نشریه انرژی های تجدیدپذیر و نو
سال دهم شماره 2 (پیاپی 20، پاییز و زمستان 1402)

Increasing energy demand and establishing a balance between production and consumption are important challenges for grid operators. Furthermore, environmental and economic constraints prevent the solution of these problems by conventional methods like the consumption of fossil fuels and the construction of new power plants in proportion to the growth of energy consumption. The hybrid system of Compressed Air Energy Storage and Pumped Hydroelectric (CAESPH) due to advantages such as no requirements for fossil fuels and scalability can prevent the loss of excess energy by storing. Another crucial factor in utilizing this system is power generation control. Due to the novelty of the CAESPH, few studies have examined its performance in conjunction with power generation systems. In this paper, the performance of this energy storage system in the integrated state with wind farm and electricity grid was analyzed and evaluated. For this purpose, the wind data of the selected station were software-modeled, then the comprehensive software modeling system was developed and its performance was analyzed with selected parameters for a cycle. Finally, the system behavior in application with the electricity grid and wind farm under different scenarios was software simulated for one week. According to the results, the Round-trip efficiency of the system is about 49% and this amount is about 7% less in the first cycle than in the next cycles. Also found that this system has good potential for integration with wind farms and electricity grids and with proper design can provide the required power consumption without interruption.

As the main factor of countries' economic development, which are also needed by all generations. In recent years, the issue of energy supply has been one of the significant challenges, the main reason for which is dependence to the limited supply of fuel. The way to end this problem seems to optimize energy consumption and re-switch to renewable energy. In this research, a building in the new city of Andisheh is analyzed considering environmental conditions and geographical directions using Carrier air conditioning software, and its thermal and cooling loads are examined for two different compositions of external walls. After selecting the optimal mode, the building is rotated 45 degrees clockwise, which by examining eight different directions, the minimum and maximum heating load required are equal to 124502.8 and 129579.3 kcal per hour and its cooling load were equal to 53.53 and 55.44 tons of cooling, respectively. In the second step, in order to use renewable energy considering the average daily radiation of 5.2 kWh in the new city of Andisheh, the project of hot water consumption using solar energy led to savings of 18945.16 Cubic meters of natural gas per year. The economic study of this issue shows that the return on investment of solar water heaters is 11.26 years, which is not cost-effective in the current economic situation.

Hydrogen is usually used as a means of storing the energy produced from renewable energy resources. The electrolyzer, meanwhile, is a system by which hydrogen can be produced sustainably. In the present paper, a Concentrated Photovoltaic Thermal/Organic Rankine Cycle (CPVT/ORC) system coupled with a PEM electrolyzer system is simulated and evaluated. Concentrated solar radiation is used as the input energy of the coupled system. Part of this radiation is converted directly into electrical energy using the Photovoltaic (PV) panel, and the rest enters the organic Rankine cycle system as heat. The heat in the cycle is converted into mechanical power by the turbine and finally into electrical energy by the generator. The total electrical power generated by the organic Rankin panel and cycle enters the electrolyzer for producing hydrogen. A combination of MATLAB and REFPROP software was used to simulate the system performance.  The most striking result is that that the net generating power of the system is equal to 3820 watts, which is equivalent to producing 0.02072 grams per second of hydrogen and 0.0829 grams per second of oxygen.

The present study aims to propose and evaluate a new hybrid system consisting of a desiccant cooling system and earth-to-air heat exchanger (EAHE). The thermal performance of the proposed system is compared with the usual desiccant cooling system and an evaporative cooler. The analogy method is used to model a desiccant wheel. To investigate the heat transfer in EAHE and soil around it, the EAHE and soil around it are divided into several equal parts. The heat transfer problem in the solution domain is solved using resistance-capacity models. The simulations are performed for Tehran city using outdoor realistic weather data. The results reveal that in the proposed hybrid cooling system, the average temperature of the entering air a room is 1.1 and 5.3 °C lower than that of the usual desiccant cooling system and the evaporative cooler, respectively. The EAHE parametric analysis shows that by increasing the pipe length from 30 m to 50 m, the average cooling capacity of the overall system increases by 3.44%. It was also found that increasing the pipe diameter does not affect the cooling capacity significantly. Increasing the volume flow rate value from 200 to 400 cfm increases the average cooling capacity by 94.58%.

The major part of energy consumption in buildings is related to air conditioning systems. Since selection of a suitable air conditioning  system in any climatic zone has a major impact on reducing energy consumption as well as preparing thermal comfort conditions, in this study, the performance of the fan coil system with radiant chilled ceiling system with pipes embedded in concrete is compared and evaluated. In the radiant cooling system, the cooling tower is used as the sole source of cold water supply required, and since the effective operation of the cooling tower depends on environmental conditions, the performance of the cooling system in different climatic conditions has been studied. For thermal comfort assessment and performance analysis of two mentioned systems, Energy Plus software has been used. The performance of these systems has been compared in the cities of Ahvaz, Tehran and Tabriz. The cities of Ahvaz, Tehran and Tabriz represent hot and semi-humid, hot and dry, temperate and dry climates, respectively. The results show that the radiant chilled ceiling system integrated to cooling tower is capable to provide thermal comfort conditions in Tehran and Tabriz climatic conditions. Furthermore, the energy consumption of cited cooling system is significantly lower than a Fan coil system. The simulation results confirmed that the radiant cooling consumed 50-65% less energy in comparison to a benchmark fan coil system in Tabriz and Tehran, respectively.

