Renewable Energy Resources and Technologies
Armin Motamed Sadr; Mehran Ameri Mahabadi; ٍٍEbrahim Jahanshahi Javaran
Abstract
In this research, the performance of an asphalt solar air collector was experimentally tested and the daily thermal and exergy efficiencies of the collector were analyzed. The sun's radiant energy is absorbed by asphalt and converted into thermal energy. Then, it is transmitted to aluminum pipes buried ...
Read More
In this research, the performance of an asphalt solar air collector was experimentally tested and the daily thermal and exergy efficiencies of the collector were analyzed. The sun's radiant energy is absorbed by asphalt and converted into thermal energy. Then, it is transmitted to aluminum pipes buried under the asphalt and, finally, to the air passing through the pipes. A suction fan induces the ambient air to the collector. The experimental results show that the daily thermal efficiencies at mass flow rates of 0.007 (kg/s) and 0.014 (kg/s) are 11.98% and 24.10% and daily exergy efficiencies are 0.34% and 0.66%, respectively, showing the increase in daily energy and exergy efficiencies with increasing the air mass flow rate. In addition, results show that as the flow rate increases, the outlet air temperature decreases. The presence of temperature difference between the inlet and outlet of the collector in the last hours of the day, when the sun's radiation is low, indicates that asphalt acts as a thermal energy storage medium.
Renewable Energy Resources and Technologies
Abir Hmida; Abdelghafour Lamrani; Mamdouh El Haj Assad; Yashar Aryanfar; Jorge Luis Garcia Alcaraz
Abstract
Around the globe, a 60 % increase in energy demand is predicted to occur by the end of the year 2030 due to the ever-increasing population and development. With a registered temperature up to 50°C in August 2020, which is classified as one of the hottest regions in the world, the demand for cool ...
Read More
Around the globe, a 60 % increase in energy demand is predicted to occur by the end of the year 2030 due to the ever-increasing population and development. With a registered temperature up to 50°C in August 2020, which is classified as one of the hottest regions in the world, the demand for cool temperatures in Gabes-Tunisia to achieve the thermal comfort of people ensuring the product storage has become more and more intense. Removing heat from buildings represents the most extensive energy consumption process. In this paper, an absorption-refrigeration system driven by solar energy is proposed. A parametric simulation model is developed based on the TRNSYS platform. A comparison between different models for global radiation calculation and experimental meteorological data was carried out. It has been proven that the Brinchambaut model seems to be the most convenient in describing the real global radiation, with an error of up to 3.16%. An area of 22 m² of evacuated tube solar collector ensures the proper functioning of the generator and achieves a temperature up to 2°C in the cold room.
Renewable Energy Resources and Technologies
Soheil Fathi; Abbas Mahravan
Abstract
In many middle- and high-income countries, existing buildings will occupy the majority of building areas by 2050 and measures are needed to upgrade the mentioned buildings for a sustainable transition. This research proposes a method to mitigate the energy consumption of existing educational buildings ...
Read More
In many middle- and high-income countries, existing buildings will occupy the majority of building areas by 2050 and measures are needed to upgrade the mentioned buildings for a sustainable transition. This research proposes a method to mitigate the energy consumption of existing educational buildings using four energy efficiency measures (EEMs). The proposed method divides simulations into two main parts: simulations with and without using heating, ventilating, and air conditioning (HVAC) systems. Four passive EEMs are used, including window replacement, proposed shading devices, new insulations, and installing a new partition wall for the entrance part of the building. This research uses a simulation-based method to examine the effect of each EEM on the energy consumption of the building using DesignBuilder software. The steps of data collection and modeling in this research include collecting raw data related to the physical characteristics of the building experimentally and creating a basic model. Afterwards, simulation scenarios were defined based on the proposed method, and several simulations were carried out to examine the impact of each EEM on the energy performance of the building. Two environmental parameters of the simulation process, including indoor air temperature (IAT) and relative humidity (RH), were used. The measures reduced the heating and cooling demands in the building by 80.14% and 15.70%, respectively. Moreover, the results indicated that the total energy consumption of the building were reduced by 10.44% after retrofitting measures.
Renewable Energy Resources and Technologies
Mohammed Ali Sami Mahmood; Sergei Kuzmin
Abstract
Solar Organic Rankine Cycle (SORC) is a successful approach to sustainable development and exploiting clean energy sources. The research aims to improve and evaluate the energy efficiency of the SORC for combined heat and power generation for a residential home under the climatic conditions of Baghdad, ...
