Iranica Journal of Energy & Environment
Volume:16 Issue: 3, Summer 2025

In this study, the thermodynamic and thermoeconomic analysis of a multigeneration system which produces power, cooling, domestic heating, hydrogen and freshwater has been carried out. The main source of energy for this system is a solar parabolic trough collector (PTC). The working fluid applied for this solar collector is Al2O3-Therminol VP1 nanofluid. The subsystems of this multigeneration system are a steam Rankine cycle for power production, an organic Rankine cycle for power production, a double-effect absorption refrigeration system for cooling production, a domestic water heater for hot water production, a PEM electrolyzer for hydrogen production and a RO desalination unit for freshwater production. In the ORC cycle a TEG unit is applied instead of the condenser for extra power production. The system is analyzed by using the EES software. The effects of different parameters as well as the effects of nanoparticles on the performance of the proposed system were investigated. According to the results, the energy and exergy efficiency of the system are 33.81 % and 23.59 %, respectively. Among the studied working fluids in the ORC cycle, n-pentane shows the best performance. The energy and exergy efficiency of the system increases by the nanoparticle volume concentration and the solar radiation increase. Moreover, the collector inlet temperature has a negative effect on the hydrogen and freshwater production rates. Finally, it is proved that the PTC collector has the highest amount of exergy destruction rate in the studied system.

This study investigates the enhancement of thermal performance in Evacuated Tube Solar Collectors (ETCs) by integrating graphene nanoparticles into the heat transfer fluid. Improvement the efficiency of ETCs is crucial for maximizing solar energy utilization, particularly in regions with diverse climatic conditions. To achieve this, we conducted experiments comparing the thermal performance of the ETC under two conditions: with and without graphene nanoparticles, and at varying flow rates of condenser water (5, 10, 15, and 20 L/h) in an open space in Babol, northern Iran, over two periods in August 2022. Measurements included ambient temperature, input and output water temperatures, heat pipe temperature, and water flow rate. Key performance indicators, such as the average Nusselt number, useful heat output, and convection heat transfer, were calculated. The results indicate that the Nusselt number increased by 10.64% and overall thermal performance improved when utilizing the acetone-graphene nanofluid at a flow rate of 20 L/h under vacuum conditions (-0.6 bar) with a volume fraction of 0.08% nanoparticles. This work demonstrates a significant enhancement in thermal energy storage capabilities of ETCs, showcasing the potential of nanofluids in solar thermal applications, thereby contributing novel insights into the engineering optimization of solar collectors.

In this work, a natural ventilation system as an energy-efficient strategy is simulated to assess its performance in providing thermal comfort and indoor air quality in an office space. A three dimensional CFD model is implemented to predict temperature and velocity distribution in the space. Due to the presence of the openings and elevated air speed, a naturally ventilated space is considered as a non-uniform thermal environment. In such environments, the whole body thermal sensation is affected by local thermal sensation of different body parts. So, the CFD model is coupled with the standard thermal comfort model and the PMV and PPD indices are assessed at different heights according to ISO standard to evaluate the local thermal sensation of individual body parts. Afterward, the effects of outdoor air temperature as well as location and dimension of the openings are evaluated. The results show that in the outdoor temperature of 24 ℃ and 26 ℃, the PMV index is nearly between -0.7 and +0.7 and the PPD is less than 15%, which are the recommended range considering the category C of ISO 7730. In addition, the best thermal comfort conditions are achieved by considering the openings with 10% of the wall area.

