نشریه انرژی های تجدیدپذیر و نو
سال نهم شماره 2 (پیاپی 18، پاییز و زمستان 1401)

The main purpose of this study is to investigate the causal relationship between consumption of energy carriers and economic growth in all provinces of Iran over the period 2011-2018 using Hsiao’s Granger, and Toda and Yamamoto causality approach in panel data. In this regard, variables including gross domestic product, labor force, investment, unemployment rate and consumption of energy carriers (Oil, Gas, Petrol and Gasoline) have been used in the regression model. According to the estimation results, there is a unidirectional causality running from consumption of energy carriers to economic growth, so with an increase in consumption of energy carriers, economic growth increases. This one-way causality is confirmed in both approach. Therefore, according to the results of the research, the policy recommendation is that the government create jobs in the society by giving part of the development credits to the banks in case of the consumption of energy carriers, and cause the labor force employment in the society. The practical benefit of granting such an option is that the more people involved in the production of goods and services, the greater the economic growth.

The The wind turbine converts the kinetic energy of the wind current into the rotational energy of the rotor shaft. The use of vertical axis wind turbines as a source of clean energy production is of great importance. Among the advantages of vertical axis wind turbine over horizontal axis wind turbine are low production cost, lightweight, the efficiency of the installation, and use in residential zones. The darriues blades of vertical axis wind turbines are more in the kind of straight or helical blades. The central difficulty of Darius vertical axis wind turbines is their primary self-starting, which is the basis of this study. They increase self-initiation at low speeds. For this purpose, Darius vertical axis wind turbine was designed and built-in CATIA software. NACA0015 is made for airfoils and the material used for straight and porous blades is plain aluminum sheet and porcelain embossed sheet, both of which are series alloys of aluminum and the equipment used in manufactured and calibrated Manufacturing and calibrating. The result showed that the Ambas blade wind turbine needs less torque to start up to a speed of 9m/s than the vertical blade axis wind turbine.

The depletion of fossil energy resources and their limited resources on the one hand and the amount of pollution on the use of these fuels on the other hand, led different countries to use available and clean energies such as solar, geothermal, waves and wind. In the meantime, the use of geothermal energy is welcomed due to its simple equipment and especially its use in certain areas is very useful. The geothermal heat exchanger consists of a tube that is installed deep in the ground and mortars are used around this pipe to fix and increase performance. Since the type of this mixture is effective on the amount of geothermal energy received by heat exchangers, in this study, the effect of using different compounds in the structure of mortar around pipe is investigated. The thermal analysis of straight tube heat exchanger was performed in different cities in Iran and according to the best thermal performance, Tabriz is selected for further study. Based on the results of different mixtures around tube in Tabriz it is revealed that if the sand-bentonite combination is used, the energy extraction rate will increase by 10% compared to native soil and increasing water content up to a point will result in more energy exchange.

In the process of economic growth and development, energy has always been mentioned as a driving force to accelerate this process. Given the limited reserves of fossil fuels in the world today, we can no longer rely on these energy sources alone. There are several grounds put into question the increasing reliance on fossil fuels in Iran: steady growth of energy consumption, investment inseparability of fossil fuels, limited financial resources, high water intensity in developing fossil fuels and in particular in the course of their conversion into electricity, the country's low resilience due to the intense concentration of production and refining platforms and oil and gas transmission and distribution networks, low labor intensity of fossil energies along with severe pollution following their consumption. This have made the country's shift towards renewable energy inevitable. However, despite these facts and the emphasis from policy makers and upper hand policies (which stipulates that the share of renewable energies in the electricity supply must reach at least 5% till 2021) the share of the renewables in the total energy supply of the country is still very low and far behind the plans. In this paper, employing an evidence-based method, it is shown that developing renewable energies in Iran, is not any longer a choice amongst several choices, rather, it has become an inevitable policy.

Increasing energy consumption in today's world and the resulting major environmental problems have made efforts to develop renewable energy and reduce energy consumption as an effort to improve environmental issues, especially global warming, become a major concern in modern world research. It is predicted that by 2050, energy consumption and environmental damage will increase by 1.8%  annually. In addition, with the sharp increase in cooling and heating needs in various industries, and especially the need for thermal energy around the world, the need for appropriate technology that improves thermal performance in various systems, is very important. The result of these restrictions has been a move towards renewable energy and a reduction in fossil fuel consumption. On the other hand, new technologies such as batteries and drugs are highly dependent on temperature changes. The use of phase change materials (PCMs) to store thermal energy in various industries can solve energy shortage problems. This article provides an overview of energy management practices using PCMs. The background of PCMs in different industries was also examined. The application of PCMs in construction, batteries, home water heating systems and other applications was investigated. A summary of the PCMs used is also provided.

