نشریه انرژی ایران
سال بیست و ششم شماره 1 (پیاپی 98، بهار 1402)

A data center is a place where a large group of computer servers and network equipment are assembled using infrastructure and communication facilities for computing and hosting a large collection of data. In other words, the data center is the location of a large number of computer servers that perform computing, storage, and data transfer work together without interruption. The buildings of most of these centers have advanced security systems, ventilation system, fire extinguishing system and electricity distribution system, which are equipped with emergency power system [1] and diesel generator. The implementation of a data center is generally based on a large network of processing and storage resources. Since heat dissipation in rack servers is constantly increasing, it is important to properly design the air conditioning system in the data center to prevent the destruction of devices due to high heat. More than half of the energy consumption of a typical data center is spent on physical infrastructure. In this study, in order to optimize energy consumption in data centers and increase efficiency, first temperature indicators are introduced and then implemented on simulated models. At the end, the optimal model is introduced.

Nowadays, with technological advances and the increasing trend of cryptocurrency prices and its profitability, crypto mining has gained significant attention. On the other hand, since power consumption by miners is calculated based on electricity export price, their operating cost increases by the increase in foreign currency rate, which leads to less profitability of crypto mining. In this regard, using a combination of renewable power plant such as solar and small-scale power plants can reduces the operational costs and helps economic saving. In this research, simultaneous investment in solar and small-scale power plants to generate electricity demand for miner devices has been investigated. First off, a mathematical model based on the present value of capital and operational costs is presented to determine the optimal capacity of each power plant. Then, the economic feasibility has been analyzed using the net present value (NPV) method. The simultaneous construction of small-scale and solar power plants is compared with three other scenarios: construction of solar power plant, construction of small-scale power plant, and using main grid electricity. According to the obtained results, the construction of a small-scale power plant together with a solar power plant will provide the best results.

Today, combined heat and power generation systems have been taken into consideration by the developed country for residential use, due to reduced losses, high efficiency and help to network security. In order to use these systems in the country, the target market must be identified, then, by examining the economic conditions and creating incentive schemes to encourage residential customers to use these systems. For this purpose, in the present article, firstly, the most suitable province for the use of such systems was selected and then, by using the amount of electricity consumption and residential gas consumption, a comparison between the current system and the use of the mCHP system was made. According to the price Realistic economic analysis was carried out and further emissions of air pollutants were studied for both systems. The results show that Tehran province is the best province for this product market. Also, considering the current tariffs, the use of this system can return after six years, while the amount of pollutants production, and, from the current system are 60.9, 60.3, 54.7 And 100% more than mCHP. Finally, given the economic consideration and the need for countries to pay attention to reducing emissions, the use of the mCHP in conjunction with the Ministry of Energy's support policies can be implemented in our country.

The purpose of this study is to optimize the form of solar greenhouse in an energy efficient residential building in Tabriz. For this purpose, descriptive-analytical research and simulation methods have been used. In this way, the initial data is categorized and then analyzed in Design Builder software and Energy Plus engine. During the research, energy consumption in different modes: conditions of use of solar greenhouse, insulation and double glazed windows, solar greenhouse with insulation (in both natural and artificial ventilation) and the different modes of the greenhouse in terms of materials, form and dimensions together Has been compared and the optimal conditions of the system have been concluded. The result of which can be concluded by comparing different scenarios: the optimal mode of using a solar greenhouse for an energy efficient building in Tabriz climate, a rectangular greenhouse with a maximum side of 30 meters south and It is made of rock wool insulation, in which a double-glazed window with a thickness of 4 and 6 mm and argon gas is used

The solar cell parameters by combining two organic cations formamidinium (FA) and methylammonium (MA) in site A of triple-cations and double-anions perovskite absorbing layer including Br and I in site x have been investigated by simulation with SCAPS software. First, the defect density of the perovskite layer was changed from 1×1013 to 1×1017 (cm-3) and its effect on the performance of the solar cell was investigated. Then, the thickness of the perovskite absorber layer was changed from 200 to 1200 nm and for the different density of the perovskite layer defects, the manner and extent of the changes in the parameters of the solar cell were observed. In the next step, by changing the defect density of the perovskite/ETL interface from 1×1011 to 2×1013 (cm-3), the capacitor of the interface has increased which has reduced the efficiency and fill factor of the solar cell. Finally, the diffusion length of the carriers (L) has been changed from zero to about 4 μm and with its increase, the functional parameters of the solar cell have increased.

Blades and wings are based on aerodynamic surfaces called airfoils. Although airfoils are optimized for working conditions, they still have limitations in performance because they have a fixed shape and cannot meet all working conditions. In scientific references, techniques called flow control are used to expand the working area of airfoils and improve their behavior. One of the methods of controlling the flow on airfoils is the boundary layer suction method, in which the dead and energyless layer near the surface is pulled out of the fluid and the surrounding energy fluid takes its place. In this article, first, the 660 kW turbine of Vestas company was selected as a sample model, then its geometry was created, and its three-dimensional model and computational network were developed, and its results were fully simulated and validated with the experimental data of that turbine. Finally, by using the boundary layer suction method and by applying the correct amount of suction intensity, the aerodynamic performance of the rotor can be improved by 8%. Since the system is not always efficient, the system must be pumped, controlled or shut down to return to the initial configuration.