The long interruption in power supply due to the naturally occurring extreme events causes very adverse impacts on the customers and essential services. In recent years, weather-related hazards have become more severe. Thus, it is very important to incorporate resiliency as an attribute of the modern distribution system to deal with such disastrous events. The application of distributed generation (DG) and automatic line switches is drawing the attention of researchers to foster resiliency planning. However, a review summary focusing on the topical part of resiliency is still beyond the scope of the practitioners and researchers. This paper highlights a strategic review of various existing techniques toward resiliency-oriented approaches. Later, an attempt was made to summarize an analytical survey on the existing research related to the application of DGs and switches to prosper resiliency in power distribution systems. This study portrays an interesting model to enable resiliency considering DG, switches, and customer power consumption patterns during natural calamities. Further, the economic aspect of local generation employment and network power loss minimization is also embedded in the planning problem. The simulation of the proposed planning model on a standard distribution network depicts an encouraging resiliency improvement result.
Recently, coal power plants across Europe have been reopened. Alternative fuels are needed for energy autonomy purposes, for a smoother transition to the post-lignite era and for sustainable development. In this work, different categories of municipal solid wastes (MSW) and their blends with lignite were studied for their potential use as alternative fuels. Seventeen samples were studied using several techniques: gross calorific value (GCV), proximate analysis, ultimate analysis, ion chromatography, ash elemental analysis, thermogravimetric analysis, kinetic modeling and thermodynamic analysis. A determination of empirical chemical formulas was performed. Slagging/fouling potential was evaluated with various indices including modified indices that take into account ash production and GCV. Maximum emission factors were calculated and defined per produced MJ. Also, an environmental footprint index was developed regarding the environmental impact of solid wastes. The GCV experimental results were compared with those of twenty different empirical models. Moreover, several case studies were performed to evaluate the potential of covering the energy demands, with combustion of MSW, in Greece and Europe. The results showed that MSW as a primary/secondary fuel is an attractive solution considering the fact that it boasts better characteristics in comparison with lignite. Moreover, the environmental footprint index (EFIsw) of the MSW revealed a much smaller environmental impact. The high N content is not always translated to high emissions if NO is expressed per produced MJ (gNO/MJ). In addition, MSW can also be used as a significant contributor in covering energy demands regarding the energy recovery potential.
In many developing countries in the tropical region, 3-wheeler vehicles are one of the most common means of transportation for low- and middle-income people. As the 3-wheeler vehicle is small in size, open on both sides, and the engine is placed just behind the passenger seats, it becomes unbearably hot inside of the vehicle, especially during hot sunny days. The actual 3-wheeler vehicle is scaled down to 1/6th for the two prototype models, and sodium sulfate decahydrate (Na2SO4.10H2O) is used as a PCM (phase change material) on the roof in one model to reduce the indoor temperature. In open and sunlit environments with high and low ambient temperatures, single- and double-layer PCM is employed on the roof under the conditions of an open window and door as well as being enclosed with cardboard and plastic. When double-layer PCM was employed in the model enclosed by cardboard, the maximum difference between the interior and ambient temperature was 7.5 °C, whereas for single-layer PCM used in the same configuration, the maximum temperature reduction was 3.8 °C. The experimental study was further carried out on two actual (full-scale) 3-wheeler vehicles by considering 4 different scenarios. The interior temperature of the vehicle with PCM on the roof was reduced by an average of 4 °C as compared to the vehicle where no PCM was used. However, while the engine was operating and there were occupants inside the car, the PCM layer was unable to efficiently reduce the interior temperature. Additional PCM layers may be installed close to the engine to control the interior temperature.
Nitrate presence in surface and groundwater is an environmental problem because this contaminant in high concentration can cause several healthy risks to the living being. In this sense, the present article aimed to evaluate the microalga Tetradesmus obliquus as an alternative in the remediation of groundwater contaminated by nitrate, mainly. Experiments were carried out in batch and semicontinuous modes with surface and forced aeration, light intensities between 50 and 200 µmol m−2 s−1, initial nitrate concentration up to 400 mg L−1 and using synthetic and real effluent. The bioreactors were operated between 3 and 15 days. The nitrate and phosphorus removal rate for the real effluent (containing 100–150 mg L−1 of nitrate and supplemented with 20 mg L−1 of phosphorus) reached 100 and 94%, respectively. In semicontinuous mode, volumetric replacement rates (v/v) of 20, 40, 60, and 80% were tested in 3 days cycles of volumetric replacement time and obtaining, until the third cycle, stability of the process for the replacement rates of 40 and 60% (considering the maximum limits of legislation for nitrate and phosphorus and biomass production).
This work presents the development, experimental validation, and application of a control volume element model of 3D finite heat transfer method to optimize a new convective heat system for phytosanitary treatment of wood pallets. A new treatment system consisting of a heat-recovering design for exhaust gases from a distillery boiler is presented. The 3D spatial domains are discretized with hexahedral blocks to modeling and optimize the operational parameters when block-type pallets are treated. Accordingly, an energy balance is applied and the resulting system of differential equations is discretized in time domain to obtain the spatiotemporal temperature profile in the pallet block as critical geometry. The 3D model is adjusted by correlating simulated with experimental data. Overall heat transfer coefficients are obtained. Temperature and treatment time are optimized. Optimal conditions are found for the studied system with air temperature at 80 °C and 137 min treatment time. The thermal efficiency of the new treatment system is found as 9.14% and the index of energy consumption is 0.37 kWh with a cost of 0.53 € per treated pallet at the studied conditions. The economic feasibility of the new treatment system is discussed.