In this research and for the first time, the performance of hybrid solar-gas turbine power plants modified with humidification-dehumidification (HD) desalination process was simulated with TRNSYS. The system included a 4.6 MW gas turbine, solar tower and HD process with air heater and open cycle for water and air. The results showed that in the hybrid solar-gas turbine power plants, the solar power supplied about the 35-45% of required energy and the amount of fossil fuel consumption was reduced. Also, the emission of CO2 was declined for about 40%. The electric power and efficiency of hybrid system was slightly lower than gas turbine only due to the pressure losses in piping and receiver of solar system. The results of HD desalination indicated that the increase in the temperature and relative humidity of the inlet air increased the amount of fresh water production and increase in the temperature of inlet saline water declined its production. Moreover, the amount of fresh water production had an optimum value respect to the mass flow rate of air and with increasing the air flow, the amount of fresh water production increased and then decreased. In addition, if the mass flow rate ratio of saline water to dry air was equal to 1.8, the gain output ratio (GOR) had a maximum value of 2. Variation of GOR in terms of returned air at different inlet air temperatures was explained.

The sad situation of modern buildings is that they are far from natural elements such as open air, sunlight and the sky. Many modern apartments are just a windowless dovecote. This research has been done in four stages. In the first step, through content analysis method by collecting information from literature review of the optimal approach to internal and external sources, a preliminary framework for examining the best way of tasks was found for the efficiency of the day light. In the second and third stages, to obtain the daylight in the internal spaces of the housing, the simulation method is selected from the available alternatives and the fourth step is selecting the alternative system and performing calculations using Dialux software with artificial lighting mode. The results show that optical fiber can be an appropriate replacement for natural light in interior spaces. The results of lighting calculations in Dialux software show that the use of this system has increased the power consumption for these spaces from 388.2 to 6 watts per hour, which is a significant reduction. In addition, fiber optics can bring natural light into deep floor plans in different floors and improve the efficiency of the building and increase the quality of living space, including normalizing sleeping and waking conditions, increase disinfecting properties for residents and finally, it reduces the volume of emissions of greenhouse gases and saves energy.

Open space in residential complexes is a context for the generation of social relations along with environmental performance. Thermal comfort and appropriate architectural features attract people to these spaces. Airflow is one of the most fundamental parameters of outdoor thermal comfort, which is influenced by various factors, including the geometry of buildings. The present study investigated the effect of geometric modifications of buildings on wind flow pattern around the blocks in a residential complex. The case study is a residential complex consisting of 9 midrise blocks. The geometric shape of the blocks was modified and simulated in three steps and the effect of these modifications on the outdoor wind performance was evaluated. The main research method was descriptive analytical method with numerical simulation strategy and analysis of the results was conducted by logical reasoning. The models were simulated in Ansys Airpak 3.0.16 and their results were presented in the form of quantitative outputs, graphic contours as well as several charts. The results of numerical simulations proved the effect of building geometry on the outdoor wind flow pattern around the buildings. The results indicated an increase of 13.83% and 6.76% in average and maximum outdoor air velocity under the influence of buildings geometry modification. Among the studied geometries, the T-shaped form with proper wind flow conduction improved wind behavior in inter-block and inter-row domains. However, L-shaped forms (M3 model) significantly reduced the flow velocity in the inter-block areas by blocking the wind flow.

Fuel cells and photovoltaic systems have many applications among renewable energy systems. DC converters play an important role in these systems. According to characteristics of renewable systems and nonlinear behaviour of the DC converters, control of them is essential. In this paper, the control of a DC modular converter is investigated. This converter is based on a three-level boost converter. This topology can increase the output voltage level compared to the input voltage level and balance the DC output voltage. There are two capacitors in each module of the converter and a capacitor is shared between two modules. The performance of the indirect sliding mode controller is compared with a classic PI controller. The system is simulated using MATLAB/ Simulink software. The simulation results are presented in several scenarios. The dynamics of the input powers and the voltage balance are studied. These tests are performed under changes in the input power, the resistance load and the input voltage. It is obvious that the proposed controller has good performance during operating point changes. The superiority of the proposed controller over the classic controller is shown for all tests. In transient mode, the linear controller is unable to balance capacitor voltages by changing the input power, input voltage and load.

