Tag Archives: renewable resources

654-663 L. Avotina, A. Zarins, J. Nesenbergs, E. Vanags, A. Lescinskis, A. Ansone, T. Selga, M. Baryshev and G. Kizane
Impact of storage conditions on preparation of activated carbon from sheep wool fibres
Abstract |

Impact of storage conditions on preparation of activated carbon from sheep wool fibres

L. Avotina¹*, A. Zarins¹², J. Nesenbergs¹³, E. Vanags⁴, A. Lescinskis¹, A. Ansone¹, T. Selga⁵, M. Baryshev⁶ and G. Kizane¹

¹University of Latvia, Institute of Chemical Physics, Jelgavas Str. 1, LV-1006 Riga, Latvia
²Daugavpils University, Faculty of Natural Sciences and Mathematics, Parades Str. 1A, LV-5401 Daugavpils, Latvia
³Riga Technical University, Faculty of Materials Science and Applied Chemistry, Institute of Materials and Surface Engineering, P. Valdena Str. 3/7, LV-1048 Riga, Latvia
⁴University of Latvia, Institute of Solid State Physics, Kengaraga Str. 8, LV-1063 Riga, Latvia
⁵University of Latvia, Faculty of Biology, Jelgavas str. 1, LV-1004 Riga, Latvia
⁶Riga Stradins University, Institute of Microbiology and Virology, Ratsupites Str. 5,
LV-1067 Riga, Latvia
*Correspondence: liga.avotina@lu.lv

Abstract:

In the European Union, up to 200 thousand tons (Zoccola et al., 2015) of sheep wool fibres, that are not used for textile fabrication, are a secondary by-product with wide field of application possibilities, including preparation of activated carbon. Taking into account, that wool fibres can be stored for long time, under impact of the local climate conditions (including low temperatures) before their application, for example, under variety of temperature, presence of air and light, different moisture conditions, it is necessary to estimate the impact of wool’s storage conditions on the preparation of activated carbon. In the present work, various parameters, such as, temperature, presence of air and daylight as well as humidity, were selected for comparison. After storage of wool fibres under selected various conditions, thermogravimetry/differential thermal analysis (TG/DTA) followed by with Fourier transform infrared (FTIR) spectrometry were used in order to estimate the impact of each parameter on the thermal decomposition processes: release of moisture, sulphur and nitrogen containing compounds and oxidative degradation followed by release of carbon dioxide. It was estimated, that one year of storage under varying conditions does not significantly affect the thermal decomposition properties of the wool fibres. However, minor impact of humidity absorbed from air on wool is observed. Wool samples that were stored at elevated humidity gave higher residual carbon yield (R) in comparison to the fibres stored in dry conditions. The obtained results are used to develop recommendations for preparation of activated carbon from wool fibres and for its application in air filtrating systems.

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553-562 M. Märss,, A. Annuk, A. Allik and J. Uiga
AC-link based new microgrid system for research of local power flow management
Abstract |
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AC-link based new microgrid system for research of local power flow management

M. Märss¹⋅²,*, A. Annuk¹, A. Allik¹ and J. Uiga¹

¹Institute of Technology, Estonian University of Life Sciences, Kreutzwaldi 56, EE51014 Tartu, Estonia 2Tallinn University of Technology, Department of Electrical Engineering, Ehitajate tee 5, EE19086 Tallinn, Estonia; *Correspondence: maido.marss@emu.ee

Abstract:

This paper gives an overview of a distributed energy technology laboratory, where diverse approaches are studied to effectively integrate distributed generation into power systems. The laboratory is equipped with small-scale power generation devices including wind turbine (3.5 kW), PV array (2.5 kW), synthetic energy generator (3.6 kW) and also batteries, ultra capacitor, programmable load (6.2 kW), weather station, power flow and power quality control and monitoring system. The laboratory is used for researching and applying energy-management technics to control energy storage and increasing power reliability and power quality in small-scale generation units. On-site measured data of power consumption and production can be linked to the laboratory and simulated online with synthetic energy generator and programmable load. It is also possible to scale the measured data and model systems with variable sizes. As a result the stability of variable systems can be tested with different storage capacities and load management techniques.

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357-366 V. Osadcuks, A. Pecka and R. Selegovskis
Energetic balance of autonomous hybrid renewable energy based EV charging station in winter conditions
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Energetic balance of autonomous hybrid renewable energy based EV charging station in winter conditions

V. Osadcuks*, A. Pecka and R. Selegovskis

Faculty of Engineering, Latvia University of Agriculture, J. Cakstes blvd. 5.,LV-3001 Jelgava, Latvia; *Correspondence: vtl@tvnet.lv

Abstract:

The paper presents an experimental research on energetic balance of an autonomoushybrid renewable energy based electric vehicle (EV) charging station. The experimental chargestation is located in the central part of Latvia in Jelgava city. The station is built using standardsmall-scale hybrid power system equipment: 24 V 300 Ah lead-acid battery, 2 kW photovoltaicarray, 300 W wind generator, hybrid charge controller and 1.6 kW inverter. The station iscapable to perform mode 1 EV charging (220 V, 50 Hz, up to 1.6 kW). The aim of the researchis to evaluate the operational possibilities, technical self-consumption and overall energybalance of the renewable resources based station during a winter period. Analysis on availablepower for EV charging, self-consumption and affecting environmental factors during a 6-dayperiod is performed. The time period was chosen to include days with temperatures below andabove zero and various levels of solar irradiation. Conclusions about possibilities andusefulness of winter-period exploitation are given.

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