1,721,455 research outputs found
Modeling and Simulation of Solar Systems Employing Collectors with Colored Absorber
No full textTo avoid the monotony of the black colored flat plate solar
collectors we can use absorbers of blue, red-brown, green or other color. Because
of the lower collector absorptance these collectors have lower thermal efficiency
than that of the usual black type collectors, they are however of more interest to
architects for applications on traditional or modern buildings. In this paper
applications of solar collectors with colored absorbers are presented and analyzed
with respect to their performance, aiming to give guidelines for their wider use on
buildings. These systems are simulated with TRNSYS on an annual basis at two
different locations, Nicosia, Cyprus and Athens, Greece. The results show that the
energy output depends on the absorber darkness. For a medium value of the
coefficient of absorptance, the colored collectors give satisfactory results with
respect to the drop of the amount of collected energy, compared to collectors with
black absorbers. This implies the use of slightly larger collector aperture area to
have the same energy output as that of typical black colored collectors
SDEWES 2018 - 13th Conference on Sustainable Development of Energy, Water and Environment Systems
No full textBuilding façade integrated solar thermal collectors for water heating: simulation model and case studies
No full textThis paper presents a dynamic simulation model for the energy and economic performance assessment of a novel building integrated solar collector prototype, for Sanitary Hot Water (SHW) production and space heating. The investigated device is a Flat-Plate Solar Thermal Collector (FPC) with water working fluid, suitably designed to be integrated in the building envelope (Building Integrated Solar Thermal System - BISTS). The developed model was conceived for assessing the active effect of the collector as well as the influence of its building integration on the building thermal behaviour and thermal loads (i.e. overheating). The main differences of the proposed novel collector with the existing technologies consist in the system simplicity and low fabrication cost. The developed simulation model, written in MatLab environment, is implemented in a suitable computer code. Such tool is validated by taking into account the data collected through a suitable experimental analysis recently carried out in Limassol (Cyprus). In order to assess the system performances and to show the features of the developed simulation model, several comprehensive case studies were developed. In particular, they refer to the installation of the examined FPC prototype on south facing façades of different buildings, e.g. characterized by diverse uses and envelope weights, and located in several weather zones. For each weather zone and building typology, a suitable parametric analysis, focused on several system design and operating parameters, is carried out. Suitable reference system layouts are also taken into account for comparison purposes (e.g. buildings without and with stand-alone solar collectors). Simulation results show that interesting energy, economic and environmental advantages are always obtained through the adoption of such prototype. The energy performance and the payback periods strongly depend on the simulated weather zone
A building integrated solar air heating thermal collector prototype: modelling, validation and case study
No full textIn this paper, the thermal performance analysis of a prototype Flat-Plate Solar Thermal Collector (FPC), using air as working medium, is presented. The collector is designed to be integrated in the building envelope (Building Integrated Solar Thermal System - BISTS), Figure 1. With respect to existing commercial collectors, such prototype is characterized by low cost materials and fabrication. In order to predict the thermal performance of the investigated system, a numerical simulation model is developed. The model, written in MatLab environment, is implemented in a suitable computer code for dynamically assessing the system energy, economic and environmental performances. Specifically, the model is capable to predict the collector active effects (e.g. air heating for ventilation purpose, etc.) and the passive ones due to the building integration on the heating and cooling loads. The prototype simulation model was validated by means of experimental data collected in Limassol (Cyprus) during experimental testing. In order to assess the system performances and to show the features of the developed simulation model, several comprehensive case studies are developed. The operation and performances of both the stand-alone and the building integrated collectors are analysed. In particular, the FPC prototype is integrated in the south facing façade of a high-rise building, characterized by diverse uses (dwelling and office buildings), located in different weather conditions (cold and warm climate zones). In addition, for comparison purposes, a building reference system layout is taken into account. With the aim at optimizing some collector design and operating parameters, a suitable parametric analysis is also carried out for the stand-alone collector layout. Simulation results show that interesting energy performances can be achieved, especially for climates with a long heating season
Experimental evaluation of a Hybrid Photovoltaic/Solar Thermal (HyPV/T) Façade Module
Full text linkThe Energy Performance of Buildings Directive and Renewable Energy Framework Directive require that Renewable Energy Systems (RES) are actively promoted in offsetting conventional fossil fuel use in buildings. A better appreciation of solar systems integration will directly support this objective, leading to an increased uptake in the application of renewables in buildings. By integrating these systems into the building elements (walls, roofs, etc.) not only means replacing a conventional building material (and associated costs), but also aesthetically integrating it into the building design leads to improved architectural integration.A modular Hybrid Photovoltaic/Solar Thermal (HyPV/T) Façade technology that utilizes Integrated Collector Storage (ICS) solar technology, providing cost effective solar PV and thermal energy collection for direct use in the building, whilst providing significant thermal insulation has been developed and evaluated experimentally at Ulster University. The HyPV/T system, based upon a patented ICS solar thermal diode concept and shaped into a flat modular profile incorporating PV cells/module can provide space heating, domestic water heating and power generation. The complete system is designed to be compatible with traditional façade structures and fenestration framing arrangements, facilitating direct integration into new and retrofit building applications.The experimental thermal performance of a prototype HyPV/T unit has been determined under constant indoor solar simulated conditions. The thermal and electrical performances of various modified HyPV/T designs have been investigated and the thermal collection efficiencies, ‘diodicity’ and heat loss performance are presented. The ability for a single product to offer multiple functionality in a unique modular design and being the first to use ICS technology, presents a huge commercial opportunity. The HyPV/T whilst offering a more cost effective solar investment will combine performance and quality and be fit for purpose, robust, visually appealing and exceptionally easy to install. These characteristics are expected in all premium solar collector-related products
