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Torrefaction is considered as a method for producing biofuels with improved characteristics compared to those of the “raw” biomass (higher calorific value, moisture resistance, better grindability). The torrefaction process is an endothermic process that is usually carried out in a gaseous atmosphere in the absence of oxygen. To reduce the required heat input, it is proposed to employ the oxidative torrefaction and conduct the process in a fluidized bed agitated with flue gases containing less than 6% oxygen. Preliminary studies of the oxidative torrefaction of sunflower husks, including thermogravimetric analysis of the treated material, have shown that the heat treatment time for the biomass should be at least 5 min. A fluidized bed is a reactor with ideal mixing of the treated material where uniform treatment of raw material particles cannot generally be attained. To overcome this disadvantage of the fluidization technique and achieve the required residence time for biomass in a fluidized bed during a continuous torrefaction process, it was proposed to equip a torrefaction reactor with a series of vertical baffles spaced at 50 mm. These baffles induce a loop-like flow of the processed biomass from the inlet to the outlet of the reactor. To investigate the residence time for husk particles in the reactor, a tracer, which was colored to husk particles' color with a water-soluble dye which did not change the weight and size of the particles, was injected into the bed of uncolored particles. Tracer samples were taken every 30 s at the outlet of the reactor and were analyzed using a special procedure to determine the fraction of colored particles in each sample. This enabled us to gauge the time during which the colored particles injected into the fluidized bed reached the point of their discharge from the bed. Studies performed in a “cold” model of the reactor showed that a series of vertical baffles in the bed can provide the required residence time for biomass in a reactor including commercial reactors. Plates can provide the necessary biomass residence time in the reactor.

Abstract An ideal tracker which follows the sun both north-south and east-west is designed and constructed. It is suitable for mounting a linear concentrator, focusing parabolic concentrator or photovoltaic array of aperture area 2 m2. The apparatus is built with two axes equational mount and controlled by a microprocessor system. The tracking is carried out by utilizing the astronomical coordinates of the sun. As such the present system gives improved tracking capability over the conventional sensor controlled tracker systems. The performance of the tracking system was studied with photovoltaic array mounted on it and tracking error of less than one degree was achieved. This tracking error can be reduced further by proper software.

Solar energy, since it is available every day, is seen as one of the most valuable renewable energy resources. Thus, the energy of sun should be efficiently used in various applications. The most known applications that use solar energy are heating water and spaces. High efficiency solar collectors need appropriate selective surfaces to absorb the heat. Selective surfaces (Selektif-Sera) used in this study are applied to flat collectors, which are produced by a roll to roll cost effective coating of nano nickel layers, developed in Selektif Teknoloji Co. Inc. Efficiency of flat collectors using Selektif-Sera absorbers are calculated in collaboration with Institute for Solar Technik Rapperswil, Switzerland. The main cause of high energy consumption in industry is mostly caused from low temperature level processes. There is considerable effort in research to minimize the energy use by renewable energy sources such as solar energy. A feasibility study will be presented to obtain the potential of solar thermal energy utilization in the textile industry using these solar collectors. For the feasibility calculations presented in this study, textile dyeing and finishing factory located at Kahramanmaras is selected since the geographic location was an important factor. Kahramanmaras is located in the south east part of Turkey thus has a great potential to have solar illumination much longer. It was observed that, the collector area is limited by the available area in the factory, thus a hybrid heating generating system (lignite/solar thermal) was preferred in the calculations of this study to be more realistic. During the feasibility work, the calculations took into account the preheating process, where well waters heated from 15 °C to 30-40 °C by using the hot waters in heat exchangers. Then the preheated water was heated again by high efficiency solar collectors. Economic comparison between the lignite use and solar thermal collector use was provided to determine the optimal system that can be used efficiently. The optimum design of solar thermal systems was studied depending on the optimum collector area. It was found that the solar thermal system is more economic and efficient than the merely lignite use. Return on investment time is calculated as 5.15 years. {"references": ["http://www.aee-intec.at/0uploads/dateien561.pdf, Accessed on 18/05/2016.", "http://www.solarthermalworld.org/sites/gstec/files/SoPro_Leaflet_en.pdfAccessed on 18/05/2016.", "Kalogirou S. \"The potential of solar industrial process heat applications\", Applied Energy, 2003, vol. 76, no. 4, pp. 337-361.", "S Mekhilef, R Saidur, A Safari, \"A review on solar energy use in industries\", Renewable and Sustainable Energy, 2011, vol. 15, no. 4 pp. 1777-1790.", "Taibi, E, Gielen D, Bazilian M. \"Measuring energy poverty: Focusing on what matters\", Renewable and Sustainable Energy, 2012, vol.16, no.1, pp. 735-744", "Faninger, G., \"The potential of Solar Heat in the future energy system\", IFF-University of Klagenfurt, Austria; www.uni-klu.ac.at/iff/ikn/downloads/Potential_of_Solar_Heat.pdf, Accessed on 18/05/2016", "Vannoni, C., Battisti, R., Drigo, S., Potential for Solar Heat in Industrial Processes, Task 33, 2008. Solar Cooling and Heating Committee of the International Energy Agency (IEA).", "TMMOB Mechanical Engineering Chamber Report, \"T\u00fcrkiye'nin Enerji G\u00f6r\u00fcn\u00fcm\u00fc\", 2012, pp. 1588", "Kad\u0131rgan F., Roll to roll manufacturing of solar selective sheets, PCT patent, PCT/IB2010/055006, WO/2012/059789 \n[10]\thttp://www.estif.org/fileadmin/estif/content/policies/downloads/D23-solar-industrial-process-heat.pdf, Accessed on 20/05/2016"]}

