Search

This study investigates the viability of hybrid photovoltaic (PV), wind, and fuel cell (FC) systems for on‐grid and off‐grid operations for the Ashrayan‐3 housing project in Bangladesh, with an increased focus on sustainable energy solutions. Motivated by the issue of the delivery of proper and sustainable energy services to remote locations, we conducted an extensive analysis of load demand and found that an average daily demand of 46,176.65 kWh exists, with a peak load of 4852.8 kW. In this research, the HOMER software has been used to make a simulation of five different hybrid system configurations with differing mixes of renewable technologies. From the analyses, the systems based 100% on renewable resources suffer more initial capital costs, with a total net present cost increase of up to 20%, in comparison to conventional systems. On the other hand, the systems give much lower operational costs and cost of energies (COEs) of a minimum of $0.0253/kWh, reported from the on‐grid PV‐based system. On the other hand, the off‐grid PV–FC–wind turbine system showed a COE of $0.286/kWh, along with a decrease in CO2 emissions by about 15,000 kg/year, showing a 30% decrease, compared with on‐grid systems. The results form a basis for the conclusion that such hybrid renewable energy systems are both economically and environmentally feasible. They can reduce COEs by up to 70% in off‐grid systems. This proves that the quality of life and energy security in developing regions will be highly increased, supporting the goals of sustainable development. [ABSTRACT FROM AUTHOR]

This study attempted to identify the effect of optimized intake manifold geometry on the behaviors and emission level of hydrogen compressed natural gas (H2CNG) fueled engine. For this purpose, a commercial Hyundai Sonata spark ignition engine (SIE) is modified to operate with CNG and hydrogen blend. The optimal intake pipe length was predicted using an analytical acoustic method. A new intake manifold is designed and implemented utilizing natural supercharging managed by over-pressure waves acoustic propagation. Several tests are conducted on the engine using the new manifold with a speed range from 1000 to 5000 rpm. Based on various engine speeds, the variation of brake torque (BT), in-cylinder pressure, NOx and CO emissions investigated by using gasoline, CNG and hydrogen CNG blend (HCNG) fueled engines via external mixtures. The first finding of the study is that the novel geometry improves the in-cylinder pressure by 10% at 3500 rpm. However, high engine speeds show a reduction of 14% in NOx and 40% in HC while speeds below 2000 rpm reduce CO by 40%. The second finding is that the new optimized geometry serves to get rid of both the auto-ignition and the backfire for high ratio of hydrogen in the blend. [ABSTRACT FROM AUTHOR]

High‐energy demand with rapid industrialization and mechanization combined with environmental pollution due to the burning of fossil fuels has driven a shift toward renewable energy. Biogas derived from biomass is a potential renewable energy source that can be used in different sectors such as transportation sector, electricity generation, heat production, combined heat and power (CHP) systems, and fuel cells. Moreover, the upgraded biogas can be applied as transportation fuel via an internal combustion chamber (for internal combustion engine (ICE) vehicles), and electricity station (for electric vehicles). In the present work, a conceptual review of biogas‐based electrical power production systems is presented. It is clear that the conventional types of biomass contain a high amount of pollutants and unwanted constituents, which lower the lower heating value (LHV) of biogas fuel. Moreover, the energy and exergy efficiencies of biogas applications are influenced by these components. Consequently, several biogas‐upgrading technologies have been elaborated to increase the LHV of biogas fuel by removing biogas pollutants. So, the energy and exergy analyses of biogas‐driven plants are discussed in this regard. Also, the economic analysis of biogas‐fueled systems is measured through the connection between biogas production, purchased electrical power, and selling of an additional amount of biogas. Biogas represents an important source of renewable energy as shown before, and it helps in waste management and W‐to‐E (waste to energy) conversion, which allows utilizing huge amounts of wastes instead of disposal or landfill procedures. However, handling of biogas from production to utilization has an impact on the environment. Therefore, the assessment of the environmental impacts of biogas plants is presented. In addition, a combination of the biogas energy with other sources, especially renewable energy sources (eg, solar‐biogas, geothermal‐biogas, wind‐biogas, CHP, CCHP, and concentrated photovoltaic‐biogas), and reusing waste energy for other tasks (eg, employing the waste heat from a gas turbine) are examined. [ABSTRACT FROM AUTHOR]

End pumped lasers are highly efficient lasers particularly in diode lasers using micro lenses. The common cooling method for end-pumped systems is using water jacket or copper tube surrounding the laser rod. In this paper, the temperature distribution within a water jacket and a fiber laser end pumped by a top hat beam is studied analytically. The temperature distribution is obtained by considering the radial heat convection with fully developed laminar flow neglecting the axial heat conduction. The effect of laser dimensions and the Brinkman number on the temperature distribution are presented. The results indicate that the temperature distribution is strongly dependent on the Brinkman number. The results are presented in dimensionless form so that they can be applied to any end-pumped laser rod and fluid types. The main output of this work is that it is better for cooling purposes to have low Br values. [ABSTRACT FROM AUTHOR]

Recently, energy‐related CO2 emissions are considered as one of the most crucial issues and are promptly augmented due to further urbanization. In this paper, in order to model and calculate yearly CO2 emission, an artificial neural network is used. For the first time, the IWO‐SVM method has been applied in modeling energy‐related CO2 emissions. In this regard, consumption of different energy sources such as renewable energy, natural gas, coal, and oil, and GDP of the G8 countries in various years (from 1990 to 2016) are regarded as input in the present study. For the aim of evaluating the exact ability of the SVM and SVM‐IWO models, the performance of these models in three different modes is carried out on the basis of the number of data in the test and train sections. For this purpose, implementations are split into three categories (a = 80% of the data for the train section and 20% for the test section; b = 70% of the data for the train section and 30% for the test section; and c = 60% of the data for the train section and 40% for the test section). Furthermore, five scenarios were selected on the basis of the number of input parameters and input parameters for achieving the best model. As indicated in the results in all scenarios, the correlation of the model with the hybrid invasive weed algorithm based on SVM is more favorable than that in the support vector machine model, due to better training of the SVM‐IWO model than the SVM model. Moreover, the technological orientations of the G8 countries to mitigate CO2 emissions are determined through patent analysis. While the patents have essential information, investigating the published patent by a country could be helpful for determination of technological orientations. Hence, all published patents by these countries are extracted and deeply analyzed. In the next step, to find out main technological approaches, all patents and their intents have been studied. Eventually, the technological life cycles and trends of each main technology are drawn. [ABSTRACT FROM AUTHOR]