The use of thermodynamic cycles for power generation is very important. The use of renewable energy in thermodynamic cycles instead of a heat source causes these cycles to become popular from an environmental point of view. In this study, Organic Rankine cycle (ORC) is considered for power generation. Ground source at 100 °C and flat plate collectors (FPC) have been used to provide the required heat. Also, an off grid residential building with 408 residents has been considered to provide power. For energy storage, the hydrogen system including proton electrolyte membrane (PEM) electrolyzer and fuel cell has been used. This cycle is used to supply the demand of the building from an economic and environmental point of view, with variable decisions of collector area, flow rate and tank volume for multi-objective optimization. The generated energy is initially consumed in the building and the excess power is stored in the form of hydrogen to be used during power shortage hours. The results showed that the payback time of the studied cycle is 6.32 years and the levelized cost of electricity (LCOE) was 0.26 $.kWh-1. Also, from the environmental point of view, 583.3 tons of CO2 will be reduced throughout the year.

In recent decades, problems such as air pollution and the reduction of fossil fuel resources led to the development of electric vehicles. Wireless power transmission is an efficient and reliable way to charge fixed and mobile electric vehicles. One of the main problems in the dynamic wireless power transmission method is the amount of constant power transmission and its fluctuations. The purpose of this paper is to compare six different types of winding structures for choosing the best type of winding for the transmitter side in the application of dynamic charging of electric vehicles. In this paper, the winding function method is used for more accurate modeling of coils in terms of spatial harmonics and calculation of their self and mutual inductances by changing the location of the vehicle. Also, for coil excitation, instead of using the common single-phase inverter, a three-phase type is used to reduce the power ripple. The comparison is made in the aspect of the transmission power amount and its ripple. Modeling and simulation results are presented to confirm the actual results.

The weak convection mechanism in photovoltaic/thermal (PV/T) systems leads to numerous studies dealing with this problem. This study analyzes a new, affordable method to improve convection in PV/Ts and increase their thermal/electrical efficiency. The use of metallic porous materials with high thermal conductivity is a robust approach to increase the efficiency of PV/Ts by accelerating the cooling rate of PVs. In this study, the robust method is experimentally investigated, and the effectiveness of using porous materials to improve the efficiency of PV/Ts is evaluated. For this purpose, an experimental setup was fabricated, and two scenarios were investigated: a non-porous PV/T and a porous one in which steel wool was used as a porous material. The acquired results revealed that using steel wool reduces the PV temperature by 9.9 oC and increases the outlet temperature by 4.41 oC at the air flow rate of 0.17 kg/s. Lowering the PV temperature increases the electrical power generated while the electrical efficiency improves by nearly 11.18%. The higher outlet temperature causes a higher thermal efficiency; hence, using porous materials increases the thermal efficiency by 50.7%. In conclusion, using porous materials is a robust, affordable approach to improve the thermal/electrical efficiency of PV/Ts.

This study aimed to provide a clean energy-based growth model emphasizing public policy. The study's statistical population in the quantitative section in the first stage was the members of the fuzzy Delphi panel, consisting of 15 people from the most suitable group of experts regarding deep knowledge, breadth of view, and sufficient experience to achieve valid and accurate results. In the next step, the statistical population included all managers and experts of the Ministry of Energy in 2023-2024, totaling 327 people, using the Cochran formula through simple random sampling. The findings from the qualitative stage were analyzed using MAXQDA software. In the quantitative section, fuzzy Delphi tests, structural equation techniques, and the best-worst method were used with the help of SPSS, SmartPLS, Lingo, and Excel software. From the analysis of 15 interviews, 213 primary codes were extracted, 67 basic themes, and after categorization, ten organizing themes. The quantitative section's findings demonstrated that all correlations were acknowledged and that there was a meaningful route between all variables. Also, in prioritizing the indicators of the clean energy-based growth model with an emphasis on public policy, it was determined that the indicators of strategies for using clean energy were the priority, policies for using clean energy in the second priority, culturalization in society for using clean energy in the third priority, and the consequences of clean energy development in the fourth priority.