Grid connection of photovoltaic systems: technical and regulatory issues
No full textThe days when grid-connected photovoltaic (PV) generation could be treated merely as a small local reduction in load of the distribution network are past and the opportunities, and challenges, posed by PV systems are now of major concern to those developing and operating power systems. This chapter examines the current and future issues that are raised by PV generation assuming a major role in supplying electrical power. It considers the technical and regulatory aspects of the connection of PV systems to the public electricity distribution network but also its integration into the entire power system. Particular aspects of connection addressed include: thermal limits, voltage rise, DC injection, and reverse power flow. The additional features that will be required from PV inverters in the future including coupling them with energy storage and providing: synthetic inertia, frequency support, and fault current control are also considered
Improved ECMWF forecasts of direct normal irradiance: A tool for better operational strategies in concentrating solar power plants
Full text linkTo contribute for improved operational strategies of concentrating solar power plants with accurate forecasts of direct normal irradiance, this work describes the use of several post-processing methods on
numerical weather prediction. Focus is given to a multivariate regression model that uses measured irradiance values from previous hours to improve next-hour predictions, which can be used to refine
daily strategies based on day-ahead predictions. Short-term forecasts provided by the Integrated Forecasting
System, the global model from the European Centre for Medium-Range Weather Forecasts
(ECMWF), are used together with measurements in southern Portugal. As a nowcasting tool, the proposed
regression model significantly improves hourly predictions with a skill score of z0.84 (i.e. an increase of z27.29% towards the original hourly forecasts). Using previous-day measured availability to
improve next-day forecasts, the model shows a skill score of z0.78 (i.e. an increase of z6% towards the
original forecasts), being further improved if larger sets of data are used. Through a power plant simulator (i.e. the System Advisor Model), a preliminary economic analysis shows that using improved
hourly predictions of electrical energy allows to enhance a power plant’s profit in z0.44 MV/year, as compared with the original forecasts. Operational strategies are proposed accordingly
Experimental evaluation of a Hybrid Photovoltaic/Solar Thermal (HyPV/T) Façade Module
Full text linkThe Energy Performance of Buildings Directive and Renewable Energy Framework Directive require that Renewable Energy Systems (RES) are actively promoted in offsetting conventional fossil fuel use in buildings. A better appreciation of solar systems integration will directly support this objective, leading to an increased uptake in the application of renewables in buildings. By integrating these systems into the building elements (walls, roofs, etc.) not only means replacing a conventional building material (and associated costs), but also aesthetically integrating it into the building design leads to improved architectural integration.A modular Hybrid Photovoltaic/Solar Thermal (HyPV/T) Façade technology that utilizes Integrated Collector Storage (ICS) solar technology, providing cost effective solar PV and thermal energy collection for direct use in the building, whilst providing significant thermal insulation has been developed and evaluated experimentally at Ulster University. The HyPV/T system, based upon a patented ICS solar thermal diode concept and shaped into a flat modular profile incorporating PV cells/module can provide space heating, domestic water heating and power generation. The complete system is designed to be compatible with traditional façade structures and fenestration framing arrangements, facilitating direct integration into new and retrofit building applications.The experimental thermal performance of a prototype HyPV/T unit has been determined under constant indoor solar simulated conditions. The thermal and electrical performances of various modified HyPV/T designs have been investigated and the thermal collection efficiencies, ‘diodicity’ and heat loss performance are presented. The ability for a single product to offer multiple functionality in a unique modular design and being the first to use ICS technology, presents a huge commercial opportunity. The HyPV/T whilst offering a more cost effective solar investment will combine performance and quality and be fit for purpose, robust, visually appealing and exceptionally easy to install. These characteristics are expected in all premium solar collector-related products
Smart grid and energy storage
No full textSmart Grid is a radical transformation of the electric power system that would facilitate an increase in the utilization of solar energy. It makes use of advanced Information and Communication Technology systems to give improved visibility and allow intelligent automation and control of the distribution system that would remove many of the present barriers to the connection of PV. Battery energy storage is a key element of PV smart grids as it allows the use of energy to be decoupled from the solar resource. Li-ion batteries are at present the most promising technology for energy storage in smart grids and are being marketed by several manufacturers for domestic PV/battery systems. These offer the possibility of augmenting the value of PV systems by maximizing self-consumption, increasing revenues from Time of Use tariffs and by providing ancillary services to the power system
Solar energy engineering: processes and systems
No full textAs perhaps the most promising of all the renewable energy sources available today, solar energy is becoming increasingly important in the drive to achieve energy independence and climate balance. This new book is the masterwork from world-renowned expert Dr. Soteris Kalogirou, who has championed solar energy for decades. The book includes all areas of solar energy engineering, from the fundamentals to the highest level of current research. The author includes pivotal subjects such as solar collectors, solar water heating, solar space heating and cooling, industrial process heat, solar desalin
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