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Abstract Copper is a common impurity in photovoltaic silicon. While reported to precipitate instantly in n-type Si, copper causes light-induced degradation (Cu-LID) in p-type Si. Recently, partial recovery of Cu-LID was observed after only few minutes of dark annealing at 200 °C. In this contribution, we investigate the effects of the dark anneal on Cu-LID-limited minority carrier lifetime both experimentally and by simulations. Surprisingly, after initial recovery, the dark anneal results in further degradation corresponding to a many-fold increase in recombination activity compared to the degraded state after illumination. This anneal-induced degradation can potentially cause additional losses in accidentally Cu-contaminated devices when exposed to elevated temperatures, for example during recovery and regeneration treatments of solar cells. Transient ion drift measurements confirmed that the anneal-induced degradation cannot be attributed to residual interstitial Cu after illumination. After hundreds of hours of annealing, the samples showed another recovery. To analyze these experimental results, a comparison to simulations is performed at the end of the paper.

Oil shale, as an unconventional fossil fuel, exhibits unique properties compared with coal and other petroleum. Due to the nature of sedimentary rock, large amounts of inorganic mineral impurities in rock matrix reduce the grade of oil shale, whilst increase the grinding resistance. This investigation presents the effects of microwave-enhanced pretreatment on the nature of oil shale and compared with conventional preheating process. Two Chinese oil shale from Fushun and Xingsheng Deposits were grounded and sieved into a size fraction (1-1.18mm) and were cut into eighteen cube-shaped specimens respectively. The prepared samples were processed accordingly to investigate how the grindability changed, in comparison to that of raw samples, and how the fundamental chemical properties of oil shale were altered after pretreatment. Quantitive data were used to assess the effects of different pretreatment methods on oil shale milling performance in a lab-scale pulverizer along with the impacts on moisture content, chemical properties. The uniaxial compressive strength (σmax) of Fushun oil shale was reduced 63.1% and the breakage rate increased 44.9% by short exposure to microwave irradiation. In conclusion, microwave-enhanced pretreatment presents significant improvement in oil shale milling performance compared to conventional preheating process in terms of breakage rate (Si) and uniaxial compressive strength (σmax) which showed negligible alterations. © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of ICAE2018 - The 10th International Conference on Applied Energy.

AbstractThe paper presents the concept, implementation and results of the hardware-in-the-loop test bench (HiL) established for a medium-scale parabolic trough collector system under construction. The 122.4m2 plant heats the make-up water of a fossil-fired steam boiler in a meat factory in Austria. The test bench consists of a plant model implemented in a Real-Time machine, which is electrically connected to the plant control hardware (PLC) through several I/O terminals. Within the test bench, it is possible to run different test cycles and emulate critical operation scenarios like collector loop overheating. The control strategy of the solar plant can be checked with minimal risk. The test bench also enables to improve the control ability to cope with weather and sensor disturbances. A suitable fault detection strategy is prepared, which minimizes the risk of component damage and enhances the plant availability.

AbstractThe energy sustainability, in the era of sources diversification [1], can be guaranteed by an energy resources utilization most correct, foreseeing no predominance of one source over the others in any area of the world but a proper energy mix, based on locally available resources and needs [2]-[4]. In this scenario, manageable with a smart grid system [5], [6], a virtuous use of RES must be visible, recognizable and quantifiable, in one word traceable [7]. The innovation of the traceability concept consists in the possibility of having information concerning the exact origin of the electricity used for a specific end use, in this case EV charging [8]. The traceability, in a context of increasingly sustainability [9], [10] and smartness city, is an important develop tool because only in this way it is possible to quantify the real emissions produced by EVs and to ensure the real foresight of grid load. This paper wants investigate the real ways to introduce this kind of real energy accounting, through the traceability.

AbstractA high-pressure/high-temperature reactor has been used to lead PVT and H2-solubility experiments in saline solutions covering conditions for which no data are available in literature: salinity up to halite concentration, pressure up to 200bar and temperature up to 373K. The hereby presented preliminary results show significant deviations from theoretical models. Further analysis and more measurements are needed to assess precision and reproducibility of these measurements; however they pinpoint the importance of experimental work to reliably constrain predictive models.

Abstract This paper presents a new analytical expression intended to accurately evaluate the leakage inductance of transformers in the step-up DC-DC conveter in the high frequency range in which the behavior of the magnetic field within the windings is altered. Unlike conventional expressions, which usually overestimate the leakage inductance at higher frequencies, this expression accounts for high frequency behavior of the magnetic field and provides high accuracy when operating at high frequencies. These high accuracy and applicability makes the derived expression of interest for designers to avoid time consuming finite element simulations without compromising with accuracy. The expression is validated by 2-D FEMM simulation, as well as by measurement.

Abstract The continued development of amine solvents for post-combustion CO2 capture is essential to the large-scale success of this technology, with particular interest in high capacity and uptake promoter blends. Some of these solutions also show reduced corrosive tendencies in the presence of carbon steel, a significantly cheaper alternative to the stainless steels generally employed. Optimization of the solution composition and reduced corrosion could yield both a decrease in capital and operating costs. Solutions (30% by weight) of monoethanolamine (MEA) or piperazine (PZ) were blended with either methyldiethanolamine (MDEA) or 2-amino-2-methyl-1-propanol (AMP). At 120 °C, Solutions containing PZ outperformed those with MEA showing the formation of good protective siderite (FeCO3) crystal layers, reducing continued oxidation of Fe from the surface and therefore corrosion.