Effect of different design aspects of pipe for earth air tunnel heat exchanger system: A state of art

Earth air tunnel heat exchanger (EATHE) is a promising passive technique to provide thermal comfort condition in buildings. EATHE system uses undisturbed temperature of the ground for heating/cooling of air. Despite the several advantages, this technique has not become much popular owing to its high capital cost (mainly pipe cost and trench excavation cost) and large land area requirements. The primary objective of this study is to present a comprehensive review of different EATHE pipe layouts, pipe properties and positioning of the pipe with their advantages and limitations. It is observed that the ring pipe layout is the most cost-effective pipe-layout for small size EATHE system because it saves excavation cost by using a trench of the existing foundation of the building. However, Grid pipe-layout is an ideal layout for a large size EATHE system. Multi-layer pipe layouts should be used to reduce the land area requirement significantly. Moreover, EATHE system can be installed beneath the building (under building foot-print) to eliminate extra land area requirement for the installation of EATHE system. This review article shows that the Initial capital cost and land area requirement for the EATHE system can be substantially reduced by using appropriate pipe layout. It can be concluded that if EATHE system is installed with proper design strategies, it will be a clean and cost-effective method for building heating/cooling with significant power savings.     

浅谈城市生活垃圾综合处理工程的总体规划设计

成功的总体规划是保证工程正常运行的前提。本文试图通过工程实例说明在进行环保工程的总体规划时，更应根据生产工艺、物料走向、防火及环境保护等结合厂(场)区的地质和气象等自然条件进行统筹安排，力求做到布置合理，达到建设快、投资省、运行经济安全的目的。     

EFFECT OF SYSTEM LAYOUT ON SUBSURFACE DRAINAGE COST IN FLAT IRRIGATED LAND1

ABSTRACT: The economic feasibility of large-scale subsurface drainage projects in irrigated land is affected by construction costs. This study was conducted to evaluate the effect of two different types of subsurface drainage system layout on construction costs for a 1000 ha pilot area located in the Nile Delta of Egypt. The two types of layout studied were the conventional layout currently used in Egypt and the modified layout that was developed for reducing water losses from rice fields. When compared to the conventional layout, the modified layout resulted in a reduction of 6.74 percent in construction costs (714,464 US$ versus 766,142 US$). This cost reduction is explained by the need for lesser lengths of large diameter collector pipes with the modified layout, which results from the smaller drainage area of subsurface drainage systems (average 23.7 versus 30.8 ha). We have found that the cost of subsurface drainage can be minimized by reducing the area drained by each subsurface drainage system.     

Electricity systems with near-zero emissions of CO2 based on wind energy and coal gasification with CCS and hydrogen storage

Emissions from electricity generation will have to be reduced to near-zero to meet targets for reducing overall greenhouse gas emissions. Variable renewable energy sources such as wind will help to achieve this goal but they will have to be used in conjunction with other flexible power plants with low-CO₂ emissions. A process which would be well suited to this role would be coal gasification hydrogen production with CCS, underground buffer storage of hydrogen and independent gas turbine power generation. The gasification hydrogen production and CO₂ capture and storage equipment could operate at full load and only the power plants would need to operate flexibly and at low load, which would result in substantial practical and economic advantages. This paper analyses the performances and costs of such plants in scenarios with various amounts of wind generation, based on data for power demand and wind energy variability in the UK. In a scenario with 35% wind generation, overall emissions of CO₂ could be reduced by 98–99%. The cost of abating CO₂ emissions from the non-wind residual generation using the technique proposed in this paper would be less than 40% of the cost of using coal-fired power plants with integrated CCS.     

Feasibility of mercury removal from simulated flue gas by activated chars made from poultry manures

Increased emphasis on reduction of mercury emissions from coal fired electric power plants has resulted in environmental regulations that may in the future require application of activated carbons as mercury sorbents for mercury removal. At the same time, the quantity of poultry manure generated each year is large and technologies that take advantage of the material should be explored. The purpose of the work was to obtain preliminary data to investigate if activated chars made from different poultry manures could adsorb mercury from simulated flue gas. In laboratory experiments, activated chars made from chicken cake and litter removed mercury from the gas as well as a commercial alternative. It was also found that acid-washing these chars after activation may improve pore structure but does not influence the mercury removal efficiency. Activated chars were also made from turkey cake and litter. These raw materials produced activated chars with similar pore structure as those made from chicken manure, but they did not adsorb mercury as well. Acid-washing the turkey manure-based chars improved their performance, but this step would add to the cost of production. Preliminary evaluations suggest that unwashed activated chars may cost as little as $0.95/kg to produce.     

