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    Energy plus standard in buildings constructed by housing associations?
    (Elsevier, 2012-12)
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    In order to achieve national, European and international energy goals, energy efficiency strategies in the building sector have to be implemented. The passive house standard and low energy standards are already successfully established in single dwelling houses. These high performance standards are starting to penetrate into the sector of housing associations. A case study about an apartment building constructed by a housing association is presented here. It describes the monitoring concept and the results of the 1st year of monitoring. Depending on the definition of the zero energy building standard (extent of loads included in the balancing), the building could be classified as an energy plus building or as a building, which uses more energy, than is supplied by on-site generation. If the building's total energy use (including user specific loads) is defined as load, only 34.5% of these loads were provided by the net energy output of the PV system. If only the heating energy demand is defined as load, the PV system even yielded a surplus of 45.6% of the energy load.
      1Scopus© Citations 16  205
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    Potential of different Sorghum bicolor (L. moench) varieties for combined ethanol and biogas production in the Pannonian climate of Austria
    (Elsevier, 2013)
    Theuretzbacher, Franz 
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    Bauer, Alexander 
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    Lizasoain, Javier 
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    Becker, Manuel 
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    Rosenau, Thomas 
    The objective of this study is to estimate the energetic yields of a combined ethanol and biogas production from three different sorghum varieties, and to compare them to a similar estimate for maize in order to demonstrate the suitability of sorghum as an alternative biomass source. The sorghum varieties “SG1” (Sugargraze I) and “SG2” (Sugargraze II), which produce fermentable sugars, as well as the grain variety “C” (Chopper), which produces starch, were grown on experimental plots in eastern Austria. The harvested biomass was analysed for its contents of cellulose, hemicellulose, lignin, crude protein, crude fats, starch and sugar. For the calculation of the energy output, ethanol and biogas yields were calculated corresponding to accepted standard methods. The potential of sorghum for energy production has been demonstrated. The highest energy outputs were achieved by the SG1 and the C varieties, delivering approximately 150 GJ ha−1 and 156 GJ ha−1. Compared to data obtained from different maize varieties in the same year and under similar conditions, this means an equal or even increased energy output per hectare. The SG2 variety only yielded 121 GJ ha−1 worth of ethanol and biogas. Bioethanol and biogas production were unequally distributed between sugar and starch varieties: SG1 provided 70% of its energy output as methane and the rest as bioethanol, whereas the grain variety C yielded 46% methane and 54% bioethanol.
      1Scopus© Citations 17  85
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    Comparative thermodynamic analysis of an improved ORC process with integrated injection of process fluid
    (Elsevier, 2022-12)
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    Beckmann, Georg 
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    In contrast to water-steam Rankine cycles, the ORC process uses organic working fluids. For working fluids of the dry class, a recuperator heat exchanger is frequently installed to increase the cycle efficiency. This paper analyses an improved ORC process with these features: A liquid working fluid stream is injected into the vapour flow between the high-pressure and the medium-pressure stage of the turbine. Furthermore, the recuperator is replaced by a spray condenser. The main objective is to increase efficiency with moderate changes in the process layout. A thermodynamic comparison of the improved process with a state-of-the-art ORC process is carried out by simulations and optimisations. A significant efficiency gain for the improved ORC process is obtained by a combination of the aforementioned features, mainly because of an increase of the mass flow in the economiser of the vapour generator (better heat utilization) and a corresponding mass flow in the medium stage of the turbine (additional power production). As a use case, waste heat utilization from clinker cooler at a temperature level of 275 °C was simulated. The improved process would lead to a significant increase in the overall net efficiency by up to 14%, compared to a state-of-the-art ORC process.
    Scopus© Citations 13  198  119