Journal of Solar Energy Research
Volume:3 Issue: 4, Autumn 2018

One of the main issues to build a photovoltaic plant is to specify the type of mounting structure used for solar panels. Making a proper choice for the structure type is crucial to harvest the maximum performance from the PV plant. In this paper, two of the most common types of structures have been investigated by analyzing two 2.4 kW PV systems. One system has a fixed structure and the other one has a single vertical-axis structure. The energy production, performance ratio and final yield of both systems have been monitored, analyzed and compared over a one-year period. Performance of PV plants is often predicted by modeling tools prior to the construction of plant and the results of simulations are usually considered as a reliable source to design a PV plant and supply the equipment. Thus, the accuracy of modeling tool results are vital for both investors and installers. Therefore, PVsyst as one of the most commonly used modeling tools has been studied by simulating both PV systems and comparing the predicted and measured data. The error margin of simulations has been within the range of 1%, 3% and 1% for generated energy, performance ratio and final yield respectively, and the tracker system generated 28% more energy compared to fixed system in one year.

A comprehensive thermodynamic analysis is used to characterize the exergy destruction rate in any part of the solar air preheating system (SAPHS) and calculate its efficiency. The system consists of a solar evaporator, a heat exchanger to air preheating and an auxiliary pump. A computer simulation program using EES software is developed to model and analyses the SAPHS. The system provides preheated air during the year. The thermodynamic analyses involves the determination of effects of air preheating (APH) heat exchanger pinch point temperature, solar radiation intensity and overall heat loss coefficient of the solar evaporator on the performance of the SAPHS. The result showed that the main source of the exergy destruction is the solar evaporator. In the solar evaporator, 115.9 kW of the input exergy was annihilated. Other main source of exergy annihilation is the APHHE, at 7.45 kW. The overall energetic and exergetic efficiencies of the SAPHS were 70.11% and 9.766%, respectively.

world. The satisfactory and reliable performance of solar water heaters require accurate sizing and designing of the components as well as precise prediction of useful energy intake. This is of greater significance in cold areas due to higher thermal loss and lower solar radiation. Hence, optimization of the system parameters to obtain sufficient efficiency is quite an important matter. This study evaluated the long-term and annual performance of solar water heaters in the cold city of Sanandaj, Iran using TRNSYS software. In the first phase, the general parameters and components of the system were optimized and in the second phase, the performance of the optimized system was assessed. The effects of changing parameters such as storage tank volume, collector area and collector slope on the monthly and yearly performance of the solar water system were analyzed. It was found that 0.35-0.45 m2 was the optimum annual volume of storage tank for the weather conditions of Sanandaj city. Moreover, the optimized values of collector area and its optimized slope were reported to be 8 m2 and 40-60º, respectively. The results showed a direct correlation between environmental conditions and useful energy intake. With regard to time and energy intake, August was found to be more uniform than other months. At the end, the monthly efficiency of the system was evaluated and the findings indicated a proportional efficiency for the system. The maximum monthly efficiency was found to be about 61% in July and minimum level was 42% in January.

Nowadays, Because of the sharp decline in fossil resources, producing power by renewable energy is growing rapidly. Photovoltaic (PV) technology is one of the most popular ways for generating electricity. In hot days of year, which the maximum irradiation of sun is available, because of high cell temperature, the efficiency of PV cells is falls down. In this paper, in order to decrease the temperature of PV cells, the use of carbon nano fluid for cooling the PV panel is investigated. The results show that after 4.5 hours of beginning the test, the temperature of PV panel with carbon nano fluid cooling is fixed at 32°C, while the temperature of conventional panel is about 83°C. This temperature difference improved average efficiency around 5.75%. Moreover, in this study, calculation of output power of a 10-KW PV power plant, with and without cooling is performed.

