Solar Energy

Journal: Solar Energy

Abbreviation

Sol. energy

Publisher

Elsevier

ISSN

0038-092X
1471-1257

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Publications 1 - 10 of 57

Assessment of rooftop photovoltaic potentials at the urban level using publicly available geodata and image recognition techniques
Mainzer, Kai; Killinger, Sven; McKenna, Russell; et al. (2017)
Solar Energy
The local generation of renewable electricity through roof-mounted photovoltaic (PV) systems on buildings in urban areas provides huge potentials for the mitigation of greenhouse gas emissions. This contribution presents a new method to provide local decision makers with tools to assess the remaining PV potential within their respective communities. It allows highly detailed analyses without having to rely on 3D city models, which are often not available. This is achieved by a combination of publicly available geographical building data and aerial images that are analyzed using image recognition and machine learning approaches. The method also employs sophisticated algorithms for irradiance simulation and power generation that exhibit a higher accuracy than most existing PV potential studies. The method is demonstrated with an application to the city of Freiburg, for which a technical PV electricity generation potential of about 524GWh/a is identified. A validation with a 3D city model shows that the correct roof azimuth can be determined with an accuracy of about 70% and existing solar installations can be detected with an accuracy of about 90%. This demonstrates that the method can be employed for spatially and temporally detailed PV potential assessments in arbitrary urban areas when only public geographical building data is available instead of exact 3D city model data. Future work will focus on methodological improvements as well as on the integration of the method within an urban energy system modeling framework.
Correction for the absorber edge effect in analytical models of flat plate solar collectors
Eismann, Ralph; Prasser, Horst-Michael (2013)
Solar Energy
Thermochemical energy storage via isothermal carbonation-calcination cycles of MgO-stabilized SrO in the range of 1000–1100 °C
Gigantino, Marco; Kiwic, David; Steinfeld, Aldo (2019)
Solar Energy
The reversible gas-solid thermochemical reaction between CO2 and SrO to form SrCO3 is considered for storing high-temperature heat delivered by concentrated solar energy systems. To maintain cycling stability, MgO-stabilized SrO-based materials were synthetized with various precursors and support contents by the co-precipitation, sol–gel, wet-mixing and dry-mixing production methods. Samples were analysed by thermogravimetry over multiple consecutive carbonation-calcination cycles in the range of 1000–1100 °C. The best performance was obtained by using the wet-mixing method with strontium acetate hemihydrate and porous magnesium oxide as precursors: the formulation with 40 wt% SrO featured stable chemical conversion over 100 consecutive carbonation-calcination cycles at 1000 °C and yielded gravimetric energy density of 0.81 MJ/kg.
Experimental study on a direct water heating PV-T technology
Cen, Jiajun; du Feu, Roan; Diveky, Matus; et al. (2018)
Solar Energy
Satellite-derived solar radiation for intra-hour and intra-day applications: Biases and uncertainties by season and altitude
Carpentieri, Alberto; Folini, Doris; Wild, Martin; et al. (2023)
Solar Energy
Regional to European scale intra-day forecasts of solar resources and photovoltaic (PV) power generation are of key relevance for operators of solar plants and power grids, as well as power traders, who seek to optimize revenues and maintain grid stability by matching power supply and demand. Our study addresses a key prerequisite for such forecasts: the accuracy of intra-hour and intra-day surface solar radiation (SSR) estimates of the HelioMont Meteosat product, a state of the art satellite product particularly suited for the Alpine region. A second satellite product, SARAH-2, as well as longer time scales, are also examined for comparison. The satellite SSR estimates are analyzed based on 136 ground stations across altitudes from 200 m to 3570 m in Switzerland in 2018. In peak daytime periods, the instantaneous satellite SSR deviates from the ground-measured SSR by a mean absolute deviation (MAD) of 110.4 and 99.6 W/m2 for SARAH-2 and HelioMont, respectively. For the daytime SSR, the instantaneous, hourly, and daily-mean MADs amount to 91.7, 81.1, 50.8, and 82.5, 66.7, 42.9 W/m2 for SARAH-2 and HelioMont, respectively. SARAH-2 drastically underestimates instantaneous SSR in winter at altitudes above 1000 m, possibly due to snow cover. HelioMont performs better in this respect, but the remaining substantial, spatially and temporally heterogeneous biases we identify pose a challenge with regard to the use of HelioMont for accurate intra-day PV estimates and forecasts.
