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Concentrating photovoltaic (CPV) systems have emerged as a transformative technology that incorporates radiation concentrators into the photovoltaic system to enable radiation to be concentrated onto a receiver—the solar cells. Different concentrator configurations have different impacts on the performance of the solar photovoltaic system. This research work aims to analyze the impact of different concentrators, comparing and identifying the most efficient structures for capturing and concentrating solar energy. Aiming at a deep analysis and comparison among concentrators shapes, this research work presents a unique investigation and revision among different structures such as flat, triangular, LFR, and parabolic concentrators. Moreover, since, in the UV–visible–NIR region, metals’ reflectance varies with the incident wavelength, five metals were considered: aluminum, gold, platinum, copper, and silver. Additionally, the research focuses on studying the effects of parameters critical to the quality of the concentration on the power obtained and on the uniformity of the radiation distribution on the surface of the receiver, as well as on the number of solar rays that reach the receiver. The power on the receiver increases proportionally with the number of reflector concentrators in the system and their reflectance. For parabolic geometries, the optical efficiency is affected by the receiver’s shadow on the concentrator and, in the case of the LFR, by a non-ideal alignment of the reflectors in relation to the receiver. However, in parabolic concentrator geometries, uniformity is usually lower, since in these configurations, the radiation is focused on specific areas of the receiver, usually the central zone.

Abstract This research work aims to study photovoltaic systems that generate energy for self-consumption using different traditional technologies, such as silicon, and emerging technologies, like nanowires and quantum. The photovoltaic system without batteries was implemented in a residential property in three different places, in Portugal. According to Portuguese Law, the sale of surplus energy to the grid is possible but the respective value for its selling is not defined. To evaluate the project viability, two different analyses are considered: with and without the sale of surplus energy to the grid. Results show that if there is no sale of excess energy produced to the grid, the project is not economically viable considering the four different technologies. Otherwise, using traditional technologies, the project is economically viable, presenting a payback time lower than 10 years. This shows that the introduction of nanostructures in solar cells is not yet a good solution in the application of solar systems namely with the current law. Furthermore, independently of the used technology, the current Portuguese law seems to difficult the investment return, which should not be the way to encourage the use of renewable sources.

Abstract The climate changes observed over the last decades have been promoting a massive transformation on the energy sector, that is still, in truth highly dependent on fossil fuels. Renewable energies are a plausible alternative, because they have lower emissions of toxic gases in comparison with non-renewable ones. In the group of renewable energies, solar technology has the biggest overall potential, mainly because it is cheap and easy to set. Several solar technologies allow to equip their photovoltaic panels with concentrators, mostly to increase the output power and possibly their efficiency. However, some problems related to the use of concentrators have to be dealt in order to improve the entire photovoltaic system performance. One of these issues is the corrosion of the concentrators, leading to a premature ageing and, consequently an increase in maintenance costs. This problem is going to be analysed in this paper, presenting some simulation from a ray traicing software and also some experimental results, from our own laboratory experiences. The used software allows to trace the solar rays of the concentrator, in order to assess the effect of the defects caused by corrosion due to the ambient circumstances. After it, experimental results will help to analyse this effect and to prove simulation ones.

Abstract Currently, the nine islands of the Autonomous Region of the Azores have fossil fuel-fired power stations as the main source of electric power. Each island has an independent electrical system classified as an isolated micro-system, given its size and location. The aim of this paper is to analyse the best set of technologies to have nine sustainable hybrid systems. For this purpose, some factors will be considered, such as actual data production of the island, economic scenarios, growth perspectives of consumption and reliability of supply. The results of these studies will allow us to conclude on the applicability of these systems and to quantify the consequent socio-economic, environmental and fossil energy-saving benefits. A system is projected to the archipelago, in order to reduce the energy production due to non-renewable energies, budgeted on 783.28 million euros, which intend to instal wind farms and photovoltaic parks (using polycrystalline and cadmium telluride technologies).

Renewable resources for producing energy for self-consumption are growing, namely solar energy. This work focuses on the comparison of photovoltaic systems for energy production for self-consumption on a property in three different regions of Portugal using traditional and emerging technologies, without batteries’ implementation. According to Portuguese law, there is no stipulated value for selling surplus energy produced by a self consumption unit, to the public grid. In order to analyse the economic viability of the project, two scenarios are studied: the delivery, at zero cost of the surplus energy produced to the grid, and its sale. Furthermore, the same analysis is carried out considering partial shading on the photovoltaic generator. The results show that if there is no surplus production sale to the grid, the project becomes economically unviable for the four PV technologies. Otherwise, for the traditional technologies, the project is economically viable, presenting a payback time lower than 10 years. Using emerging technologies, the project becomes economically unviable. When applying partial shading on the generator, the project becomes, in all the scenarios under study, economically unviable. It can be concluded that introducing nanostructures in solar cells to power an infrastructure is not, for now, the best solution from an economic point of view, considering the current legislation. In addition, the shading makes the projects under study unviable, as it is a factor that cannot be controlled in its entirety.

Photovoltaic technology and unmanned aerial vehicles are both alluring areas with a lot of potential to explore. Consequently, they have an ability to adapt and progress when faced with new challenges, hence their wide range of applications. An auspicious combination between the two is born from the Unmanned Aerial Vehicles’ (UAVs) inability to to overcome some of its problems, namely the autonomy one. This article springs from the need to vanquish the problem, finding a more permanent solution. Its aim consists in the installation of solar photovoltaic panels in the structure of a UAV, with the objective of studying being its influence on the vehicle’s time of flight. To accomplish this, a theoretical study will be made, encompassing all the potential variables together with its influence. In order to verify the credibility of these claims, a prototype, based on the original aerial vehicle structure form and material, is constructed, using a finite element tool. Later, the prototype is used to evaluate possible harsh circumambient air to structure interactions, modeled by the fluid motion describer Navier–Stokes equations. For a smooth approach involving lighter computational power, a RANS model is used to asses the equations. Based on its results the chosen solar technology credibility is evaluated. A simulation of solar cells will also be carried out, accepting as input previously studied parameters which will modify its performance. Bearing in mind the produced results, it is concluded that the solar panels can only significantly augment the time of flight in very specific conditions.