Sharif Digital Repository

In this thesis, Optimum Counterweight and Spring Balancing of a novel kind of mechanism called a general 3-RPS parallel robot in Dynamic Motion are investigated. Balancing is explained as the set of configurations on robot inertial and dimensional parameters which, when convinced, certify that the weight of the links produce less force at the actuators for any configuration of the robot, under dynamic or static behaviors. In the references, different procedures have been suggested for balancing that consisted of counterweights, springs, and other auxiliary equipments. Study represents the essential information for having optimum spring and counterweight balancing in a new (3RPS) robot using... 

Recently, the tradeoff between low energy consumption and high fault-tolerance has attracted a lot of attention as a key issue in the design of real-time embedded systems. Dynamic Voltage Scaling (DVS) is known as one of the most effective low energy techniques for real-time systems. Control-theoretic DVS techniques, which have been exploited recently for DVS-enabled systems, are able to adapt well to dynamic workload. In this thesis, we have combined the above two important issues i.e., the control-theoretic DVS and fault-tolerance, and investigated reducing the energy consumption of fault-tolerant hard real-time systems using feedback control theory. Our proposed feedback-based DVS method... 

Reducing energy consumption is one of the challenges facing wireless sensor networks with many solutions introduced for them with each having advantages and disadvantages. Some of the solutions introduced are based on using movable sinks. In this project, we attempt at proposing a place for the establishment of sinks using genetic algorithm that can reduce energy consumption in the net knots and increase the net life. This work should be done after reviewing the results of past researches and introduced methods. We will analyze the practicality of the proposed model using simulation and will show their advantages over the previous mentioned methods  

A large number of sensors are spread for monitoring of an area in a random manner. The aim is to have an efficient design for energy that can protect the coverage of the area. A number of sensor nodes that have high density and which are in the area have the duty of monitoring of the area. The aim of this process is to determine of maximum number of separate collections that they have a direct influence upon the life span of the network. The idea behind this approach is that the nodes in areas with low availability are less used as a data routing as well as nodes that have remaining energy. In order to reach this objective, the importance of each sensor node for its duty of protecting... 

There are different technologies for supplying water from alternative sources that meet different needs. In relation to thermal technologies such as multi-effect distillation, the highest water quality is obtained, there is no limit on the concentration of the incoming water, and there is the least need for maintenance. On the other hand, thermal technologies consume higher energy than membrane technologies. In this process, the better the heat transfer, the number of steps can be increased, and this means the production of more distilled water for the same amount of thermal energy. The distilled water layer on the surface of the heat exchanger has a high thermal resistance compared to the... 

Optimizing and reducing energy consumption will be a feature of smart cities in the future. In addition to the technical aspects of a technology, one of the most important obstacles to its lack of development is not considering economic factors. Investigating the economics and calculating the cost of using IoT systems in the energy sectors of a smart city is one of the most important issues. Using existing systems in buildings or adding limited and inexpensive hardware to make a building smart can make smartening a cost-effective operation and more widespread. In this research, a proposed architecture based on edge processing is described. In addition to receiving and displaying camera... 

Due to the energy crisis in recent years, much of which is due to excessive energy consumption in the air conditioning of buildings, many studies have been conducted from the perspective of engineering sciences on the subject of insulation and optimization of buildings. This study aims to investigate the conditions of thermal comfort from the mental and psychological perspective of human beings, which is the basis of the individual's decision to accept thermal adaptation behavior in the standard temperature range. In this study, the thermal adaptation model was designed on the theory of programmed behavior, which can explain the adaptation of individuals to the comfort temperature region.... 

The building sector consumes a significant amount of potable water. It also consumes 30-40% of the world's end-use energy, and this will be even higher, considering the amount of energy consumed in water and wastewater treatment processes. In Iran, buildings account for about 35% of end-use energy consumption. Therefore, the focus on green buildings has increased as a response to growing concerns about climate change and global warming. This study seeks to develop an optimal model to meet the energy and water demand of a building considering the water and energy nexus. This model has been developed for the Energy Engineering Department in order to become a green building. As a result, the... 

