摘要:

A number of alternative methods can be used to generate forecasts of electricity consumption. However, it is seldom possible to compare the accuracy of forecasts generated by different statistical methods. Hawaii provided a unique opportunity for such a comparison because of the availability of the Hawaii Energy Demand Forecasting Model (HEDFM). HEDFM is an econometric-based simulation system designed to provide detailed annual consumption forecasts for various fuel types from 1978 to the year 2005 for the State of Hawaii. This article evaluates the accuracy of electricity consumption forecasts using various commonly employed methods and compares them with forecasts from HEDFM. Traditional forecasting methods based on average historical growth rates or the historical relationships between electricity consumption and key economic and demographic variables such as de facto population and per capita income did not perform well. Quadratic exponential smoothing outperformed all other methods. HEDFM, an econometric model, tracked reasonably well. In particular, simulation results have shown that econometric models such as HEDFM can produce accurate forecasts if independent variables can be predicted with a reasonable degree of certainty.

ISSN:0090-8312    

DOI:10.1080/00908319408909079

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This article proposes an integrated multiobjective decision-making (MODM) model to deal with energy supply mix problems in Taiwan based on its characteristics. The analytical framework integrates multiobjective programming (MOP), multicriteria decision making (MCDM), and group decision making (GDM) methods and considers decision dependencies existing in the time horizon. The integrated model has the advantages of flexibility, reasonableness, and robustness. The analyzed outputs, including alternatives, the preferred solution, and the best compromise solution, are provided as a basis for decision making.

ISSN:0090-8312    

DOI:10.1080/00908319408909080

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Most of the studies of the impact of global warming on energy use have employed aggregated utility models and have found that global warming would produce about a 2% decrease in heating requirements per PC and comparable increases in cooling requirements. The one significant exception is a German study that utilized building energy models and determined that the increase in cooling would be somewhat larger, due to the effects of increased humidity with atmospheric warming. This study utilizes the DOE2 building energy model on a prototype commercial building and demonstrates that increased humidity could be a significant factor in total building energy use, particularly in the more humid parts of the United States. The study also demonstrates that the effect can be overcome with advanced building designs.

ISSN:0090-8312    

DOI:10.1080/00908319408909081

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Optimal management strategies for herbaceous biomass production depend on the interaction of crop and environmental resources and the resulting yield patterns through time. The objectives of this study were to determine the production potential of different perennial herbaceous biomass crops under several management regimes and to test regression analysis as a method for determining the effect of stand age on the production potential of these species on representative soils of the Eastern Great Lakes Region of the United States. Eastern gamagrass, flatpea, reed canarygrass, switchgrass, and mixtures of alfalfa-smooth bromegrass, timothy-redtop-red clover, and naturalized meadows were grown at three fertility levels under two cutting-management regimes for up to 5 years at various locations in New York State. Annual yields ranged from about 4 to more than 12 Mg ha−1, depending on species, soil, and crop management. Regression analyses revealed four patterns of change with time and provide a convenient method for modeling these crop yield patterns.

ISSN:0090-8312    

DOI:10.1080/00908319408909082

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Geothermal resources are present, in different forms and quantities, all over the world. The high-enthalpy resources (temperatures above 225°C) and part of the medium enthalpy resources (between 225° and 125°C) are concentrated mainly along belts that coincide with the margins of the lithospheric plates. The low-enthalpy resources (less than 125°C) are present in all countries. Small geothermal resources belong for the most pan to the category of medium-low enthalpy resources and are capable of feeding electric power plants of a maximum capacity of 10 MWe, and any type of nonelectric plant. Electricity generation is the best known and most important utilization of geothermal energy. In 1993 the total installed geothermoelectric capacity in the world had reached 5915 MWe. This figure includes the approximately 80 MWecoming from small geothermal resources. For the year 2000 the total installed geothermoelectric capacity is expected to reach 10,197 MWe. Electricity generation can be achieved utilizing fluids at temperatures above 150°C in conventional condensing or back-pressure power plants, and fluids with a temperature as low as 85°C, in binary-cycle plants. Direct applications of geothermal heat (nonelectric uses) are a viable option with resources of any temperature. At the moment there are nonelectric plants in the world to a total of more than 11,000 MWeThe most common nonelectric uses of geothermal energy are district heating, agriculture (greenhouse heating and animal husbandry), aquaculture, and industrial processes. There are, however, numerous other forms of utilization that have been in operation for many years (such as oil recovery) or are now being experimented (such as fog dispersal systems on airport runways). The environmental impact of geothermal energy is related mainly to the atmosphere (chemical pollution) and the surface and underground waters (chemical and thermal pollution). It is a relatively minor impact, especially with regard to the nonelectric uses, and is certainly lower than the pollution deriving from fossil fuel plants.

