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In recent years, a wide range of strategies has been implemented in different EU-countries to increase the share of electricity generation from renewable energy sources. This paper evaluates the success of different regulatory strategies. The most important conclusions of this analysis are: (i) regardless of which strategy is chosen, it is of overriding importance that there should be a clear focus on the exclusive promotion of newly installed plants; (ii) a well-designed (dynamic) feed-in tariff system ensures the fastest deployment of power plants using Renewable Energy Sources at the lowest cost to society; (iii) promotion strategies with low policy risks have lower profit requirements for investors and, hence, cause lower costs to electricity customers.

Abstract In this paper, a process for the fermentative production of hydrogen is analysed with respect to its exergy efficiency. Parametric studies show the influence of used feedstock, applied process parameters as well as process and heat integration measures on exergy efficiency. It is shown that heat integration and recirculation of fermentor effluents reduce process irreversibilites and the amount of exergy leaving the process in waste streams. Nevertheless, depending on the used feedstock, a large amount of exergy leaves the process via by-products. Internal use of by-products and waste materials for providing process heat could increase chemical exergy efficiency up to 74%.

Most plastic products in circulation worldwide are based on fossil petroleum and are not biodegradable,which is known to be one of the biggest burdens and threats to the environment. One possible solution to this problem could be the use of bio-based and biodegradable polyhydroxybutyrate (PHB). Undernitrogen and phosphate depletion, Synechocystis sp. PCC 6714 produces PHB. As a positive side-effect,this method also binds the greenhouse gas CO2 through photosynthesis.This thesis analyses the results of a series of experiments carried out as part of basic research to better understand a possible PHB production process. The main goal was to investigate the effects of different lactose concentrations between 1 and 10 g/L from concentrated whey on the microorganism,particularly on the PHB production. The following three main results were obtained:Firstly, the cyanobacterium strain used could not metabolise lactose and even showed lower growth andPHB content of 2.2% at 1 g/L lactose compared to 4.2% without the addition of whey in the shake flaskexperiment. When upscaling in a photobioreactor, the same ratios were observed between cultivationswith and without whey, with the PHB content doubling to 6.5 and 10.5% (volumetric productivity 7.7and 21.1 mg/L/day).Secondly, the standard hydrolysation method for PHB quantification with concentrated sulfuric acid was compared with the alkaline sodium hydroxide method using a multivariate data analysis.Subsequently, the more promising acidic method was further optimised to reduce viscosity of sulfuricacid, gaining an optimum at 160 min, 14 M H2SO4, 100°C.Thirdly, as an alternative to the state of the art methods for recovering PHB, which use, e.g. the harmful chloroform, three ionic liquids based on the cation 1-Ethyl-3-methylimidazolium with three differentanions Dimethylphosphate, Acetate or Chloride were tested to dissolve the biomass but not thebiopolymer. 1-Ethyl-3-methylimidazolium Dimethylphosphate completely dissolved the biomass at75°C after 1 h and did not decompose or dissolve the PHB so that it could be implemented in a complete recovery process.

Mit der vorliegenden Arbeit werden die Emissionen eines Biomasseheizwerkes der Firma URBAS messtechnisch erfasst. Mit diesen Istwerten wird ein Vergleich mit der vorhandenen Literatur gezogen, um eine Reduktion der NOx-Abgaswerte erreichen zu k��nnen. Dazu wird in der einschl��gigen Literatur der theoretische Hintergrund recherchiert, analysiert und es werden m��gliche L��sungswege dargestellt. Das Hauptaugenmerk dieser Arbeit liegt im Feststellen von Prim��rma��nahmen zur Vermeidung von Emissionen. Im Ausblick auf zuk��nftige Entwicklungen wird theoretisch auf die Sekund��rma��nahmen eingegangen. Der Praxisteil dieser Arbeit beinhaltet die Erfassung, Aufbereitung und den Vergleich von messtechnischen Daten einer Anlage der Firma URBAS. Diese sind die Grundlage f��r die Festlegung von m��glichen Prim��rma��nahmen. With the paper in hand the emissions of a biomass heating plant manufactured by the company URBAS are technical measured. These actual values will be compared with values from literature to be able to reach a significant reduction of NOx-emissions. In addition the theoretical background is investigated at corresponding literature, by analysing and showing possible solutions. The main focus of the paper is to lock primary tasks in prevention of emissions. About secondary tasks is only talked theoretically due to prospective developments. The praxis part of the paper includes the coverage, the preparation and the comparison from technical measured data of a plant by company URBAS. These are the basis for the settling of possible primary tasks.

