Energy
N. Tayari; M. Nikpour
Abstract
New designing techniques have been used recently in design phases of buildings to adapt human thermal comfort. Due to wide range of energy consumption within a building, it is impossible to make a proper decision about the impact of different energy efficiency strategies without simulation tools. Architects ...
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New designing techniques have been used recently in design phases of buildings to adapt human thermal comfort. Due to wide range of energy consumption within a building, it is impossible to make a proper decision about the impact of different energy efficiency strategies without simulation tools. Architects need to understand the accuracy and precision of simulation software to use them as valuable tools to predict energy consumption. This research aims to investigate the validity of DesignBuilder simulation software by using the actual traditional house in terms of heat gain. In this study, the comparative method was used to determine the differences in heat gain in a traditional courtyard house in Kerman that was simulated using DesignBuilder software and measured experimentally. This study also reveals that the difference between simulation results and empirical measurement is not more than 10%. It can be concluded that DesignBuilder has enough validity to calculate the amount of heat gain in the rooms adjacent to courtyards.
Energy
F. Chabane; N. Moummi; C. Toumi; S. Boultif; A. Hecini
Abstract
This study aimed to compare global solar radiation on the horizontal area between two models of Chabane Foued and M.Capderou. The model of Chabane has been interested in pollution factors such as TL (turbidity), BE (Angstraon), and the chemical components of the air such as WV, O3, CH4, CO, CO2, and ...
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This study aimed to compare global solar radiation on the horizontal area between two models of Chabane Foued and M.Capderou. The model of Chabane has been interested in pollution factors such as TL (turbidity), BE (Angstraon), and the chemical components of the air such as WV, O3, CH4, CO, CO2, and the especial part the new pollution factor such as hbeam, kbeam, and kdiffuse, which all influenced onto solar radiation, and the model of Capderou has been used the atmospheric disturbance to calculate the direct and diffuse components of radiation received on a plane, while the constituents of the atmosphere (absorption and diffusion) can be expressed by disturbance factors, which is very necessary to determine irradiation In the clear sky. The results reveal a significant difference between the two models with approximated curves. The difference between the models probably returns to the nature of the geographic site which the authors used and injected into the models.
Energy
M. Esmaeili Shayan; M. R. Hayati
Abstract
Having kilometers of asphalt road, yet with this heat going to waste, an attempt has been made in this research to extract the road's renewable energy heat. The purpose of the experiment is to compare the energy and exergy efficiency of various materials of asphalt solar water heaters (ASWH), as well ...
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Having kilometers of asphalt road, yet with this heat going to waste, an attempt has been made in this research to extract the road's renewable energy heat. The purpose of the experiment is to compare the energy and exergy efficiency of various materials of asphalt solar water heaters (ASWH), as well as heat transmission through the water tube and how friction affects exergy destruction. The water flow rate of one ASWH was 0.01 kg/s, while that of the other was 0.02 kg/s. Each ASWH has an area of 0.5 square meters. The copper tube is buried 10 mm deep in the asphalt. 15 degrees is the angle of inclination. The results indicate that the energy and exergy efficiencies are reasonably high for the water flow rate of 0.02 kg/s. Depending on the water flow rate, asphalt temperature, and sunlight intensity, the energy and exergy efficiencies changed from 32% to 65% and 5.8% to 16%, respectively. The water flow rate is an essential parameter for estimating the internal convective heat transfer coefficient and Reynolds number in order to calculate the friction factor in the copper tube based on internal convection heat transfer. In contrast, the friction factor is a consequence of the pressure loss and exergy degradation induced by friction.
Energy
A. Yousefi; R. Shafaghat; M. Beykani; A. Aghajani Afghan; S. T. Seyyed Mostafa
Abstract
Surface piercing propellers are special supercavitation propellers operating at free surface. These propellers are designed to have the best performance at the highest speed. The geometric parameters of the number of blades and the pitch ratio will significantly impact the critical advance coefficient ...
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Surface piercing propellers are special supercavitation propellers operating at free surface. These propellers are designed to have the best performance at the highest speed. The geometric parameters of the number of blades and the pitch ratio will significantly impact the critical advance coefficient range, ventilation and consequently the hydrodynamic performance of the propeller. Therefore, in this paper, the effect of two crucial parameters of pitch ratio and number of blades were experimentally studied in free surface water tunnel. After calibration and evaluation of uncertainty, two 5-bladed propellers with same section profile and pitch ratio of 1.5 and 1.4 used to investigate effect of pitch ratio. The results of two 5-blade and 6-blade propellers with same section profile and pitch ratio of 1.4 were compared. The immersion ratio was 40%, and the shaft inclination angle was zero. Results showed that increasing the pitch ratio increased the thrust and torque coefficients by 30%; while increasing the critical advance coefficient. Consequently that has led to the development of a full ventilation range and improved hydrodynamic performance of the propeller. In addition, by increasing the number of blades, at values greater than the critical advance coefficient, the thrust and torque coefficients were increased by 10%. However, the critical advanced coefficient changes were negligible. Comparing the results in the three-dimensional contours showed that with the change in the number of blades, by increasing the pitch ratio, the critical advance coefficient increased; which led to a further increase in efficiency.