Read More
Solar Organic Rankine Cycle (SORC) is a successful approach to sustainable development and exploiting clean energy sources. The research aims to improve and evaluate the energy efficiency of the SORC for combined heat and power generation for a residential home under the climatic conditions of Baghdad, Iraq. Thermoeconomic analysis was carried out for the proposed energy supply system. Refrigerant HFC-245fa was used as a working fluid in a solar organic Rankine cycle, and oil poly alkyl benzene (TLV-330) was suggested as a heat transfer fluid in the solar collector field. Parametric studies for some key parameters were conducted to examine the impact of various operating conditions on energy efficiency. The results showed a significant improvement in energy efficiency. The maximum efficiency of SORC CHPG reached 79.14% when solar heat source temperatures were in the range of 100 to 150°C and the solar radiation was at a maximum value of 870 W/m2 at noon on the 15th day of July in Baghdad. The maximum energy produced by SORC CHPG was 472.5 kW when the optimal average value of global solar radiation was 7.5 kWh/m2/day in June. The economic investigations revealed that the payback period of the new energy supply system was 10 years with the positive net present cost when the solar power plant was working 18 h/day.
Renewable Energy Resources and Technologies
Dnyaneshwar S. Malwad; Deepak C. Sonawane
Abstract
Preserving food from harvest to consumer level is a challenge in the agriculture sector. Drying is a crucial post-harvest technique that lowers moisture to levels suitable for storage. Solar drying is a traditional renewable energy drying process. Different solar drying methods have been developed ...
Read More
Preserving food from harvest to consumer level is a challenge in the agriculture sector. Drying is a crucial post-harvest technique that lowers moisture to levels suitable for storage. Solar drying is a traditional renewable energy drying process. Different solar drying methods have been developed to speed up the drying process and maintain the product's nutritious content. Indirect solar drying is one of the efficient drying methods that has better control over the drying temperature. Indirect solar drying has developed into a desirable, effective, and environmentally responsible drying technique when combined with solar collectors and thermal storage. Flat plates, evacuated tubes, and concentrated solar collectors are used in indirect solar dryers along with direct air heating or thermal storage systems. This study aims to review the improvement in the drying rate with different air heating mechanisms. Flat plate collectors with liquid working fluid are employed to heat the air, whereas in evacuated tube collectors, the air is directly heated passing through the tubes. Working fluids, air temperature, air velocity, and solar radiation are important dryer parameters affecting the drying rate. The paper also discusses the usage of heat storage devices for continuous drying operations. The drying time is greatly reduced through integration with latent and sensible storage technologies. Products that have been dried using indirect solar dryer and appropriate drying models are tabulated. Aspects of indirect solar drying and challenges in drying time reduction are also reported.
Renewable Energy Resources and Technologies
Satyaprasad Mohapatra; Akshaya Kumar Patra; Debswarup Rath
Abstract
The design of a Spotted Hyena Optimization Algorithm-Variable Parameter Tilt Integral Derivative with Filter (SHO-VPTIDF) controller for improved performance and enhanced devaluation of harmonic components of grid-connected photovoltaic systems is the main objective of the suggested manuscript. The SHO-VPTIDF ...
Read More
The design of a Spotted Hyena Optimization Algorithm-Variable Parameter Tilt Integral Derivative with Filter (SHO-VPTIDF) controller for improved performance and enhanced devaluation of harmonic components of grid-connected photovoltaic systems is the main objective of the suggested manuscript. The SHO-VPTIDF controller is proposed by reformulating Tilt Integral Derivative Controller with Filter (TIDCF). The TIDCF is characterized by longer simulation time, lower robustness, longer settling time, attenuated ability for noise rejection, and limited use. This research gap is addressed by replacing the constant gains of TIDCF by variable parameter tilt integral derivative with filter. The VPTIDF replaces the constant gains of TIDCF with error varying control parameters to improve the robustness of the system. The photovoltaic system with nonlinearities causes power quality issues and occasional faults, which can be detected by using Levenberg-Marquardt Algorithm (LMA) based machine learning technique. The novelties of the proposed manuscript including improved stability, better robustness, upgraded accuracy, better harmonic mitigation ability, and improved ability to handle uncertainties are verified in a Matlab simulink environment. In this manuscript, the SHO-VPTIDF and the Direct and Quadrature Control based Sinusoidal Pulse Width Modulation (DQCSPWM) method are employed for fault classification, harmonic diminishing, stability enhancement, better system performance, better accuracy, improved robustness, and better capabilities to handle system uncertainties.
Renewable Energy Resources and Technologies
Reza Roohi; Masoud Akbari
Abstract
The design of novel and effective receivers is one of the most challenging aspects of solar energy harvesters, especially for Parabolic Dish Collectors (PDCs). The variation of solar flux due to the solar time and sky clearance index can affect the output thermal energy of the collector. One of the major ...
