Sharif Digital Repository

This experimental study evaluates the implementation of atmospheric water generator (AWG) apparatus for rural households to supply the needed water. Humid (atmospheric) air is sucked into the condenser and passed through an air filter by a fan; since the temperature of the condenser is lower than the ambient air temperature (dew point temperature), the moist in the atmospheric air is condensed and freshwater is collected which is stored in a tank and after 7 stages of purification will be ready to drink.Data of this project is obtained from Kish Island’s weather station to find the average temperature and humidity. Kish Island is chosen for this project because of its high humidity and... 

The effect of using backpressure of air injection in a microchannel on internal flow pressure drop were investigated in this study. Multiphase flows are commonly encountered in gas and oil industries. Flow fields in production operations are often complex and include multiphase flows of gas and liquid. Previously, because of their complex nature, these flow patterns have been mostly investigated only experimentally and empirical correlations based on the experimental data. From another point of view, it is almost impossible to experimentally realize all the flow conditions for each of the flow patterns. Nowadays computer facilities provide the tool to construct and use large-scale... 

This study is aimed at simulation of the flow of air and aerosol particles through a single square fibrous filter media made up of micro fiber as well as the importance and effect of different fiber’s cross-sectional shapes and arrangements on particle deposition and filtration efficiency. An understanding of the role of changing the laminar flow regime from laminar vortex shedding "(Re"=100" and Re"=200")" to subcritical flow "(Re"=1000")" developed for the first case. The study deals with parallel and staggered multi-fibrous filter media with circular, elliptical, and equilateral triangular micro fiber’s cross-sectional shape of the transient laminar vortex shedding flow "(Re"=200")" .... 

Using clean and renewable energy as driving force for vehicles is becoming more and more important because of rising fuel prices and also environmental concerns. Using solar and wind power for direct use in vehicles seems impractical with today’s technology. Compressed air can serve as an intermediate medium to store energy and utilize it for running vehicles. The main purpose of this research was to conceptually design an air driven vehicle with acceptable performance in a city for everyday life. After a brief history, at first step advantages and disadvantages of using air as driving force of vehicle is studied. This study was carried out in different categories including cost, capability... 

Poly (lactate-co-glycolate) is a typical biocompatible and biodegradable synthetic polymer. Addition of TiO2 nanoparticles improved compressive modulus of PLGA scaffolds and reduced fast degradation. Porous 3D scaffolds, which are synthesized using biocompatible and biodegradable materials, could provide suitable microenvironment and mechanical support for optimal cell growth and function. A novel method has been applied to fabricate PLGA/TiO2 scaffolds without using any organic solvent or porogen for nucleation compared to former ways, with aim of improving the biocompatibility, macroscale morphology and well inter-connected pores efficacy: Air-Liquid Foaming. Adjustment of the foaming... 

Atmospheric corrosion as one of the most principal factors of destruction is not Climatic map of atmospheric corrosion is closely related to air and atmospheric factors among which we can point out to different types of atmospheric pollutions such as NOX, SOX gases and pendant materials as well as the rate of humidity and rain and even the rate of sun radiation. The effects of these factors beside each other cause the speed of corrosion from a climate to another climate to be changed, which is presentable in form of a map. There is a 2 method to provide this map. First build up a station to measure the corrosion data and collect them in a long period of time. This method are time consuming... 

To meet the high energy demand in greenhouse cultivation, clean technologies have been suggested. This research provides a computational and modeling framework to examine the integration of three systems including a photovoltaic panel, earth_air heat exchanger, and industrial symbiosis, to produce three types of energy (electricity cooling, and heating) in a Venlo-type greenhouse. To estimate the minimum energy required to maintain environmental parameters in optimal plant conditions, an energy demand model was developed with the ability to consider the effect of energy stored in the ground. For a greenhouse in Tehran, the annual heating requirement was calculated as 432 kWh/m2 and 227... 

Air pollution has been one of the most important problems in Tehran in recent years. So that the number of deaths due to air pollution in Tehran reaches more than 7000 cases per year. More than 75% of air pollutant emissions in Tehran city (including 60% of PM2.5 emissions) originate from mobile sources. Considering the harmful effects and damages caused by air pollutants, it is important to examine and evaluate the effects of hybrid-electric vehicles on the emissions of the transportation sector and air quality, especially in areas with a large population and realized high traffic load. On the other hand, the continuous reduction of renewable electricity production costs makes electricity a... 

Air pollution is a prevalent and pressing issue in Tehran, with significant impacts on both the environment and human health. this study uses statistical techniques, such as Pearson correlation, to determine the direction of influence of meteorological parameters on air pollutant concentrations, and Convergent Cross Mapping to quantify the causal relationship between meteorological parameters and ambient air pollutant concentrations, as well as feedback effects. Additionally, the research delves into the correlation between consumption of fossil fuels and air pollutants, as well as the relationship between lung cancer incidence and mortality by histological subtype and long-term exposure to... 

Passenger cars (PCs) are of particular importance among mobile air pollutants emissions sources due to their population and significant share in air pollutants emissions and gasoline consumption. Moreover, ownership and use intensity of PCs are affected by socio-economic situation. The present study projects the future trends of air pollutants emissions and fuel consumption from PCs in Tehran by 1415 and assesses the effect of economic situation on the emission trends and effectiveness of emission reduction polices. Accordingly, the present study develops an interdisciplinary modeling framework, which combines econometric models with a bottom-up emission estimation model to simulate the... 

