Sharif Digital Repository

The plasmonic effects of infiltrated silver (Ag) nanoparticles, with different contents, inside a nanostructured TiO2 film on the photovoltaic performance of dye-sensitized solar cells (DSSCs) are explored. The synthesized Ag nanoparticles are immobilized onto deposited TiO2 nanoparticles by a new strategy using 3-mercaptopropionic acid (MPA), a bifunctional linker molecule. Transmission electron microscope (TEM) images show that monodispersed Ag and polydispersed TiO2 nanoparticles have an average diameter of 12 ± 3 nm and 5 ± 1 nm, respectively. Moreover, Fourier transform infrared spectroscopy (FTIR) analysis reveals that Ag nanoparticles were successfully functionalized and capped with... 

Herein, we demonstrate a facile low temperature chemical bath deposition approach to deposit a light scattering layer on a nanostructured mesoporous TiO2 bottom layer in a dye-sensitized solar cell architecture. Large TiO2 nanoparticles were formed on the top surface of photoanode electrodes via hydrolysis of TiCl4 at 70 °C. We controlled the size and agglomeration of these TiO2 nanoparticles by altering the concentration of TiCl4 in the chemical bath during the hydrolysis process. Electron microscope images revealed that mono-dispersed scattering particles having uneven surfaces with diameters between 100 to 300 nm formed on the mesoporous titania layer. The scattering behavior of the... 

A precise model of the behavior of complex systems such as solar chimney power plants (SCPP) would be much beneficial. Also, such a model would be quite contributing to the control of solar chimney operation. In this paper, the identification and modeling of SCPP utilizing ANN and Adaptive Neuro Fuzzy Inference System (ANFIS) are discussed. The modeling is based on the data of three working days which were taken of a built pilot in University of Zanjan, Iran. The input parameters are time, radiation and ambient temperature, while the output is the air velocity at the inlet of the chimney. The results of ANN model and ANFIS model were compared; it was found that ANFIS model exhibited better... 

This paper describes the designing and evaluation of an alternative energy system which consists of PEMFC, PV, PEM electrolyser, methane reformer and hydrogen tank. In order to find out the minimum capacity of the components, a system sizing model is developed in MATLAB based on meteorological and electrical demand data. Three scenarios are considered based on different combinations of solar energy and fossil fuel energy as energy resources. The heating energy produced by the fuel cell is recovered for supplying domestic hot water while the system would supply electrical energy. Results show that system sizing strongly depends on scenarios and unit cost of electricity decreases through the... 

Increasing energy demand has led to a substantial growth in the use of wind energy across the world, which can be attributed to the low initial and running costs and rapid and easy deployment of this technology. The development of hydrogen from wind energy is an excellent way to store the excess wind power produced, as the produced hydrogen can be used not only as clean fuel but also as input for various industries. Considering the good wind potentials of Yazd province, the variety of industries that are active in this area, and the central location of this province in Iran, which gives it ample access to major transport routes and other industrial hubs, hydrogen production from wind power... 

Observing the growing energy demand of modern societies, many countries have rec-ognized energy security as a looming problem and renewable energies as a solution to this issue. Renewable hydrogen production is an excellent method for the storage and transfer of energy generated by intermittent renewable sources such as wind and solar so that they can be used at a place and time of our choosing. In this study, the suitability of 15 cities in Fars province, Iran, for renewable hydrogen production was investigated and compared by the use of multiple multi-criteria decision-making methods including ARAS, SAW, CODAS, and TOPSIS. The obtained rankings were aggregated by rank averaging, Borda... 

Photovoltaic (PV) panels provide a suitable way for the direct conversion of solar energy into electricity. The electrical output and efficiency of PV modules are dependent on working temperature. The present study contributes to investigate the efficiency of utilizing a flat plate closed-loop pulsating heat pipe (CLPHP) to cool down a PV panel in both thermal and economic aspects. Accordingly, a numerical investigation is employed to obtain the surface temperature and electrical gain of the PV panel through four scenarios, including natural cooling without additional equipment, CLPHP-based passive cooling, CLPHP-based active cooling, and a conventional flat plate cooling methods. The... 

The main focus of this paper is to present thermodynamic and economic analyses and multi-objective optimization of a novel geothermal-solar multigeneration system. The system aims to produce hydrogen, freshwater, electricity, cooling load, and hot water and designed based on geothermal and solar energy. After modeling and thermodynamic and economic analysis, exergy destruction rate, exergy efficiency and, cost rate were calculated for each component of the system. The results showed that the highest amount of exergy destruction was related to parabolic trough collectors (PTCs) and absorption chillers. To select the geothermal fluid of the organic Rankine cycle (ORC), several different fluids... 

Pulsating heat pipes (PHPs) are compact cooling equipment used for various applications. This type of heat pipes can be used in renewable energy systems, cooling electronic devices, heat recovery systems and many other applications. Since PHPs have superior thermal performance, by applying them in energy systems enhance their efficiency. In addition, PHPs are a reliable medium for cooling various devices which have high heat flux. In this study, various works conducted on the applications of PHPs are reviewed and analyzed. It is concluded that PHPs are efficient and reliable devices for utilization in various energy systems. Moreover, at very low temperatures, such as cryogenic applications,...