Iranica Journal of Energy & Environment
Volume:14 Issue: 2, Spring 2023

This research, conducted in Gotvand, southwest of Iran, compared the energy consumption of two cucumber production systems: field and greenhouse production systems. In this study, energy inputs of two production systems of cucumber (including seed, pesticide, human labor, machinery, diesel fuel, electricity, organic manure, chemical fertilizer) were determined from questionnaires completed by farmers. The results of the experiment indicated that the energy input of the two cultivation systems was not significantly different in input energies. In both cucumber production systems, the most input energy was allocated to nitrogen fertilizer (57% and 53% for field and greenhouse, respectively) followed by diesel fuel (21% in both production systems). Non-renewable energies accounted for 90 and 88% of the total energy input to the farm and greenhouse systems, respectively. Total output energy of field and greenhouse cucumber production system was 33000 and 34000 MJ, respectively. Reducing the consumption of nitrogen fertilizer through the use of appropriate crop rotation is a suitable solution to improve energy efficiency in the cucumber production system.

The present manuscript aims to identify the advantages and consequences of hydropower development, showing a view of trends finding the status and situation in Brazil, Colombia, and Ecuador. This study uses a non-experimental methodology based on a comprehensive literature review of relevant papers retrieved from 41 selected papers that are summarized covering different application areas in these selected countries. In addition, the non-experimental methodology is guided by a perspective design sequential with a qualitative phase defining two indicators that do a relation between the people and the installed capacity in megawatts (MW) and energy production in gigawatts hour (GWh). The results show Colombia has the main installed capacity and energy generation per capita, followed by Ecuador, and finally, Brazil. According to the models and studies, the general hydropower potential of Brazil, Colombia, and Ecuador decreases as time goes on because this renewable energy affects the water quality, interacting deeply with the surrounding environment. However, in South American countries only 34% of hydropower potential has developed.

With surge irrigation, applying surges to an area is a cheap labor task. In industrialized nations, a variety of electronic valves for discontinuous water application (surges) are available; but their pricing prevents their usage in emerging regions. Additionally, these valves are too advanced for use by growers in underdeveloped nations. As a result, a basic Automatic Surge Gate was developed and tested in the labs to assess its effectiveness in terms of producing on-off surges. The reservoir was built to hold or collect low inflows for barrier functioning, and the gate was positioned on the suction side of the reservoir. Inflow rates, pinions, and poundage placements on the gate lever were the working parameters defined for the gate functioning. In the current investigation, three inflow rates 134, 169, and 187 l/s were employed. By leveraging the low inflows to the reservoir, the automatic surge gate demonstrated the possibility for automating the on-off action. The surge gate produced sizeable outflows even at the lowest inflow rate of 134 l/s into the reservoir. Power-law equations were discovered to be a good representation of the behavior in the statistical models that were also created using quasi statistical method.

The city of Yazd has a large number of traditional houses. Houses with central courtyards and an Iwan were suitable for establishing thermal comfort conditions. In this research, the effect of Iwan's depth and the ratio of the adjacent room's openings on the comfort condition in the residential courtyard buildings in Yazd city were evaluated. The current research aims to provide an optimal model of the Iwan to increase sustainable development and use such models as the Iwan in contemporary housing in the hot and dry climate of Yazd. In order to investigate the effect of parameters, samples from the north-facing room and south-facing room in a central courtyard model with different proportions of the Iwan and different sizes of the window were simulated in Design Builder software. The results showed that the depth of Iwan and window to wall ratio's (WWR) of the adjacent room’s window significantly affects the comfort (according to cooling load, heating load, and energy consumption) in this room. The results obtained in this research will be a new window to recover the concepts of old patterns and help to solve climate problems.

In this study, renewable energy sources including a high-temperature solar parabolic trough collector and geothermal water integrated with a modified Kalina cycle, a combined ORC-EJR cycle, an electrolyzer, an RO desalination unit, and a domestic water heater. SiO2 and TiO2 nanoparticles dissolved in Therminol VP1 are applied as the working fluid of the solar collector. A comparative analysis of introduced working fluids is performed from energy, exergy as well as cost analysis point of view to evaluate their efficiencies. Solar irradiation, ambient temperature, and collector inlet temperature were the parameters investigated to discover their effects on energy and exergy efficiency, solar collector outlet temperature, hydrogen production rate, and freshwater production rate. The highest generated outlet temperature of the solar collector outlet was 693.8 K obtained by Therminol VP1/SiO2 nanofluid. The maximum energy and exergy efficiencies of the proposed system were 36.69 % and 17.76 %, respectively. Moreover, it is found that by increasing the solar collector inlet temperature, the hydrogen production rate decreases while the water production rate increases.

This paper investigates the effect of the immersion ratio parameter on the hydrodynamic performance of three surface-piercing propellers with diameters of 0.125, 0.132 and 0.140m at different advancing speeds. Experimental tests have been carried out in the free surface water tunnel of the Babol Noshirvani University of Technology. The results showed that the maximum thrust coefficient of three propellers occurs in the velocity range of 3-3.5 m/s. This interval represents the transition area of the three propellers. Also, the effect of the blockage ratio on the hydrodynamic coefficients of three propellers relative to the advance coefficient has been studied. By increasing the immersion depth raises the propeller's wet surface and increases the thrust and torque hydrodynamic coefficients. However, growing the propeller's diameter to 0.140m causes the effect of the blockage ratio parameter by increasing the immersion and the propeller's torque experiences a decreasing trend. Therefore, maximum propeller efficiency value with diameter 0.140m in immersion ratio 0.60 and 0.70, incresing 38% and 44%, respectively; relative to other proepllers. Also, the curve of the efficiency gradient of three propellers in the optimum immersion ratio of 0.40 compared to the advancing coefficient shows that the maximum efficiency gradient occurs in the range of 0.7 to 0.9.