ISSN:0090-8312    

DOI:10.1080/00908319408909083

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A method for characterizing and predicting the performance of demulsifiers that involves the relationship between the film pressure of the demulsifier and the normalized area and the solvent properties of the demulsifier has been developed. This procedure can be used both to choose the proper demulsifier and to develop effective new compounds by determining the effect of changes in the interfacial properties of different solvents. This article highlights some of the results on the basis of the study of demulsifiers (surfactants) efficacy in different solvents and discusses the surface active behavior of selected demulsifiers and identifies how Us efficacy can be enhanced by changing its bulk physiological behavior. The surfactant activity of the demulsifier is dependent upon the bulk phase behavior of the chemical when dispersed in the crude-oil emulsions. This behavior can be monitored by determining the demulsifier pressure-area isotherms for adsorption at the crude oil-water interface. The demulsifier concentrate is generally too viscous to be handled neatly, so a solvent is added to improve handling. However, careful selection of the solvent can significantly improve the surface activity of the demulsifier. It is proposed that the correct solvent is one that allows the demulsifier to dissolve totally without irreversible aggregation. The consequences of this solvent selection are improved surfce activity and emulsions resolution efficiency.

ISSN:0090-8312    

DOI:10.1080/00908319408909084

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A traditional cooking system for rural areas in India has been studied. An improved stove has been designed, fabricated, tested, and evaluated by improved combustion. Hand-operated bellows, instead of a traditional blow pipe, is suggested for sustaining combustion.

ISSN:0090-8312    

DOI:10.1080/00908319408909085

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The San Giuliano low-temperature hydrothermal system is located at the foot of the Pisan Mounts in Tuscany, the most important geothermal region in Italy. Eleven water points with temperatures within the range 16-40°C and salinity between 0.6 and 2.4 g / l are distributed along the superficial contact between the Mesozoic carbonate aquifer formations outcropping on the relief and the low-permeability deposits of the Pisan plain. Hydrogeological and geophysical investigations, as well as periodic geochemical and isotopic samplings and temperature measurements of the different water-points, were carried out during the period 1988-91. These observations indicate that thermal, low-tritium, calcium-sulphate waters rise toward the surface from a reservoir made up of a Triassic evaporitic sequence through a buried fault located in the vicinity of the margins of the Pisan Mountains. The presence of a low-permeable cover, represented by Quaternary and Neogenic deposits, allows only the local upflow of thermal water and a poor flow rate at the wannest springs. These springs, located in the central part of the prospect, are used in the Spa facilities. Most of the thermal water, blocked by the impervious cover, moves laterally within the system and mixes with young, cold, meteoric water. Most of the water points represent mixtures in different proportions of the Spa water and this meteoric component. The local carbonate outcrops probably represent the main recharge areas for the system. However, assuming that a regional circulation could be present, a large amount of water, at temperatures between 70 and 80°C, as suggested by geothermometric indications, could be found at depth.

ISSN:0090-8312    

DOI:10.1080/00908319408909086

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Emissions reduction from a power system in India is traditionally considered in terms of installation of expensive abatement equipment. This paper describes a systems approach to achieve emission reduction targets for different pollutants in a least-cost manner that considers a wide range of options viz. adjustment within the system through integrated operations of the system and alternative mines-power station coal-supply linkages, coal imports, switching to cleaner modes of generation (from coal to gas), and installation of abatement equipment. A linear programming modeling framework is developed for the three electricity regions of India (western, southern, and northern) for different emission reduction levels for the four pollutants CO2, SO2, NOx, and fly ash. The model considers the detailed coal mines-to-power plant linkages, the coal import for the coastal coal-based plants, details of all major interstate and inter-regional transmission lines, and the generating unit characteristics. It is found that installing abatement equipment is an attractive option for reducing fly ash and NOx, that an additional gas-generation capacity is needed to reduce SO2along with abatement, and that the share of gas generation increases drastically when a CO2reduction constraint is incorporated.

ISSN:0090-8312    

DOI:10.1080/00908319408909087

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A new method has been developed to recover upgraded lighter-hydrocarbon liquid oil from an asphaltene-containing oil material (tar sand, asphalt, heavy oil, shale oil, coal liquids, etc.). The process describes dispersing particles of the carbonaceous material in an aqueous solution containing an inorganic base (NaOH, Na2SiO3, etc.) and / or surfactant at ambient temperatures and pressures. With the aid of sonication energy, the inorganic base and / or surfactant will combine with the polar components of the fuel to speed the recovery of upgraded oil material. The reaction process essentially removes and / or converts the asphaltene fraction in the bituminous material to lighter fractions. The process is highly efficient, and the reaction time in minutes for the samples is examined. The reaction mechanisms are related to principles of sonochemistry as well as membrane mimetic chemistry.

ISSN:0090-8312    

DOI:10.1080/00908319408909088

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor