Sharif Digital Repository

In order to improve the efficiency of atriums, effective parameters in ventilation and acceleration of airflow are numerous. Nevertheless, parameters such as shape and height of atrium, geometry of the inlet and outlets, opening areas and the presence of heat sources in each store play a vital role. In structures higher than one floor, there is no significant airflow in the upper floors and the ventilation of atrium is unpleasant for residents. Air movement in the building is done by buoyancy-driven force and hot air upward movement due to pressure differences.This study attempts to improve the natural ventilation performance with changing mentioned parameters. So for this purpose, 3D... 

This thesis studied the definition of a green building and the elements associated with the construction of a green residential apartment in comparison with traditional buildings with respect to condition of Karaj city. The first step in green construction is preparing a guideline. For this, LEED (Leadership in Energy and Environmental Design) the most well-known code for green buildings is used and Adapted with Iran’s National Building Regulations. Creating a checklist to rate buildings is one of the most important parts of Green Building Regulations. To achieve the points, US LEED certification is analyzed in both qualitative and quantitative perspectives. A questioner is applied in... 

According to increase of multimedia applications such as video surveillance and environment monitoring in Wireless Multimedia Sensor Networks (WMSN), energy conservation and prolonging network lifetime become increasingly important. Therefore, energy conservation and maximization of system lifetime are commonly recognized as a key challenge in the design and implementation of WMSNs. In these networks, nodes sense the area with high degree of correlation due to the overlapping Field Of Views (FoVs) and causes wasting network energy. We present “overlapped region detection clustering” as a new clustering method to reduce redundant video streams and overcome waste of the energy. We apply scene... 

Nowadays Wireless Sensor Networks are used in different situations such as greenhouse, agriculture, military applications and etc. The problem of Wireless Sensor Network is that the sensor nodes have limited the energy source. Besides, the power source of sensor nodes is not rechargeable or replaceable. So, one of the main challenges in Wireless Sensor Networks is saving energy. Whereas, most power is consumed due to transmissions, recently a lot of activities have been accomplished in order to reduce transmission times. In this thesis we have focused on a network coding method which is called Sensecode. Sensecode is a technique for reducing communications between nodes. Actually network... 

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... 

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... 

In a steel production plan primary resources entered the process are converted to high value products and byproducts. To this end, resources need to pass several consecutive process that require utility streams. One could not achieve the optimum operation of an industrial process unless they maximize the product and minimize the utility and waste. Therefore, it is important to consider the process stream integrated. The aim of this work is to find the optimum consumption of water and energy in a steel production and to calculate the potential reduction in water and energy resource destruction. Present work could be define a mathematical programing problem in which water users and all streams... 

Enormous amounts of water and energy are lost by scrubber utilization for furnace exhaust gas washing during direct iron reduction process. Hence, the aim of the current research is design and construction of a system which could be employed instead of scrubber within direct iron reduction process considering the equipment size constraints.To this end, the substitute system was manufactured after dimensional analysis and simulation of lab model compared to the prototype regarding the implementation limitations. The model has been tested in different operating conditions and empirical relations have been extracted for general analysis of direct iron reduction process. The case study here is... 

In this thesis the superstructure of continuous monitoring system has been developed to help energy service companies’ network. Suggested superstructure consists of three main sections: data acquisition, data analysis and decision-making, optimizer. Historical data and data which picked up by sensors are imported in decision support tool. Input data are analyzed by technical, economical and environmental models and converted to actionable indicator for best management of the project to promote energy saving project. Because the ESCO income obtained from the energy saving project, development of analytical decision support tool will help ESCO to evaluate the procedure of the project.... 

Lack of resources, environmental limitations, the incresed price of the water used by industrial processes, and the growth of the industry have caused the necessity of minimizing the heat and water consumption in industries become more vital. Therefore, in addition to the methods of energy integration for reducing the energy consumption, some other methods are being utilized to minimize the required fresh water or the production of the waste water in the industries. Studies show that regarding the direct impact that these two objects have on each other, a separate minimization of them cannot lead to the total optimization of the system. Thus, their minimization should be achieved while... 