Environment
E. O. Dada; F. A. Oke; Y. O. Balogun
Abstract
Earthworms and crabs are known to influence the physicochemical state of their respective soil habitats through their bioturbation actions. While earthworm-bioturbated soils have been well documented to positively affect plant growth, not much is known about the effects of crab-bioturbated soil on plant ...
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Earthworms and crabs are known to influence the physicochemical state of their respective soil habitats through their bioturbation actions. While earthworm-bioturbated soils have been well documented to positively affect plant growth, not much is known about the effects of crab-bioturbated soil on plant growth. In this study, we compared the growth performance of four varieties of Phaseolus vulgaris (bean) seedlings in earthworm-bioturbated soil, crab-bioturbated soil, and unbioturbated soil collected within the same proximity of a wetland habitat. Seeds of Phaseolus vulgaris were planted in replicates in each soil type, and allowed to grow for 15 days. Physical growth was measured using a metre rule. Biochemical growth parameters were measured using standard procedures. The differences in stipule length of bean seedlings grown in all the soil types were generally not significant (p > 0.05). However, seedlings grown in earthworm-bioturbated soil and crab-boturbated soil recorded significantly higher (p < 0.05) stipule weight, relative to those grown in unbioturbated soil. Bean seedlings grown in earthworm-bioturbated soil recorded the highest and significant (p < 0.01) concentrations of chlorophyll, total sugar, starch, nitrogen, and crude protein, relative to those grown in crab-bioturbated and unbioturbated soils. This was followed by seedlings grown in crab-bioturbated soil which recorded significantly higher (p < 0.01) concentrations of these biochemical parameters, relative to those grown in unbioturbated soil. The significantly higher biochemical and marginally better physiological growth recorded for seedlings in bioturbated soils indicate that earthworms and crabs both contribute significantly to wetland productivity, through their bioturbatiion activities.
Energy
A. Amini; N. M. Nouri
Abstract
The Surface-Piercing propeller blades move in and out of the water with each rotation to reduce the immersion depth from the free surface to the shaft axis . The main challenge facing surface piercing propellers, however, is their lower efficiency at lower advance velocity, compared to other propulsion ...
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The Surface-Piercing propeller blades move in and out of the water with each rotation to reduce the immersion depth from the free surface to the shaft axis . The main challenge facing surface piercing propellers, however, is their lower efficiency at lower advance velocity, compared to other propulsion systems. To improve the performance of the propeller, an aeration mechanism was used at low advance velocities so that air was blown to the surface behind the propeller. Experimental studies were carried out on a propeller model in the Hydrotech laboratory of the Iran University of Science and Technology, and the effect of the injected air velocity ratio was evaluated at different immersion ratios. Based on the results obtained, it was concluded that an increase in the injected air velocity ratio could only promote thrust enhancement under specific conditions. For immersion ratios of 0.85 and more, as well as advance coefficients of 0.6 and more, a change in the velocity ratio of the injected air could not lead to an improvement in thrust. The best performance was identified with an immersion ratio of 0.4 and an advance coefficient of 0.4, while thrust performance at below or above of this condition declined .
Energy
H. Eskandari
Abstract
Agriculture is a system exhibiting high levels of energy consumption. Thus, energy analysis is crucial for improving the energy efficiency of agricultural systems. In this research, the input energy of an irrigated wheat production system, including seeds, machinery, fertilizer, irrigation, electricity, ...
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Agriculture is a system exhibiting high levels of energy consumption. Thus, energy analysis is crucial for improving the energy efficiency of agricultural systems. In this research, the input energy of an irrigated wheat production system, including seeds, machinery, fertilizer, irrigation, electricity, diesel fuel and human labour, were determined and thereby the net output energy, energy efficiency and energy productivity were calculated for energetic system evaluation. For reaching this goal, 110 farmers were asked to complete the questionnaires in which cultivation information such as machinery, diesel fuel, grain produced per hectare, cultivation method, the method and the duration of water supply, workers, chemical materials which were used for plant treatment. The results showed that the total input energy for producing irrigated wheat was 42,481 MJ.ha-1. Energy efficiency was achieved as 1.56, suggesting that the total output energy of the system was more than the input energy. The net output energy, indicating the rate of obtained net energy from the system, was 23,819 MJ.ha-1. Electricity and fertilizer were the inputs consuming the most energy in an irrigated wheat production system, in which 41% and 31% of the total consumed energy were devoted to electricity and fertilizer, respectively. Therefore, the appropriate management of electricity and fertilizer through advanced methods of irrigation and the precise calculation of plants’ required nutrient elements can result in the improvement of the energy efficiency of the system. Reducing seed bed preparing operations (decrease diesel fuel consumption) may also increase the energy efficiency of the wheat production system
Energy
S. Prem Kumar; G. Kumar
Abstract
In solar drying, the moisture content of a product is reduced through the use of sunlight. Solar drying is practiced since civilization for the drying of crops. The dried crop has a longer shelf life and requires less storage space. For crop drying, hot air is required in the moderate temperature range ...
