Showing 26 results for Type of Study: Research
Morteza Deilami, Pedram Pournaderi,
Volume 4, Issue 1 (9-2023)
Abstract
Heat transfer has an effective role in industrial and engineering applications. In this study, the effect of Al2O3 nanoparticles on laminar forced convection heat transfer flow in a tube is studied. Governing Equations are discretized using the finite difference method on a staggered grid. Nanofluid flow is simulated using single-phase and mixture models. Simulation results show that the average Nusselt Number increases with an increase in the Reynolds Number. Also, by increasing the volume fraction, the average Nusselt number and consequently the heat transfer rate increases. The results of the mixture model are in better agreement with experimental results than the single-phase model.
Dr Mohammad Sajjadnejad,
Volume 4, Issue 2 (11-2023)
Abstract
Nowadays, lithium-ion batteries have been commercialized and extensive research is done on improving their properties. The things that are currently the major part of the research are reducing the price of the battery, increasing the energy density of the battery, increasing the lifespan and improving the safety of the battery. In military applications and aviation industries, special attention is paid to battery reliability and safety. The gradual degradation of the materials used in lithium-ion batteries over a long period of time has a negative effect on the electrical performance, lifespan and safety of the battery. This is through increasing the electrical resistance of the battery and even cutting the internal connection of the battery, producing corrosion products and creating passive films on the surface of the material, creating pollutants inside the battery that may react with active materials and leading to loss of uniformity in the material enters the battery and the electrolyte is destroyed. Most of the materials used in lithium-ion batteries were modified after identifying these problems in the battery structure. This article mainly deals with the phenomenon of corrosion in positive and negative current collectors in lithium-ion batteries.
Soraya Rostami, Elahe Mansouri, Zahra Abbasi,
Volume 4, Issue 2 (11-2023)
Abstract
Biomass energy, generated from organic waste and residues produced by living organisms, is recognized as one of the most promising renewable energy resources after solar energy due to its considerable energy potential. The regulatory framework governing the development, construction, and operation of renewable power plants plays a crucial role in reducing investment risks and promoting the deployment of sustainable energy systems. This paper provides an overview of the current regulations, licensing procedures, and implementation process for biomass power plants in Iran. Furthermore, based on the existing legal and regulatory framework, a localized software package, BIO-ECO, has been developed to perform the economic assessment of biomass power plants. The software was developed as part of the research project entitled "Development of Economic Assessment Software for Solar, Biomass, and Geothermal Power Plants in Iran" conducted at the Niroo Research Institute. BIO-ECO provides a practical and localized platform for evaluating the economic feasibility of biomass power projects in accordance with Iranian regulations and administrative procedure. Thereby can support investors, developers, and decision-makers in planning and investment activities.
Dr. Alireza Khoshroo,
Volume 4, Issue 2 (11-2023)
Abstract
This study evaluates the indices of energy consumption and carbon dioxide (CO₂) emissions in sugarcane production systems of seven agro-industrial units in Khuzestan Province, Iran. For this purpose, data on agricultural input consumption and sugarcane yield were collected from selected farms and analyzed using conventional energy analysis methods. The results showed that the total input energy consumption was 123,000 MJ ha⁻¹. Among the energy inputs, nitrogen fertilizer represented the highest share of input energy consumption (26% of total energy input), followed by irrigation water, electricity, diesel fuel, and sugarcane seed cuttings. Energy use efficiency, energy productivity, specific energy, and net energy in sugarcane production were calculated as 0.76, 0.63 kg MJ⁻¹, 1.57 MJ kg⁻¹, and −29,143.16 MJ ha⁻¹, respectively. In addition, the total greenhouse gas emission was estimated to be 4,081.65 kg CO₂ eq ha⁻¹. The results indicate that the high contribution of non-renewable energy sources in the energy input of sugarcane production presents serious challenges in terms of agricultural sustainability and environmental pollution. Therefore, the adoption of appropriate management strategies aimed at reducing non-renewable energy consumption, improving input use efficiency, and promoting the use of renewable energy sources is essential for enhancing agricultural sustainability and mitigating environmental impacts in sugarcane production systems.