Increased demand for fossil fuels has led to climate change, global warming, and declining energy reserves. The use of renewable energy, such as solar energy, is a suitable approach to generating electricity and heat. One of the common systems in using solar energy is parabolic collectors, which enable this clean energy by converting the incoming radiation into thermal energy. In the present paper, to assess the potential of climates to make optimal use of solar parabolic collectors, a numerical model was developed in MATLAB software. Then, while validating the model with existing experimental results, the effect of climate change has been studied in four areas: energy, exergy, economy, and environment. For this purpose, five cities: Rasht, Shiraz, Tehran, Abadan, and Sanandaj, have been selected as representatives of Iran's climate and energy efficiency and exergy, the unit cost of energy, and the amount of carbon dioxide produced during the life cycle of the system has been obtained. The results show that Shiraz, with a  Semi-Arid Cool climate and thermal efficiency of 72% and a unit cost of  0. 035 $/ kWh, is the optimal climate in the fields of energy and economy, and Sanandaj with a Humid Continental climate and exergy efficiency of 17. 7% is the optimal climate in the field of exergy. In the environment, Rasht, with a Humid Subtropical Climate, was introduced as the optimal climate.

Using the dynamic facades, the exterior of building is removed from the rigid state and in addition to adapting to the needs of users and the environment, it is possible to reduce energy consumption in the building. In this research, while introducing a dynamic facade in the building, the movement patterns of the elements that make up the facade were introduced. To analyze the characteristics of dynamic facades, specifications of 50 world-class dynamic projects with dynamic facades which were built in the last four decades in terms of type of use, the main purpose of dynamic application in facades, materials used and classification of facade movement mechanism, have been examined and the results were analyzed. The major objective of the dynamic facade design is light management and visual exploitation, and the most common application of this facade is in cultural and office buildings, according to the features of the examples. Photovoltaic cells, light-sensitive diaphragms, and solar panels are the most frequent materials and propulsion systems in most of the examples, with sliding and rotating motion being the most common pattern. Finally, the origami model designs and presents a dynamic facade example that may be employed in our country's hot and dry environment.

Using the solar concentrating systems leads to an increase in the solar power radiation hitting the Photovoltaic (PV) panel surface which in turn increases the power generated by PVs. However, the concentrated radiation, on the other hand, raises the PV panel temperature, decreasing its operational efficiency. Cooling techniques (usually water) are used in these systems to reduce the PV operating temperature. In this way, the temperature of the operating fluid rises after cooling the PV panel and its heat can be used for heating purposes in cold seasons and to generate electricity in hot seasons through Organic Rankine Cycle (ORC) technology, which significantly increases the overall efficiency of the combined system. This paper aims to investigate the technical and economic aspects of a hybrid Concentrated Photovoltaic Thermal / Organic Rankine Cycle (CPV/T-ORC) system for simultaneous generation of power and heat in the summer and winter seasons. The results of the analysis show that for the ORC investment cost of 2000$/kW, the return on investment is 3.58 years and for the ORC investment cost of 3500$/kW, the return on investment is 5.81 years.

In hot and dry climates, protecting the building from receiving light and heat energy from the sun is one of the first measures to optimize energy consumption and create thermal comfort for residents. The present study, which has been done by software simulation method, with the aim of determining the most suitable facade in terms of energy consumption, investigates the thermal behavior of facades of an office building in the climate of Tehran. In order to achieve the best option, the thermal behavior of the four facades "single skin with fixed canopy "Double Skin Façade with glass", "Double Skin Façade with movable canopy" and "kinetic facade" on both north and south fronts are evaluated. Findings from calculations show that the annual energy consumption, including: cooling, heating and electric lighting is less on the south side than on the north side. Also, assuming other operating conditions are stable, "movable" awnings perform better than "fixed" awnings. In terms of the type of facade, the "kinetic facade" with the ability to adjust its components such as direction of rotation, opening and closing, has a good performance in reducing the amount of energy consumed by the building compared to other facades. So that this facade with the ability to reduce the amount of energy consumption of the building by 42.3% compared to the conventional single-skin facade, the most optimal facade is determined in this research.

