Iranica Journal of Energy & Environment
Volume:12 Issue: 3, Summer 2021

In the present paper, the use of radiating gas instead of air inside the cavity of compound parabolic collectors (CPSs) is suggested and verified by numerical analysis. The collector under study has a simple cone shape with flat absorber which is filled with a participating gas such as carbon dioxide instead of air for the purpose of increasing the thermal performance. In numerical simulation, the continuity, momentum and energy equations for the steady natural convection laminar gas flow in the CPC’s cavity and the conduction equation for glass cover and absorber plate were solved by the finite element method (FEM) using the COMSOL multi-physics. Because of the radiative term in the gas energy equation, the intensity of radiation in participating gas flow should be computed. Toward this end, the radiative transfer equation (RTE) was solved by the discrete ordinate method (DOM), considering both diffuse and collimated radiations. The  approximation was employed in calculation of the diffuse part of radiation. It was observed that the gas radiation causes high temperature with more uniform distribution inside the cavity of collector. Also, numerical results reveal more than 3% increase in the rate of heat transfer from absorber surface into working fluid and hence a desired performance for the collector because of the gas radiation effect.  Comparison between the present numerical results with theoretical and experimental data reported in the literature showed good consistency.

The Polyester synthetic fiber (PSF) industry has recycled Polyethylene Terephthalate (PET) bottle into raw material and converted them into economically valuable textile materials. This study was aimed to provide an overview of wastewater treatment from PSF industry in minimizing its impact on the environment. The study of wastewater treatment from PSF industry has been carried out in chemical-physical treatment. The Jar Test experiment has been conducted with coagulant and flocculant addition into 1,000 mL of wastewater inside a 1 L beaker glass. Wastewater was treated with 3 coagulants and flocculant doses variation with range of PAC 175-225 mg/L and PE 0.25 mg / L. The results showed that the dose utilization of 200 mg/L of 5% Poly Aluminum Chloride (PAC) coagulant solution and 0.25 mg/L dose of 0.02% Poly Electrolyte (PE) flocculant solution could produce a treated wastewater that has complied with the effluent quality standards. The application of this optimum dose can reduce wastewater pollutants subtances of PSF industry which can minimize its impact on the environment.

As COVID-19 has propagated well-known, governments have taken nationwide moderation to restrain it, from regulations to moves toward off the economization as a whole. Know-how its outcome is imperative to help larger policies for nations that are not but preponderant or in the outcome of a succeeding epidemic. Here we demonstrated that the aggregated conquest in electricity decay in the five-month sequential homestay management became among 3% and 12% in most affected European and Asia countries; besides, Florida, which has not proven any continuous variation. For the reason that Italy, France, Spain, China, and India got greater fundamental damage through the limit of July, especially Britain and Germany are under the baseline. We also showed that the connection between severity and the curtailment of covid-19 based electricity decay is not linear. Those findings showed the extremity of the disaster in different nations and could further look at the upcoming, similar global crisis.

In this research work, the effect of rice husk ash (RHA) along with and without superplasticizer (SP) on the properties of concrete was investigated. The good workability and compaction is key parameter for strength and durability of concrete, and it may achieved by adding SP in to the concrete.  In India RHA is available in huge quantity. It is byproduct of agriculture. In present research ordinary portland cement (OPC) was replaced by 10 to 50% RHA. The fresh properties as workability and hardened properties of concrete as compressive strength were examined. For durability test water absorption, acid attack and sulphate attack tests were conducted.The test results show that at 10%RHA with SP the maximum strength of concrete was attained with respect to control concrete mix (CM). The satisfactory test results were shown for durability and strength. Such kind of blend concrete is more efficient to enhance the properties of concrete which reduce the consumption of cement. The utilization of agricultural byproduct makes concrete sustainable and reduce environmental problems.

In this study, a mathematical model was used to predict the dynamic behaviour of the system under conditions of imperfect mixing in an Anaerobic Digestion (AD) process. To evaluate the system performance, the effect of mixing parameters by calculating the quantities of methane gas produced, system power, and effluent quality was investigated. Numerical results showed that with an increase in the mixing rate (α) by 20%, methane production rate, power production, and the effluent COD removal efficiency of the system increased by 19%, 19% and 12%, respectively. At an equal mixing rate, the amount of methane produced in influent with a concentration of 12.1% was 4.5 times higher than the influent with a concentration of 2.5%, while no significant change was observed in the effluent quality. Additionally, it was found that the mixing rate effect is more important than the mean cell retention time in the anaerobic reactor. The best fitted correlations for methane production rate and effluent COD removal efficiency using regression analogy at different organic loads of wastewater are presented.

Water systems such as pipelines, pumping stations and other channels in horizontal flow have the potential as pico scale hydropower. This study aims to observe the effect of the number of blades and the blade angle on the electric power generation in the small bulb turbine on horizontal flow. This study also observes how the number of blades and blade angle affected the electrical power generated using analysis of variance. The level on the parameter number of blades used was 4, 5, 6, and 7 blades, while the level parameters on the blade angle were 15, 20, 25, and 30 degrees and each level was tested 4 replication at the discharge of 13 L/s. This paper shows the results of turbine performance in the form of angular velocity, electric power, efficiency, and the test results of the analysis of variance using SPSS 17 software. The results of the study show the number of blades 5 with a 20 degree blade angle of the best performance compared another the number of blades and the blade angle with an efficiency of about 50%. The results of the analysis of variance show the blade angle of the blade has a more dominant effect on electrical power than the number of blades.

