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Other Presentations | 2019

Betrieb bei maximaler Effizienz und minimalen Emissionen durch CO-Lambda-Optimierung

Zemann C, Hammer F. Betrieb bei maximaler Effizienz und minimalen Emissionen durch CO-Lambda-Optimierung. Heizwerke-Betreibertag 2019, Sieggraben, 07. Oktober 2019 (oral presentation).

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Studien | 2019

Bioenergy in Austria

Bacovsky D, Matschegg D. Bioenergy in Austria. Federal Ministry for Transport, Innovation and Technology. 2019:52.

Federal Ministry for Transport, Innovation and Technology

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Conference contributions | 2019

Bioenergy retrofits for Europe´s industry - the BIOFIT project (Horizon 2020)

Reumerman P, Vos J, Rutz D, Janssen R, Bacovsky D, Gröngröft A, Saastamoinen H, Karampinis E, Ballesteros M, Johansson D, Kazagic A, Wanders M, Meeusen M, Hull A, Kiartzis S, Garcia J. Bioenergy retrofits for Europe´s industry - the BIOFIT project (Horizon 2020). 27th European Biomass Conference & Exhibition (Poster). May 2019.

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Other Publications | 2019

BIOFIT – Bioenergieumrüstungen für Europas Industrie

Bacovsky D. BIOFIT – Bioenergieumrüstungen für Europas Industrie. Highlights der Energieforschung 2019. October 2019.

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Conference contributions | 2019

Biomassevergasung als künftige Säule der Gasversorgung in Österreich

Strasser C. Biomassevergasung als künftige Säule der Gasversorgung in Österreich. 10. Internationale Anwenderkonferenz Biomassevergasung. Dec 2019.

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Conference contributions | 2019

Biomassevergasung als künftige Säule der Gasversorgung in Österreich?

Strasser C. Biomassevergasung als künftige Säule der Gasversorgung in Österreich?. 10. Internationale Anwenderkonferenz Biomassevergasung. December 2019

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Technical Reports | 2019

C200600_1 - Experimental Campaign Summer 2019

Fürsatz K, Kuba M, Karel T, Priscak J. C200600_1 - Experimental Campaign Summer 2019. Report on experimental test runs. November 2019.

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Conference contributions | 2019

Catalytic tar reforming with sewage sludge char of a producer gas from fluidized bed co-gasification of sewage sludge and wood

von Berg L, Doğan C, Aydın ES, Retschitzegger S, Scharler R, Anca-Couce A. Catalytic tar reforming with sewage sludge char of a producer gas from fluidized bed co-gasification of sewage sludge and wood. 27th European Biomass Conference & Exhibition (Poster). May 2019.

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Fluidized bed gasification of sewage sludge is a promising method for its valorisation due to the fuel flexibility of the process. The main drawbacks are the impurities present in the producer gas, with a high tar content, and its low calorific value. In this study, sewage sludge and wood mixtures are gasified in a fluidized bed. A tar cracking reactor is used to reduce the amount of tars and to increase the calorific value of the producer gas. Sewage sludge char is employed for tar cracking with a real producer gas, showing the feasibility of the process with a tar conversion of about 80% at the beginning. The test was conducted for several hours and tar deactivation was observed, which lead to a decrease of tar conversion to about 35% after 5 hours. Reactivating the char with steam increases again the tar conversion up to 84%, however, the subsequent deactivation was found to be faster compared to the one for fresh char. First tests using char from the gasification process in the tar cracking unit also show promising results.


Scientific Journals | 2019

Characterization and performance evaluation of ammonia as fuel for solid oxide fuel cells with Ni/YSZ anodes

Stoeckl B, Subotić V, Preininger M, Schwaiger M, Evic N, Schroettner H, Hochenauer C. Characterization and performance evaluation of ammonia as fuel for solid oxide fuel cells with Ni/YSZ anodes. Electrochimica Acta 2019;298:874-883.