Read More
The design of novel and effective receivers is one of the most challenging aspects of solar energy harvesters, especially for Parabolic Dish Collectors (PDCs). The variation of solar flux due to the solar time and sky clearance index can affect the output thermal energy of the collector. One of the major approaches to producing a uniform performance for the PDCs is the utilization of Phase Change Materials (PCMs). The PCMs can absorb the solar flux at its peak instances. Subsequently, due to the thermal buffering effect, excess energy is released in cases with lower solar flux. In the present study, a novel design of receiver with multiple layers of thin PCM inserted between the passages of the working fluid is numerically simulated. The simulations are designed to determine the effect of operational parameters on the performance of the examined novel receiver. According to the results, by increasing the Heat Transfer Fluid (HTF) flow rate from 60 to 90 kg/h, the system efficiency is increased from 53.8 to 66.4 %.
Renewable Energy Resources and Technologies
Mehdi Jahangiri; Farhad Raeiszadeh; Reza Alayi; Atabak Najafi; Ahmad Tahmasebi
Abstract
Rural tourism is an important factor in achieving economic, social, and cultural development. Given that villages in Iran do not have access to permanent electricity or are associated with high power outages, the provision of sustainable electricity through renewable energy can cause more tourists to ...
Read More
Rural tourism is an important factor in achieving economic, social, and cultural development. Given that villages in Iran do not have access to permanent electricity or are associated with high power outages, the provision of sustainable electricity through renewable energy can cause more tourists to choose these villages as their ultimate goal. Therefore, in this paper, for the first time, a hybrid system has been evaluated based on solar energy in 10 tourism target villages in Iran using HOMER software. This study investigated the design of the system with real and up-to-date data on equipment and fossil fuel prices taking into account transportation costs as well as a comprehensive study of energy-economic-environmental with electricity generation approach to the development of rural tourism. The results demonstrated that for the studied stations, the LCOE parameter was in the range of $ 0.615-0.722, the percentage of power supply by solar cells was in the range of 90-99 %, and the prevention of pollutants was 33.9-277 kg/year. According to the results, Meymand village is the most suitable and Mazichal village is the unsuitable station in the field of energy supply required by solar cells. The production pollution in the studied stations is mainly CO2 and results from the operational phase of the project and its amount is 979.5 kg/year. Given that the rural tourism has grown and become a solution for development, the authors hope that the present work results can be used as a perspective to help energy and rural tourism decision-makers.
Renewable Energy Resources and Technologies
Iman Ayoobi; Ramin Roshandel
Abstract
Light is a critical parameter for plant growth such that providing enough light for the plant can ensure better quality and higher yield in greenhouses. In many areas, in the cold seasons of the year, not enough natural light reaches the plant. Thus, to compensate for the natural light deficit, artificial ...
Read More
Light is a critical parameter for plant growth such that providing enough light for the plant can ensure better quality and higher yield in greenhouses. In many areas, in the cold seasons of the year, not enough natural light reaches the plant. Thus, to compensate for the natural light deficit, artificial light is used. Since the use of artificial light leads to energy consumption, effective parameters in the energy consumption of the lighting system such as available natural light, greenhouse shape, and the on-off plan of the lighting system should be considered. In this paper, available natural light is estimated based on greenhouse structure in five cities of Iran. Then, the natural light deficit was investigated. Finally, to achieve clean cultivation, the utilization of photovoltaic panels is investigated to compensate for the electrical energy needed for supplementary lighting. The results show that although Iran is recognized as a region with high solar energy potential, natural light is not enough for optimum tomato lighting demand. Using supplementary lighting in greenhouses could compensate for the lack of natural light in proportion to the capacity of the lighting system. In 73.22 % to 91.32 % of days in the period of September to April, the natural light is not sufficient for optimum lighting. Therefore, 98 to 377 electricity is needed to supply power for supplementary lighting system. Accordingly, the photovoltaic area and its associated with costs to compensate electrical energy consumption for the supplementary lighting is estimated to be 0.47 to 2.58 per m2 of greenhouse area, which is equal to $ 171.08 to $ 939.12 per m2 of greenhouse area, respectively.
Renewable Energy Resources and Technologies
Anupama Subhadarsini; Babita Panda; Byamakesh Nayak
Abstract
The solar photovoltaic system is modeled in Simulink using Matlab. Boost converter, FOTIDC controller, and Reduced Switch Multilevel Inverter are all included in this PV system (RSMLI). With regard to solar photovoltaic systems, the focus of this study is on the Fractional Order Tilt Integral Derivative ...
Read More
The solar photovoltaic system is modeled in Simulink using Matlab. Boost converter, FOTIDC controller, and Reduced Switch Multilevel Inverter are all included in this PV system (RSMLI). With regard to solar photovoltaic systems, the focus of this study is on the Fractional Order Tilt Integral Derivative Controller (FOTIDC). In the suggested control technique, Hybrid Genetic Particle Swarm Jaya Optimization is used to optimize the control parameters (HGPSJO). Jaya Optimization (JO) is a hybrid of the Particle Swarm Optimization (PSO), Genetic Algorithm (GA), and GA/PSO algorithm optimization techniques, combining the best of each for improved control executions. Control performance is enhanced using a fractional calculus-based technique to redesign the Tilt Integral Derivative Controller (TIDC) in order to reduce noise and harmonic distortions. Harmonic distortion and voltage magnitude are reduced by applying the proposed control method to the PV system. Simulated Matlab environments are used to test the stability, robustness, and stability of the proposed system as well as its capacity to reduce harmonic distortions. It is also compared to other well-known control techniques in order to ensure that the real-time implementation is properly validated.
