Results 1 - 10 of 20
Results 1 - 10 of 20. Search took: 0.02 seconds
|Sort by: date | relevance|
[en] This report presents the results of the 2018 study of the collective solar thermal market in France: 1 - Methodology; 2 - General feeling of interviewed actors; 3 - Market trends: 2017 sales evolution, activity during the first half of 2018, main obstacles to market development; 4 - Market structure: competition, distribution per market segment and type of application, the challenge of the on-line installations follow up, feeling regarding design office skills, feeling regarding dynamical implementation; 5 - Development perspectives: short and medium-term vision, reactions with respect to the 'Solar Plan', acting against the sluggish performances of the sector, the perspectives offered by the ecological taxation, efforts made on communication, large-scale installations perspective (industrial solar heating, district heating), perspectives of solar coverage rate increase, R and D actions; 6 - Public authorities action; 7 - Synthesis.
[en] Solar thermal energy is no doubt the ultimate physical form for transferring heat to water without emitting greenhouse gases or pollutants. Yet in 2017 the sector struggled to survive in the hot water production and heating market. According to EurObserv'ER, the annual solar thermal collector surface area in the European Union dropped below the 2 million m2 mark, i.e. by 24.2% compared to the previous year's installed surface area. The individual national market figures vary widely, with several countries showing encouraging signs. Concentrated solar power is another way of harnessing direct sunlight. The technology consists of concentrating the sun's rays using mirrors to heat a fluid to high temperature, produce steam and thus produce electricity. The European Union's installed base has remained at almost the same level since 2014 and stood at 2 314 MW at the end of 2017. The global market whose growth has been sluggish over the past two years (110 MW in 2016 and 100 MW in 2017) should pick up speed from 2018 onwards
[en] Ocean thermal energy conversion is a power cycle that generates power using the temperature difference between the surface water and deep water of the ocean. In this study, the performance analysis of a transcritical carbon dioxide Rankine cycle for ocean thermal energy conversion and optimization using genetic algorithms are conducted. A simple Rankine cycle and a Rankine cycle with a feed-liquid heater are considered, and a solar-boosted ocean thermal energy conversion system is applied to construct a transcritical cycle. From the results of the analysis, the exergy efficiency increased as the turbine inlet temperature increased, and the heat source outlet temperature was lower in the transcritical cycle. The exergy efficiency due to the turbine inlet pressure and the intermediate pressure of a Rankine cycle with a feed-liquid heater were nonlinear, and there was an optimization point. Then, the genetic algorithm calculated the optimal values by reflecting all of the independent variables in the transcritical cycle. From the results of the optimal value analysis, it was found that the exergy efficiency of a Rankine cycle with a feed-liquid heater was improved compared to that of a simple Rankine cycle.
[en] This report presents the results of the 2018 study about the collective solar thermal market in France. Content: 1 - Market trends: 2017 sales, first half 2018 activity, main brakes to market development; 2 - Market structuration: competition, market segment distribution and type of application, challenge of installations connected follow up, perception about design consultant skills, perception about dynamical commissioning; 3 - Development perspectives: short- and medium-term vision, reactions with respect to the 'solar plan', actions against sector counter-performances, perspectives opened by the ecological tax law, actions of communication, prospects of large area facilities (industrial solar heat, solar district heating), prospects of solar coverage increase, R and D actions; 4 - Public authorities action: heat fund impact, 2012 thermal regulations impact; 5 - Synthesis.
[en] This report presents the first results of the quantitative aspect of the 2017 market follow-up of individual solar-thermal facilities: 1 - Methodology of the study; 2 - 2017 market figures (sales, regional distribution of solar water heater and combined solar system sales, overseas market, European trend); 3 - Market structure (distribution channels, installers, building type, sales revenues); 4 - Solar water heaters segment; 5 - Combined solar systems segment; 6 - Makers/retailers/installers sales revenues; 7 - Average prices (individual solar water heaters, optimised solar water heaters, average prices/m2 trend in continental France since 2005, average prices in overseas territories, individual combined systems average price, average prices/m2 trend in continental France since 2005).
