نشریه انرژی های تجدیدپذیر و نو
سال یازدهم شماره 1 (پیاپی 21، بهار و تابستان 1403)

The use of water electrolysis to produce hydrogen gas has received much attention in recent years, because in this method, water is decomposed into hydrogen and oxygen gas without any pollution. In this research, an organic Rankine cycle (ORC) is simulated and analyzed to utilize waste heat to run an electrolyzer. The power generated by ORC is used to produce hydrogen gas in proton exchange membrane electrolyzer (PEME). Model and codes for the electrolyzer is done by EES software, and thermodynamic analyzes are utilized in order to examine the performance of the proposed model. For the evaporator temperature of 67 ℃, the ORC power and thermal efficiency are obtained at 220 kW and 8.5 %, respectively. The production capacity of the electrolyzer considered in this research is 27 kg per hour of hydrogen gas with a temperature of 80 ℃ and a pressure of 101 kPa. Water electrolysis is performed using direct current between two electrodes, anode and cathode, which are separated by a membrane. To validate the simulated model, membrane potential at different values of current density is calculated.

Today, the use of integrated (hybrid) energy supply systems due to the reduction of electrical and thermal losses, better control of distributed generation sources to better feed the system loads, reduce the emission of environmental pollutants and increase the reliability of load supply even in the event of failure , Is on the rise. In this research, an optimal and economical method to design a hybrid energy supply system based on CHP sources and photovoltaic sources to combined heat and power required by consumers, taking into account various costs such as initial investment cost, operating cost, Fuel costs, maintenance costs and various technical constraints such as production limitations of each source, power exchange with the upstream network and maintaining power balance are presented. Inheritance (genetic) algorithm has been used to solve the resulting optimization problem due to its good ability to solve complex problems with a large number of variables. The results show that in designing the system to supply electricity and heat, the system connected to the grid requires lower operating costs than the other two modes and the possibility of exchanging power with the upstream network due to the purchase of electrical power required from The network significantly reduces system costs in the event of a shortage of photovoltaic panels and the sale of power to the grid during off-peak hours and overproduction, as well as during peak hours of the upstream grid, where electricity prices are higher.

Clean energy is currently one of the most important needs of mankind. So Iran is looking for clean energy, as one of the participating members in international climate change protocols. Therefore, the required wind speed for use in small domestic turbines was investigated in the northwest of Iran (East-West Azarbaijan, Ardabil, Zanjan provinces). One of the ways to produce clean energy is using of small wind turbines for the energy consumption of households. In this project, the climatic data of wind speed of NASA and the synoptic stations of the northwest of the country were studied in the period from 2010 to 2022. MERRA model data was obtained from NASA's GIOVANNI website and the analysis of these data were done in GIS program. Also, the wind speed data was obtained from the synoptic stations in the northwest of the country from the Meteorological Organization was analyzed and investigated. The required wind speed of small wind turbines was calculated by drawing tables and graphs. The wind speed was calculated 5 to 15 meters per second and at the height of 8, 10, 15, 25, 35, 40, 50 meters. Furthermore, it was calculated by existing mathematical relationships. Also very suitable, suitable and unsuitable places for installing small turbines were identified in terms of wind speed. Of course, the proper use of small turbines requires long-term studies of 30 to 50 years.

Due to the increasing environmental pollution and the reduction of fossil fuel resources, the choice of a suitable alternative for non-renewable fuels has been given much attention. Among several alternative fuels, biodiesel is also clean and is produced from renewable sources. In this work, the mathematical modelling and optimization of the catalytic transesterification process for producing soybean oil biodiesel by MATLAB software and differential evolution algorithm has been investigated. The potassium hydroxide was selected as a homogenous catalyst for transesterification reactions in a batch reactor. Based on the experimental data, a model has been proposed to predict the biodiesel production in the catalyst concentration range of (0.4-1wt%), methanol to oil molar ratio range of (5-12) and temperature range of (25-65 °C). In addition, the unknown kinetic parameters of this model have been calculated. There was a good consistency between the model and experimental data. The modeling results showed that there is a relationship between biodiesel yield and effective parameters (temperature, oil to alcohol molar ratio and catalyst concentration). By increasing the temperature and oil to alcohol molar ratio and decreasing the catalyst concentration, the yield of biodiesel increases. Finally, the model was assisted to find the optimal conditions of transesterification reaction to maximize biodiesel yield. In the optimal conditions (catalyst concentration of 0.4501 wt%, molar ratio of methanol to oil of 15 and temperature of 70°C) the biodiesel yield reached 96.87%.