IMPACT OF THERMAL STANDARDS ON POWER PLANT WATER CONSUMPTION1

Power plant water consumption (evaporative water loss) for various river temperature standards is presented for existing and proposed power plants located along the Missouri and Upper Mississippi Rivers in the MAPP geographical area. Thermodynamic and economic models are combined to evaluate the cooling related water consumption at various river thermal standards. The existing thermal standards and a number of other hypothetical thermal regulations including the extreme cases of no thermal standards and no allowable heated discharges are examined to show the dependence on thermal standards of power production related water consumption. A critical appraisal of the cost of thermal standards in terms of water consumption is thereby possible so that subjective assessments of the standards can proceed with full knowledge of the tradeoffs involved between the “water costs” of power production and environmental enhancement.     

Large-scale baseload wind power in China

This paper presents a novel strategy for developing wind power in large-scale (multi-GW) wind farms in China. It involves combining oversized wind farms, large-scale electrical storage and long-distance transmission lines to deliver 'baseload wind power' to distant electricity demand centers. Baseload wind power is typically more valuable to the electric utility than intermittent wind power, so that storage can be economically attractive even in instances where the cost per kWh is somewhat higher than without storage.
The prospective costs for this approach to developing wind power are illustrated by modifying an oversized wind farm at Huitengxile, Inner Mongolia. The site has an average power density of 580 W/m² at 50 m hub heights and is located 500 km north of Beijing. Using locally mass-produced wind turbines there are good prospects that wind power would be cost-competitive with coal power, on a lifecycle cost basis, while providing substantial net environmental benefits.
Finally, the institutional challenges related to the prospect of large-scale wind energy development are addressed. Especially important are policies aimed at developing the capacity for mass production of as much of this technology in China as is feasible. Promising instruments for speeding up the introduction of this technology include: (i) international joint ventures between foreign vendors and developers and Chinese manufacturers; and (ii) wind resource development concessions.     

RESIDUAL POWER AND ECONOMIC FEASIBILITY OF A SOLAR POWERED IRRIGATION SYSTEM1

ABSTRACT: The problem of nonmatching irrigation and solar power production seasons creates the problem of what to do with the surplus power. The economic law of opportunity cost dictates that substitution for currently commercially purchased power is the best use for this power. This law also allows for new power using enterprises that satisfy specific criteria to be used on the farm before sale of the residual to a local public utility can be considered. Economic and Financial Evaluation of the solar powered irrigation system show that the price of commercially purchased power must reach 9.5 cents per Kwh before the system is feasible under the ideal assumption of complete use of the residual power to substitute for commercially purchased power.     

Exergoeconomic Environmental Optimization of Piston-Prop Aircraft Engines

In this study, exergy, exergoeconomic, exergoenvironmental analyses, and exergoeconomic environmental optimization are applied to a four-cylinder, spark ignition, naturally aspirated and air-cooled piston-prop aircraft engine in the cruise phase of flight for the first time to the best of the authors` knowledge. Here, three piston-prop aircraft engine parameters (altitude, air–fuel ratio (AF), and rated power setting (PS)) are selected for optimization purposes. All exergy, exergoeconomic, and exergoenvironmental values are calculated first. These values are then optimized to find the best results of all analyses. The best altitude, AF ratio, and PS values are finally found while the maximum exergy efficiency, the minimum product specific environmental impact, and the minimum average unit fuel exergy cost are obtained. The best results of optimization indicated that the maximum exergy efficiency varied between 19.54% and 19.80%, the minimum unit fuel exergy cost ranged from 126.30 $/GJ to 127.23 $/GJ, and the minimum specific environmental impact of production was in the range of 8.70–9.59 mPts/MJ. Based on the results obtained, for ensuring the optimum conditions, the low AF ratios and the low-altitude flight at high rated power settings have to be selected.     