Nowadays, the automobile industry is moving towards hybridized and fully electric vehicles. The industry has been slowly moving towards this future from decades. Firstly, hybrid and semi-hybrid cars became famous, and now due to the advancements in battery technology, fully electric cars are becoming increasingly popular. Due to the car manufacturers designations, the electric cars have reached the stage of mass production. Many countries such as the U.S., Germany, and France have pledged to reduce the usage of gasoline and diesel cars, and increase the use of electric vehicles due to the diminishing non-renewable resources. In this paper, electrification of an electric vehicle has been performed, in which the solar energy has been used along with the traditional plug-in energy to power the vehicle. The solar energy absorbed from the sun by the solar panel is converted into chemical energy, and stored in batteries. Therefore, the solar-powered electric car can work with an electric motor instead of an Internal Combustion Engine (ICE) to drive the car. Also, the motor can run on AC current which is converted by the inverter from DC current stored in batteries. To drive the car in electric mode, a 360 V Li-polymer battery pack with 100 kWh energy capacity has been proposed to install in the car. Thus, the approach of transforming solar energy into chemical energy, and converting chemical energy to mechanical energy have been applied in this solar-powered electric car. Moreover, the functionality of off-road driving, as well as on-road has been considered. In order to increase/decrease the ground clearance of the car, equipping the car with air suspension system has been investigated.

In the world today, fossil fuels as conventional energy sources have a crucial role in energy supply since they are substantial drivers of the “Industrial Revolution”, as well as the technical, social, and economic developments. Global population growth along with high levels of prosperity have resulted in a significant increase in fossil fuels consumption. However, fossil fuels have destructive impacts on the environment, being the major source of the local air pollution and emitter of greenhouse gases (GHGs). To address this issue, using renewable energy sources especially solar energy as an abundant and clean source of energy, has been attracted considerable global attention, which can provide a large portion of electricity demand. To make the most of solar energy, concentrated solar power (CSP) systems integrated with cost effective thermal energy storage (TES) systems are among the best options. A TES system has the ability to store the thermal energy during sunshine hours and release it during the periods with weak or no solar radiation. Thus, it can increase the working hours as well as the reliability of a solar system. In this paper, the main components of the solar thermal power systems including solar collectors, concentrators, TES systems and different types of heat transfer fluids (HTFs) used in solar farms have been discussed.

The penetration level of the photovoltaic (PV) systems is growing in the distribution networks throughout the world. On the other hand, the voltage drop across the feeder and the voltage imbalance are important issues in radial distribution networks. One of the most effective methods to deal with these problems is reactive power injection by PV-based multiple distributed static compensators (D-Statcom). Hence, a method based on the integral to droop line algorithm, which can regulate the reactive current injection for the voltage control by optimizing the droop coefficient and integral gain, has been proposed in this paper. Therefore, genetic algorithm (GA) is used to minimize the voltage deviation (VD) and voltage unbalanced factor (VUF). The proposed method has been simulated and evaluated on the typical low voltage (LV) 3-phase distribution network. The results indicate that the voltage profile along the feeder has been improved from a poor range to the acceptable range of 0.95 to 1.05, and therefore VUF’s reach to under 0.15. Hence, optimal use of PV-Dstatcom’s capacity and validity of the mentioned method are obtained.

A novel multi-generation energy system fueled solar and biomass energy are suggested and investigated, in the viewpoints of thermodynamic and thermoeconomic analyses. Electricity, heating and cooling power are supplied by means of a Rankine cycle, a heater, a double effect absorption chiller, a liquefaction natural gas subsystem, a multi-effect desalination system, a parabolic Trough solar collector and a combustion burner is utilized. Results show that, the system is capable to produce 16.11kW electricity, 28.94 kW heating power, 23.41 kW cooling power, 8.8 kg/h fresh water and 0.02 m3/h liquefied natural gas with the energy and exergy efficiencies of 46.8 %, 11.2%, and product cost rate of 15.16 $/h. Finally, a parametric study is carried out in order to survey the dependency of the thermodynamic and thermoeconomic performance upon the decision variables such as stack gasses temperature, temperature difference of evaporaor1, evaporaor2 temperature and Turbine inlet temperature.