The purpose of this study is to develop a simulated model of a greenhouse using two different ventilation systems, a fan&pad system and an air-soil converter equipped with a sprinkler in order to compare the cooling performance of these two systems in hot seasons. The main focus of the analysis of the results is on how the temperature and humidity are distributed throughout the greenhouse space. In order to develop a three-dimensional model with computational fluid dynamics method, greenhouse simulation in Ansis software has been used. The development of ventilation model in the greenhouse is done by creating boundary conditions using optimal design. Also, to simulate soil-air conditioning... 

The present study simulates the diffusion of nitrogen oxides from a typical thermal power plant by AERMOD. The amount of diffusion of nitrogen oxides in the environment in two sample days was assessed, one in the cold season and the other in the warm season. In the pessimistic state of the power plant on the sample day of the warm season did not cause the ambient concentration to exceed the standard level of clean air.In order to evaluate the share of different emission sources in the study area, emission sources are divided into three groups: industrial, suburban transportation and urban resources (domestic and intra-city transportation) and two modes of emission are considered. On the... 

One of the best ways to reduce water consumption is using air cooled heat exchangers, because they work in a completely closed cycle which does not require makeup water. However because of their high surface area and high-technology production method, their production cost is significantly high. Air cooled heat exchangers have relatively high exergy destruction because of low U heat-transfer coefficient. In present research, single-objective and multiple objective optimization problems are developed to minimize total annual cost and exergy destruction. Also the influence of temperature changes on these two objective functions have been evaluated by Monte Carlo simulation. In next step,... 

Nowadays, one of the most important challenges in developing and operating greenhouses in the agricultural sector is to supply them with energy. Hence, in recent years, the development of greenhouses with the goal of increasing energy efficiency and reducing production costs has been considered by the hands-on-cluster of this field. As a result, one of the main goals for the development of high-productive greenhouses is to reduce the energy consumption index for the production of a unit of product. Another challenge in the greenhouse is the high consumption of water for evaporative cooling systems. On the other hand, the supply systems for heating, cooling and ventilation should be able to... 

In the past due to the lack of mechanical systems for air conditioning in the interior spaces, the buildings were designed to be able to maximize the use of natural forces such as solar and wind power. Natural ventilation is an old method of using natural forces. For example, wind tower is one of the traditional elements for using natural ventilation in the warm seasons for benefiting from wind and sun energy. In our country, Iran, in cities like Yazd, which are located in a warm and dry climate, the use of wind towers is very common and our predecessors were pioneer in this field. With the passage of time and the development of mechanical air conditioning systems, the use of natural... 

About 6.5 million people die from air pollution annually, of which 5.5 million are from the Asian continent. By considering reduction of life span and external costs associated with the emission of air pollutants, the importance of environmental impact assessment and managing the reduction of pollutant emissions becomes even more important. Meanwhile, the largest share (85%) of pollutant emissions is related to the supply and demand sectors of energy carriers. Therefore, the design and development of the environmental impact assessment system of energy flows is a necessity in the process of sustainable development of the energy sector.A key policy challenge in Tehran megacity is to curb high... 

In the last three decades, the world has experienced enormous increases in energy consumption as a consequence of the economic and population growth. This causes renewable energy and energy recovery to become a requirement in building designs rather than option. A direct expansion (DX) air conditioning system is an efficient way to supply fresh and dehumidified air to a built environment a long side it plays a key role in preventing the spread of respiratory diseases. To improve the efficiency of a conventional DX system in hot and humid regions, fresh air dehumidification and conditioning systems with energy recovery measures are the key equipment to reach such a goal. To achieve this goal... 

One of the issues that today is considered by planners and system operators in power systems, especially the Iranian power grid, is the high variation and the lack of uniformity of load curves in different hours of the day. This has led to the use of all installed capacity of the country's production only in peak hours, and in the low and intermediate times, a large amount of installed capacity is out of the circuit, which means Unused capital. This problem is more or less seen in world power networks with high load variation curves. Also, the production of renewable energies has always been fluctuating, and the production of power control to improve this fluctuation is very important. This... 

Evaporative cooling systems are of most common cooling systems which their electricity consumption is much lower than vapor compression cooling systems. Enhancement of these system’s performance could help to propagate these systems and also decrease the electricity consumption and corresponding emissions in large scale. In this thesis, first a modified cycle is proposed for evaporative cooling. Then, in order to use evaporative cooling in humid climates, a desiccant wheel is implemented in this modified evaporative cooler. As using evaporative cooling will cause high water consumption, a novel cycle is proposed for desiccant based evaporative cooling which is able to cover system water... 

Considering the increasing importance of energy conservation in recent decades, different technologies regarding energy system have been developed to satisfy this goal. Building section is responsible for a big portion of final energy consumption and greenhouse gasses emission around the globe. Utilizing energy consumption reduction techniques in the building sector is among the foremost solutions to achieve the energy conservation potentials in this sector which would be followed by a decline in greenhouse emissions. Considering the contribution of heating and coling systems in a building’s energy use, optimizing these systems could have a huge effect on a building’s final energy...