Cost analysis in laccase production

In this paper the cost of producing the enzyme laccase by the white-rot fungus Trametes pubescens under both submerged (SmF) and solid-state fermentation (SSF) conditions was studied. The fungus was cultured using more than 45 culture medium compositions. The cost of production was estimated by analyzing the cost of the culture medium, the cost of equipment and the operating costs. The cost of the culture medium represented, in all cases, the highest contribution to the total cost, while, the cost of equipment was significantly low, representing less than 2% of the total costs. The cultivation under SSF conditions presented a final cost 50-fold lower than the one obtained when culturing under SmF conditions at flask scale. In addition, the laccase production under SSF conditions in tray bioreactors reduced the final cost 4-fold compared to the one obtained under SSF conditions at flask scale, obtaining a final price of 0.04 cent €/U.     

炼油工业推行清洁生产浅析

从清洁生产角度出发,在布局、结构和规模等三个方面分析了炼油工业现状与发展趋势;通过对产业政策相关要求的解读,阐明了炼油工业清洁生产技术导向和管理措施,为推动行业清洁生产发展提供借鉴。     

Pricing behaviour and market power in North American non-ferrous metal industries

The paper considers the degree to which declining market power explains modifications in pricing behaviour observed since the late 1970s in the North American aluminium, copper, lead and zinc industries. More precisely, it relates those changes in pricing policies to the price elasticity of demand facing the dominant strategic group in each industry, the cost elasticity of supply and to the management's ability to coordinate or internalize conduct decisions. The results suggest that the firms in the copper and lead industries do not hold as a group any form of market power. In the case of the aluminum industry, a notable increase in the price elasticity of demand since the end of the 1970s, a sustained decrease in the concentration ratio and a rigid production process are weakening the presence of market power in that industry. The results are inconclusive in the case of the zinc industry since the determinants of market power move in opposite directions.     

Measurement of market power for the environmentally regulated Korean iron and steel manufacturing industry

For industries in which where market prices of certain inputs are not available, measuring the degree of market power by using the markup over the marginal market cost may be inappropriate. With regard to the Korean iron and steel manufacturing industry, which is subject to environmental regulations, the calculation of the price of abatement capital is hindered by a lack of relevant data. To increase the reliability of market power markups, this paper estimates the restricted cost function in which abatement capital is assumed to be quasi-fixed at an optimal level and the supply relation. The degree of market power for the industry, measured as the ratio of the estimated market power markup to the supply price, was estimated to be 0.54 on average between 1982 and 2001. The results indicate that ignoring environmental regulations can overstate the degree of market power by approximately 12%.     

Optimal planning of co-firing alternative fuels with coal in a power plant by grey nonlinear mixed integer programming model

Energy supply and use is of fundamental importance to society. Although the interactions between energy and environment were originally local in character, they have now widened to cover regional and global issues, such as acid rain and the greenhouse effect. It is for this reason that there is a need for covering the direct and indirect economic and environmental impacts of energy acquisition, transport, production and use. In this paper, particular attention is directed to ways of resolving conflict between economic and environmental goals by encouraging a power plant to consider co-firing biomass and refuse-derived fuel (RDF) with coal simultaneously. It aims at reducing the emission level of sulfur dioxide (SO(2)) in an uncertain environment, using the power plant in Michigan City, Indiana as an example. To assess the uncertainty by a comparative way both deterministic and grey nonlinear mixed integer programming (MIP) models were developed to minimize the net operating cost with respect to possible fuel combinations. It aims at generating the optimal portfolio of alternative fuels while maintaining the same electricity generation simultaneously. To ease the solution procedure stepwise relaxation algorithm was developed for solving the grey nonlinear MIP model. Breakeven alternative fuel value can be identified in the post-optimization stage for decision-making. Research findings show that the inclusion of RDF does not exhibit comparative advantage in terms of the net cost, albeit relatively lower air pollution impact. Yet it can be sustained by a charge system, subsidy program, or emission credit as the price of coal increases over time.     