Billboards are one of the types of structures that wind load can be the dominant lateral load on this type of structures. Since billboards are usually placed in public places, destroying these structures under wind can cause irreparable damage. In this research, using wind tunnel testing and numerical modeling based on computational fluid dynamics (CFD), the effect of wind on single-plate, two-plate, and triangle billboards has been investigated. The models used in the wind tunnel are made using wood at a scale of 0.01. To find the critical loading pattern of wind load, the structure in the wind tunnel is rotated every 5 degrees concerning the wind direction, and the wind pressure values are recorded. The maximum displacement in single-plate, two-plate, and triangular billboards with tubular column sections is obtained at θ= 45°, θ= 45° and θ= 15°, respectively. Due to the nature of the wind flow, rectangular columns are unsuitable for billboards because the stiffness of the column also changes with the change of the wind angle relative to the billboard.

This study investigates the integration of a concentrated photovoltaic thermal (CPVT) module with a supercritical carbon dioxide (sCO₂) ejector refrigeration cycle to enhance sustainable cooling technologies. This research is significant as it explores the potential of sCO₂, a low-impact working fluid, in improving cooling efficiency within a novel energy system. The system’s performance was evaluated using calculations conducted in EES software, focusing on energy and exergy efficiencies, exergy destruction, and economic viability. The results revealed that the integrated system achieved notable energy and exergy efficiencies of 30.62% and 11.43%, respectively. Exergy destruction analysis identified the CPVT module and the boiler as the main sources of inefficiency, accounting for 77% and 14% of the total exergy destruction. Economic analysis highlighted the CPVT module as the primary investment cost driver. Sensitivity analysis demonstrated that increasing the solar panel area led to higher exergy destruction and costs without significantly improving efficiencies, while increasing the pump discharge pressure enhanced thermal efficiency but reduced exergy efficiency. These findings suggest that optimizing pressure levels within 6.5 to 11 MPa can lead to substantial variations in system performance, with thermal and exergy efficiencies varying by 82% and 18%, respectively. The novelty of this work lies in its comprehensive integration of CPVT and sCO₂ technologies, offering new insights into efficiency trade-offs and economic considerations for advanced cooling systems, thereby extending beyond previous literature efforts.

The thermoelectric module is advantageous due to its non generation of toxic waste and versatility across different scales.  As a renewable energy source and an alternative to fossil fuels, TEM is recognized as a promising candidate for energy extraction and thermal regulation. However, despite its potential as a renewable energy source, it seems that based on its limited efficiency and high costs necessitate an investigation into the key parameters affecting its performance. This involves the application of suitable methodologies to improve them in industries. In this study, the thermoelectric module has been numerically simulated, in order to investigate the influential parameters through statistical methods. The investigated parameters include the geometrical parameters of the rectangular leg pairs, such as their length, width, height, distance between them, quantity, as well as the temperature of the heated surface and the electric current input to the module. The cold side temperature and input voltage has been analyzed as responses by considering the affecting parameters. Analysis of variance (ANOVA) and central composite design have been employed to analyze responses. Moreover, in order to examine the impact of influential parameters on responses, a statistical sensitivity analysis was performed using the design of experiments and response surface methodology (RSM). The appropriate response functions were observed between factors and responses obtained from the statistical procedures. The study found that reducing the cross-section area of leg pairs from 4 mm² to 2 mm² and the hot surface temperature from 100°C to 50°C led to a 15% increase in input voltage. Furthermore, increasing the electric current from 2A to 4A and the height of leg pairs from 5 mm to 10 mm caused a 20% increase in input voltage and a 10% decrease in cold surface temperature.

Shortage of safe drinking water is a major problem in Bangladesh, especially during the dry season from November to March. Due to high population growth, the crisis of healthy drinking water is increasing day by day. Rainwater is a major source of pure drinking water. Rainwater harvesting has proven to be the most economical and environmentally friendly method. So, it can hold great potential to deal with the current problem of acute arsenic poisoning and pure water scarcity in Bangladesh. To overcome this problem a model rainwater harvesting (RWH) system has been demonstrated in Faridpur, Bangladesh. The research showed that by utilizing 1037 buildings as catchment areas and installing storage tanks in 20 unused spaces of government offices, it is possible to address the entire drinking water scarcity issue in Faridpur Municipality. The study also investigates the quality of local pipe-well water and the quality of the stored rainwater. The findings of present study showed the quality of harvested water is much better than the pipe-wells water. The runoff reduction through Rainwater Harvesting was 14.82% which can significantly reduce the water logging and water pollution problem of Faridpur city. The findings of this work provide a potential blueprint for expanding water access throughout Bangladesh and other countries facing similar challenges.