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Ammonia appears to be a promising fuel for solid oxide fuel cell systems: it is a carbon-free species, can be stored easily and offers an excellent energy density with a high hydrogen content. This work shows comprehensive investigations of the direct operation of ammonia on an industrial-sized solid oxide fuel cell with Ni/YSZ anode. In the course of this study, ammonia exhibited excellent performance as a fuel for solid oxide fuel cells, although test results equivalent to those of hydrogen/nitrogen fuel mixtures were not attained. Electrochemical impedance spectroscopy proved the reduced performance output of ammonia as fuel to result from its endothermic decomposition. This significantly increased the ohmic resistance, which is mainly influenced by the ammonia flow rate. Operation in counter-flow is more favorable than in co-flow, as lower ohmic and diffusion resistances were measured. Twenty-four-hour stability tests showed stable behavior at 800 °C and a voltage decrease of 2% at 700 °C. Investigations of the anode micro-structure suggest that nickel nitriding occurred, as microscopic pores, particle enlargements, and agglomerations were identified at the metallic parts.


Technical Reports | 2019

CO-Lambda optimization

Operation of biomass boilers at maximum efficiency and with complete combustion

Zemann C, Gölles M. CO-Lambda optimization - Operation of biomass boilers at maximum efficiency and with complete combustion. 2019.

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Technical Reports | 2019

CO-Lambda-Optimierung

Betrieb von Feuerungen bei maximalem Wirkungsgrad und vollständigem Ausbrand

Zemann C, Gölles M. CO-Lambda-Optimierung - Betrieb von Feuerungen bei maximalem Wirkungsgrad und vollständigem Ausbrand. 2019.

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Reviewed Conference Papers | 2019

Co-Simulation of an Energy Management System for Future City District Energy Systems

Moser AGC, Muschick D, Gölles M, Lerch W, Schranzhofer H, Nageler PJ et al. Co-Simulation of an Energy Management System for Future City District Energy Systems. In Proceedings of the International Conference on Innovative Applied Energy. 2019.

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The continuous increase of (volatile) renewable energy production and the development of energy-efficient buildings have led to a transformation of city districts’ energy systems. Their complexity has increased significantly due to the coupling of the different energy sectors like heating, cooling and electricity. Such complex multi-energy systems can be operated more efficiently and reliably if knowledge of their specific components (in terms of mathematical models) as well as knowledge of weather forecasts is incorporated in a high-level controller, which is typically referred to as an Energy Management System (EMS). However, still little comprehensive information on the costs and the practical advantages of such systems is available. For this reason, a simulation environment to estimate the real costs and advantages of the use of such an EMS is required. Consequently, this work focuses on the development of an EMS for future city districts’ energy systems and the development of a co-simulation environment in order to demonstrate the benefits of the use of the developed EMS in comparison to a conventional control strategy. The co-simulation is implemented with the aid of the co-simulation platform Building Controls Virtual Test Bed (BCVTB) and consists of the following parts: a non-linear, thermoelectric model and a control block containing either the conventional control strategy or the EMS. The thermoelectric model is built up using the well-established simulation tools TRNSYS and IDA-ICE, simulating the energy hub of the city district and the districts’ buildings, respectively. The control block is simulated using MATLAB, where IBM ILOG CPLEX is used for solving the resulting mixed-integer linear program (MILP) of the EMS. Finally, an economic model for financial (and ecological) assessment of the operation is simulated with the aid of the software package Dymola. To put the developed EMS and the co-simulation into practise a case study based on a new city district in Graz, Austria, which is currently in the planning stage, is carried out. The integration of the responsible planners and investors in the modelling process guarantees the models’ practical applicability. In the case study the performance of the originally planned conventional control strategy is compared with the performance of the developed EMS using annual simulations with a simulation time step of 1 minute, and a 24 hour prediction horizon and a 15 minute time step for the EMS. For a more robust and realistic comparison both control strategies are simulated for different scenarios considering current and future (2060) climate conditions, medium and high energy demands (load), ideal and real load prediction methods and varying import prices for electricity from the electricity grid. The results show that the use of the developed EMS strategy results in reduced annual total costs (considering operational and investment costs of additionally suggested distributed energy resources) in comparison to the conventional control strategy. Furthermore, the annual CO2-emissions could be reduced by increasing the self-consumption of the installed (renewable) energy resources and thus decreasing the necessary energy imports from the electricity and the heating grid.