Renewable Energy Resources and Technologies
Rahul Dogra; Sanjay Kumar; Nikita Gupta
Abstract
The use of these conventional resources causes continuous depletion of fossil fuels and increased greenhouse effect. Solar power is the major renewable resource used for power generation across the globe. Solar energy activities depend on the available potential of any geographical location. Therefore, ...
Read More
The use of these conventional resources causes continuous depletion of fossil fuels and increased greenhouse effect. Solar power is the major renewable resource used for power generation across the globe. Solar energy activities depend on the available potential of any geographical location. Therefore, prior to the installation of solar technologies for these activities, estimation of solar potential is very important due to costly technologies. Data of solar potential is not present at every location in Himachal Pradesh (H. P.) due to the high cost of measurement instruments. The objective of this study includes the solar potential estimation for 12 cities of the H. P. The present study could be divided into two parts. Initially, Artificial Neural Networks (ANNs) are utilized to estimate global sun radiation utilizing meteorological and geographical data from 23 places. The ANN model with seven input parameters including latitude, longitude, altitude, air temperature, humidity, pressure, and wind speed were used to estimate the solar irradiation. Statistical indicators including Mean Absolute Percentage Error (MAPE) were used for the performance evaluation of these ANNs. The minimum MAPE value was obtained to be 2.39 % with Multi-Layer Perception (MLP) architecture 7-11-1. For the 12 districts of the H. P., the acquired network 7-11-1 was utilized to estimate Global Solar Radiation (GSR). The output of ANN model was implemented in Geographic Information System (GIS) environment to obtain the solar potential map for each month. The available map of the present study may be helpful for solar application in each district.
Renewable Energy Resources and Technologies
Mehran Gheyrati; Asadollah Akram; Hassan Ghasemi-Mobtaker
Abstract
The orientation of greenhouses is one of the effective factors in terms of radiation they receive. In the present study, a multi-span greenhouse (40 m × 93.5 m with a coverage area of 5457.44 m2) located in the central region of Iran was investigated in three orientations including: North-South ...
Read More
The orientation of greenhouses is one of the effective factors in terms of radiation they receive. In the present study, a multi-span greenhouse (40 m × 93.5 m with a coverage area of 5457.44 m2) located in the central region of Iran was investigated in three orientations including: North-South (N-S), East-West (E-W), and Northeast-Southwest (NE-SW: the most frequent orientation of the existing greenhouses in the study area). The solar irradiation received on the outside surface of the greenhouse cover and the amount of irradiation captured inside the greenhouse for each orientation during the cold season were calculated using mathematical modeling and the results were compared. According to the results, in the E-W orientation, the main sections of receiving solar irradiation, such as the south and north roofs, have a better angle toward the sun; therefore, the quantity of solar irradiation captured inside the greenhouse with the E-W orientation was on average 361.48 MJ day-1 more than that with the N-S orientation. The north wall of the greenhouse could not receive the beam radiation for all the orientations investigated, and the total irradiation captured by this section was composed of the diffused radiation and the ground-reflected radiation, which is an important result for insulation of some surfaces of greenhouses.
Renewable Energy Resources and Technologies
Hadi Farzan
Abstract
Recently, novel techniques have been developed in building industries to use solar heating and cooling systems. The current study develops a Solar-powered Heating and Cooling (SHC) system for an office building in Kerman and assesses the transient dynamics of this system and office indoor temperature. ...
Read More
Recently, novel techniques have been developed in building industries to use solar heating and cooling systems. The current study develops a Solar-powered Heating and Cooling (SHC) system for an office building in Kerman and assesses the transient dynamics of this system and office indoor temperature. To this end, TRNSYS simulation software is utilized to simulate system dynamics. The developed system comprises Evacuated-Tube solar Collectors (ETCs), heat storage tank, heat exchanger, circulating pumps, axillary furnace, cooling tower, single-effect absorption chiller, and air handling unit. The office indoor temperature is assessed in two scenarios, including commonly-insulated and well-insulated envelopes, while window awnings are used to prevent the sun from shining directly through the windows. The results illustrate that the SHC system can meet the thermal loads and provide thermal comfort in line with ASHRAE standards. The indoor temperature reaches 21 °C and 24 °C on cold winter and hot summer days by using the SHC system; however, without the SHC system, the indoor temperature experiences 15 °C and 34 °C on cold and hot days, respectively. The SHC system provides 45 °C and 15 °C supply air on cold and hot days to keep the indoor temperature in the desired range. A thermostat monitors the indoor temperature and saves energy by turning off the system when no heating or cooling is required. Furthermore, the ETCs can run the SHC system for a long time during daytime hours, but the axillary heater is still essential to work at the beginning of the morning.