Providing electrical, thermal and cooling energy in greenhouses is a very important issue. Due to the low efficiency of most of the conventional systems in greenhouses, the use of simultaneous production of electricity, heat and cooling (CCHP) systems has been highly considered in recent years. The main purpose of this article is the technical and economic feasibility of CCHP technology for use in a greenhouse in Tehran. In this research, a cucumber greenhouse with an area of 1 hectare, which consists of two structures of 0.5 hectare, has been analyzed and investigated. In order to analyze the technical-economic system used, calculations for four scenarios including the basic and conventional system, CCHP with absorption chiller and selling electricity to the grid, CCHP with absorption chiller and self-supply and CCHP with compression chiller and self-supply accepted. According to the results obtained for each scenario as well as the comparison of the selected scenarios, the greenhouse considered for the implementation of the CCHP system is not economical. The results of the research show that in case of using the CCHP system with absorption chiller and selling electricity to the grid, in order to make the system economical, the minimum rate of buying electricity from these units should be 3223 Rials per kilowatt hour. In the CCHP system with absorption chiller and self-supply, if the location of the greenhouse is such that 176 kilometers of transmission line is needed, this scenario becomes economical.

Given the global price of oil and the constraints on energy production from fossil fuels, the use of clean and renewable energy has attracted much attention recently. Among renewable energy sources, energy generation by photovoltaic systems is a very attractive option for energy production due to unlimited solar energy and radiation potential. Photovoltaic systems are usually installed in arid and semi-arid areas, and these areas face the problem of dust deposition. This issue becomes important when studies show that photovoltaic systems are strongly influenced by natural factors, and these natural factors have an impressive impact on the performance and efficiency of these systems. To maintain the efficiency of photovoltaic systems, it is necessary to remove dust and choose an appropriate cleaning method. In this study, some of the purification methods studied have their characteristics and disadvantages identified. Also, in this study, an automated method called automatic water purification method according to the studies performed, will bring promising results. The proposed method for a 20kW power plant belonging to Zabol University will also be reviewed. Models for the application of this method in agriculture were studied and the studied model makes the use of photovoltaic systems in agriculture more attractive. This study can give a good indication to the users of small and medium power plants to choose the best Cleaning method.

Nowadays, the use of smart home appliances has made home energy management more advanced and sophisticated, so determining the optimal timing of home appliances is necessary to define the optimization problem and choose a suitable solution to achieve the necessary benefits for residential consumers. It also helped electricity suppliers by reducing energy consumption. Unlike hybrid electric vehicle (HEV) batteries, which can only charge with an electric motor plug-in hybrid electric vehicle (PHEV) can charged via a mains connection. To optimize the economics of PHEVs, it is necessary to determine an energy management strategy to coordinate the distribution of power between several energy sources. In this paper, after expressing the generalities and background of the subject, the modeling method and the formulation and problem-solving method for determining the optimal energy management strategy in smart power grids with the presence of connectable electric vehicles reviewed. The cost of electricity consumption in a micro grid including a smart home presented and the multi-objective water cycle optimization (MOWCA) method used to solve the resulting optimization problem. The simulation results show that the use of renewable energy sources, battery storage, and electric vehicles by then proposed method increases consumer benefit.

So far, no scientific study has been conducted on the impact of economic openness on energy efficiency in selection of developing countries. In this research, the impact of economic openness on energy efficiency in selection of developing countries has been investigated. In this regard, the present article has answered the question of what is the effect of openness of the economy on energy efficiency. By removing countries with incomplete information, the sample is selected for 24 countries out of a total of 87 developing countries. The data and variables related to the sample in this study are annual and due to the lack of data before 2013 and after 2020, the statistical data used in the period (2013to2020) are included. The econometric method used in this study the Generalized Method of Moments (GMM).The results of the study showed that the trade openness index has a positive effect on energy efficiency and has the greatest impact on other variables of the model. Also, inflation rate, natural resource rent, and population growth rate have a negative effect and variable the education index also has a positive effect on energy efficiency, which is in accordance with the theoretical foundations of the research.

Due to the absence of pollution and the availability of sunlight in different parts of the globe and tropical regions, the production of electrical energy through solar radiation has received much attention from researchers. In this research, first, the trend of increasing the share of renewable energies, including solar energy, in the production of electrical energy in the world has been investigated. Then, while analyzing the potential of Iran and the city of Birjand for the construction of photovoltaic power plants, its components and technical considerations have been taken into consideration. In the following, the future options for using the photovoltaic power plant in the Kavirtire factory located in Birjand city are examined, in the following, the technical and economic model for the construction of a 10MW photovoltaic power plant to supply the electricity required by the Kavirtire factory by RETscreen software is designed and developed. Then, considering the existing assumptions, the economic analysis of the project is done in the usual ways, and the results of the economic analysis indicate that according to the calculated internal rate of return and the positive balance of the net present value, the present project is financially It is completely justifiable and the risk of the investment return time of the project is equal to 7.3 years and the return time of the investor is 8.4 years and the project risk is 10%.