Conference contributions | 2019

Co-Simulation of an Energy Management System for Future City District Energy Systems (Presentation)

Moser AGC, Muschick D, Gölles M, Lerch W, Schranzhofer H, Nageler PJ et al. Co-Simulation of an Energy Management System for Future City District Energy Systems. International Conference on Innovative Applied Energy. 2019. (Oral presentation, 15.03.2019.)

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Slides of the talk "Co-Simulation of an Energy Management System for Future City District Energy Systems"


Scientific Journals | 2019

Cultivation of the microalga Eustigmatos magnus in different photobioreactor geometries and subsequent anaerobic digestion of pre-treated biomass

Gruber-Brunhumer MR, Schöberl A, Zohar E, Koenigsberger S, Bochmann G, Uher B, Lang I, Schagerl M, Fuchs W, Drosg B. Cultivation of the microalga Eustigmatos magnus in different photobioreactor geometries and subsequent anaerobic digestion of pre-treated biomass. Biomass and Bioenergy 2019.105303.

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Microalgal biomass as a feedstock for biogas production is linked to the parameters biomass productivity and biogas yield. Besides an easy-to-use strain for anaerobic digestion, the photobioreactor (PBR) design is important. A microalgae strain selection revealed Eustigmatos magnus (SAG 36.89) as the most promising strain yielding an average of 100 mg total suspended solids (TSS) L−1 day−1. The strain was tested in cost-effective sleevebag-PBR-systems of 10 cm, 20 cm and 30 cm diameter facing the light from the front or laterally. Highest mean productivity on a volumetric basis was measured in PBRs with the lowest diameter (104 and 117 mg L−1 day−1. The highest productivity per m−2 was achieved in 10 cm PBRs with front light configuration (9.35 g TSS m−2 day−1). The lateral light configuration of 10 cm PBRs had positive aspects such as the lowest mean water demand to produce 1 kg TSS (481 L−1 kg−1) and the lowest mean energy demand for medium separation of 1 kg TSS (106 Wh). The concentrated microalgal biomass was then subjected to ultrasonication and thermal pre-treatment (90 °C and 120 °C) and tested in BMP tests. Mesophilic anaerobic mono-digestion of untreated microalgae biomass led to a methane (CH4) yield of 343 L−1 kg−1 volatile solids (VS). Thermal pre-treatment at 120 °C resulted in significantly increased CH4 yields of 430 L−1 kg−1 VS. As thermal pre-treatment can be easily installed nearby a biogas plant it could be an interesting option for AD of microalgal biomass with only little investment.


Conference contributions | 2019

Customizing biomass as reducing agent in blast furnace steelmaking – preliminary results

Strasser C, Kienzl N, Martini S, Dißauer C, Deutsch R. Customizing biomass as reducing agent in blast furnace steelmaking – preliminary results. 27th European Biomass Conference & Exhibition (Poster). May 2019.

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The reduction of greenhouse gas emission is an important issue for steel industry. One possibility is to use biomass-based reducing agents, also called bioreducers, to replace a least partly the fossil reducer agents. To produce bioreducer we treated woody biomass in a lab-scale muffle furnace, we performed grinding experiments with a ball mill, we analyzed the particle size distribution with laser diffraction and we used a rotating device, the revolution powder analyzer, for flow behavior investigations. Our preliminary results show that treatment temperatures >250 oC bring adequate increased calorific value and improved grindability. For a certain treatment temperature the particle size distribution and as well the flow behavior shows similarities to lignite.


Conference contributions | 2019

Decomposition of tars in dual fluidized bed gasification – mechanisms of formation and decomposition in long-term operation

Umeki K, Priscak J, Kuba M. Decomposition of tars in dual fluidized bed gasification – mechanisms of formation and decomposition in long-term operation. ICPS 2019.

