Sharif Digital Repository

As efficiency of PV modules decreases with temperature rise, cooling methods can increase the power output and efficiency. One of the strategies for this purpose is passive cooling by implementing fins to the backside of a module. In the present study, annual energy output of a 50 W panel is analytically calculated in two unfinned and pin-finned cases based on hourly meteorological data for Shiraz, Iran. The results show that with the installation of 2-cm, 4-cm and 6-cm aluminum pin fins with finned-to-total-backside-area ratios of 0.17, 0.27 and 0.55, the power output increases by 1.24–4.16%, compared to the unfinned case. This increase is equivalent to 1.04–3.50 kWh more electrical energy... 

A desalination system consumes energy for production of freshwater. Since the solar energy is a low-cost, environmentally clean, and available energy throughout the world, it could be the best source of energy for such systems. In this work, a modified desalination system is presented which uses advantages of thermosyphon heat pipes as a fast and high performance thermal conducting device, and at the same time, employs the advantages of evacuated tube collectors (ETCs) which are flexible and have high performance in adverse weather conditions. Results show considerable increase in the production rate of desalinated water and system efficiency with a maximum production rate of 1.02 kg/(m2 h)... 

This study aims to investigate the hydrogen production process using an integrated system based on solar energy. This system includes an evacuated tube collector to absorb solar energy as input energy of the system. A parametric analysis was conducted to determine the most important design parameters and evaluate these parameters' impact on the system's objective functions. For identifying the optimum system conditions, multi-objective optimization was performed using particle swarm optimization (PSO) algorithm. The results obtained from the parametric analysis show that an increment in the collector mass flow rate and the turbine inlet temperature, as well as a decrement in the collector... 

Hybrid nanofluids have several advantages compared with the conventional types due to their modified properties. Their enhanced thermophysical and rheological properties make them more appropriate for solar energy systems. In this review paper, an overview of solar energy systems is represented, and afterwards, applications of hybrid nanofluids in various solar technologies, especially solar thermal, are reviewed. Comparison between the nanofluidic systems, and the conventional ones is performed in order to gain a deeper insight into the advantages of using nanofluids. According to the results of the reviewed studies, the most important reason for performance enhancement of nanofluidic solar... 

In this study, titanium dioxide (TiO2) nanotube array (TNA) films are fabricated via anodization of titanium (Ti) sheet. After annealing, the films consisted of well ordered, vertically oriented TNAs of 125±6nm diameter, 38±3nm wall thickness, and 2.9±0.3μm in length. Cadmium sulfide (CdS) nanoparticles are deposited on the synthesized TNAs by sequential-chemical bath deposition (S-CBD) method with different immersion cycle (n) to produce heterogeneous TNA/CdS-n (n=10, 20 and 30) nanostructures. UV-visible absorption spectra of the samples revealed that the absorption edge of CdS modified TNAs was shifted to a higher wavelength with respect to the pure TNAs indicating band gap reduction of... 

Perovskite solar cells (PSCs) have attracted significant attention due to their excellent efficiency reaching 22.1% in just the past few years. Despite their high efficiency, the limited long-term stability of PSCs has to be overcome. Moisture environments has been recognized as a main degradation pathway of perovskite materials. This review summarizes recent studies about relationship of the stability of PSCs with moisture environment. We also discuss the current standard strategies for enhancing the stability of PSCs by modifying the properties of either the perovskite material itself or its interfaces. © 2018  

Perovskite solar cells (PSCs) have attracted significant attention due to their excellent efficiency reaching 22.1% in just the past few years. Despite their high efficiency, the limited long-term stability of PSCs has to be overcome. Moisture environments has been recognized as a main degradation pathway of perovskite materials. This review summarizes recent studies about relationship of the stability of PSCs with moisture environment. We also discuss the current standard strategies for enhancing the stability of PSCs by modifying the properties of either the perovskite material itself or its interfaces  

Organic Rankine Cycles (ORCs) are promising approaches for generating power from medium or low temperature heat sources. In this regard, ORCs can be used to indirectly produce power from solar energy. Due to intermittent nature of solar energy, storage unit should be coupled with solar ORCs to improve the output power and operating hours. In this article, studies on solar ORCs integrated with various types of storage units were reviewed; the main findings of such studies were extracted and provided. Based on the findings, several factors such as the temperature and pressure at the inlet of the turbine, as well as the operating condition affect the performance of solar ORCs with thermal... 

In this study, the optimal sizing and performance analysis of a standalone integrated solar power system equipped with different storage scenarios to supply the power demand of a household is presented. One of the main purposes when applying solar energy resource is to face the increasing environmental pollutions resulting from fossil fuel based electricity sector. To this end, and to compare and examine two energy storage technologies (battery and hydrogen storage technology), three storage scenarios including battery only, hydrogen storage technology only and hybrid storage options are evaluated. An optimization framework based on Energy Hub concept is used to determine the optimum sizes...