| 1. |
- Leckner, Bo G, 1936, et al.
(author)
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Co-Combustion of Sludge with Coal or Wood
- 2004
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In: International Journal of Power and Energy Systems. - 1078-3466. ; 24:3, s. 172-178
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Journal article (peer-reviewed)abstract
- There are several options for co-combustion of biomass or waste with coal. In all cases the fuel properties are decisive for the success of the arrangement: contents of volatile matter and of potential emission precursors, such as sulphur, nitrogen, chlorine, and heavy metals. The content of alkali in the mineral substance of the fuel is important because of the danger of fouling and corrosion. Research activities at Chalmers University of Technology include several aspects of the related problem areas. An example is given concerning emissions from co-combustion in circulating fluidized bed with coal or wood as base fuels, and with sewage sludge as additional fuel. Two aspects of the properties of sludge are studied: emissions of nitrogen and sulphur oxides as well as of chlorine, because the contents of the precursors to these emissions are high. The possibility of utilizing the phosphorous in sludge as a fertilizer is also discussed. The results show that emissions can be kept below existing emission limits if the fraction of sludge is sufficiently small (
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| 2. |
- Löfström, Erica, et al.
(author)
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On the invisible socio-technical systems – the great unknown
- 2010
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In: International Journal of Power and Energy Systems. - 1078-3466. ; 30:3, s. 176-182
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Journal article (peer-reviewed)abstract
- Energy is an important resource in society and we often depend on energy in our everyday life. Energy-related emissions constitute at the same time a major environmental load, and we need to use energy more efficiently. To develop sustainable energy systems users need to transform their behaviour and start reflecting on their energy use. The aim of this paper is to discuss different methods to visualize energy use in households. We will discuss experience from three different methods, namely information, time-diaries and a power-aware cord. Every method has its drawbacks, but combining the three methods could be one way to highlight households’ energy use and their possibility to energy conservation. By using the results from the introduction of time-diaries and technical artefacts in households when developing information campaigns and in energy guidance, we can find strategies that appeal more closely to peoples’ behaviour, hence making it easier for households to put the advice into practice in their everyday lives.
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| 3. |
- Mahmood, Yasser Ahmed, et al.
(author)
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Evaluation and Selection for Availability Improvement of Frequency Converters in Electrified Railway
- 2014
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In: International Journal of Power and Energy Systems. - 1078-3466 .- 1710-2243. ; 34:4, s. 162-172
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Journal article (peer-reviewed)abstract
- Railway traction power supply systems (TPSSs) that work at low frequencies contain frequency converters (FCs) that convert the adequate power from a public grid to a traction grid. Availability and system importance analysis is a key aspect of overall system performance. It identifies the weakest areas of a system and indicates where resources must be invested to achieve maximum improvement. Availability analysis of FC types is crucial to reduce outages of traction power that lead to traffic delays and cancellations due to unavailability of FCs. The aim of this study is to rank FC types on the basis of priority of needs for reliability and maintainability improvement so that the availability can be enhanced. The proposed approach involves collection of outage data by calculating performance measures, and then these measures are compared via a comparative chart. Thereafter, opinions of experts are collected and aggregated through linguistic variables, and the FC types are then identified using analytic hierarchy process. Reliability, availability and maintainability (RAM) have been used as the criteria to identify the FC types. In addition to power sharing, capacity and service factors are considered to be productivity measures. Probabilistic performance indexes are used to measure availability, maintainability and productivity, whereas the mean number of outages is used as a reliability index.
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| 4. |
- Maidana, C. F., et al.
(author)
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Thermodynamic analysis of oxygen-enhanced combustion processes
- 2016
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In: International Journal of Power and Energy Systems. - : ACTA Press. - 1078-3466 .- 1710-2243. ; 36:1, s. 31-36
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Journal article (peer-reviewed)abstract
- This paper presents a thermodynamic analysis of the process known as oxygen-enhanced combustion (OEC). In order to have a better evaluation of this process, a simple system was modeled, composed only of the main components needed to simulate an OEC process. The concentrated oxidant stream required for the OEC process is provided by a polymeric membrane set. Results show an increase of the energetic efficiency, from 22% to 58%, compared to regular atmospheric combustion. The exergetic efficiency follows the same trend, from 18% to 48.5%. A reduction of more than 60% of specific pollutants emissions is shown. The assessed technique points out to be energetically more attractive than cryogenics for small plants, the size limit depending on operating conditions.
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| 5. |
- Mossberg, Magnus
(author)
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Forecasting Electric Power Consumption Using Subspace Algorithms
- 2007
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In: International Journal of Power and Energy Systems. - 1078-3466 .- 1710-2243. ; 27:4, s. 393-397
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Journal article (peer-reviewed)abstract
- A new approach for electric power consumption forecasting that consists of using subspace identification techniques is presented in the paper. The new and powerful subspace identification techniques are introduced to the members of the power system engineering community who are not familiar with them, and it is shown that they can be an important tool in this area of electrical engineering. The usefulness of the techniques is illustrated on real data, and the identified models give reliable 24-h ahead predictions.
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