Renewable Energy Resources and Technologies
Sepideh Rahmati Dehkordi; Mehdi Jahangiri
Abstract
In Iran, due to the problems and constraints of fossil fuels and the need to maximize the use of solar potential, one of the best ways is the application of photovoltaic systems integrated with buildings. Due to the significant dependence of solar cell performance on the availability of radiation, it ...
Read More
In Iran, due to the problems and constraints of fossil fuels and the need to maximize the use of solar potential, one of the best ways is the application of photovoltaic systems integrated with buildings. Due to the significant dependence of solar cell performance on the availability of radiation, it is necessary for architects to have an accurate assessment of the amount of electricity produced in different conditions. Therefore, in the present work, using HOMER software, the energy-econo-Enviro (3E) potential of a Building Integrated Photovoltaic (BIPV) in Abadan was studied. The effect of slope and azimuth of solar cells as well as cloudiness and system losses were investigated using sensitivity analysis. The results showed that the PV-grid system was the most economical option and after the azimuth angle of zero degree, the positive azimuth angle was the most economical. The results also showed that the slope of 30 degree and the angle of azimuth equal to zero was appropriate, for which the price per kWh of generated electricity was calculated to be $0.09. For the use of solar cells in the vertical wall of the building, the southwest direction was the most suitable and based on the results, it was suggested that the western wall of the building should be in the form of “inclined PVs with windows”. The authors of this paper hope that the results of the present work can be used by architects and energy decision-makers as a guide in developing the BIPV use in Iran.
Renewable Energy Resources and Technologies
Sina Eterafi; Shiva Gorjian; Majid Amidpour
Abstract
In this study, the effect of covering the aperture area of a conical cavity receiver with an ultra-white glass on operational parameters of a Parabolic Dish Collector (PDC) was numerically and experimentally investigated under climate conditions of Tehran (35.44° N latitude and 51.10° longitude). ...
Read More
In this study, the effect of covering the aperture area of a conical cavity receiver with an ultra-white glass on operational parameters of a Parabolic Dish Collector (PDC) was numerically and experimentally investigated under climate conditions of Tehran (35.44° N latitude and 51.10° longitude). The main components of the experimental setup include a dish reflector, a conical cavity receiver, Heat Transfer Fluid (HTF), hydraulic and cooling cycle, and a sun tracker. For this purpose, a conical cavity receiver with an ultra-white glass cover on its aperture was numerically modeled in Fortran software. During the evaluation, environmental parameters including ambient temperature, solar radiation, and wind speed were considered as inputs of the model. The results revealed fair agreement between the numerical and experimental data with the maximum error of approximately 4.63 % and 7.89 % for receivers with and without the glass cover on the aperture, respectively. For a steady-state analysis, the mean values of useful energy ( ) absorbed by the receiver were calculated as 1,253.25 W and 987.68 W, while thermal efficiency ( ) of the receiver was calculated as 52.61 % and 40.69 % for receivers with and without glass cover, respectively. The results revealed that both and followed a similar trend of the variations in the HTF’s temperature between the inlet and outlet of the receiver. Also, the overall heat loss coefficient ( ) and the collector heat removal factor ( ) were calculated as 420.76 W/m2°C and 0.62 for the conical cavity receiver with the glass cover.
Renewable Energy Resources and Technologies
Najmeh Salehi; Arash Mirabdolah Lavasani; Ramin Mehdipour; Mohammad Eftekhari Yazdi
Abstract
One of the best and most important types of concentrating solar power plants is the linear Fresnel collector. The thermal performance and application of absorber in a solar power plant can be enhanced using direct steam generation technology. A particular discrepancy between the present study and others ...
Read More
One of the best and most important types of concentrating solar power plants is the linear Fresnel collector. The thermal performance and application of absorber in a solar power plant can be enhanced using direct steam generation technology. A particular discrepancy between the present study and others lies in our attempt at applying a new method for calculating critical heat flux based on Look-up Table. In the current study, effects of nanofluid on the length of the critical heat flux and convection heat transfer coefficient were investigated. The nanoparticles considered in this study were aluminum, silver, nickel, and titanium dioxide at concentrations of 0.01, 0.1, 0.3, 0.5, 1 and 2 %. Modeling results revealed that the heat transfer coefficient increased upon enhancing the volumetric concentration of nanoparticles, thereby improving this coefficient at 2 vol. % nickel nanoparticles, which was 10.6 % above the value of pure water. On the other hand, thermal efficiency was enhanced when nickel nanoparticles were dispersed in pure water such that increase rates of thermal efficiency equaled 11.2, 10.8 and 11.3 % in the months of June, July, and August, respectively, when the volume concentration of nanoparticles was 0.5 %.
