1,113 research outputs found
Building-Integrated Photovoltaics in Existing Buildings: A Novel PV Roofing System
No full textAmong renewable energy generation technologies, photovoltaics has a pivotal role in reaching the EU's decarbonization goals. In particular, building-integrated photovoltaic (BIPV) systems are attracting increasing interest since they are a fundamental element that allows buildings to abate their CO2 emissions while also performing functions typical of traditional building components, such as sealing against water. In such a context, since one of the main challenges to decarbonizing the building sector lies in the retrofitting of existing buildings, the current paper is focused on the design, development, and testing of a novel roofing BIPV system. The entire research was carried out as part of the Horizon 2020 HEART project. In more detail, the research analyzed the requirements of typical pitched tile roofs, which are currently the most common type in Europe, and developed a universal photovoltaic tile that can be easily and quickly integrated into such a type of roof. The research was also aimed at minimizing the embodied energy of the component and promoting disassembly and recycling at the end of life, fully in line with a circular economy perspective. The adopted design and development processes are described in detail in the present paper, along with the results of several tests performed in the field. In addition, further development prospects of the component, aimed at meeting the integration requirements in historic buildings, are finally presented
Towards an holistic approach to energy access in humanitarian settings: the SET4food project from technology transfer to knowledge sharing
No full textThe increasing number of displaced people in the world not only requires rapid humanitarian actions, but also attention to host communities and a holistic and long-term vision. Energy has not been really considered a major topic in people displacement, yet, resulting in negative impacts on several aspects, including food security. New solutions are required, in terms of energy planning, technology development, and adaptation, as well as decision making, sensitization, training, and support to humanitarian actors. The Sustainable Energy Technologies for food security (SET4food) project phase 1 (2014–2015) developed a number of tools to support identification, adaptation, and introduction of appropriate solutions, tested some pilot innovations in critical areas, and promoted the enhancement of humanitarian response capability in the energy sector via an extensive capacity building program. In addition, a second phase of the project (2015–2018) fostered networking and collaboration between the main actors by developing an e-sharing platform, called ENERGYCoP, including a global not-for-profit community of practices for humanitarian professionals working in the energy sector. The platform may enable the shift from traditional “technological transfer” to a more participative approach on co-design and technological cooperation activated by a knowledge sharing mechanism. This paper outlines the main challenges and the achieved results of SET4food, providing recommendations for researchers and practitioners on the way forward
Thermal-electrical optimization of the configuration a liquid PVT collector
No full textThe study focuses on the optimal thermal and electrical configuration of hybrid Photovoltaic-Thermal (PVT) collectors. The electrical production of a PVT system is, in fact, highly affected by the temperature of the PV cells. In a PVT collector a temperature gradient exists along the absorber, so not all cells may be able to operate with the same electrical characteristics due to their temperature coefficient. In order to evaluate temperature distribution on solar
cells, thermal analysis has been carried out with computational fluid dynamic (CFD) software. The study was focused on two absorbers types, characterized by different designs: a serpentine tube absorber and a parallel tubes absorber. Starting from the thermal analysis, alternative electrical configurations were simulated in order to define the best solution to maximize as much as possible the photovoltaic performance
Active refrigeration technologies for food preservation in humanitarian context â A review
No full textFood preservation is one of the most neglected pillars of food security in humanitarian context. In particular, few preservation practices for both raw and cooked food are in place, due to the lack of appropriate technologies, very limited access to energy, especially electricity, and affordability. This situation is quite common not only in humanitarian settings, but also in all the countries with very limited access to modern forms of energy, like majority of Sub-Saharan Africa and part of Asia. In general, food preservation in areas without access to power grid can be provided through active/passive refrigeration, characterized respectively by the use or not of an energy source such as electricity or fuels to run the refrigeration process. Currently, off-grid active refrigeration technologies have a high potential, but in commercial solutions there are still room for improvement. In such context, this work aims at presenting a comprehensive review of scientific and grey literature on active refrigeration technologies for food preservation and related practices, also describing relevant experiences focused to the implementation of innovative refrigeration systems in humanitarian contexts. In detail, the first part of the work takes in consideration the capability of refrigeration to preserve different types of foods in various boundary conditions. The second part deeply analyses different active refrigeration technologies, comparing the solutions under an economic, technical and social point of view, also reporting some representative experiences within humanitarian projects to demonstrate pros and cons of various possible solutions. In the last part of the work an overall comparison and main recommendations are provided in order to identify the best technology for each specific application context, highlighting at the same time where the need of further research has to be mainly focused
PV technologies performance comparison in temperate climates