Buildings are responsible for 40% of total energy consumption worldwide. A significant portion of this energy contributes to building temperature control, and energy storage is an effective way to reduce energy consumption and to levelize the supply of heat load. A solution for reducing energy consumption in the building is to increase the thermal inertia of the building and to store energy using smart materials in the building components. Materials with phase change can stabilize the internal temperature of the building.In the present study, model is exmined with the help of modeling the thermal behavior of a room in Tehran in summer, using MATLAB software. The problem is solved by the... 

Increasing global final energy demand and the use of fossil fuels to meet this amount of energy demand have raised concerns about environmental impacts of fossil fuel consumption and the reduction of fossil energy reserves. Among the energy consumer sectors including industry, transport activities, agriculture, and households, the household sector is one of the most important sectors, regarding its share of total final energy consumption. Heating and cooling systems, which mainly use fossil fuels, are the biggest energy consumers in the household sector. Hence, optimal management of the heating and cooling systems can play an effective role in reducing energy costs in buildings. In 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... 

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... 

Combined geothermal heat pump and solar collector system is a kind of load supply system for dwellings and greenhouses that operates by relying on renewable energies. The advantage of this system over conventional systems is lower power consumption. The aim of this study is to optimize the hybrid system so that in addition to reducing energy consumption and exergy destroied of the system, economically be minimized. In fact, in this study, we are dealing with an issue that should be optimize from different aspects. firstly, thermodynamic modeling for vertical ground source heat pump is done and then by considering 11 decision variables, the system is optimized by using single-objective and... 

Energy efficiency for Iran, which has large reserves of oil and gas but also has a high energy consumption is important because it ensures the country's energy security and saving each energy unit creates energy exports opportunity. Buildings have high energy saving potential; this sector uses about thirty percent of energy consumption (about half the gas and thirty percent of the annual electricity consumption). Households are not motivated in saving energy because government pays energy subsidy. In this research building energy consumption (in Tehran) modeled by bottom up approach. Then the effect of economic incentive tools such as subsidy, loan and tax on motivation in energy saving... 

The exit flue gas temperature of conventional gas fired boiler is generally high and considerable energy is lost to environment. Therefore, new methods are needed to recover water and heat from boiler flue gas in order to reduce overall plant water consumption as well as to increase energy efficiency and mitigate detrimental emissions. This project involved design of a heat and water recovery system including condensing heat exchangers to be used in residential buildings. In this project based on simulation of heat and water recovery system the recoverable amount of heat and efficiency improvement potential at various conditions such as different exit flue gas temperatures and different... 

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... 

Smart consumers have a major role in the development of the smart grid. On the other hand, increasing need for more flexibility in DGs highlights the consumer’s role. This is possible with the development of smart appliance and appropriate communications infrastructure to active consumers. Today, with the development of smart grids, it is possible to control different parts of home energy systems and manage energy consumption. In this project a comprehensive model has been developed to optimize energy consumption in smart home. In the next phase of the thesis, due to the random nature of solar energy and electric vehicles, stochastic model of smart home energy system is discussed. At this... 

In this thesis, we consider the simulation and active control of a centrifugal compressor in during surge occurrence. Surge, as an aerodynamic instability in compressors, causes to severe decrease of efficiency and loss of energy and with stabilizing the compressor in this condition, efficiency and system reliability increase. Nowadays, anti surge systems are used for surge avoidance in different industrials. They recycle the compressed gas from compressor down-stream to up-stream in instability condition and cause to exit the operation point from unstable zone. In this thesis, at first compression system is modeled based on Greitzer model and governing equation of compressor shaft in surge... 

In recent years, the country's electricity industry has faced many problems. On the one hand, the number of consumers and the intensity of their consumption have increased, and on the other hand, the production sector has been facing many problems. Since the management of these systems requires the development of mathematical models, the introduction of various operational indices and system analysis, in order to provide solutions to reduce consumption, increase production and reduce environmental damage, in this research Bistoon Kermanshah steam power plant, as a selected power plant, is simulated in both design and operational conditions, by the information available in the design...