Abstract Aerogel based insulation plaster has the potential to facilitate the thermal retrofit of historic buildings as its deployment can accommodate the requirements of historical preservation. Thereby, the thermal resistance of historical facades can be increased while maintaining their appearance. The present contribution includes the results of a long-term empirical examination of aerogel containing plaster systems especially for historic buildings under real conditions. In the course of this study, multiple test fields with aerogel insulation plaster were applied to the external walls of an existing room in a university building. Thereby different finishing coatings as well as variations with and without reinforcement mesh were considered. Over a period of three years, external and internal environmental parameters as well as hygro-thermal conditions (temperature, moisture concentration, heat flux) at multiple layers within the test fields were monitored. Moreover, the external appearance of the test fields was regularly captured via observation and photographic documentation. The measured data provided the basis to compare the actual thermal transmittance of the test fields with calculation results based on declared material properties. In addition, the results facilitate the comparison of the different solutions. Specifically, the results suggest a promising thermal performance level (in view of considerably lower U-values) as compared to conventional plaster products. Furthermore, the findings document the role of the finishing layer’s composition in view of the occurrence of potential cracks in the facade.

The building sector is one of the highest energy consumers in Austria. The potential to save energy in existing buildings is very high. Current Austrian policy incentives encourage home owners to renovate buildings to meet the European requirements, reduce energy consumption, and reduce CO2 emissions. Nevertheless, there are often discrepancies between the measured and calculated energy consumption results despite efforts to take parameters into account such as the exact geometry and thermal properties of the building, energy demand for hot water, heating, cooling, ventilation systems, and lighting in the planning phase for selecting the best reconstruction option. To find the answer to this problem, many buildings are carefully investigated with the help of measurements, interviews, and simulations. This paper presents the analysis and results of the investigation of the impact of lifestyle on the energy demand of a single family house. The impact on energy performance of the most important parameters was observed by systematically changing parameters such as changing from a decentralized to a centralized heating system, considering various technologies and fuels for producing electricity and heat, use of renewable energy sources. Different occupant behaviours were changed systematically. The effects of these measures are analysed with respect to primary energy use, CO2 emissions and energy costs. The results of these investigations show that the lifestyle and occupants’ living standard is mainly responsible for the differences between the calculated and measured energy consumption.

The present study investigates how three different silicate-based bed materials behave in bubbling fluidized bed combustion of a model agricultural residue with respect to ash composition, namely barley straw. Quartz, natural K-feldspar, and olivine were all used in combustion at 700 °C, and the resulting layer formation and bed agglomeration characteristics were determined. Based on this, a general reaction model for bed ash from agricultural residues was proposed, taking into account the reactivity of the different silicates investigated towards the main ash-forming elements K, Ca, and Si. The proposed reaction model links bed material interaction with K-rich bed ash to the degree of polymerization of the silicate bed material, where addition reactions occur in systems with high polymerization, predominately in quartz, and substitution reactions dominate for depolymerized silicates such as K-feldspar and olivine. Validerad;2024;Nivå 2;2024-03-11 (hanlid);Full text license: CC BY

First experiments with biogenic residues and a plastic-rich rejects and woody biomass blend were conducted in an advanced 1 MW dual fluidized bed steam gasification demonstration plant at the Syngas Platform Vienna. Wood chips, bark, forest residues, and the plastic-rich rejects and woody biomass blend were tested and the tar composition was analyzed upstream and downstream of the upper gasification reactor, which is designed as a high-temperature column with countercurrent flow of catalytic material. Each feedstock was gasified with olivine as bed material in demonstration scale and is compared to the gasification of softwood pellets with olivine and limestone in pilot scale. A reduction in tar content was observed after countercurrent column for all feedstocks. However, a shift in tar species occurred. While styrene, phenol, and 1H-indene were predominant upstream, naphthalene and polycyclic aromatic hydrocarbons (PAHs) were the prevailing tar species downstream the countercurrent column. Hence, an increase of i.e. anthracene, fluoranthene, and pyrene from the upstream concentration was observed. For pyrene, up to twice the initial concentration was measured. This recombination to PAHs was observed for all feedstocks in demonstration- and pilot-scale. The only exception occurred with limestone as bed material, characterized by a higher catalytic activity in comparison to the typically used olivine. In the perspective of the integrated product gas cleaning, tar with higher temperature of condensation are separated more efficiently in the installed scrubbing unit. Hence, the recombination facilitates an overall decline of tar content after the gas cleaning.