In this study, natural coarse aggregates were replaced with coarse recycled concrete aggregate (RCA) in 0 %, 50 %, and 100 % extracted from construction and demolition wastes. Their recycling could lead to a greener resolution for preserving the environment and paving the way for sustainability through solid waste management. The compressive strength of 0 %, 50 % and 100 % RCA at 365 days was reduced by 3.97 %, 4.88 %, 6.81 %, respectively, compared to the compressive strength at 28 days. Tensile strength at 365 days was reduced by 4.31 %, 6.50 % and 9.83 % compared to tensile strength at 28 days. There was no discernible effect of water type on the strength properties of concrete. Compared to other combinations, 100 % RCA concrete experiences a greater percentage of weight loss owing to evaporation of free water. When temperature was elevated, the concrete matrix expands and deep cracks were observed on the concrete surface. The overall performance of recycled aggregate concrete was not much influenced by the use of such aggregates, so these findings will add a new achievement to a sustainable construction through solid waste management.

Today, the focus on the sustainability issue in universities has become of significance considering the climatic and environmental issues. Therefore, universities are moving toward uniting the sustainability methods in their systems. Currently, many universities in Iran are performing essential activities in relation to environmental issues. This study is to determine the share of universities in sustainability quantitatively, and then it analyzes their activities. This research evaluates their activities in two steps based on the clustering and the efficiency of their performance. In the first step, the universities are grouped into homogenous clusters based on hierarchical clustering method with regards to their activities in sustainability area. Following that, the Comparative Table is used to calculate the gained percentage in each index based on the mean of the scores of each group using the data of the year 2021. This is done to have a better understanding of the performance of each cluster and the universities priorities for becoming greener and more successful in green-metric system. By evaluating the productivity and the efficiency of the universities, this study represents the most sustainable universities in group one (as the highly sustainable) and group two (as moderately sustainable) which have achieved the maximum grade in energy, transportation, research and instructive areas. These results also show that environmental variables (including water management, waste and infrastructure management) need to be taken into account by universities.

This paper introduces a novel harvester to store the electrical power, which comes from the power of external applied electrical voltage. In the last decade, most of the energy harvesters have been designed and analyzed in the form of cantilever beams. In the present article, the harvesters are analyzed as a cantilever beam with the Euler-Bernoulli beam assumptions. The beam of energy harvester consists of an active Magneto-electro-elastic (MEE) layer attached to the piezoelectric layer. Assuming that the connection of these layers is perfect, the uni-morph configuration is investigated. The magneto-electro-elastic governing coupled equations of the MEE energy harvester are derived for a harmonic external applied electrical voltage in the transversal direction based on Euler-Bernoulli theory, Gaussian law, and Faraday law. These equations are solved analytically to find out the amount of harvested power and voltage. The obtained results state that by adjusting the electromechanical parameters, up to 66% of the input power and 27% of the applied voltage can be harvested. Choosing the right geometric parameters can increase the harvested power and voltages connected to the electrodes and external coil by 120.31%, 49.05% and 60.98%, respectively. Finally, the results prove the usefulness and efficiency of the dual-usage (actuator-harvester) of the new energy harvester.

In this study, first-law, second-law, and exergo-economic investigations are accomplished to recover the waste heat of a two-shaft turbofan engine applying a supercritical carbon dioxide Brayton cycle. The efficacy of different operating parameters including the inlet temperature of the turbine, the pressure ratio of the compressor, and Mach number on the performance of the proposed system in terms of energy and exergy performance, exergy destruction rate, and annual levelized cost of investment have been examined. The results indicate that the energy performance of the cycle is specified as 42.94%, the second-law performance of the cycle is calculated as 85.88% and the whole power generation amount of the system is achieved to be 9806 kW. Also, the results display that among the various components of the proposed system, the maximum amount of exergy destruction occurred in the low-pressure compressor, the fan, and the mixer. It is found that by increasing the inlet temperature of the high-pressure turbine, the first-law efficiency and the second-law efficiency of the proposed cycle decrease while the total cost rate and exergy destruction rate increase. Moreover, it is inferred that the thermodynamic efficiency of the system rises when the pressure ratio of the compressor and Mach number increase. The outcomes also demonstrate that concerning the capital costs and exergy destruction costs of components, the highest amount is obtained for high-pressure turbine and recuperator, which are 326.3 $/h and 358.4 $/h, respectively.

Solar air heaters (SAHs) have an inherent drawback: the conventional mechanism is low inside these collectors’ types. Use of perforations is a simple technique to improve convection, and this investigation experimentally assesses a novel design SAH utilizing three inclined perforated absorber plates. Two scenarios are considered to assess the dynamics and efficiency of this perforated SAH, including mair = 0.012 kg/s and 0.024 kg/s. Numerous sensors monitored the dynamics of the perforated SAH and ambient factors for 12 hours in October 2022. The experimental outcomes illustrate that the perforation method remarkably enhances the thermal efficiency of the perforated SAH compared with standard smooth SAHs. The daily thermal efficiency of the perforated SAH reaches 73.30% and 82.65%, while the outlet air temperature experiences peak values of 39 oC and 42 oC at noon and keeps within 90% of its maximum value for 2 hours for the scenarios considered. Improving the convection mechanism causes the flowing air to extract the absorber’s thermal energy more effectively. Hence the SAH can produce an airstream near its maximum temperature for an extended duration. In conclusion, the perforation method is a robust, simple method to boost the thermal efficiency of SAHs.