The fixed pricing of selling solar electricity in the geographical area of Iran, regardless of the country's different climatic and solar conditions, leads to a reduction in production incentives. According to the atlas of the average annual solar radiation (photovoltaic), the central provinces of the country are classified into 10 groups. The base group of price correction is selected using statistical models of mode and median. Cities of Ahvaz, Bandar Abbas, Bushehr, Bojnoord, Urmia, Ardabil, Gorgan, Sari and Rasht which are among less sunshine Ing groups are using about 46% of household electricity consumption. In order to match between electricity production and consumption in different locations concerning sustainable development approach, instead of increasing the production of fossil electricity and/or increasing the length of transmission lines we can use the different purchasing price policy (price discrimination policy).According with the results of this research the level or the Internal Rate of Returnof the base group (33.15 percent), we can set the new guaranteed rates for Gilan, Mazandaran, Golestan, Ardabil, North Khorasan, West Azerbaijan, Khuzestan, Hormozgan and Bushehr as 67, 50, 36, 25, 15, 15, 7, 7, and 7 percent,respectively. Zahedan, with an internal rate of return of 36.24 and a 4-year net return on normal capital, is the most capable city in Iran in the economic evaluation of photovoltaic electricity.

The growth of population, industry, and energy consumption in recent years has led to environmental problems and energy crises which are unprecedented in the life of the earth. Considering the high share of buildings in energy consumption, it is important to reduce the energy consumption of buildings and benefit from clean energy sources. Therefore, by knowing the methods of energy saving and clean sources of energy and examining their performance, an important step can be taken in the direction of sustainable development. With this aim, in the present research, the technical, environmental, and economic performance of the solar photovoltaic-thermal system for heating the building of a 24-class school was investigated by simulation in the software. The results showed that the photovoltaic-thermal system with an efficiency of more than 50% has the possibility of providing 41.1 MWh of thermal energy in the cold months of the year for the school building, which in some cases will be even more than the consumption requirement. The thermal energy provided by this clean system will reduce the production and emission of more than 9 tons of air pollutants. This system has the possibility of producing 73 MWh of electrical energy at the same time as providing thermal energy. The thermal and electrical power of the system can prevent the production and release of more than 53 tons of air pollutants yearly.

Nowadays, due to the fact that people spend a significant percentage of the day hours in closed environments, providing quality natural light in these spaces will be essential. On the other hand, one of the important challenges of direct light entering space is the issue of glare, which requires fundamental considerations. The current research is trying to use the western front for natural light by providing solutions to create visual comfort. The basic question is: To what extent is the water wall in the west wall effective in improving visual comfort conditions from the perspective of glare? To what extent is the fluid color between the wall and the dimensions of the water wall effective in reducing glare? Following the steps of the research, by simulating the basic model in "Rhino" software, specifying the values of variables and entering data in "Grasshopper" software, and using "Ladybug" and "Honey Bee" plugins, the results are obtained. It has been compared in a comparative way. On the other hand, there is a direct relationship between the reduction of glare despite the fluid pigment and the reduction of the dimensions of the water wall. The results indicate that the water wall with 0.36 units, the water wall with blue color with 0.32 units, and the water wall with the same area of the window with 0.3 units have had a significant decrease.

Nowadays, the rapidly growing energy consumption in the world along with the shortage of ‎‎fossil ‎‎fuels and their high ‎environmental pollution has led to increased attention to renewable ‎‎energies such ‎as solar, wind, and geothermal ‎energies. ‎Among these, solar energy has many ‎advantages such as no ‎ecological and ‎noise ‎pollution and free use. ‎However, photovoltaic power ‎plant output, due to its ‎dependency on solar irradiance and other weather ‎‎conditions, has ‎‎uncontrollable uncertainty. ‎Therefore, for providing high-quality electric energy for ‎end-consumers and enhancing the ‎reliability of ‎the system, photovoltaic power output needs to be predicted ‎‎accurately. The aim of this paper is to ‎‎address this issue ‎by proposing three short-term photovoltaic power-forecasting models based on ‎deep-learning neural ‎‎networks, which differ in terms of input types and network structures. The proposed ‎models use ‎long short-term ‎memory (LSTM) in their structures and historical power outputs and ‎weather conditions as their ‎inputs to forecast one-‎hour-ahead PV power. ‎Conducted experiments show ‎that employing weather ‎conditions, in addition to ‎the historical ‎‎output powers, increases the prediction ‎accuracy. Moreover, ‎utilizing more complicated ‎network ‎structures leads to ‎performance improvements.‎

