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Primary Energy (primary + energy)

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Engineering44%

Terms modified by Primary Energy

  • primary energy consumption
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    Selected Abstracts

    Hydrogen for the Mobility of the Future Results of GM/Opel's Well-to-Wheel Studies in North America and Europe

    FUEL CELLS, Issue 3 2003
    U. Winter
    Abstract General Motors conducted two well-to-wheel studies for fundamental clarification on the question of which is the cleanest and most environmentally sustainable source of energy for the mobility of the future. In both studies the complete energy chains were analyzed from fuel production using primary energy to the actual consumption of the fuel in the car, i.e. from the well up to the wheels of the vehicle (well to wheel). The aim of the studies was to evaluate total energy consumption on the one hand and, on the other, the total greenhouse gas emissions arising between the production of a fuel and its final use to power an automobile. The results of the studies clearly show that fuel cell vehicles can greatly reduce greenhouse gas emissions from passenger cars or, if they run on hydrogen from renewable energy sources, they can eliminate them entirely. Regenerative fuels, however, will be more expensive than current products. With the fuel cell, because of its superior efficiency (35 , 45% less energy consumption well to wheel), it will be possible to keep individual mobility affordable in the future. [source]

    Scattering of elastic waves in media with a random distribution of fluid-filled cavities: theory and numerical modelling

    GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 3 2004
    Tae-Kyung Hong
    SUMMARY The propagation of elastic waves is modelled in media with a random distribution of fluid-filled circular cavities, which display high physical impedance in contrast to background media. Theoretical attenuation expressions for media with circular cavities, which may be filled with any material (e.g. vacuum, fluid, elastic materials), are formulated using an ensemble treatment for first-order transmitted waves. Numerical estimates of scattering attenuation rates agree with the theoretical results well. The scattering attenuations (Q,1) are proportional to the scale of cavities and the number density (,, number of cavities per area in a medium). The decrease of primary energy with the size of cavities does not result in the increase of coda energy owing to the increase of both purely backscattered waves from cavities and the trapped waves inside cavities. Scattering properties (e.g. scattering attenuation, coda energy, phase fluctuation of primary waves) in media with randomly distributed cavities are very different from those in stochastic random media. It appears that heterogeneities with high impedance in the earth may not be well represented with stochastic random heterogeneities. [source]

    A review on energy, economical, and environmental benefits of the use of CHP systems for small commercial buildings for the North American climate

    INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 14 2009
    P. J. Mago
    Abstract The use of combined heating and power (CHP) systems to produce both electricity and heat is increasing rapidly due to their high potential of reducing primary energy consumption (PEC), cost, and emissions in domestic, commercial, and industrial applications. In addition to producing both electricity and heat, CHP systems can be coupled with vapor compression systems to provide cooling. This paper analyzes a natural gas engine CHP system together with a vapor compression system for different American climate zones. Performance is measured in terms of operational costs, PEC, and carbon dioxide emissions as a percent of a reference building. The objective of this paper is to compare the performance of a CHP system operating 24,h a day with a system that only operates during typical office hours. Furthermore, the system is optimized based on reducing PEC, minimizing costs, and reducing emissions. In addition, the benefits of CHP systems based on the Energy Star program and the Leadership in Energy and Environmental Design (LEED) program are presented. Results show that, in general, it is more beneficial to operate the CHP system during typical office hours than to operate the system 24,h a day. Also, the CHP system performance strongly depends on the location where it is installed. In addition to reductions in cost, primary energy, and emissions, CHP systems can help achieve the Energy Star label for commercial office buildings and help obtain LEED points that go toward achieving LEED certification status. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Financial costs and environmental impact optimization of the energy supply systems

    INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 1 2002
    L. I. González-Monroy
    Abstract We have designed and implemented a tool to evaluate and optimize energy supply systems, so that the financial costs, the consumption of primary energy or the amount of harmful emission to the environment are minimized. We have set-up a general description of these systems and have applied a heuristic optimization method, Simulated Annealing, that allows us, in an efficient way, to determine the best way to fulfil different types of energy demand using a set of facilities of energy transformation and storage. We have also considered the time correlation introduced by the storage devices or transport processes and the possible behaviour of the system when the external conditions (fuel prices, demand profiles, etc.) change. Copyright © 2002 John Wiley & Sons, Ltd. [source]

    The price of natural gas

    OPEC ENERGY REVIEW, Issue 4 2001
    A.M. Samsam Bakhtiari
    Natural gas used to be a relatively Cheap primary energy source, always at a discount to crude oil (on a comparative British thermal unit basis). It gradually evolved into a major resource during the 20th century , reaching a 24 per cent share of global primary energy in 1999. In the year 2000, natural gas prices in the USA rose to unheard-of highs of $10/million Btu, ushering in a new era, with natural gas at a 120 per cent premium to crude oil. This clearly was a watershed for gas, somehow similar to the 1973-74 watershed for oil prices. And similarly, any return to the status quo-ante looks rather improbable, although a number of experts (alongside the International Energy Agency) still believe the 2000 price ,spike' to have been "only transitory" The consequences of higher gas prices (at a level equal to crude oil prices on a Btu basis) will be multifaceted and momentous, altering habits and uses in downstream industries and economic sectors, as well as providing added income for major gas-exporters, such as Russia, Canada and Algeria. Another potential consequence of the 2000 watershed might be to propel US standard prices (such as the ,Henry Hub' spot) to international status and gas price-setter, as the ,WTI spot' became an "international benchmark" for crude oils in the post-1993 era. For the time being, the equality of gas and oil prices has become the new norm; but, in the longer term, a discount of crude oil relative to natural gas might be envisaged, as the latter is a cleaner fuel and emits less carbon dioxide when used. [source]