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Technical Reports | 2019

Deliverable 4.2 Development of protocols relevant for biochemical and thermochemical conversion of biomass

Oliveira C, Carvalheiro F, Duarte KC, del Campo I, Fryda LE, Banks S, Anca-Couce A, Gírio F, Retschitzegger S. Deliverable 4.2 Development of protocols relevant for biochemical and thermochemical conversion of biomass. BRISK II - Deliverable. November 2019

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Technical Reports | 2019

Deliverable 5.1 - Interim Report on Tasks 5.1 – 5.5

Retschitzegger S, Kienzl N, Wang S, Yang W, Banks S, Colmenar I, et al. Deliverable 5.1 - Interim Report on Tasks 5.1 – 5.5. BRISK II - Deliverable. March 2019.

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Technical Reports | 2019

Deliverable 6.2 Improved and extended tar protocol

Anca‐Couce A, von Berg L, Kienzl N, Martini S, del Campo I, Funcia I, Kraia T, Panopoulos K, Fryda K, Geusebroek M, Engvall K, Tuomi S. Deliverable 6.2 Improved and extended tar protocol. BRISK II - Deliverable. December 2019.

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Technical Reports | 2019

Deliverable 7.3 - Infrastructure upgrading / modifications: biobased intermediates conversion

Panopoulos K, Bampaou M, Retschitzegger S, del Campo Colmenar I, Zimbardi F, Girio F, Anca-Couce A, Safi C. Deliverable 7.3 - Infrastructure upgrading / modifications: biobased intermediates conversion. BRISK II - Deliverable. November 2019.

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Conference contributions | 2019

Development of a New Method for Investigation of the Ash Melting Behavior in the Fluidized Bed Conversion Processes

Priscak J, Kuba M, Hofbauer H. Development of a New Method for Investigation of the Ash Melting Behavior in the Fluidized Bed Conversion Processes. ICPS 2019.

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Peer Reviewed Scientific Journals | 2019

Double-cropping systems based on rye, maize and sorghum: Impact of variety and harvesting time on biomass and biogas yield

Wannasek L, Ortner M, Kaul HP, Amon B, Amon T. Double-cropping systems based on rye, maize and sorghum: Impact of variety and harvesting time on biomass and biogas yield. European Journal of Agronomy 2019.110:125934

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Climate change affects the frequency and intensity of extreme weather, the results of which include production losses and climate-induced crop productivity fluctuations.

Double-cropping systems (DCSs) have been suggested as a way to increase biomass-production while simultaneously delivering environmental benefits. In a three-year field-test, two DCSs based on maize and sorghum as the main crop and rye as the preceding winter crop were compared with each other and compared with 2 single-cropping systems (SCSs) of maize or sorghum; there were comparisons of growth dynamics, optimal harvesting and growing time as well as biomass and methane yield. In addition, the impact of variety and harvest time on the winter rye optimal biomass yield was studied.

The experiments clearly showed the superiority of the DCS over the SCS. Within the DCS, the rye/sorghum combination achieved significantly higher biomass yields compared to those of the rye/maize combination. The highest dry matter biomass yield was achieved during year 1 at 27.5 ± 2.4 t∙ha−1, during which winter rye contributed 8.3 ± 0.7 t∙ha−1 and sorghum contributed 19.2 ± 1.8 t∙ha−1. At the experimental location, which is influenced by a Pannonia climate (hot and dry), the rye/sorghum DCS was able to obtain average methane yields per hectare, 9300 m3, whereas the rye/maize combination reached 7400 m3. In contrast, the rye, maize and sorghum SCSs achieved methane yields of 4800, 6100 and 6500 m3 ha−1, respectively. The study revealed that the winter rye and sorghum DCS is a promising strategy to counteract climate change and thus guarantee crop yield stability.


Peer Reviewed Scientific Journals | 2019

Effects of partial maize silage substitution with microalgae on viscosity and biogas yields in continuous AD trials

Gruber-Brunhumer MR, Montgomery LFR, Nussbaumer M, Schoepp T, Zohar E, Muccio M, Ludwig I, Bochmann G, Fuchs W, Drosg B. Effects of partial maize silage substitution with microalgae on viscosity and biogas yields in continuous AD trials. Journal of Biotechnology 2019;295:80-89.