Hajar Moghadas, Karim Tabatabai,
Volume 4, Issue 2 (11-2023)
Abstract
The H-type cap is one of the most widely used chimney caps in heating and industrial systems. Despite its extensive application, no specific standard has yet been established for determining the optimal dimensions of this type of cap. In the present study, the effect of the H-cap and its geometric dimensions on the performance of a chimney with a diameter of 20 cm and a height of 3 m is investigated. To generate a buoyancy-driven flow of hot air, a heat source with a constant temperature of 1800 K was placed at the bottom section of the chimney. The flow is driven solely by buoyancy forces resulting from the elevated temperature of the air surrounding the heat source, which, together with the chimney draft, induces a turbulent upward flow. This turbulent flow is modeled using the standard k-ε turbulence model. Simulations were carried out for the chimney without a cap, as well as for chimneys equipped with H-caps having various diameters and brim lengths (ranging from 15 to 25 cm). The average velocity and total pressure at the chimney inlet were evaluated for all cases. The results indicate that adding an H-cap with a diameter and brim of 20 cm reduces the average velocity by approximately 2.6%. This reduction is attributed to energy losses caused by the presence of the cap along the flow path. A cap with a diameter of 15 cm and a brim of 20 cm results in a significant reduction of 26% in velocity, whereas a cap with a diameter of 25 cm and a brim of 20 cm increases the velocity by 7%. The maximum velocity was observed for the cap with both diameter and brim equal to 25 cm, while the minimum velocity corresponded to the cap with a diameter of 15 cm and a brim of 20 cm. The findings also demonstrate that, among the various geometrical parameters, the cap diameter has a more dominant influence on chimney draft performance. Furthermore, the optimal performance is achieved when the diameter and brim of the cap are equal. These results are of considerable importance for optimal design, safety improvement, and energy efficiency enhancement.
Dr. Mostafa Nejatolahi, Dr. Saeed Ghobadpouri, Mr. Ali Adnani,
Volume 5, Issue 1 (8-2024)
Abstract
The simultaneous use of a large number of air-conditioning units in hot regions has driven Iran’s summer peak electricity demand beyond the capacity of the national grid, resulting in scheduled hourly power outages in buildings and industries. In response, the government is pursuing an increase in electricity-generation capacity through the construction of new gas-fired, nuclear, and solar power plants. Alongside this supply-side approach, reducing building cooling loads can reduce electricity demand during peak hours and thereby help alleviate pressure on the grid. Wall insulation and the installation of double-glazed windows are among the most important measures for improving the thermal performance of building envelopes, as they reduce heat transfer through the envelope and, consequently, cooling loads and summer electricity demand. However, low energy tariffs reduce building owners’ economic incentive to implement these measures. Therefore, this study evaluated their effects on the energy consumption of a residential building in Gachsaran, a city in a hot climate, using actual utility bills and hourly simulation in DesignBuilder. Polystyrene insulation thicknesses ranging from 1 to 20 cm were evaluated. The 3-cm-thick insulation layer had the shortest payback period and was therefore selected for comparison with double-glazed windows. The simulation results showed that the building’s annual peak cooling load occurred at 13:00 on 4 July. At this time, both measures reduced peak electrical demand by approximately 9%. However, wall insulation reduced annual cooling electricity consumption by 9.1%, compared with 7.45% for double-glazed windows. In addition, the initial cost of insulation was 36.6% lower, while its annual financial savings were 25.3% higher than those of double-glazed windows. Furthermore, by reducing winter heating loads, wall insulation can reduce natural-gas consumption, help maintain gas supply to gas-intensive industries such as cement plants, and reduce the use of mazut in power plants.