An affordable green energy source—Evolving through current developments of organic,dye sensitized,and perovskite solar cells

Intensive R&D efforts made in solar photovoltaic area has enabled Si, GaAs, CdTe, and CIGS devices exhibiting nearly ideal efficiencies. However, cost incurred per unit energy does not allow them to qualify for alternate energy source besides environmental issues at production floors. Consequently, search is still continuing not only to reduce cost by improved efficiency, reduced materials cost, and simplified processing resulting in a cleaner and greener technology. Current successes in organic, dye-sensitized, and perovskite solar cells with efficiencies in 10–15% range raise concrete hope for evolving a low cost and green technology involving solution processable organic/inorganic compounds extendable to roll-to-roll production. The current status and future prospects of these three promising routes are reviewed here highlighting the possibility of an emerging alternate green energy source to supplement the conventional ones at commercial level.     

WATER SUPPLY AS A LIMITING FACTOR IN WESTERN ENERGY DEVELOPMENT1

ABSTRACT: This paper discusses the consumptive water needs of the various energy conversion processes including oil shale retorting, coal gasification and liquefaction, electric power generation, and slurry pipelines. Projected energy development water needs in the upper Colorado River and Upper Missouri River basins are compared with projected agricultural needs and water available. The comparative cost and values of water to energy and agricultural development are discussed to emphasize this as well as the political and social factors entering into the picture.     

Comparative study of photovoltaic technologies based on performance,cost and space requirement: Strategy for selection and application

The module performance is an important consideration for selecting PV technologies for electricity production, as well as the economic aspect. Also, PV energy yield under varying environmental conditions is largely dependent on the type of technology used. Therefore, this article presents a comparative analysis of different PV modules, of the same power, namely, monocrystalline, polycrystalline, amorphous silicon and hybrid, based on performance, cost and space requirement. The performance is evaluated in terms of module power output, yield, capture losses, fill factor and efficiency, according to the IEC 61724 standards, using Gwako, Nigeria as a case study. A novel technique called Fundamental PV Module Performance Analysis is used to analyze and compare the performance of the PV modules. The performance of a single module is then employed to calculate the overall performance of a PV array designed for a small off-grid house, and a suitable module is determined amongst the modules under study. Results provide insights into the behaviors of the different technologies with the environmental factors of the location, which have an impact on their power and kWh/kW outputs and the efficiency. This knowledge, coupled with the understanding of the constraints of cost and the module space requirements would be useful to researchers, engineers, installers etc. in Nigeria, for planning and developing photovoltaic electric systems for off-grid applications.     

Optimization of grid tied hybrid power system in smart premises

Tapping of renewable energy sources like solar and wind is given great priority by power producers all over the world. Technical problems of linking them to the grid are solved. The cost constraints of utilizing renewable energy at specific locations are to be determined. In this work, a model is developed for grid tied hybrid power system (HPS) consisting of photovoltaic (PV) module and wind mill at the roof top of smart premises. The grid is capable of delivering and receiving energy. Objective function is formed with constraints taking into account the cost of PV module, wind mill, and grid tied inverter with controller. The constraints are rating of HPS and energy that can be delivered to the grid. Using this model, case studies were conducted in three locations in India, each location having two different demands. The results are presented. With the optimal rating of HPS, results shows that, conventional energy cost is higher.     

PCB影响辐射骚扰超标之分析

本文就通过信息产品的PCB LAYOUT的电源布局不合理而引起的产品辐射骚扰测试超标现象，逐一发现、分析、解决之辐射骚扰超标的问题，然后提出改正之方法并且加以验证之。最后对以上之现象加以综述，并且对将来类似产品的PCB LAYOUT提出了建议及见解。     

Benefit–Cost Analysis of StormwaterQuality Improvements

The major purpose of this paper is to explore the potential value of benefit–cost evaluation for stormwater quality management decisions at a local level. A preliminary benefit–cost analysis (BCA) screening method is used for maximum extent practicable (MEP) analysis, identifying promising management practices, and identifying societal and economic tradeoffs for local stormwater problems. Ballona Creek, a major urban storm drain in Los Angeles, California, USA, is used to illustrate the practicality of the benefit–cost evaluation. The Ballona Creek example demonstrates the economic limits of stormwater management in an urban region and attests to the value of coordinated basinwide management compared to uncoordinated management by individual landowners. Evaluation results suggest that in urban areas, the benefit of stormwater quality improvements might be far greater if accompanied by comprehensive redesign of drainage networks and neighboring land uses. In this case, benefit–cost analysis is found to be useful for evaluating and understanding stormwater management alternatives despite the uncertainties in characterizing stormwater quality and the effects of stormwater management on improving receiving water quality.