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In solar drying, the moisture content of a product is reduced through the use of sunlight. Solar drying is practiced since civilization for the drying of crops. The dried crop has a longer shelf life and requires less storage space. For crop drying, hot air is required in the moderate temperature range of 40 to 75℃. Solar dryer makes it possible to obtain better product quality. Over the past 20 years, numerous experimental projects have been carried out in the field of solar dryers. Most conventional dryers are not able to operate continuously during the off sunshine time. However, attempts were made to develop uninterrupted solar drying systems by incorporating an energy storage facility and a hybrid mode of operation. Sensible and latent heat storage methods are widely used to store solar energy. Heat storage materials store energy in the form of heat during sunshine and release it whenever it is required. Biogas backup, Chemical heat pump, Photo Voltaic, and Fluidized bed methods were integrated with solar dryers for uninterrupted operation. In this article, the discussion is made about different dryers. Also, the challenges and scope in the area of the solar dryer are highlighted.
Energy
R. Aghagolzadeh Silakhor; O. Jahanian; B. Alizadeh Kharkeshi
Abstract
Using cogeneration systems is a great way to tackle fossil fuel consumption problems. This paper introduces a Combined Cooling Heating Power (CCHP) system to recover the waste heat of an RK215 heavy diesel engine as a prime mover. Therefore the CCHP system consists of Internal Combustion Engine (RK215), ...
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Using cogeneration systems is a great way to tackle fossil fuel consumption problems. This paper introduces a Combined Cooling Heating Power (CCHP) system to recover the waste heat of an RK215 heavy diesel engine as a prime mover. Therefore the CCHP system consists of Internal Combustion Engine (RK215), a heat storage tank, and an absorption chiller. Also, the system has been studied in four modes: CCHP, CHP, CCP, and single generation. The waste heat ratio has changed due to a y factor, and the effect of this different parameter, such as the start of fuel injection and exhaust gas heat, on the system's efficiency by considering first and second laws of thermodynamic in different operating modes has been investigated. The system's highest energy and exergy efficiency in CCHP mode is equal to 50.46 and 30.8%, respectively. According to the result, as the CCHPs cooling load to the absorption chiller increases, the performance also rises. Also, the system’s carbon dioxide emissions reduction has been studied. The results showed that using different modes for waste heat recovery can reduce carbon dioxide by up to 30% approximately for different modes. Also, the fuel energy saving ratio (FESR) has been investigated, and the results showed that systems in CCHP, CHP, and CCP modes could have FESR approximately equal to 21%.
Energy
F. Najjari Seresht; A. Hakimi Oskui; S. Salkhi; E. Imani
Abstract
The building envelope is one of the most influential factors in energy consumption. Therefore, optimizing the facade of the building with new technologies is one of the most effective passive solutions to provide thermal comfort. The purpose of this research is to design a composite facade, which according ...
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The building envelope is one of the most influential factors in energy consumption. Therefore, optimizing the facade of the building with new technologies is one of the most effective passive solutions to provide thermal comfort. The purpose of this research is to design a composite facade, which according to the two main driving forces; the pressure difference caused by the heat flow (air flow and wind force) and the insulation of the air, for a residential building with a typical plan of Yazd in the hot and dry climate of Iran. That can be used to reduce the heating and cooling load of the building. For this purpose, firstly, the effect of two types of two-skin facades - floor-to-floor and all-over two-skin facades - compared to the model without two-skin facades in cooling and heating energy consumption throughout the year was modeled and analyzed with Design Builder version 6.1 software. The results of the constructions show the possibility of reducing about 60% of cooling energy through the creation of air conditioning and 26% of heating energy through the creation of thermal insulation in the residential building simulation model throughout the year by means of two combined shells. The findings of this research lead to the creation of more efficient energy solutions by creating innovation and combining new technologies according to climatic conditions.
Environment
Z. Dorrani; H. Farsi; S. Mohamadzadeh
Abstract
In traffic monitoring for video analysis systems, vehicle shadows have a negative effect on their performance. Shadow detection and removal are essential steps in accurate vehicle detection. In this paper, a new method is proposed for shadow detection using a novel convolution neural network architecture. ...
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In traffic monitoring for video analysis systems, vehicle shadows have a negative effect on their performance. Shadow detection and removal are essential steps in accurate vehicle detection. In this paper, a new method is proposed for shadow detection using a novel convolution neural network architecture. In the proposed method, the edges of the image are first extracted. Edge extraction reduces calculation, and accelerates the execution of the method. The background of the frame is then removed and the main features are extracted using the ResUNet-a architecture. This architecture consists of two parts: the encoder and the decoder, which detect the shadow at the decoder output and then remove it. Deep learning is used to detect shadows, which increases the accuracy of the analysis. The ResUNet-a architecture can learn complex, hierarchical, and appropriate features from the image for accurate feature detection and discarding the irrelevant shadow, thereby outperforming conventional filters.The results show that the proposed method provides better performance on NJDOT traffic video, highway-1, and highway-3 datasets than popular shadow removal methods. Also, the method improves the evaluation criteria such as F-measure and runtime. The F-measure is 94 and 93% for highway-1 and highway-3, respectively.