Renewable Energy Resources and Technologies
Daryoosh Borzuei; Seyed Farhan Moosavian; Abolfazl Ahmadi; Rouhollah Ahmadi; Kourosh Bagherzadeh
Abstract
Energy plays a vital role in all human life activities. Due to the problems caused by fossil fuels in recent decades such as global warming, greenhouse gas emissions, ozone depletion, etc., the use of renewable and clean energy has been considered. An experimental facility for the acquisition of reliable ...
Read More
Energy plays a vital role in all human life activities. Due to the problems caused by fossil fuels in recent decades such as global warming, greenhouse gas emissions, ozone depletion, etc., the use of renewable and clean energy has been considered. An experimental facility for the acquisition of reliable data from Parabolic Trough Solar Collectors (PTCs) was established to develop a robust analytical model. A wide range of Heat Transfer Fluid (HTF) flow rates (0.0372-0.1072 kg/s) and solar radiation (400-900 W/m2) were used to determine PTC parameters such as the outlet temperature of HTF loss and temperature distribution. Vacuum conditions in the receiver were considered effective in terms of thermal efficiency. Also, three types of HTF including two oil fluids (Syltherm 800 and S2) and water were examined. The temperature distribution showed that when Syltherm 800 or S2 passed through the absorber tube, the outlet temperature was higher than water: 2.84 % for Syltherm 800 and 3.72 % for S2. Since the absorber tube temperature was much higher than water, the heat loss in this condition was considered for oil HTF. Of note, the results demonstrated that use of the vacuum tube could diminish heat loss for the oil HTF. The effect of solar intensity increases from 600 W/m2 to 900 W/m2 on the maximum temperature of the receiver tube indicated that when Syltherm 800 was used as an HTF, this temperature increased by 35.1 % (from 167 °C to 219 °C), while this percentage was 32.7 % and 6.8 % for S2 and water, respectively.
Renewable Energy Resources and Technologies
Nima Amani; Abdul Amir Reza Soroush
Abstract
One of the main reasons of environmental pollution is energy consumption in buildings. Today, the use of renewable energy sources is increasing dramatically. Among these sources, solar energy has favorable costs for various applications. This study examined a commercial building in a hot and humid climate. ...
Read More
One of the main reasons of environmental pollution is energy consumption in buildings. Today, the use of renewable energy sources is increasing dramatically. Among these sources, solar energy has favorable costs for various applications. This study examined a commercial building in a hot and humid climate. The findings showed that choosing the optimal angle of solar panels with the goal of optimized energy consumption would yield reduced costs and less environmental pollutants with the least cost and maximum energy absorption. In this study, to calculate the energy requirements of the building, DesignBuilder software was used. To study the solar angles and estimate the energy produced by the solar panels, Polysun software was used after simulating the building energy. Energy simulation results showed that the whole building energy consumption was 26604 kWh/year. Finally, the evaluation results of solar panels showed that the energy produced by photovoltaic modules at an optimal angle of 31° would be equal to 26978 kWh/year, which is more than the energy required by the building. This system can prevent 14471 kg of carbon dioxide emissions annually. Sustainable energy criteria showed that for the studied building, photovoltaic modules could be used in energy production to reach a zero-energy system connected to the grid with an annual energy balance.
Renewable Energy Resources and Technologies
Aychar Khajavipour; Mohammad Reza Shahraki; Faranak Hosseinzadeh Saljooghi
Abstract
The energy of processes is mainly supplied by fossil fuels. Short life of fossil energy sources and increasing environmental pollution caused by fossil fuels and increasing demand have made researchers introduce new solutions for supply of energy. Energy production in a photovoltaic solar power plant ...
Read More
The energy of processes is mainly supplied by fossil fuels. Short life of fossil energy sources and increasing environmental pollution caused by fossil fuels and increasing demand have made researchers introduce new solutions for supply of energy. Energy production in a photovoltaic solar power plant is cost-effective due to being clean and renewable. The power generation of these plants is affected by their site due to climate conditions, effective radiation periods, and the rate of solar radiation absorption. Therefore, finding the optimal location to establish a solar power plant is important. Identifying effective location criteria and the importance of these criteria is effective in choosing the optimal location.In this research, in the first phase, the effective criteria in locating a photovoltaic solar power plant were investigated based on the Delphi method. Then, in the second phase, based on the criteria identified in the first phase, fuzzy hierarchy method was used to compare the criteria with each other and determine the importance of each of them. The results of the study showed that the rate of solar radiation and average temperature were the most important criteria in locating photovoltaic solar power plant. Moreover, the criteria of slope, distance to main roads, distance to power lines, and land use were of highest importance in locating a photovoltaic solar power plant.