Energy consumption and pollutions especially carbon dioxide emissions are two of the main challenges in the cement industry. 5-7 percent of world’s carbon dioxide emissions is due to cement production while 900 kg of carbon dioxide is emitted for the production of a tone of cement. The main source of carbon dioxide emissions in a cement plant is the combustion of fuel to provide heating demands and also converting the ore into clinker. Therefore, any improvement in energy efficiency in a cement plant could reduce carbon dioxide emissions resulting from the combustion. Important ways of energy recovery in a cement plant are using the energy recovered from the exhaust gas in the preheater... 

Micro Combine Heat and Power (Micro CHP) systems are one of the most important devices for energy saving that produce heat and power with the use of natural gas or other fuels. This research presents technical and economical feasible study of using Micro CHPs in different climatic zones of Iran. In order to economic studies in different climates of Iran, these zones are categorized in to five; Tehran, Rasht, Bandar Abase, Ardebil and Yazd, based on weather condition. Specifications of each zone, such as heating and cooling degree days and other parameters that are required for estimating energy consumption is determined. The calculation of energy consumption has been conducted based upon... 

Increasing electric energy consumption has necessitated long term planning of power generation based on the concept of least cost planning. Minimization of energy supply and optimization of technology mix had been considered as the main objective functions. But issues on the energy productivity, demand side management, externalities and internalizing external costs have dominated energy scheme which has lead to the development of comprehensive criteria such as Integrated Resource Planning (IRP) and Total Resource Cost (TRC). In these cases it is aimed to develop a comprehensive view of the energy planning that may include the case of DSM and externalities. The objective of the present... 

In this research, numerical simulation of the impact of a drop on a flat surface with oblique velocity has been performed, using two-phase model of Lattice Boltzmann Method (conservative phase-field). During impact, it is important to investigate two-dimensional drop dynamics and to evaluate the effectiveness of the numerical method used. The model used here restores conservative phase field and preserves mass both locally and globally. In addition, to calculate the slope of the phase field, it calls the center points without engaging finite difference calculations. This makes it efficient for running parallel computations. A fixed dry and hard surface is considered and the drop impacts it... 

First stage blades tempreture in the turbine rotor section for the advanced turbines has increased up to 1100oc. The blades should be under mentioned condition for the long times up to 70000 hours and accordingly creep happens. Fatigue–creep interaction is the main reason for the failures of many engineering components under high temperature and cyclic loading. In this thesis, a model for the life prediction of fatigue–creep interaction which was developed by other investigators has been modified to predict fatigue–creep interaction on the nickel-based superalloys. In this model, the law of energy conservation and the momentum conservation principle are used to describe the process of... 

In opportunistic networks, the nodes have ad-hoc communications that are formed directly between them, without any infrastructure, and not by any using any other intermediate node. In case that the destination node is not in the same region as the source during the sending of a message, the source will send the message to one or a few of its neighbors so that they can store and carry out the message to the original destination in cooperation known as Store-Carry-Forward Mechanism. Remarkably, in most cases, the devices involving in this type of network, e.g., smartphones, have limited source of energy or they use a battery, there is a need to minimize the energy consumption in the nodes.... 

During the last decades, the exponential population growth as well as the adverse impacts of climate change have brought about serious challenges in supplying freshwater demands. In this regard, buildings account for a considerable portion of freshwater withdrawal. Accordingly, urgent measures should be taken to tackle this crisis. Rainwater harvesting (RWH), Greywater recycling (GWR), and Hybrid rainwater greywater (HRG) systems are considered efficient substitute resources that are able to reduce the consumption of water supplied by centralized networks in buildings. Nonetheless, there is a vital need for the financial and technical assessment of these systems. Additionally, multiple... 

The purpose of this study is to introduce a new indicator to estimate the amount of irrigation water in excess of the need and also to determine the optimal irrigation pattern to reduce water loss in agriculture. According to the Food and Agriculture Organization of the United Nations, the major loss of fresh water takes place in agriculture, and the reduction of water resources is more significant in developing countries that do not have advanced agricultural equipment. One of the challenges in the studies related to reducing the amount of water used in agriculture is a lack of knowledge on the spatial distribution and temporal changes in water loss in a region. Although estimation of...