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The work presents an example of practical application of gas flow modeling results in the network, that was obtained for the existing gas network and for real data about network load depending on the time of day and air temperature. The gas network load in network connections was estimated based on real data concerning gas consumption by customers and weather data in 2010, based on two-parametric...
We present a meta-analysis of long-term energy-system scenario studies. The meta-analysis comprises a qualitative taxonomy of modeling approaches and a quantitative decomposition of scenario results across heterogenous studies. The analysis is exemplified by technology-detailed scenario studies of the Swiss electricity system. In the decomposition approach, we assess the variability across scenario...
This paper focuses on the frequency-based design of a FPSE (free piston Stirling engine) using a GA (genetic algorithm). First, a mathematical description of the FPSE is presented. The engine design parameters including mass and stiffness of power and displacer pistons and cross-sectional area of the displacer rod are considered as unknown variables. Then, based on a desirable operating frequency,...
DED (Dynamic economic dispatch) problem schedules generation units during the whole dispatch period in order to minimize the fuel costs. On the other hand DRPs (Demand Response Programs) focus on increasing customers' benefit and improving network reliability. If these two problems are optimally integrated considering their interactions at each side, they will be implemented more effectively. One...
Five different models for calculating solar module temperature, output power and efficiency for sunny days with different solar radiation intensities and ambient temperatures are assessed in this paper. Thereafter, modeled values are compared to the experimentally obtained values for the horizontal solar module in Nis, Serbia. The criterion for determining the best model was based on the statistical...
The combustion of fossil fuels for energy generation has contributed considerably to the effects of climate change. In order to reduce fossil fuel consumption, designers are increasingly seeking to reduce the energy consumption of products over their life cycle. To achieve a significant reduction in energy consumption, it is essential that energy considerations are incorporated within the design phase...
Starting from PES (primary energy saving) and CSR (cost saving ratio) definitions the work pinpoints a “grey area” in which CHP (combined heat and power – cogeneration) units can operate with profit and negative PES. In this case, CHP can be profitably operated with lower efficiency with respect to separate production of electrical and thermal energy. The work defines the R-index as the ratio between...
Ever-increasing energy demand has motivated the energy researchers to seek alternative sources. Ocean wave energy is a promising candidate of renewable energy, holding great potential for contribution to power demands when converted to different forms of usable energy. Iran has long marine boundaries and hence, has excellent marine energy resources which makes it a suitable place for harvesting wave...
The modification of anode materials is important to enhance the power generation of MFCs (microbial fuel cells). A novel and cost-effective modified anode that is fabricated by dispersing manganese dioxide (MnO2) and HNTs (Halloysite nanotubes) on carbon cloth to improve the MFCs' power production was reported. The results show that the MnO2/HNT anodes acquire more bacteria and provide greater kinetic...
An effective optimization method is presented for the shape design of the axis-symmetric wind lens aiming at velocity augmentation and drag force reduction. The profile of the wind lens is approximated by a polynomial function. Velocity and drag force are calculated by CFD (Computational Fluid Dynamics) method. The wind lens profile is optimized adopting GA (genetic algorithm). GA and CFD method are...
The thermal performance of a standing column well system is sensitive to geological and hydrogeological conditions and is maximized in the conditions of stable groundwater temperature, high well yield, and shallow water level. Intricate heat transfer phenomena in the standing column well system leads to difficulties in establishing unified detailed guidelines for the design, installation, and operation...
In this paper, comparative performance analyses of the irreversible OMCE (Otto Miller cycle engine), DiMCE (Diesel Miller cycle engine) and DMCE (Dual Miller cycle engine) based on the MP (maximum dimensionless power) output, MPD (maximum dimensionless power density) and MEF (maximum thermal efficiency) criteria have been performed by taking irreversibility due to irreversible-adiabatic compression...
The thermodegradation of soybean biodiesel stabilised with conventional antioxidants BHT (butylated hydroxytoluene) and PG (propyl gallate) in combination with an alternative additive based on the anthraquinone compound DHQ (1,4-dihydroxyanthraquinone) was investigated by simulating an accelerated storage process at temperatures from 85 to 110 °C. The effectiveness of different combinations of PG...
Wheat is one of the most cultivated grains internationally. In 2012, Mexico allocated 578,836 ha to this crop. In the Valley of Mexicali, Baja California, Mexico, wheat is the main crop with 72,206 ha in 2012. The crop generates about 527,103 t/year of wheat straw. At the end of each harvest season, most of this residue is open burned, without productive use, causing environmental pollution. However,...
This paper addresses the optimal stochastic scheduling of the distributed generation units in a micro-grid. In this way, it introduces a new sufficient stochastic framework to model the correlated uncertainties in the micro-grid that includes different types of RESs such as photovoltaics, wind turbines, micro-turbine, fuel cell as well as battery as the storage device. The proposed stochastic method...
Based on the benchmark pressurized molten carbonate fuel cell hybrid system without CO2 capture, this paper proposes a novel pressurized molten carbonate fuel cell hybrid system with CO2 capture. Firstly, the benchmark system is optimized to obtain the optimum fuel cell operating pressure, under the same pressure the performance of the new system is investigated and compared with that of the benchmark...
In this article, a transformer-less 3P3W SAPF (three-phase three-wire shunt active power filter) integrated into the distributed energy network which embeds line-interactive UPS and bi-directional chopper-fed energy storage equipment. The proposed system operates in two operating modes of line-interactive UPS (uninterruptible power supply) with bi-chopper-fed battery energy storage stage. In normal...
This study aims to optimize DER (distributed energy resource) system with respect to economic and environmental objectives. In particular, we developed a mixed-integer linear programming model with multiple objectives at a neighbourhood level containing residential and office buildings. The equipment and layout of the district energy (power, heating, and cooling) networks were selected from several...
In the ethanol production process from sugarcane molasses, the distillation process is a high-energy demand stage. The distillation energy efficiency is strongly associated with the alcoholic fermentation performance in the process. The final ethanol concentration in the alcoholic wines has a direct impact on consumption of thermal energy in ethanol separation. In this paper, ethanol production with...
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