Renewable Energy Resources and Technologies
Somayeh Naserpour; Hasan Zolfaghari; Parviz Zeaiean Firouzabadi
Abstract
One of the most important characteristics of site selection for solar energy system installations and optimum solar energy harvesting in the hilly or mountainous terrains is knowledge about the amount and duration of solar radiation within such topographic terrains. Solar radiation data are not readily ...
Read More
One of the most important characteristics of site selection for solar energy system installations and optimum solar energy harvesting in the hilly or mountainous terrains is knowledge about the amount and duration of solar radiation within such topographic terrains. Solar radiation data are not readily available for most mountain terrains because of their rugged topography. For these areas, solar radiation data can be obtained through alternative methods such as the Hemispherical Viewshed Algorithm in which spatial and temporal variations of radiation are calculated in terms of elevation, slope, and terrain. In this study, this algorithm was used to estimate and model solar radiation in the Paraw Mountain in Kermanshah. The inputs for this method were ASTER Digital Elevation Model (DEM) with a spatial resolution of 30 m and meteorological parameters that affect solar radiation. The slope and aspect maps were created from ASTER DEM and layers for monthly direct, diffuse, global, and radiation periods were generated for the year 2016. The results showed that in the Paraw Mountain, the amount of solar radiation received was dependent on the slope orientation, as the north and northeast-facing slopes received the lowest and the south and southwest-facing slopes and the flat areas received the highest direct and global radiation (i.e., in terms of this factor, these landscapes can be recommended as the best site for solar energy system installations and optimum solar energy harvesting). The sum annual radiation period varies from 382.67 to 4310.9 hours, the total radiation received annually varies between 1005.56 and 7467.3 MJ/m2, and the sum monthly solar radiation is the highest in July (181.49-842.26 MJ/m2) and lowest in December (25.42-319.90 MJ/m2). Statistical error comparisons between station-based measurements and model-based estimates were performed via R2, measures. As a result, this model was recommended for solar radiation estimation with acceptable accuracy, especially in high areas with rugged topography where solar radiation data are not readily available.
Renewable Energy Resources and Technologies
Mohammad Reza Shekari; Seyed Mohammad Sadeghzadeh; Mahdi Golriz
Abstract
In recent decade, Perovskite Solar Cells (PSCs) have received considerable attention compared to other photovoltaic technologies. Despite the improvement of Power Conversion Efficiency (PCE) of PSCs, the chemical instability problem is still a matter of challenge. In this study, we have fabricated two ...
Read More
In recent decade, Perovskite Solar Cells (PSCs) have received considerable attention compared to other photovoltaic technologies. Despite the improvement of Power Conversion Efficiency (PCE) of PSCs, the chemical instability problem is still a matter of challenge. In this study, we have fabricated two kinds of PSCs based on gold and carbon electrodes with the optimal PCE of about 15 % and 10.2 %, respectively. We prepared a novel carbon electrode using carbon black nanopowder and natural graphite flaky powder for Hole Transport Material (HTM) free carbon-based PSC (C-PSC). Current density-voltage characteristics over time were measured to compare the stability of devices. Scanning Electron Microscope (SEM) and Energy-dispersive X-ray Spectroscopy (EDS) analyses were carried out to study applied materials, layer, and surface structures of the cells. The crystal structure of perovskite and its association with the stability of PSCs were analyzed using an obtained X-ray diffraction (XRD) pattern. As a result, the constructed HTM-free C-PSC demonstrated high stability against air, retaining up to 90 % of its optimal efficiency after 2000 h in the dark under ambient conditions (relative humidity of (50 ± 5); average room temperature of 25 °C) in comparison to constructed gold-based PSCs (Gold-PSC) which are not stable at times. The experimental results show that novel low-cost and low-temperature carbon electrode could represent a wider prospect of reaching better stability for PSCs in the future.
Renewable Energy Resources and Technologies
Seyed Ali Akbar Fallahzadeh; Navid Reza Abjadi; Abbas Kargar; Frede Blaabjerg
Abstract
This study investigates a new double-stage single-phase Grid-Connected (GC) Photo-Voltaic (PV) system. This PV system includes a DC-DC Positive Output Super Lift Luo Converter (POSLLC) and a single-phase inverter connected to a grid through an RL filter. Due to its advantages, the POSLLC was used between ...