Iranian vernacular architecture has rich experiences in terms of coordinating with its surroundings. although, high energy consumption was one of the major concerns in the past decades. According to statistics presented by Iranian Statistics Center, 40% of the country's energy consumption is relevant to the construction industry. However, about 70% of consumption is used solely for space heating and cooling. In the meantime, windows have a significant influence on the thermal performance. Ganjei-Zade House in Tabriz is one of the monuments and includes two parts. The north side of Qajar era and the western side was added to the former building in Pahlavi era. The present article deals with the study of the evolution of windows from Qajar to Pahlavi in Ganjei-zade house and the amount of heat dissipation from windows. These evaluations has been carried out by simulating Ganjei-zade house in the DesignBuilder software. The research related to this article was conducted based on analytic and comparative method and the purpose is to provide the important criteria for windows in residential buildings in the cold climate of Tabriz considering native architecture solutions in order to reduce heat dissipation. The conducted calculations confirm that the amount of heat losses from windows from Qajar to Pahlavi era, has been reduced by 22.2% and the amount of heat dissipation per square meter of windows from Qajar period to Pahlavi was decreased by 58.33%.

Due to the increasing use of concrete, researchers and engineers are constantly tried to improve its mechanical and physical properties as well as its efficiency. Hence, they have made use of the most diverse products and the most modern concere technologies. In the present study, oak bark ash and macro fly ash have been used as the most widely used pozzolans in the concrete industry. The parameters of concrete and the percentages of materials used in its structure remained constant, but different percentages of oak bark ash and macro fly ash have been added to the mix design. Brazilian method and bending strength of concrete was applied. The parameters of concrete density, concrete consistency, compressive strength, and tensile strength have been investigated..Therefore, the existing materials required necessary tests; based on obtained resulted, an optimal design for the concrete mix was introduced from which the necessary specimens were taken into consideration. Then, oak bark ash was used as an additive, in proportions of 0.2 and 0.4% by the total weight of cement, and macro fly ash was used to replace cement as a variable in various proportions of 5, 10, 15 and 20% by total weight of cement. Based on the existing variables and the control design, a total of 15 groups of mix designs were introduced. The statistical population includes 45 cubic specimens (15×15×15), and 45 cylindrical specimens (15×30) for tensile strength test using Brazilian method. Also 45 bending beam specimens having dimensions of 10×10×50 were examined. Finally, after analysis of the obtained results, we dentified the superior mix design had the best performance and that both additives affected all studied parameters, including concrete consistency, density, compressive strength, tensile strength, and bending strength of concrete. However, macro fly ash had a great effect on the conrete strength. The obtained results also indicated that excessive use of any additive could have adverse effects on the mechanical properties of the concrete.

Today, most industries use statistical quality control tools to improve quality and reduce the defective products and waste, but the high volume of data requires the help of a powerful tool to control processes. One of the objectives of the present study is to predict defective products and prevent their production using data mining tools due to the high power in data analysis and its predictive nature, which is less used in the industry. In this study, the statistical population of all parts produced in 2017 by Shabrun Company. The statistical sample is 2400 pieces of radiators that were randomly selected from the production line. In the operational phases of data mining, three decision tree algorithms were used: C&R Tree, Quest Tree and Chaid Tree. Using these algorithms, the most important criteria affecting quality control and rules leading to the quality of parts were determined. Comparative results showed that despite the validity of all three algorithms, the C&R Tree algorithm had the highest accuracy. Adherence to the rules resulting from the implementation of these algorithms has led to the detection and prevention of waste generation, which has increased efficiency and prevented the loss of time and cost in this production unit.

A building envelope plays a key role in controlling the internal environmental conditions. The evaluation of façade designs for naturally ventilated residential buildings in the temperate and humid climate of Iran was carried out to optimize façade design for energy saving. Firstly, the common types of building materials were identified through a field study. In the next step, a computer simulation was conducted to investigate the impact of façade design parameters, including U- values, window to wall ratio (WWR), the open able part of the window, and the length of shading devices on buildings energy consumption. The simulation results indicate that the building envelopes constructed with Lightweight Steel Framed (LSF), 3D Panels, and Autoclaved Aerated Concrete (AAC) blocks are more effective than the other investigated materials, for reducing heating and cooling loads of the building. Using these materials can reduce the energy consumption for heating and cooling by 45%. Large and unprotected windows increase the building energy demands and require additional control devices. Therefore, 25%WWR, with 300mm horizontal shading devices in four steps, light opaque internal curtains, and windows with low emission glass parts that are closed during noon and afternoon hot hours were suggested and analyzed for the studied climate.

Alkaline proteases are the most important groups of commercial enzymes, which have been broadly used in industrial processes. In this study, Bacillus sp. PTCC 1538 was selected as a biological agent to produce alkaline protease. Enzyme production under submerge fermentation using industrial waste effluent was investigated. Since the costs of the raw material plays an important role in the cost of enzyme production, corn steep liquor (CSL) was selected as a low-cost substrate to reduce the cost of enzyme production. Various carbon sources were used as the auxiliary substrates to enhance enzyme production. Results showed that maximum enzyme activity was obtained when wheat bran was used as an auxiliary substrate. Optimal media composition and growth conditions for alkaline protease production were defined. The optimum conditions were found to be pH 8, incubation temperature of 37 °C, CSL inoculum size of 5 v/v %, yeast extract and wheat bran concentrations of 2 and 6 g/l, respectively. CaCl2 was used as an activator to enhance proteolytic activity of the enzyme. Under optimum condition, enzyme activity of 100.7 U/ml was obtained at CaCl2 concentration of 1.5 g/l.