Increasing concern about the reduction of fossil fuel resources in today's societies has led to a greater tendency towards renewable energies. Therefore, solar energy is the most available renewable source. Most of the solar cells do not have the optimal efficiency. The most effective solution to solve this problem is to increase the efficiency of solar modules by combining them with other systems. One of these systems is the two-shell facade. By combining this system with solar panels, a new technology called photovoltaic systems integrated with the facade of the two building shells is introduced. The purpose of this research is to analyze several types of photovoltaic systems integrated with the facade of two building shells to observe its effect on the air conditioning load of the building and to optimize the parameters involved in this system for a hot and semi-arid climate. The results show that the temperature inside the building using the two-shell facade is two degrees Celsius lower than the simple case on average every month due to the greater heat transfer of the two-shell facade. The amount of cooling consumed inside the building is lower in the case of using the two-shell facade than in the simple case. In the summer, due to the intensity of solar radiation suitable for the city of Tehran and the lighting of the facade of two skins, the temperature inside the building rises and the need for more cooling is needed for proper air conditioning inside the building.

Natural gas has been suggested in the literature as a bridge fuel to reduce near term carbon dioxide emissions. The present study investigates the direct and indirect effects of fuel-switching toward natural gas. An energy supply model named MESSAGEix is used along with transportation demand regression equations. The MESSAGEix energy supply model is based on the reference energy system and can assess the energy life cycle effects of switching between energy carriers. The framework is used to estimate the direct and indirect effects of switching from gasoline to compressed natural gas in the light duty transportation sector of Iran. The relative price of gasoline to natural gas is changed by 20% and 73% in two scenarios. Results show that the greenhouse gas emission effects act through five main channels: direct gasoline and gas substitution effect, income effect, upstream gas and upstream oil and energy supply system costs. The greenhouse gas emission is reduced due to the direct and indirect effects by around 2100 and 5100 gigagram carbon dioxide equivalent in scenarios 1 and 2 of relative price change. The total energy system costs also decrease by 0.3% and 1.3% respectively.

The importance of innovation and technology development and understanding the complexities of these processes have led numerous researchers to present and develop different theories during the recent years. One of the pervasive and successful theories of the past years in the field of innovation and technology studies is the approach of innovation systems. The shortcomings and weaknesses of the innovation system approach and its inadequacy in analyzing the complexity of the innovation process and technology development became one of the drivers for presenting the theory of innovation ecosystems. Despite the number of studies, in none of the presented articles, a specific technological innovation system was criticized from an ecosystem perspective. In this study, the photovoltaic TIS of Iran is criticized from an ecosystem perspective by using governance changes of innovation ecosystems. According to the results of this study, the approach of the TIS does not provide effective policies to overcome the challenges in innovation systems due to its detailed and linear view of technology development. Also, the approach of TIS does not pay attention to the co-creation of value and the evolution and co-evolution of actors and the innovation system, and it does not pay attention to the diversity of actors and the relationship between them. The one-dimensional view of TIS does not have the ability to monitor the monocentricity or polycentricity of the innovation system and the functional redundancy of the system, and with insufficient indicators, it makes mistakes in identifying the development stage of the system.

The proportions of light-wells that are specified in the Code four of the National Building Regulations of Iran are determined only for one-floor to four-floor buildings. These proportions are based on land area and number of floors. Furthermore, the determination of the proportions of buildings with more than four floors up to 23 meters is dedicated to the decision of the architectural designer. The purpose of this study is to determine the light-well's proportion for a five-floor residential building so as to have the required lighting in close spaces next to the light-wells. First, the performance of the given proportions in the Code Four for four-floor buildings was studied. Second, various proportions of light-well were examined for a four-floor and a five-floor building. In every stage, the results were compared with the standards of lighting. The lighting process was carried out by using Grasshopper, Honeybee, and Ladybug plugins. These plugins use Radiance and Daysim engines for calculation. Also, this study was carried out using the Spatial Daylight Autonomy and under real sky conditions. The results show that the given proportion in Code Four does not meet the lighting's requirement. The required proportion of the light-well for a four-floor building is 5.5 × 6.5 m. Besides, the required proportion of the light-well for a five-floor building is 6 × 7 m.

Due to the environmental problems associated with fossil fuels and increasing energy needs, renewable wind energy will play a vital role in changing the future energy structure in Iran and the world, so the evaluation of wind resources plays an important role in exploiting this resource. In this research, wind information of the Karun region, with three-hour time intervals recorded in the eleven-year period (2010-2010), has been used in three stations in the south, northeast, and northwest of the city. In order to conduct this research, the wind energy potential in the region was evaluated with the aim of identifying the most suitable points for the installation of wind turbines, using the Weibull distribution function, and calculating the wind speed and density on a monthly and annual average. The annual windflowers of the stations in the study area were also plotted by processing the data of the mentioned statistical period using the WRPLOT software. The results showed that the stations in the south and northwest of the city at an altitude of 100 meters above the ground with an average annual speed of 4.04 and 7.08 meters per second and wind power density of 212 and 215 watts per square meter, respectively, have better talent and potential.

