Size optimization of the grid-connected solar-wind hybrid system in Net Zero Energy Buildings: A case study

This study proposes a hybrid renewable energy system consisting of photovoltaic panels and a wind turbine to supply the total or part of the demand of a grid-connected residential building and presents the optimal system size using a genetic algorithm. Wind speed, solar irradiance, and electricity demand are monitored in 15 min intervals over a year. It is found that the optimal values for PV panels’ area, rated power of the wind turbine, and the tower height are 148.5 m2, 1.5 kW, and 20 m, respectively. These optimal values lead to a total system cost of EUR 42,218 over 20 years

Investigation of Distribution and Origin of Polycyclic Aromatic Hydrocarbons (PAHs) in Chalous River Surface Sediments

Polycyclic aromatic hydrocarbons (PAHs) are among the important organic pollutants in the aquatic ecosystems generally generated by natural and human processes. The purpose of this study was to determine the concentration and distribution of PAHs and the origin of these compounds in the surface sediments of the Protected Chalous River in Mazandaran Province. Sampling of surface sediments of the riverbed was performed at four stations located along the river (Darkala, first ring bridge, Chalous fountain bridge and estuary). The extraction and analysis of PAHs was performed using standard Soxhlet method in two stages: column chromatography and gas chromatography-mass spectrometry. The highest and lowest total amount of these compounds (∑PAHs) was observed in the surface sediments of the riverbed at the estuary and Darkala stations (903.8±144.30 and 51.71±19.33 ng/g) respectively. The trend of accumulation of PAHs in the surface sediments showed that the ∑PAHs concentration increased from the upstream to downstream in the river. Determining the origin of PAHs in surface sediments of the riverbed using isomeric diagnostic ratios showed that the origin of PAHs in the river was a mixture of petrogenic and pyrogenic sources with petrogenic dominance. According to the NOAA sediment quality standard, the sediments samples were in the range of moderate pollution in the studied stations, except at Darkala station, located upstream of Chalous river and had low pollution. The influx of agricultural effluents from the surrounding farms, the increase in population and vehicles in the area has led to an increase in the composition of PAHs in river sediments

Investigation of Heavy Metal Pollution in The Sediments of Salehieh Wetland, Karaj

With the entry of various effluents into aquatic ecosystems such as wetlands, pollutants containing heavy metals are deposited in the sediments. The aim of this study was to determine the level of heavy metal contamination of surface sediments in Salehieh Wetland, Karaj, Alborz Province. For this purpose, samples were taken from the sediments of six stations along with the wetland in May 2020. After preparation and chemical digestion of the samples, the concentration of heavy metals was determined by the flame atomic absorption instrument. Mean concentrations with standard deviation of lead, cadmium, nickel and chromium in wetland bed sediments were 14.11 ± 1.52, 1.14± 0.17, 19.87± 2.67 and 64.1± 7.03 µg/g, respectively and the accumulation pattern of heavy metals obtained was Cr> Ni> Pb> Cd. The highest concentration of metals was observed in station number 1. Comparison of metal concentrations with the values ​​of international standards showed that the mean concentrations of lead 14.11, cadmium 1.14 and chromium 64.1 µg/g were higher than LAL standards for lead (2), cadmium (0.04) and chromium (26 µg/g), respectively. The mean concentration of nickel was 19.87 µg/g, which is more than the HAL standard (15.9 µg/g). The amount of cadmium and chromium was higher than the ISQGS standards (0.7 and 43 µg/g for cadmium and chromium respectively). Therefore, increasing the concentration of these metals, especially cadmium and chromium, if not monitoring and controlling the discharge of effluent from the industrial town adjacent to the wetland, can lead to a threat to the health of ecosystems and the region

Size Optimization of a Grid-Connected Solar–Wind Hybrid System in Net Zero Energy Buildings: A Case Study

This study proposes a hybrid renewable energy system consisting of photovoltaic panels and a wind turbine to supply the total or part of the demand of a grid-connected residential building and presents the optimal system size using a genetic algorithm. Wind speed, solar irradiance, and electricity demand are monitored in 15 min intervals over a year. It is found that the optimal values for PV panels’ area, rated power of the wind turbine, and the tower height are 148.5 m2, 1.5 kW, and 20 m, respectively. These optimal values lead to a total system cost of EUR 42,218 over 20 years