A 1.2 MWth solar parabolic trough system based on air as heat transfer fluid at 500 °C — engineering design, modelling, construction, and testing
Good, Philipp; Ambrosetti, Gianluca; Pedretti, Andrea; et al. (2016)
Solar Energy
Experimental testing of a solar air cavity-receiver with reticulated porous ceramic absorbers for thermal processing at above 1000 °C
Patil, Vikas R.; Kiener, Fabio; Grylka, Adrian; et al. (2021)
Solar Energy
Concentrated solar energy can be used as the source of high-temperature heat for industrial processes, but the challenge is to design a solar receiver that can effect such a thermal conversion efficiently. This study reports on the engineering design and experimental testing of a 5 kW solar cavity-receiver containing a reticulated porous ceramic (RPC) structure that can absorb high-flux radiation volumetrically and heat up, by convection, an air flow serving as the heat transfer fluid. The thermal performance, characterized by the thermal efficiency and the air outlet temperature, was determined experimentally for four parameters, namely: RPC material (silicon-infused silicon carbide or SiSiC, alumina, and ceria), mean pore size (range 0.8–2.5 mm, corresponding to 10–30 pores per inch or PPI, at 0.90 porosity), solar concentration ratio (range 1965–3900 suns over a 4 cm-diameter cavity aperture, supplied by a high-flux solar simulator), and air mass flow rate (range 2–10 kg/h). Thermal efficiencies between 0.22 and 0.69 were obtained at steady-state air outlet temperatures ranging from 1160 to 450 °C. Larger pores enhance heat transfer while variable porosity across the RPC can reduce temperature gradients and potentially contribute to the design optimization. The highest efficiency of 0.69 was achieved by the SiSiC 10 PPI cavity at an air outlet temperature of 1133 °C and air mass flow rate of 9.9 kg/h. The solar receiver design proved to deliver a high-temperature air flow (>1000 °C) with a reasonably high thermal efficiency (>0.65).
The contribution of water surface Fresnel reflection to BIPV yield
Dammeier, Franziska; Happle, Gabriel; Rohrer, Jürg (2017)
Solar Energy
Solar assisted absorption cooling cycles for reduction of global warming: A multi-objective optimization approach
Gebreslassie, Berhane H.; Guillén Gosálbez, Gonzalo; Jiménez, Laureano; et al. (2012)
Solar Energy
his work addresses the use of absorption cycles combined with solar energy for reducing the green house gas (GHG) emissions in the cooling sector. The problem of satisfying a given cooling demand at minimum cost and environmental impact is formulated as a bi-criterion non-linear optimization problem that seeks to minimize the total cost of the cooling application and its contribution to global warming. The latter metric, which is assessed following the principles of life cycle assessment (LCA), accounts for the impact caused during the construction and operation of the system. The concept of Pareto optimality is employed to discuss different alternatives for reducing the contribution to global warming that differ in their economic and environmental performance. We also analyze the effect of taxes on CO 2 on the economic and environmental performance of the system. The capabilities of the proposed approach are illustrated through a case study that addresses the design of a solar assisted ammonia-water single effect absorption cooling system with 100kW of cooling capacity considering Barcelona weather conditions. We show that reducing the contribution to global warming considering the current energy prices and taxes on carbon dioxide emissions is technically viable but economically not appealing. We also discuss the conditions under which reducing the CO 2 emissions could become economically attractive. © 2012 Elsevier Ltd.
Projections of long-term changes in solar radiation based on CMIP5 climate models and their influence on energy yields of photovoltaic systems
Wild, Martin; Folini, Doris; Henschel, Florian; et al. (2015)
Solar Energy

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