Sharif Digital Repository

Metal oxide semiconductors are promising materials for photovoltaic systems, because they are chemically stable, almost non-toxic and abundant. These materials are cheap and have low cost fabrication process. Cu2O is the most popular metal oxide semiconductor to absorb light in Photovoltaic (PV) applications, and photocathode in the photoelectrochemical systems.In this project, thermal oxide and electrodeposition methods, both interesting and cheap, were applied for preparing Cu2O films. As inexpensive materials results in low-minority carrier diffusion length, we report on surface engineering of bulk Cu2O photocathode thorough employing nanorods of copper oxide with the average lengths of... 

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... 

Given the population growth in the world and in dire need of electricity and to reduce pollution and moving toward sustainable development, renewable energy has special importance in the world. Iran, with 300 days of sunshine a year is one of the countries with high potential in the field of solar energy but for various reasons, solar energy has no significant role in our energy portfolio. Considering the purchase of solar power by the government, reduce solar electricity costs and payback time of the factors that could make greater use of this energy. In this projects using light splitting method, in addition to reducing cell area used, by removing a significant portion of the sun's rays... 

The combination of photovoltaic technology and Organic Rankine Cycle reduces the temperature of the solar panel and, on the other hand, generates separate electricity from excess heat. The reason for the use of the Organic Rankine Cycle is the low temperature of the heat source. It is not economical to use other cycles like steam Rankine cycle in low-temperature heat sources. To maximize the plant factor of the Organic Rankine cycle system, especially when there is not enough solar radiation, it is possible to utilize the flue gas heat recovery in office buildings and reduce the cost of electricity generation. In this project, the simulation of this system is carried out for the Energy... 

This project aims to design a smart microgrid connected to the utility grid in order to supply the demand of Energy Engineering Department at Sharif University of Technology. The electrical structure of this micro-grid is included utility grid, photovoltaic system with energy storage system and a consumer. Due to the energy storage system, an operation strategy is presented that is proportionate to the installed capacities in microgrid and based on a price basis that is determined by the micro-grid operator at the beginning of each day, in order to manage energy is provided. Micro-grid energy management is divided into two sections that the implementation of each part is depended to the... 

Energy and environment crisis in past decades raised concerns about fossil fuels use and has accelerated renewable energy application in terms of solar electric, solar thermal and wind turbines. Due to the fluctuating nature in renewable resources, renewable electric power generation has a stochastic nature that makes it difficult to use by the electricity consumers. Energy storage plays a key role to put more control on renewable power generation.Lead-acid battery is a storage technology that is widely used in photovoltaic systems. Battery investment and maintenance costs account for a big part of photovoltaic system costs. Charging and discharging profiles of the battery has a great impact... 

Trends of energy consumption and global warming, air pollution, Greenhouse gas emission, depletion of fossil energy resourcec and the rise in costs of fossil resources, indicate that renewable energies are reliable alternative in energy supply systems. The purpose of the project is to investigate the contribution of renewable energy to meeting energy demand of housing units. Household energy system consists of various parts which do intreract with each other. Total household energy system may be represented with the help of reference energy system in order to consider the effect of changes in one part on the other sections. In this regard, the reference diagram of household energy supply... 

In the initial part of this research, 10 selected dams out of 647 existing dams in Iran were selected using ArcGIS software, based on 3 indicators of height above sea level, temperature, horizontal solar radiation and wind speed, and the shadow model was calculated by calculating the radiation angle. The solar radiation on the reservoir water level of one of the selected dams, which is Durood Zan Dam, was checked on 4 days of the year. In the next stage, the design of the floating part of the power plant and its related components, in 3 parts including the main door, the door The pontoon and the main pontoon were done. Platform dimensions were optimized during the design process and to... 

One of the main methods to reduce fuel consumption and emissions is using renewable energy resources. This research proposes a hybrid renewable energy system on a container ship which includes one photovoltaic solar system, and one kite system. The photovoltaic system produces a part of the ship's electric power consumption and the kite system produces propulsion force using wind energy and transmitting this force to the ship through towing rope. Different components of these renewable energy systems are connected with the internet of things technology. In the internet of things structure design section, in addition to the conceptual design of different layers with emphasis on the processing... 

Nowadays energy consumption increases in our daily life and incredibly enhancement of growth rate can be seen recent years. Hence, the use of renewable energy is prioritized. Solar energy is one of the choices because it is free and available. In this research, it has been tried to get electrical and thermal power at a reasonable cost both during the day and night. The system is equipped with a linear parabolic concentrator with a collector installed in the center of the concentrator which has been installed on its faces photovoltaic cells and thermoelectric modules, and five different systems have been tested with different components. Also, the paraffin has been used as a phase change... 

Photovoltaic phenomena is the base of Photovoltaic cells technology that can transform the solar insolation to electricity directly. In this transformation, the solar insolation intensity is the important factor to increase the performance of the Photovoltaic cells but one of the biggest barriers in the extension way of this technology is its more cost that need to be decrease. Concentration of solar radiation method is the best way to increase the performance of Photovoltaic systems and decrease its initial cost. At this project a novel structure of solar parabolic through concentrator is investigated experimentally and analytically. The usage of Thermoelectric module with Photovoltaic... 