    Energy consumption in the Islamic Republic of Iran

    OPEC ENERGY REVIEW, Issue 3 2000
    A.M. Samsam Bakhtiari
    During the 20th century, energy consumption in the Islamic Republic of Iran was continually on the increase, from a per capita level of 200 kilogrammes of oil equivalent (koe) for traditional energies at the onset to more than 1,700 koe for commercial energies at the century's close. The main stimulants fuelling Iran's energy consumption were: (i) revenue from oil exports (wealth-creating); (ii) a growing population; (iii) the countrywide rural-urban shift; and (iv) relatively low domestic retail prices charged for energy vectors. For a country well endowed with hydrocarbon resources, it is not surprising that the internal consumption of refined products and natural gas grew to fill 99 per cent of its primary energy needs. During the 1990s, domestic consumption of natural gas exploded. Gas even came to rival refined products, securing up to 45 per cent of total primary energy. Future natural gas expansion will be based upon the country's ample reserves, and gas will undoubtedly become Iran's dominant source of internal energy in the 21st century,thereby liberating liquid fuels for export. Iran's dwindling crude oil production will also put pressure on the internal use of refined products, as consumption and exports come to vie for the same barrel. Exports being vital to the national economy, consumption will have to be reined in. [source]

    Erkenntnisse über Lüftung und Energieverbrauch sowie Bodenplattendämmung aus Monitoring-Untersuchungen an einem Passivhaus-Schulgebäude

    BAUPHYSIK, Issue 1 2008
    Søren Peper Dipl.-Ing.
    Über zweieinhalb Jahre Monitoring einer Passivhaus-Schule und Kindertagesstätte (KiTa) in Frankfurt a.M. zeigt behagliche raumklimatische Bedingungen bei guten Luftqualitäten. Die Heizwärmeverbrauchswerte liegen wie erwartet niedrig und zeigen Einsparungen um 90 % gegenüber dem Durchschnitt im Bestand. Auch primärenergetisch bewertet, weist die Schule beste Resultate auf. Die Ergebnisse zu weiteren Untersuchungen der effizienten Lüftungsanlage mit Wärmerückgewinnung, den umlaufenden Dämmschürzen als Alternative zur Bodenplattendämmung und dem Einfluss der Luftwechselrate durch die Eingangstüren werden vorgestellt. Monitoring of a Passive House School Building. More than two and a half years of monitoring of a Passive House school and day-care centre in Frankfurt a. M. show comfortable indoor climate and good air quality. The space heat consumption is low and shows savings of approximately 90 % as compared to average existing schools. Excellent performance was also achieved in terms of primary energy. The results of further analyses of the efficient ventilation system with heat recovery, the perimeter insulation as an alternative to floor slab insulation and the influence of the air change due to the entrance door are presented. [source]

    Analytical Model for Predicting Thermal Bridge Effects due to Vacuum Insulation Panel Barrier Envelopes,

    BAUPHYSIK, Issue 1 2008
    Martin Tenpierik ir. arch.
    Because of a necessity for sustainability and thus for a reduction of the amount of primary energy generated with fossil fuels, vacuum insulation panels (VIP) have recently caught the attention of practitioners in the building industry. The reduction of layer thickness may be considered among the most promising features for large-scale application of VIPs in buildings. The high barrier laminate (or casing) with relatively high thermal conductivity envelops the core material, thus introducing a thermal bridge at the panel edges and corners. Especially for barrier laminates containing ,thick' metal foils, the thermal bridge effect needs to be considered thoughtfully. In this contribution analytical models are presented which on the one hand allow rapid estimation of the VIP's overall thermal performance and on the other hand show the influence of material and geometric parameters on this performance. The analytical models are validated through numerical simulations. Rechenmodell zur Vorhersage von Wärmebrückeneffekten an der Hülle aus Hochbarrierefolien von Vakuum-Isolations-Paneelen (VIP). Aufgrund der Notwendigkeit von nachhaltigem Bauen und Energieeinsparung wird zunehmend der Einsatz von Vakuum-Isolations-Paneelen (VIP) zur Wärmedämmung im Bauwesen erwogen, insbesondere ist damit die erhebliche Reduzierung der Wärmedämmschichtdicke möglich. Die Umhüllung aus Hochbarrierefolien erfordert allerdings die Berücksichtigung der Wärmebrückenwirkung. Der vorliegende Beitrag stellt Berechnungsmodelle vor, welche einerseits die schnelle Abschätzung des thermischen Verhaltens von VIP-Elementen ermöglichen und andererseits den Einfluss der Geometrie und Konstruktion der Elemente aufzeigen. Die Berechnungsmodelle wurden anhand von Simulationen validiert. [source]