Journal of Solar Energy Research
Volume:3 Issue: 1, Winter 2018

Renewable energy is a promising alternative to fossil fuel-based energy and is on the rise, largely to reduce dependency on limited reserves of fossil fuels and to mitigate impacts of climate change. Solar energy is an important source of renewable energy. The development of affordable, inexhaustible and clean solar energy technologies will have huge longer-term benefits. Among such technologies, solar ponds are considered as reliable and economical means of solar energy application. A solar pond is a body of water which collects solar radiation and stores it as thermal energy for a long period of time in the form of a simple and low cost solar energy system. Salt gradient solar pond, capable of providing a considerable quantity of hot water, is one of the most efficient and practical types of solar ponds. These ponds have received wide currency in both research and industrial fields. Heat absorbed in the salt gradient solar pond can be extracted in different ways for various thermal applications, ranging from domestic to industrial uses. The present article introduces solar ponds theory and applications with emphasis on salt gradient solar ponds including mathematical models describing their behavior.

Nowadays, the use of renewable electricity in urban outback areas has become very popular. According to the statistics, the growth in the use of local off-grid electricity has grown a lot in recent years, indicating an increasing need for this type of electrical energy. According to the fact that electrical consumers are often designed to work with alternating current, the production of electricity must have a sinusoidal waveform and, of course, within the standard limits for harmonics. Therefore, in the case of utilizing off-grid renewable sources, a standardized voltage waveform should be generated. It is achieved by employing an output filter unit. In this paper, by presenting a novel method for the LCL filter design, the output voltage and current are evaluated for a two-level three-phase inverter. The simulated and experimental results confirm the excellent performance of the designed filter.

: Sunlight is converted into electricity and heat simultaneously with the help of PV thermal panels. It is examined that the efficiency of the PVT panel is higher than the separate PV panels and solar thermal collectors’ efficiency. The electricity conversion-efficiency for a PV system is about 6% to 15% and in moreover cases 85% of the incoming solar energy is either reflected or absorbed as heat energy. Now a day’s Renewable energy has become a hot topic. The energy researchers day by day making advanced researches to make this type of system a useable one. Non-renewable sources will be approximately finished within next 100-150 years. So this type of energy is very important for everyone. Normally researches are made on producing electricity from renewable sources like sun-light, wind energy, tidal energy and etc. In this paper there is a compact review of solar photovoltaic thermal system. The performance of the solar cell decreases with the increasing of temperature. Both the electrical efficiency and the power output of PV module depend on the operating temperature. Photovoltaic thermal hybrid solar collectors, also known as hybrid PV/T systems are systems in which sunlight is converted into thermal and electrical energy both. This paper contains a combination of basic and advanced hybrid PV/T systems that are usable in Asian region.

Wireless sensors networks consist of several tiny battery powered devices which are utilized to monitor and gather information of desired area, such as a Net Zero Energy Building. As there is no way to recharge the nodes’ energy and batteries, efficient energy consumption plays crucial role in prolonging nodes’ and network’s lifetime. One of the most popular routing protocol is LEACH protocol, which suffers from drawbacks, despite several modifications have been deployed. This research aims to optimize the Leach protocol from three different aspects. Initially, the allocated energy of network is distributed to each nodes based on their distance with base station. The more distance between a node and BS, the more energy portion is allocated to the given node. Secondly, Genetic algorithm has been employed to select optimal cluster head set whose fitness function addresses number of CHs and distance between CHs and the BS. Lastly, sensor nodes are clustered by fuzzy clustering. Comparing the results with previous versions illustrates that the proposed modifications could prolong considering network and improve the energy consumption and the modified LEACH achieves 10% improvement in terms of survival rate of nodes.

Solar still is a green apparatuses for seawater desalination that can be a replace of common method of seawater vaporization using fossil fuel and condensing it, especially in Persian Gulf with hot weather which has a high radiation power of sun in summer when drinking water resources are limited. Solar still works using solar radiation that is a renewable source of energy and reduces the production of pollutant and greenhouse gases that produced using fossil fuel in a normal process. Therefore, commercialization of solar still is in direction of sustainable development. In this article, a solar still was modeled mathematically for describing the effect of parameters on performance of this device. Energy and mass balance equations were written using lumped formulation. Set of ordinary differential and algebraic equations was solved numerically using MATLAB software. Iteration method was used for estimating implicit heat transfer coefficients that are a function of temperatures. In this model effect of water depth and different daily solar profile was studied on total amount of water production. Temperature of basin water as a function of time was obtained by changing water depth, cycle number and solar flux profile. The cycle of still process was continued for several days without any brackish water make-up. The results show that at higher water depth, nightly desalinated water production continued more than lower water depth. The model indicates that at Muscat with higher solar flux, the water production and maximum of basin water temperature are greater than Shiraz with lower solar flux. It can be concluded that the potential of commercialization of solar still in an area near the sea with high solar flux is higher. But at lower initial water depth, the amount of water production at locations with lower solar flux approaches to the locations with higher solar flux.

Solar energy systems have attracted a lot of attention in the last few decades. Heat transfer enhancement (performance) of the solar thermal systems is one of the significant issues in energy usage, energy saving and compact designs. Since the nanofluids are used to improve the heat transfer characteristics and thermal properties compared with conventional fluids, replacing the working fluid with nanofluids is effective method to enhance the efficiency and performance of the solar thermal systems. This new and novel strategy is a subject of interest of researchers and literatures in recent years. The present review paper investigates applications of the nanofluids in solar thermal engineering systems include collectors and thermal energy storage systems. In addition effects of nanofluids on the performance, efficiency, economic and environmental considerations of mentioned systems are reviewed.

Solar chimney power plant (SCPP) is among the potential technologies in all over the world. In this study, a comprehensive energy and exergy analysis has been performed for SCPP. Exergy balance of the SCPP is conducted to calculate the irreversibility and exergetic efficiency of the SCPP. Influence of the effective parameters e.g. tower height, solar radiation, tower and collector radius is examined on the performance of the SCPP through the parametric study. The results show that by increasing all the effective parameters, irreversibility would increase except for tower radius. The results further indicate by increasing the collector radius, there is a maximum point from exergetic efficiency viewpoint. Eventually, increment of the effective parameters would increase the power output.

Solar storage energy using black volcanic stone (pouzzolan) as the absorber in the solar collector of the Indirect Solar Dryer with oriented flux to dry in continuous is investigated. The collector using crushed pouzzolan as absorber is exposed in the sunshine. Daily and evening experiments were conducted with different loads and oriented air flux in the drying chamber. It is observed that on the day, the irradiance do not affect outlet temperature of collector and in the evening up to 14 hours after the absence of the sun, the temperature difference between the ambient and the collector output is above 7°C. This temperature may be sufficient to reduce or to stabilizise the water intake of the product in the absence of the sun. The model of the discharge equation show that the time constant is a function of the intrinsic characteristics of the thermo physic properties of material and different heat transfers put in place.