The world's energy system is in a transition phase, one of its main features is the emphasis on renewable energies. In Iran, despite the significant potential in the field of wind and solar power plants, there is a significant gap between the installed renewable capacities and the goals of policy documents. In this article, using grounded theory analysis, intervention and contextual conditions of the renewable have been investigated. Among the intervening conditions, we can mention the increase in the exchange rate, sanctions and reduction of foreign investment in the country, centralized management and subsidized atmosphere ruling the electricity industry, the financial situation of the Ministry of Energy.The contextual conditions include the lack of agreement on why and how to develop renewable energy in the country, the government's partial view of the energy sector instead of the national view, the lack of access Investors to low-cost financial resources, a supportive atmosphere in favor of the fossil sector, and failure of financial models in the field of renewable energy, the lack of a clear strategy in the field of renewable equipment manufacturing, and inappropriate culture. According to the aforementioned cases, the effectiveness of policies which are approved in the field of renewable energy has significantly declined. This will be the result of the small capacity of power plants, the lack of proper diversity in the country's energy portfolio, the lack of role of renewable energy in the country's energy supply, and social distrust towards participation in this field.

Over the world, advancements in the design of wind turbines with augmentation are being made with the aim of producing electricity nearby users in built-up regions. By reducing the distance between the consumer and the power source, this is certain to aid in lowering the burden on the power generation system as well as the costs associated with the distribution and transmission network. By maximizing the upstream wind striking on the rotor blades, the major goals driving the development and progress of vertical-axis wind turbines (VAWTs) are raising the power coefficient and torque coefficient. VAWT produce both positive and negative torque while operating, in contrast to horizontal axis wind turbines (HAWTs). For VAWTs, the negative torque produced by the returning blade is a major problem that is counterproductive. When used to boost flow, porous blades lessen the negative torque generated by the return blades and also increase the torque by causing upstream airflow to be bent toward the leading blade. The studies conducted so far on the Darriues VAWT with porous blades are examined in this paper. Research results show that Darriues VAWT with porous blades has recorded more self-starting and turn than the Darriues VAWT base with straight blades. Moreover, the ability to self-starting torque, power, force less than the vertical axis of Darriues is required with straight blades.

Increasing consumption of energy, fossil fuels and resources that replace renewable energies. Due to its location between 25 and 40 degrees north latitude, Iran has the highest ranks in the world in terms of receiving energy. In the geographical location of Iran, the panels should be set in the direction of absolute geographical south so that they are always facing the solar window. The orientation angle of the panels is different in different seasons, and in fixed structures, this angle is adjusted based on the data of the winter season. The detector structures have a 15-30% higher efficiency than the fixed ones; But using it is not economical. Temperature has a significant effect on the efficiency of photovoltaic panels, and exceeding the temperature of 25 degrees Celsius reduces the efficiency. Among the many methods of temperature control, only the method of using phase change materials is economical and can be implemented. Inverters convert direct current into alternating current and it is necessary to use the electricity of the solar power plant. According to the criteria and weights of the effective factors, it was determined by the relevant authorities that sunny days are of special importance among the criteria. Using the Expert Choice software, the AHP method was implemented, and the criterion of the number of sunny days gained the highest importance. Among the five selected points in Kerman city, it was the first priority for the construction of a power plant.

Hydropower is one of the most cost-effective methods of generating electricity and have the largest share of global renewable electricity generation. Due to the long history of using Hydro-turbines in power generation, the related technologies are at a high level of maturity. However, still many researches are being conducted on this topic to increase efficiency, increase performance flexibility, increase life, and reduce the cost of installing, operating, and maintaining hydro-turbines. In the present work, research papers and inventions related to hydro-turbine technology have been surveyed and based on that, the technical fields that have been focused in recent researches have been identified. Due to the widespread use of Francis turbines in hydropower generation, especially in Iran, the survey is mainly focused to this type of turbine. Accordingly, the most cited technical domains of the Francis turbine include issues related to vortex and flow in draft tube, blades, cavitation, spiral case, computational fluid dynamics, and manufacturing. Also, technologies related to increasing the operating range of hydro-turbines as well as digitalization of hydro-turbine performance are the most important growing technologies related to hydropower generation.