The three low Reynolds number airfoils, NACA0015, NACA0018, and NACA0021, were examined. First, CFD and experimental testing were done in the wind tunnel using the numerical Vortex-Blade method, and it was used for the panel method of the KW-SST model. The findings demonstrated that the Reynolds numbers are more affected by airfoils when there are two airfoils present, as opposed to when there are more than two. The segmentation coefficient has been used to remove the tip radius and lift coefficient in the angle of attack less and less than other methods, according to comparison and results that showed that the method of vortex shedding and lift coefficient ratios in angle of attack between 10º and 18º in the laboratory were analyzed. In the attack angle of 10° and CFD model with a 1.8 and 2.3% error rate, increasing the attack angle of the CFD model, and Fortran at an attack angle of 18° with the 4 and 5.2% Fortran model and at the top of the CFD model for the analysis.

The use of batteries is widespread in the industry, but they have various disadvantages, and in some applications, the need for less weight or volume, higher power density or a better response to transient events is felt. Due to the practical problems of batteries and with the advancement of technology, especially in materials science, supercapacitors were introduced. Supercapacitors are advanced high-capacity electrical energy storage devices in relatively small volumes. A supercapacitor consists of two thin, high-level electrodes (plates) separated by a dielectric, providing a high energy storage density. In addition, supercapacitors have advantages over other energy storage technologies such as less carbon footprint as well as lower cost of ownership and maintenance. Applications of supercapacitors can be to provide temporary load until the backup generator is fully offline and thus reduce the need for fossil fuel generators, oscillation and stabilization of frequency changes in power systems, smoothing solar and wind energy, support Short-term and reduce the risk of breakdown in important facilities and thus improve the quality of electricity supply. Supercapacitors are used in a wide range of applications, from the power grid to the transportation sector. This article provides an overview of supercapacitors, including concepts, applications, features, advantages, and limitations. Then, their applications in different sectors of the industry, including use in the power grid and microgrid, especially their benefits in combination with renewable energy and transportation systems, are discussed. Moreover, some examples of universal implementation of supercapacitors and the benefits obtained will be explained.

Environmental concerns and the scarcity of fossil fuels have led to the rapid development of rechargeable battery technologies. It has been proven that the performance of lithium-ion batteries is susceptible to temperature, and temperature significantly affects the capacity and power of batteries. Therefore, it is necessary to build an efficient battery thermal management system to maintain the battery's operating temperature in a safe range. Utilizing PCM.s can be an exciting option in thermal management systems of lithium-ion batteries, and several studies have been conducted about them. The biggest challenge in PCM-based BTMS systems is to overcome the problems related to the poor thermal conductivity of PCMs. Many researchers in this field proposed different types of metal fins (pinned fins, circular fins, longitudinal fins, and triangular fins), metal foams (aluminum, copper, and nickel foam), metal meshes, and carbon-based nanomaterials to increase the thermal conductivity in PCM-based BTMS systems. Some proposed carbon-based composite nanomaterials are expanded graphite, carbon nanotubes, and carbon fiber. In this article, recent developments and new methods of thermal management and performance optimization of lithium-ion batteries have been reviewed.

Nowadays, wind energy is considered one of the cleanest sources of energy, and the capacity of wind power plants is growing around the world. In particular, the design and construction of small wind turbines have been the subject of much research. This article deals with the Savonius wind turbine, a well-known vertical axis turbine. First, the mechanical principles of operation of this type of wind turbine are explained. Then, the criteria for determining its efficiency and performance, such as power and torque coefficients, are stated. The sequel discusses the geometric and technical factors affecting its efficiency. These factors include the overlap ratio, number of blades, number of stages, twist angle, shaft diameter, and the installation of end plates. The current paper can be helpful for those trying to improve the performance of this type of turbine. In this regard, there are some proposed innovative designs to enhance the performance of the Savonius turbine concerning experimental results and their numerical simulations. These designs increase the maximum power coefficient to 38%, although they complicate the turbine structure. Some of these innovative designs are also reviewed.

With the increase in energy consumption and wastes generation due to human activities, anaerobic digestion (AD), a technology which turns wastes into bio-energy, is receiving more and more attention in the world. Biogas is renewable, clean and relatively mature energy, but most biogas commercial plants still need significant financial incentives. In addition, a shortage of locally available, cheaper and digestible materials reduces biogas productivity, especially for large biogas plants (larger than 1 MWat). Therefore, innovations that can improve the cost and efficiency of biogas energy technology resources are needed. Over the past few years, a number of potentially innovative processes for biogas technology have been proposed and explored. However, most of these new concepts have had little impact on technology development. Therefore, it is necessary to review the reports that compare, analyze and evaluate the appropriateness of these methods and the technological superiority and real commercialization potential. This article reviews the latest innovations and articles related to biogas production. It also provides ideas for new innovations by identifying future research needs.