Design hybrid systems to supply electrical energy for off grid domestic consumer in the remote villages in Iran are the main objective of this work. The hybrid systems considered in this study consist of photovoltaic array, wind turbine, battery and diesel generator. Measured wind speed data used for wind turbine energy production model. The hybrid system optimized to supply 6, 14, 20, 40 and 60 families in Bojnoord, Moorchehkhoort, Kish, Langrood, Khash and Meshkinshahr. The main purpose of optimization is to find the economic system, able to fulfill the energy requirements of a given load distribution; so Iran’s current economy and cost, considered. The optimized results for studied cities... 

In the present thesis, A Computer software has been developed to evaluate technical and economic aspects of photovoltaic systems, off-grid and on-grid configuration, in urban areas where the electricity grid is accessible. As a case study the building of Energy Engineering faculty with annual demand of electricity in lighting section equals to 80048 kWh was considered. Regarding incident radiation and PV system characteristics with the aid of utilizability concept, a technical evaluation has been performed then life-cycle saving index was considered as a criterion for choosing an optimum nominal size of the system. Results show that for current electricity tariff of educational buildings ... 

Despite the excellent photovoltaic performance of perovskite solar cells (PSCs), the instability of PSCs under severe environment (e.g., humidity, intense light) limits further commercialization of such devices. Therefore, in recent years, many researches are conducted on utilizing Perovskite Quantum Dots (PQDs) to enhance performance of PSCs. Herein, CsPbI3 PQDs interfacial layer is incorporated in the perovskite/hole transport material (HTM) interface, on the purpose of increasing charge carrier mobility and preventing electron-hole recombination to increase performance of the PSCs. CsPbI3 PQDs is synthesized at 170℃ with oleic acid and oleylamine as organic ligands by hot-injection... 

Dye-Sensitized solar cells are the third generation of solar cells that have the potential to increase efficiency as much as solar cells of previous generations, along with lower prices. The cathode electrode of the pigmented solar cell as one of the essential components of the cell plays the role of accelerating the oxidation reaction reduction of the electrolyte. Platinum often is used as a catalyst layer. To reduce production costs and maintain cell viability, platinum should replace with other materials at a lower cost and higher electrochemical activity. Recently, carbon materials have been considered for the production of inexpensive solar cells with suitable performance. Among... 

Due to the increasing influence of distribution generation , their effect in planning can't be ignord , especially solar panels ,which are incresing rapidly. The main purpose of this thesis is to an active distribution network that annually load bus and the amount of photovoltaic production in it increases and plan dynamically. In the planning that is done , uncertanty in the amount comsumption load and uncertanty in the pattern of sunlight and also annual innterest rates in the classical system we have planned by optimizing the network expansion costs , in addition to supplying the load bus, we can keep the voltage drop bus and line filling within the allowable . To do this , we considered... 

Nowadays, concerns about the reduction of fossil fuels and environmental issues, have made renewable resources more important. Among these resources, photovoltaic (PV) systems are more popular than others, due to their environmental compatibility and unlimited availability of sunlight. Increasing the penetration level of PV systems in electricity networks presents various technical and control challenges such as voltage and frequency variations; and protection and harmonics issues. In this thesis, voltage rise problem due to reverse power flow in distribution feeders is discussed. This is one of the main obstacles to the expansion of these resources in distribution networks.Various solutions... 

Recently a new topology, namely “common ground inverter” is introduced which since it enjoys a direct connection between AC neutral and DC ground, essentially solves the problem of leakage current in grid connected applications. Moreover, a reduced implementation price and a simple control scheme is associated with this system. The Aforementioned features have absorbed a lot of attention for further research regarding this topology. In this research one of the three introduced topologies is considered in details and its function in supplying local loads and Grid is put to the test. Moreover, important efforts have been taken to improve the properties of the inverter in terms of efficiency,... 

Over the past decade there has been dramatic increase in fossil fuel’s usage; As a consequence, world now faces problems such as: air pollution, climate change, global warming and ozone layer depletion. In addition, depletion of the fossil energy resources is growing as a serious issue. Renewable energy(RE) sources are the most promising solution to these problems. Global investment in clean energy was increased by 16% in 2014 and solar power is anticipated to become the world’s largest source of electricity by 2050 .The German government has planned to achieve a goal of 8 percent renewables for gross power consumption by 2050 .RE is still more expensive than traditional one and faces a... 

A quasi-Z-source inverter is a beneficial structure in photovoltaic applications. In a transformerless grid-connected inverter system, the common-mode voltage fluctuations cause the leakage current flow through the ground. The low-frequency harmonics of the common-mode voltage results in the malfunction of the residual current device. On the other hand, the high-frequency harmonics of the common-mode voltage cause EMI problems, additional loss and disturbance in the output currents. In this thesis, some methods are presented to reduce the leakage current in a three-phase quasi-Z-source inverter. First, different shoot-through implementation methods are investigated. By modifying the number...