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The microalga Acutodesmus obliquus was investigated as a feedstock in semi-continuously fed anaerobic digestion trials, where A. obliquus was co-digested with pig slurry and maize silage. Maize silage was substituted by both 10% and 20% untreated, and 20% ultrasonicated microalgae biomass on a VS (volatile solids) basis. The substitution of maize silage with 20% of either ultrasonicated and untreated microalgae led to significantly lower biogas yields, i.e., 560 dm³ kg−1 VScorr in the reference compared to 516 and 509 dm³ kg-1VScorr for untreated and ultrasonicated microalgae substitution. Further, the viscosities in the different reactors were measured at an OLR of 3.5 g VS dm-3 d-1. However, all treatments with microalgae resulted in significantly lower viscosities. While the mean viscosity reached 0.503 Pa s in the reference reactor, mean viscosities were 53% lower in reactors where maize was substituted by 20% microalgae, i.e. 0.239 Pa s, at a constant rotation speed of 30 rpm. Reactors where maize was substituted by 20% ultrasonicated microalgae had a 32% lower viscosity, for 10% microalgae substitution a decrease of 8% was measured. Decreased viscosities have beneficial effect on the bioprocess and the economy in biogas plants. Nonetheless, with regard to other parameters, no positive effect on biogas yields by partial substitution with microalgae biomass was found. The application of microalgae may be an interesting option in anaerobic digestion when fibrous or lignocellulosic substances lead to high viscosities of the digested slurries. High production costs remain the bottleneck for making microalgae an interesting feedstock.


Scientific Journals | 2019

Efficient Multi-Year Economic Energy Planning in Microgrids

Pecenak Z, Stadler M, Fahy K, Efficient Multi-Year Economic Energy Planning in Microgrids. Applied Energy 2019;225.

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With energy systems, the problem of economic planning is decisive in the design of a low carbon and resilient future grid. Although several tools to solve the problem already exist in literature and industry, most tools only consider a single “typical year” while providing investment decisions that last around a quarter of a century. In this paper, we introduce why such an approach is limited and derive two approaches to correct this. The first approach, the Forward-Looking model, assumes perfect knowledge and makes investment decisions based on the full planning horizon. The second novel approach, the Adaptive method, solves the optimization problem in single year iterations, making incremental investment decisions that are dependant on previous years, with only knowledge of the current year. Comparing the two approaches on a realistic microgrid, we find little difference in investment decisions (maximum 21% difference in total cost over 20 years), but large differences in optimization time (up to 12000% time difference). We close the paper by discussing implications of forecasting errors on the microgrid planning process, concluding that the Adaptive approach is a suitable choice.


Peer Reviewed Scientific Journals | 2019

Efficient Multi-Year Economic Energy Planning in Microgrids

Pecenak Zachary K, Stadler M,Fahy K. Efficient Multi-Year Economic Energy Planning in Microgrids. Applied Energy Journal by Elsevier, ISSN: 0306-2619

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With energy systems, the problem of economic planning is decisive in the design of a low carbon and resilient future grid. Although several tools to solve the problem already exist in literature and industry, most tools only consider a single “typical year” while providing investment decisions that last around a quarter of a century. In this paper, we introduce why such an approach is limited and derive two approaches to correct this. The first approach, the Forward-Looking model, assumes perfect knowledge and makes investment decisions based on the full planning horizon. The second novel approach, the Adaptive method, solves the optimization problem in single year iterations, making incremental investment decisions that are dependant on previous years, with only knowledge of the current year. Comparing the two approaches on a realistic microgrid, we find little difference in investment decisions (maximum 21% difference in total cost over 20 years), but large differences in optimization time (up to 12000% time difference). We close the paper by discussing implications of forecasting errors on the microgrid planning process, concluding that the Adaptive approach is a suitable choice.