Read More
This study investigates a new double-stage single-phase Grid-Connected (GC) Photo-Voltaic (PV) system. This PV system includes a DC-DC Positive Output Super Lift Luo Converter (POSLLC) and a single-phase inverter connected to a grid through an RL filter. Due to its advantages, the POSLLC was used between PV panel and inverter instead of the conventional boost converter. The state space equations of the system were solved. By using two Sliding Mode Controls (SMCs), PV panel voltage and POSLLC inductor current were controlled and the designed controls were compared. Two of these SMCs included a simple Sign Function Control (SFC) and a conventional SMC. To control the power injected into the grid with a unity power factor, an SMC was used. Perturb and Observe (P&O) method was employed to reach maximum power of the PV panel. The Maximum Power Point Tracking (MPPT) control generated the voltage reference of the PV panel. Similar controls were used for the boost converter instead of POSLLC. The obtained results were compared.
Renewable Energy Resources and Technologies
Ramasamy Dhivagar; Murugesan Mohanraj
Abstract
In this experimental work, the energy efficiency and performance parameters of a coarse aggregate-assisted single-slope solar still were analyzed using Taguchi analysis. The preheated inlet saline water was sent to the solar still using thermal energy accumulated in coarse aggregate to enhance its productivity ...
Read More
In this experimental work, the energy efficiency and performance parameters of a coarse aggregate-assisted single-slope solar still were analyzed using Taguchi analysis. The preheated inlet saline water was sent to the solar still using thermal energy accumulated in coarse aggregate to enhance its productivity and energy efficiency. The daily distillate of the proposed model was observed to be about 4.21 kg/m2 with the improved efficiency of around 32 %. Furthermore, the parameters that influenced the performance of the solar stills and their levels were identified using Taguchi analysis. The Signal to Noise (S/N) ratios of the coarse aggregate temperature, saline water temperature, glass temperature and energy efficiency were observed to be about 45.4 °C, 41.4 °C, 36.7 °C and 20.07 %, respectively. The results revealed that, the percentage difference between predicted and experimental values was observed to be about 1.6 %, 0.6 %, 1.5 % and 3.3 %, respectively. The optimization method confirmed that there was good agreement between the predicted and experimental values.
Renewable Energy Resources and Technologies
Muhamad Mustafa Mundu; Stephen Ndubuisi Nnamchi; Onyinyechi Adanma Nnamchi
Abstract
The present study is concerned with the development, estimation and validation of sunshine hours models (SHM) in Uganda. The SHM is based on geographical (latitude) and climatological (clearness index) indices. The meteosat data (1984-2018) acquired from the National Aeronautics and Space Administration ...
Read More
The present study is concerned with the development, estimation and validation of sunshine hours models (SHM) in Uganda. The SHM is based on geographical (latitude) and climatological (clearness index) indices. The meteosat data (1984-2018) acquired from the National Aeronautics and Space Administration were used to compute the coefficients of the models which, yielded a coefficient of determination close to unity, signifying a good association between the sunshine hours (SH) and the associated indices. The models become distributed by introducing a longitudinal function of clearness index into the primary SHM developed. Moreover, the models were subjected to statistical validation using; mean absolute relative error (MARE), root mean square error (RMSE) and mean absolute percentage difference (APD). Consequently, the primary SHM showed strong agreement with the measured SH data in the three regions with the exception of the northern region with flawed on-station data. Also, validation of the models by; {MARE, RMSE, APD} for Eastern, Central and Western regions, yielding the following results; {0.0788,0.5441,7.8778},{0.0390,0.1453,3.9013} and {0.0124,0.0528,1.2436}, respectively. The following maximum SH; 11.16, 7.87, 9.52, 8.86 and 6.06 h were recorded for Non-regional, Northern, Eastern, Central and Western regions, respectively. Further, comparative validation with redeveloped global SHM showed that the present model stands in all the regions, whereas the global models validated only in the Eastern region. This is attributed to the synergy of geographical and climatological indices against the global models only based on climatological index. The model results show the order of regional SH distribution; eastern>northern>central>western region. These results could be employed in solar power, exploitation and agrometeorology development. This study further recommends for adoption of the present model to non-equatorial regions upon redevelopment as a meaningful extension of this work.
Renewable Energy Resources and Technologies
Narges Barzanooni; Hamid Reza Haghgou
Abstract
In this paper, on the basis of Green comprehensive Plan at Hakim Sabzevari University of Sabzevar, Iran, using of active solar systems at dining hall has been evaluated. On the basis of solar measured data and some solar models and relations, solar energy on the various surfaces and tilts are ...
Read More
In this paper, on the basis of Green comprehensive Plan at Hakim Sabzevari University of Sabzevar, Iran, using of active solar systems at dining hall has been evaluated. On the basis of solar measured data and some solar models and relations, solar energy on the various surfaces and tilts are evaluated. Then electricity and thermal energy consumption are measured and new efficient lighting systems are introduced. Then photovoltaic/thermal panels and one ended evacuated tube solar collector for façade and rooftop installation are chosen. Results shows that 36683 Nm 3 /year natural gas and 87.6 tone/year pollutant are reduced. Payback time of the system based on internal energy carrier and export electricity price are 21.3 and 3.9 years respectively.