[en] The development of nanostructured solar absorbers and their utilization in applied solar devices are the need of the hour and hence the present research. The research results revealed that nano carbon and MnO2 coated absorbers could be developed by spray coating method. The research results also revealed that the crystallite sizes in the coatings of carbon and MnO2 based absorbers were in nano ranges. The observation on research results revealed that the thermal durability and thermal efficacy of the nano carbon and MnO2 coated absorbers (in 70:30 ratio) were acceptable in connection with their utilization in the solar collectors. As the thermal durability and efficacy of nano carbon and MnO2 coated absorbers were acceptable, it could be concluded that nano carbon and MnO2 coated absorbers would be integrated in solar collectors so as to improve their thermal performances. (author)
[en] Highlights: • Optical properties of core-shell NPs were discussed systematically. • Absorption efficiency can be adjusted by the core-shell or mixing ratios of NPs. • Optimized parameters of the core-shell NPs for solar absorption were obtained. • Efficiency of Au-decorated SiO2 NPs was superior to Au NPs and SiO2 NPs. - Abstract: In this study, the properties of various types of core-shell nanoparticles (NPs) were evaluated using the finite difference time domain (FDTD) method towards the enhancement of solar absorption performance. Results showed that the resonance wavelength of SiO2@Au NPs lay in the 540–900 nm range, covering the near-infrared and visible regions. The resonance wavelength of SiO2@Ag NPs lay in the 390–830 nm range, covering the entire visible region. SiO2@Au nanofluid with a core-shell ratio of φ = 0.2 exhibited the highest solar absorption efficiency with 64% less Au consumption compared to pure Au NPs. For mixed nanofluids, the mixtures featuring core-shell ratios of 0.1 and 0.6 with mixing ratios of 0.5 for SiO2@Au and 0.6 for SiO2@Ag gave the highest absorption efficiencies. In addition, the peak solar absorption efficiency of a mixed nanofluid of SiO2@Au (φ = 0.1) and SiO2@Ag (φ = 0.4) with a mixing ratio of 0.58 was as high as 94.4%. Solar thermal conversion experiments revealed that, under the same conditions, a Au-decorated SiO2 nanofluid showed a comparable efficiency to the calculated solar absorption efficiency of the SiO2@Au core-shell nanofluid (∼95.2%); it was as high as 95.9%, higher than those of Au NPs and SiO2 NPs. These results showed that adjusting the core-shell ratios and tuning the mixing ratios of different nanofluids are two efficient methods to enhance the solar absorption efficiencies of SiO2@Au and SiO2@Ag NPs under the optimal conditions.
[en] A first article proposes an overview of available technologies for the installation of wind turbines on buildings. Different types (horizontal or vertical axis) of technologies are presented, as well as their benefits and drawbacks. Different approaches are thus adopted by different French companies and start-ups, and characterised by different power levels. Experimentations performed in Germany and in Hong-Kong are mentioned along with their prices and performance. The second article addresses perspectives for the solar thermal sector, and more particularly for the integration of this energy with conventional combined cycles (Integrated Solar Combined Cycle, ISCC). This possibility seems promising as solar heat induces very interesting performance for combined cycle power plants. The article indicates the present situation of existing integrated systems. Sketches present possible arrangements, and performance are discussed, notably annual efficiencies of an ISCC installation optimised for thermal storage, and the impact of heat storage on high performance autonomous power plants
[en] Utilizing plasmonic nano-particles/structures for solar water evaporation has aroused increasing interest; however, large-scale methods are desired to boost the efficiency and improve the practicality of solar steam generation. We developed a membrane-supported floating solar steam generation system based on graphene oxide and a multiscale plasmonic nanostructure; the latter is a micrometer-sized colloidosome that was assembled from hollow and porous Ag/Au nanocubes. By taking advantage of multiscale plasmonic coupling of the particles, an extremely high solar thermal conversion efficiency up to 92% at 10 kW·m−2 (with a water evaporation rate reaching 12.96 kg·m−2·h−1) can be achieved. The TiO2 nanoparticle-modified floating system is also capable of high-efficiency dye degradation in organic-polluted water, rendering such a membrane system recyclable and scalable for practical and versatile solar-driven generation of clean water. .
[en] This report presents the first results of the quantitative aspect of the 2017 market follow up of individual solar thermal installations. Content: 1 - 2017 market figures; 2 - Market structuration; 3 - 2017 sales revenue; 4 - 2017 average prices.