Information and Communication Technology (ICT) is recognized as a critical driver of economic development in the modern era, significantly enhancing the productivity of production factors. However, the widespread adoption of ICT, particularly in countries reliant on fossil fuels, may contribute to increased greenhouse gas emissions, including carbon dioxide (CO2). So, this study investigates the interconnections among ICT, CO2, renewable energy, and Total Factor Productivity (TFP) in Iran. This descriptive-analytical and applied study used time series data from the World Bank and Iran Statistics Center from 2000 to 2023. This study, the Autoregressive Distributed Lag (ARDL) model to evaluate the long-term and short-term dynamic, unit root tests and diagnostic tests CUSUM and CUSUMQ and Canonical Co-Integrating Regression (CCR) Dynamic least squares (DOLS), and fully modified least squares (FMOLS) have been used to validate the results of ADRL estimates.The results of the ARDL estimation method showed that in the long run, TFP and economic growth on carbon dioxide had a coefficient of 0.07 and 0.14, respectively. Renewable energy consumption with a coefficient of -0.0808 had a significant negative role in reducing carbon dioxide. The coefficient of -0.286 obtained for the ICT variable at 95% indicates a reduction in carbon dioxide in parallel with the development of ICT. CUSUM and CUSUMQ confirmed the stability of the parameters, and CCR, DOLS, and FMOLS regressions confirmed the results of the ADRL model. The study recommends adopting green technologies and effective energy policies to balance productivity gains with environmental protection.

Climate change (CC) is a real challenge for the world. Iran lies in an arid part of the world and CC is adversely affecting its water resources and agriculture. Iran has taken various initiatives, enacting related laws and establishing policy measures, to respond to water scarcity and food security in the agricultural sector. This study was conducted to understand and explore Iran’s initiatives, especially through legislation and policy responses, to address water scarcity and food security under CC conditions. More specifically, it reviews and analyzes the laws and rules relevant to agricultural water management and food security for their capacity for adaptation to CC in Iran. It was found that most of the relevant laws and policy documents were established to improve water consumption patterns. However, the study identified that there are a limited number of laws and policy documents with respect to climate adaptation and mitigation for the agriculture sector. There is a need to establish special laws towards climate change adaptation and mitigation for the agriculture sector and to revisit and revise the existing laws and policy documents in this regard. Proper implementation of adaptation measures is another issue that is not fully or effectively addressed and supported by the national legislation.

This study evaluates the utilization of waste heat from a polymer electrolyte membrane fuel cell (PEMFC) across four scenarios: combined heat and power (CHP), combined cooling, heating, and power (CCHP), combined cooling and power (CCP), and hybrid power generation with an organic Rankine cycle (ORC). The methodology involves thermodynamic modelling and parametric analysis to assess energy efficiency, fuel savings, and environmental impact. The CCHP scenario demonstrates the highest overall system efficiency of 87%, achieving 46% fuel savings and a 55% reduction in CO₂ emissions. The ORC scenario, leveraging waste heat for hybrid power generation, achieves an electrical efficiency of 41% and an overall efficiency of 68%, with 26% fuel savings and a 49% CO₂ emissions reduction. This study reveals that integrating CCHP systems provides superior performance across energy, environmental, and economic metrics. The findings contribute to advancing sustainable energy systems by optimizing waste heat recovery, reducing emissions, and providing tailored solutions based on consumer demands and operational conditions.