Showing papers in "Energy in 1999"

TL;DR: In this paper, a new method for computing phase equilibria using Gibbs free energies and empirical equations for bubble and dew point temperature was proposed, and the results showed excellent agreement between calculated and experimental data.

TL;DR: In this paper, the thermal properties of laboratory-grade tetradecane, hexdecane and their binary mixtures were discussed and their potential for use as Phase Change Materials (PCMs) for cool storage.

TL;DR: In this paper, the authors make quantitative estimates of the impact of roof reflectivity on cooling and heating energy use for buildings in the US, and they estimate annual electricity savings of about 10 TWh and a net savings of approximately $750 M in annual energy payments.

TL;DR: In this paper, an analysis of the prospects of reducing the cost of wind-generated electricity is described using experience curves, and it is shown that although the experience curve for wind turbines indicates relatively moderate cost reductions, there is potential for considerable cost reductions in windgenerated electricity.

TL;DR: In this paper, an optimization procedure of a hybrid photovoltaic wind energy system is presented which can be used to satisfy the requirements of a given load distribution, and an analysis is applied to satisfy a constant load of 5 kW required for cathodic protection in offshore platforms.

TL;DR: In this article, a new model for projecting regional and world travel, which is used to develop a scenario for carbon emissions from passenger transport, is presented, and it is shown that without some action to accelerate an improvement in energy efficiency starting in the next decade, the goal of stabilization is a technically impossible task, unless zero-carbon technologies become available.

TL;DR: In this article, the authors describe the use of the decomposition technique for comparing energy-related CO2 emission levels between countries/regions and present application studies pertaining to total and per capita CO2 emissions for three OECD regions and three world regions.

TL;DR: In this article, the chemical compositions and yields of the charcoals were determined as functions of the carbonization temperature, and higher heating values (HHVs) were estimated using both ultimate and proximate analyses.

TL;DR: In this paper, the authors used univariate Box-Jenkins time-series analyses (ARIMA) for modeling and forecasting future energy production and consumption in Asturias.

TL;DR: In this paper, seven existing relationships between monthly mean clearness index and the number of bright sunshine hours are tested under the climate and latitude of Romania and new best-fit correlations are derived.

TL;DR: In this paper, the consumption pattern of electrical energy in Delhi during the period 1984-93 has been analyzed as a function of population and weather sensitive parameters, and linear multiple regression models of energy consumption for different seasons have been developed.

TL;DR: In this paper, the authors have modelled the global irradiance angular distribution, employing horizontal global irradiances as the only radiometric input, and geometric information, and obtained good results (root mean square deviation about 5%), except for surfaces affected by artificial horizon effects, which are not allowed for in this new model.

TL;DR: In this paper, the photocatalytic reduction of CO 2 using TiO 2 powders in supercritical fluid CO 2 was investigated using a stainless steel vessel at 9.0 MPa and 35°C.

TL;DR: In this paper, the authors present results of an experimental study on two-stage wood gasification and attempts to reduce the tar content of the gas, which was in the range 19-34 mg/Nm3 for a charcoal gasifier coupled with a two-staged wood gasifier.

TL;DR: In this paper, a 2.0 kWp photovoltaic power system has been installed at the University of Malaga, Spain and the array power output was estimated by using measured I-V curves for the installed modules with minimization of mismatch losses.

TL;DR: In this article, a thermodynamic model has been used to investigate vortex tube energy separation and an equation has been derived for the rate of entropy generation, which is used to model the irreversibility term.

TL;DR: In this paper, a rotary-kiln pyrolyser was designed and built to test the effects of heating methods, moisture contents and size of waste, as well as heating values, were evaluated.

TL;DR: In this paper, a thermochemical cycle for the solar production of hydrogen is proposed, which includes the conversion of solar to chemical energy by the thermal reduction of manganese(III) oxide to manganized(II) oxide at temperatures below 1900 K.

TL;DR: In this article, the authors describe the results of a time-of-use (TOU) rate option experiment which demonstrates that offering a TOU option can be profitable to a utility.

TL;DR: An inventory of biofuel combustion is used to develop estimates of the emissions of carbon-containing greenhouse gases (CO2, CO, CH4, and NMHC) in Asian countries as discussed by the authors.

TL;DR: In this article, economic analysis of a typical geothermal resource shows that potential revenues from geothermal heating or cooling can be much larger than those from power generation alone, and that combined power generation and heating may generate about 2.9 times as much revenue as Power Generation alone.

TL;DR: In this article, the influence of particle size, grade and pyrolysis temperature on the oil yield have been evaluated in a laboratory scale reactor and the activation energy was determined by using the integral method.

TL;DR: In this paper, simple models for the Ranque-Hilsch vortex tube combined with regenerative precooling are given from which an optimization can be undertaken, and bounds are obtained within this theory for the performance of the system for a given gas and pressure ratio.

TL;DR: In this paper, the application of exergy analysis to aquifer thermal energy storage (ATES) systems is investigated in order to facilitate proper assessments of overall system performances. But energy efficiency does not provide a measure of approach to ideal performance and, in fact, is often misleadingly high because some of the energy recovered can be at too low a temperature to be available for a useful purpose.

TL;DR: In this paper, the performance of double-flow type solar air heaters, in which air is flowing simultaneously over and under the absorbing plate, was investigated theoretically and experimentally.

TL;DR: In this paper, a study was conducted to determine heating and cooling degree-hours for Turkey by using weather stations around in Turkey to calculate yearly heating degree hours with base temperatures of 15, 17 and 18.3°C and yearly cooling degreehours with 24, 26, 27 and 30°C.

TL;DR: In this article, two flow-control schemes were tested and evaluated for a valve controlled by feedback from the room thermostat and a two-parameter switching control with switching intervals ranging from 30 s to 60 min.

TL;DR: In this paper, a mathematical model of an air-to-earth heat exchanger (ATEHE) is presented, where two pipes are buried in the soil, one made of PVC and one of steel, and the authors determined how the season, soil thermal conductivity and pipe spacing influence energy transfer from the soil to the ATEHE.

TL;DR: In this article, the authors calculated entropy generation due to natural convection for three radii and a wide range of Rayleigh numbers for an isothermal cylinder and identified locations of high local entropy generation for different configurations.

TL;DR: The results show to what extent each of the examined characteristics influences the countries' energy effectiveness and may be further exploited in energy-policy making and confirm that the UTADIS method is a powerful tool for examination of a wide range of real decision situations.