Solar thermal energy is an abundant and unique source of renewable energy and it will become an attractive and competitive option with the common equipment’s if these systems are incorporated with storage units. Packed bed storage system is one of the techniques to store the solar thermal energy which can be used for greenhouses heating, crop drying and space heating due to its simple mechanism and economic feasibility. In this study parameters affecting on PBSS performance and parameters which used for their performance evaluation has been explained. After that we focused on economic evaluation and some of PBSS applications. Between two types of stationary beds and fluidized beds; although the fluidized beds have higher rate of heat and mass transfer but they have more technical problems in design and construction. Between two types of radial flow and axial flow; the radial flow systems can achieve the same efficiency as axial flow system at higher cost. Among solid materials which can be used in stationary beds; cast iron has the highest level of energy density but gravel has recommended because of less refund return period than cast iron. Some of articles mentioned that sand performance is better than the others. Rectangular geometry for cross section of storage unit provides the lowest cost, but it makes high-pressure drop due to corner effects. In a study which use PBSS for greenhouse planting during the night; they see that if the system works for three months, refund return period will be five years.

Renewable energy is a suitable replacement for fossil fuels and has many applications. One of its noticeable applications is desalination which is vital regarding the current water crisis. Accordingly, renewable sources are used in the desalination of alternative to fossil fuels. Wind and geothermal power are two high-potential renewable energies combined with desalination units. However, due to some challenges, they have not developed sufficiently. Iran is one of the wealthiest countries in this type of energy and has much potential for using these technologies, which have not been applied yet. The research aims to consider the achievements of the combination of wind and geothermal energy with desalination. Also, environmental challenges and proper solutions are analyzed. In addition, offshore wind power plants, micro wind turbines, bladeless turbines, triboelectric nanogenerators, and submarine geothermal resources are concluded. In addition, nanotechnology has a significant role in enhancing these systems. Nanocomposites lead to wear reduction of the blades. Nanofluids increase the amount of absorbed heat in geothermal power plants and also reduce the earthquake risk. Graphene and the combination of zeolite and alumina increase the amount of separated salt in reverse osmosis-based desalination.

Solar energy is one of the most significant types of renewable energy needed for development. Increasing population and area of land occupation and economic problems in construction of power plants are the main obstacles to the wide solar electricity production. The main aim in this research has been the design and evaluation of home photovoltaic power plants connected to the network on roofs of buildings.  Doing so, we have used three different climate conditions; regions of cold and mountainous climate (Tabriz), mild and humid (Sari) and warm and dry (Semnan) with COM FAR software. Concerning the design principles, climatic factors such as the effect of temperature rise on the panel surface, the effect of air pollution and the average temperature of the city along with the amount of sunshine were applied. The applied discount rate was 17.3 % and the inflation rate was 20.7 %.  Semnan, with an internal return rate of 32.13%, provides the largest economic yield and Sari with a higher average temperature than Tabriz city is the lowest return city. The return period of normal capital is sixth year. The net return period is Semnan, the ninth, but Tabriz and Sari in the tenth year. In the analysis of sensitivity to increase the rate of internal efficiency, the effect of fixed costs reduction (including the cost of purchase equipment) is more dominant than the increase in the price of photovoltaic electricity. Therefore, the expansion of solar power generation requires extensive support.

The vastness of windy areas in Iran provides many opportunities for harvesting energy from wind. Vertical axis turbines, mainly as a category of small-scale turbines, are attracting interest and being further developed every day. One of these types of turbines is the Cross-Flow wind turbine (CFWT), which is a quite suitable option for urban and home applications, though its low maximum power coefficient is yet a challenge that must be addressed by feasible methods. This article reviews studies in the field of design and improvement of CFWT by changing the geometric characteristics of the turbine or providing a way to direct the wind flow into the turbine rotor. After introducing the CFWT, the methods for directing wind flow into the turbine and their effect on the power coefficient and performance of the system are described. These methods are basically divided into seven categories of Guide nozzle, Casing, Guide vane, Deflector, Cowling, Omni-Directional Guide Vane (ODGV), and Zephyr. This study indicates that a big portion of the conducted research has been on the development of ODGV. Also, this turbine was analyzed for three cities of Ardabil, Babolsar, and Zahedan in Iran based on three types of systems (direct sale, on-grid, and on-grid with batteries). The results of this study show that the direct sale approach is the best option for the utilization of CFWT in Iran, and the payback period time of fewer than 10 years is achieved only by reducing the CAPEX of the setup by 10%-29%.