No full textDuring the last decade, PV technology has been subject to a quick and remarkable improvement, affecting both the efficiency of modules and the manufacturing costs; during its period of greatest growth, the EU market was characterized by different major types of PV modules, but in many cases, due to the extremely rapid development of the sector, there is a lack of knowledge about the energy performance and behavior of such technologies under actual operating conditions. The aim of this work is thus to carry out a performance comparison of three different and representative PV technologies in temperate climatic conditions; in particular, the influence of climatic parameters on energy production was investigated, with a focus on the thermal and spectral analysis. The experimental results, referred to a monitoring period of one year, show a significant difference between the reference performances, rated under standard test conditions, and the actual daily/seasonal productivity, providing useful information about the different interaction with climate of the technologies tested
Water flat plate PV-thermal collectors: A review
No full textOver the last 30 years, a large amount of research about air PVT collectors has been carried out, but the most investigated PVT technology in recent time is based on systems using water as the heat transfer fluid, because they achieve higher overall efficiencies than air systems, due to the higher heat capacity of water. In this sense, this article presents an extensive review about water flat plate PV-thermal collectors, which are the most widespread in the current market. The review is subdivided according to the elements that compose PVT
collectors, from the cover to the insulation material, identifying the most important design parameters of them. This article gives an up-to-date review of the technology, with a specific focus on technological progress in recent years and on the future development
The first Italian BIPV project: Case study and long-term performance analysis
No full textThe estimation of long-term performances of PV systems is a crucial factor for properly assessing the energy and the cost of PV electricity and thus the cost effectiveness of different technologies. This type of prediction is often based on accelerated ageing and tests in indoor condition. However, the combination of different phenomena, such as the mean solar radiation available on the site, the presence of dust, the shadowing or UV radiation over long-outdoor exposure, affect in different ways the real performance of the PV systems.This paper presents a detailed assessment of the testing campaign on the pilot PV plant at the Politecnico di Milano, which underwent 13 years of continuous operation; such period is particularly representative because it can be considered as about half of the supposed lifetime cycle of a photovoltaic system which is usually taken into account for technical-economic evaluations.The results obtained show that the PV plant analyzed didn't present a significant decrease in long-term performance: the measured PR decay is equal to 0.37%/year. In addition, the visual inspection and IR analysis showed that no PV modules are affected by serious damage. This result is due to a good system design during the preliminary stage, high-quality components and also the back ventilation of the modules, which avoids overheating in the warmer periods of the year.Finally, an economic analysis was carried out - based on real historical data - which makes the economic evaluation more reliable
District multi-energy systems: A comprehensive review of configurations, technologies, and performances
No full textThe energy consumption of buildings is responsible for about 37% of global energy-related CO2 emissions. Although the challenge of reducing this huge carbon emission attracts numerous research projects, only a small fraction of them focusses on the configuration and performance of multi-energy systems at a district scale. District multi-energy systems (D-MESs) are considered a favorable route to integrate various energy sources/vectors and activate synergies among them, which cannot only meet the changing energy supply structure and user demands but also promote the efficient use of renewable resources. This systematic review elaborates on the state-of-the-art configurations and performance of D-MESs in mixed-use districts in terms of energy generation, distribution, and storage. Firstly, it presents a clear set of definitions related to district multi-energy systems by analyzing the background frameworks and terminologies. Then, case studies of different D-MES configurations are categorized and analyzed in terms of generation, distribution, and storage solution. In each subsection, technologies are evaluated with respect to the energy, environmental, and economic benefits. Lastly, the future perspective is provided based on the present state of D-MESs. This paper aims to outline current research gaps, such as integrating various energy vectors and investigating the mismatches. It also aims to provide a comprehensive overview of configurations and technologies to promote more effective planning and managing solutions
Design, modeling and performance monitoring of a photovoltaic-thermal (PVT) water collector
No full textOver the years, many research efforts have been spent on the development of hybrid photovoltaic-thermal (PVT) technology, which is able to produce electricity and thermal energy at the same time with better overall performances of the two separated solar technologies. The aim of this work is the design of an innovative glazed PVT component with water as heat transfer fluid and the construction of a detailed mathematical model for the estimation of its electrical and thermal production. The paper presents the design of a covered PVT collector, made with thin film PV technology and a roll-bond flat plate absorber, and a simulation model, developed through the elaboration of several mathematical equations, to evaluate the performance of covered PVT water collectors. Finally, considerations about daily and annual yield of the proposed PVT collector, compared to a standard photovoltaic module, are discussed
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