Sharif Digital Repository

Building sector is one of the largest energy conumers by being responsible for 40% of final energy consumption worldwide. In Iran, buildings consume around 32.5% of natural gas and 51.6% of generated electricity which is a significant portion of national energy system. Energy management consists of solutions which minimise energy consumption of a building while maintaining comfort conditions. The present research studies energy management solutions under a short–term model for an educational building using Energy-Plus software. The Department of Energy Engineering of Sharif University of Technology is selected as the case study and the optimal solutions has been achieved for this building.... 

As the Internet traffic grows, the energy efficiency gains more attention as a design factor for the planning and operation of telecommunication networks. Therefore, researchers begin to devise solutions for energy conservation in many scientific disciplines. In this thesis, we focus on the study of energy efficiency in optical transport networks, specially, the newly proposed Spectrum sLICed Elastic optical path (SLICE) networks architecture. First of all, we will introduce energy consuming elements in SLICE networks and their power consumption model. Next, we present a dynamic energy efficient routing and spectrum assignment algorithm (EE-RSA) with regenerator placement (RP) capability for... 

In the past few years, because of the high energy price in data centers, optimizing energy consumption has become of real importance. The disproportionate energy consumption of network devices to their utilization has led them to become one of the biggest consumers of energy inside data centers. On the other hand, the stochastic nature of network traffic among virtual machines has made the assumption of known or fixed communication volume superficial. In this research we considered a stochastic distribution of network traffic and communication volume among virtual machines trying to change the communication inside data center to communication inside hosts. Initially, we start by evaluating... 

In modern era, standpoints about atrium design have been revolutionized. In modern architecture, atrium not only designed for illuminating purposes but also designed by natural ventilation and passive cooling policies. Numerous parameters are making role in thermal efficiency of Atrium. A couple of these parameters are Atrium shape and openings area. In high rise atria the lower level rooms enjoy the advantage of buoyancy-driven ventilation while the upper level rooms suffer from its lack or weak presence. One strategy to solve this problem is designing building with various opening area in different heights but manipulating the opening size is restricted by some facts. Excessive Opening’s... 

The increasing demand of energy and energy consumption, urged researchers of different fields of science to investigate different aspects of energy efficiency methods. One way of optimization of energy consumption is to reduce drag force in moving objects in fluids. Changing the geometry of objects, bubble injection, air suction and blowing on surface, using nano fluid and superhydrophobic surface are just a number of drag reduction methods. Among the mentioned methods, using superhydrophobic surface due to its simplicity, low cost and no need to change in geometry of vehicles attracted attentions of researchers of all over the world. These surfaces with micro/nano roughness combined with... 

In recent years, great attention has been devoted to the design of artificial arms. The most crucial problem in such a design is the trajectory of movement. In this paper, a seven degree of freedom arm is modeled and simulated. Also, the optimization method named “Imperialistic Competitive Algorithm” has been modified and better performance of the new version is presented. Energy optimization is performed based on trajectory of the arm with angular velocity, angular acceleration and joint angles using modified imperialistic competitive algorithm (ICA). Considering ICA as a fast optimization algorithm, it would be reasonable to use this algorithm for robotic purposes for online answering. The... 

Fossil fuel usage caused global warming and other environmental problems. Recently, biofuels are considered as an important alternative. However, the efficient usage of water and energy in their production may accelerate their diffusion. ETBE is a kind of oxidizing fuel additive that can be biologically produced from the ethanol reaction. High water and energy consumption in the production and separation process is still a challenge. In this work, the ETBE production from lignocellulosic feed are considered. Then, the effect of different parameters are investigated by performing sensitivity analysis. In the next step, the optimal pathway of water and energy use in the production of ETBE are... 

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... 

Nowadays, due to the need of high performance systems, embedded systems have been redirected to multicore architectures. As energy consumption is one of the most important issues in embedded systems, careful considerations must be taken during the design of embedded systems to achieve low energy consumption. In this thesis, we propose the use of hybrid scratchpad memories to achieve low energy consumption. The hybrid memory uses both SRAM and STT-RAM memory. While STT-RAM has very low static energy consumption it suffers from high latency and energy consumption during write activities. In order to tackle this problem, we have devised a genetic algorithm that exploits architecture information... 

In the past few years, data centers energy consumption and their maintenance costs have become an important issue in technology world. Server consolidation using virtualization and VM live migration allows cloud data centers to improve resource utilization and hence energy efficiency. In order to save energy, consolidation techniques try to turn off the idle servers, while because of workload fluctuations, these offline servers should be turned on to support the increased resource demands. These repeated on-off cycles could affect the hardware reliability and wear-and-tear of servers and increase the maintenance and replacement costs. On the other hand, over-aggressive strategies would... 

Increase in energy consumed by buildings, which constitute about 40% of the global final energy consumption and their respective contribution to CO2 emmission has led the building owners and users toward using on–site energy production systems and especially clean energy sources. The present research aims to find the optimal solution to the building energy supply problem under current and other possible circumstances. Energy Engineering Department of Sharif University of Technology has been selected in representation of educational buildings in Iran for case study. ESM software which is based on the MESSAGE model has been used as the modeling tool. Results state that under the current... 

Continuous increase of energy demand, scarcity of resources, as well as environmental limitations have led to the need to reduce carbon emissions. In this research, an MINLP model based on the mathematical optimization formulation is proposed to reach this issue in a large cogeneration unit. Advantage of the hierarchical approach for carbon management are avoiding individual carbon reduction policies, and embedding emission control techniques in a hierarchical mathematical model that helps us to select the most appropriate policies and prioritize each other. In the carbon management hierarchy, the optimization of the base cycle is done at the first stage. Then, the use of renewable energies... 

Optimization of energy consumption is generally important in mobile networks and in particular in automotive networks. One of the challenges of installing roadside units in automotive case networks is to provide energy to the equipment assigned to these units. In some cases, power is easily available, but in many places, the cost of energy is very high and does not have economic justification. Therefore, optimization of energy consumption in roadside unit is of great importance. Typically, vehicles limitations in terms of energy consumption for communications are far lower than that of a roadside unit. In this dissertation, part of roadside communication to vehicles is shifted to the...