北极圈内整个国家供热这一明显的好…     

我国太阳能热利用进展

我国人口众多，１２．５亿人口，其中７５％生活在农村。近２０年采我国经济快速发展，人民生活不断提高，对能源的需求亦随之递增。煤是我国主要的一次能源的资源，燃煤引起的环境问题已成为我国可持续发展战略中的要认真对待的问题。开发太阳能利用是实现我国可持续发展战略的有效措施之一。１ 太阳能热利用在我国农村能源建设中的贡献 我国的太阳能热利用技术研究开发始于２０世纪７０年代未，其重点置于简单、价廉的低温热利用的适用技术，如太阳能温室、太阳灶、被动太阳房、太阳热水器和太阳干燥器。这类技术在农村得到推广应用，为缓…     

东瀛归来话氢能——记中国氢能代表团成功访问日本

2009年2月22日～28日,由中国可再生能源学会氢能专业委员会组织的中国氢能代表团成功地访问了日本.代表团共15名成员,其中9名团员为高校和研究机构的氢能专家,其余6名团员为与氢能相关的企业家,代表团成员工作领域包括氢能制备、储运、应用以及政策法规等,覆盖了氢能产业整个领域.     

我国城市生活垃圾能源化利用分析

通过对目前国内外垃圾处理方式的分析比较,并针对我国城市垃圾特点,提出了适合我国城市垃圾处理的方法及技术措施和应用前景,并提出了垃圾能源二次利用这一课题的一些研究方向。     

Epri coal ash utilization research

This paper describes a five-year Electric Power Research Institute (EPRI) project directed toward increasing ash utilization. EPRI is undertaking this program to promote the bulk sale of coal ash in high-volume applications that do not require a specific quality or class of ash; in medium-technology applications in cement and concrete; and in high-technology uses for valuable products requiring stringent quality control. High-volume applications include the use of ash in highways and railroads, backfills, and pavement base course; medium-technology applications include cement and concrete; and high-technology uses include the extraction of the mineral matter or the metals from ash.     

Energy utilization in maize production

Average physical inputs in maize cultivation in three districts of Haryana (North India) have been transformed into energy units and compared with the energy outputs of grain and byproducts. The chief inputs were in the form of farm yard manure (FYM), traditional farm equipment, tractor and fuel, followed by irrigation and chemical fertilizers. Detailed data of physical inputs were collected from 31 individual farm units of Ambala district, ranging from 0.41 to 3.24 ha. Six of these farms showed extremes of size, tractor use, fertilizer application, FYM inputs, irrigation, as well as yields of grain and byproducts. Data from these farms were analysed in terms of energy utilization. Energy use efficiency ranged from 0.06 to 0.28 for grain and from 0.29 to 1.16 for total produce. The data suggest that grain production can be increased and energy utilization improved by minimizing the use of FYM and by increased use of chemical fertilizers and irrigation.     

地热能的合理利用

从能源和环境保护的角度介绍了我国地热资源和目前的应用状况,分析了当前我国地热资源应用过程中需要解决的问题及解决方案,探讨了提高地热资源利用率的技术措施。