The Internet of Things (IoT) provides opportunities to control interconnected smart devices via pre-designed scenarios with littleor no human involvement. Due to the need for systematic improvement of industrial energy efficiency, the relevance of IoT-based energy management systems (EMS) is constantly increasing. Industrial IoT (IIoT)-enhanced EMS are created to support the digital transformation of enterprises. They increase the transparency of energy consumption statistics, enhance the personnel awareness of energy losses, provide predictive analytics tools for forecasting potential industrial accidents and future energy demand. This paper hence provides a system architecture of the energy management assistant that can be used at enterprises to archive the aforementioned aims. Authors identify the relevance of EMS, list the conditions at modern enterprises that define the requirements for the energy management assistant, demonstrate the identified requirements in the UML diagrams. Specification of energy planning and energy monitoring stages demonstrate the possibilities of the designed system architecture. For demonstration purposes, authors present examples of linear and nonlinear regression models implemented to specify energy consumption target functions based on real data. Finally, future research directions and open energy management problems are presented. The analysis has been carried out within the priority area of scientific development established in the National Research University Higher School of Economics - "Research on control methods in Cyber-Physical Systems".

This paper is concerned with the risk management practices of an electricity retailer motivated by the Dutch electricity market. We examine the effectiveness of the existing base- and peak-load futures contracts as a risk management tool for the electricity retailers. We analytically characterize the retailer’s optimal hedging policy as a function of the serial correlation of the prices and the demand profiles of its customers. We find that the retailer typically over-hedges in the futures market, and the over-hedging amount increases when both base- and peak-load contracts are used. Our findings indicate that although the existing contracts in the futures market are quite efficient to replicate the exposure from profiled customers, when industrial consumers and renewable generation are included to the retailer’s portfolio, the effectiveness of such contracts decreases substantially. In our motivating example, hedging the risk of the profiled customers with base-load contracts, the firm may reduce the variance of its cash flows by 85.9%. In addition to the base-load contracts, including peak-load contracts into the hedging portfolio of the retailer increases the efficiency of hedging to 89.3%. However, when we consider the aggregate portfolio of the retailer including profiled customers, industrial consumers and renewable contracts, the efficiency of hedging through the existing futures contracts goes down as low as 32.8% during certain periods. © 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.

With the increasing need for energy in the world, the demand for renewable energy sources is increasing day by day. This increase in energy need directs governments and private sector investors to renewable energy sources. Wind energy is one of the most important renewable energy resources on earth. In recent years, the share of wind energy in the amount of energy produced by renewable energy sources has been increasing. Wind energy emerges as a sustainable energy source due to its environmental friendliness and ability to renew itself. These features of wind energy have a great effect on the increase of its share in the energy sector. In order to get the highest efficiency from wind energy, the correct positioning of wind farms, that is, the concept of site selection is very important. One of the most important parameters in site selection of wind farms is the wind energy source and the wind speed accordingly. In order to create wind speed maps, wind speed data obtained from a certain number of stations should be interpolated for the study area. In this study, wind speed data obtained from 32 meteorology stations in Balikesir province were used. With the help of these data, wind velocity maps were created with five different interpolation methods, namely IDW, Kriging, Natural Neighbor, Spline and Trend, within the borders of Balikesir province. Finally, the results obtained by these five methods were compared with the real wind speed values according to root mean square error and evaluations were made.

Bioenergy is considered a sustainable substitute to fossil-fuel resources and the development of a prudent combination of renewable and innovative conversion technologies are essential for the valorization and effective conversion of biowaste to value-added commodities. Here, a negative pressure-induced carbonization process was proposed for the valorization of lignin-enriched biowaste precursor to bio-oil and environmental materials (biochar) at various temperatures. The high heating values (HHV) of the as-prepared biochars from the lignin enriched precursor under negative pressure (low-medium vacuum) were within 25.9-31.5 MJ/kg, which matched satisfactorily to the commercial charcoal. Whereas, the bio-oils produced from the lignin enriched precursor under vacuum conditions was a blend of complex aromatic and straight-chain hydro-carbons, including aldehyde, ketone, phenol, and furans, exhibiting ability as potential heating-oil with HHV within 21.2-28.2 MJ/kg. Moreover, the biochars produced under vacuum environments at higher temperature showed greater stability (22.5-35.9%) than those produced under N2 atmosphere.

This paper provides the rationale for applying an exergetic method when evaluating the thermodynamics of column-rectification apparatuses, while reviewing the operating profiles of typical purifying columns and purifying columns with stripping modules operating under atmospheric pressure, vacuum, and with mechanical vapour recompression. Graphical representations of the purifying column's exergy balance are provided as Grassmann-Szargut diagrams. The exergy balance data showed that the total value of exergy loss is comparable between conventional purifying columns and those equipped with a stripping module (30.94% and 30.78% efficiency, respectively); moreover, exergy loss is lower in systems where the components operate under a vacuum (31.33% efficiency). For purifying columns that operate using mechanical vapour recompression, their exergetic efficiency is highest (32.6%), which indicates that the thermodynamic precision of system being studied increases when a heat pump is used as the primary source of high-grade energy supply in the column apparatus.