1,720,983 research outputs found
Are the spectroradiometers used by the PV community ready to accurately measure the classification of solar simulators in a broader wavelength range?
No full textLatest trends in the photovoltaic sector see the use of innovative photovoltaic technologies with extended spectral responsivity ranging from 300 to 1200 nm for non-concentrating terrestrial applications, and to 1800 nm for concentrating PV and space applications. As a consequence, an update of the IEC 60904-9 standard is ongoing with a definition of new spectral ranges for the assessment of the spectral match. This poses new challenges to laboratories and research centers on whether or not they still are able to accurately measure the spectral mismatch of their sun simulator in the newly-defined spectral regions. Prior to that, there is a need to understand if the commercially available spectroradiometers are ready to extend their measurement range as prescribed by the forthcoming new standard. This paper analyses two options for an extension of the spectrum characterisation of solar simulators to 300–1200 nm and compares them in terms of spectral match of global normal irradiance (GNI) spectra acquired under natural sunlight by eight spectroradiometers during the 6th European Spectroradiometer Intercomparison. The acquired spectra are also compared in terms of an index of consistency of the spread of the measured spectra with the estimated measurement uncertainty, hereafter named as performance statistics En. Results show that all investigated laboratories assure the equivalence of the spectral match classification well below the 25% limit corresponding to class-A simulators. When considering the more stringent class-A+ corresponding to a 12.5% limit, one of the two considered options that rearranges the 300–1200 nm spectral range into 6 bands appears to still assure the equivalence of the class A+ limits among considered instruments. The En performance index analysis highlights some inconsistencies with the estimated measurement uncertainty or instrument drifts from the expected performance, and the need of further improvements in calibration, set up and measurement procedures. © 2018 Elsevier Lt
Second international spectroradiometer intercomparison: Results and impact on PV device calibration
No full textThis paper describes the results of an intercomparison of spectroradiometers for measuring global normal incidence and direct normal incidence spectral irradiance in the visible and in the near infrared, together with an assessment of the impact these results may have on the calibration of the short circuit current (Isc) of triple-junction photovoltaic devices and on the relevant spectral mismatch calculation. The intercomparison was conducted by six European scientific laboratories and a Japanese industrial partner. Seven spectroradiometer systems, for a total of 13 different instruments/channels using two different technologies and made by four different manufacturers were involved. This group of systems represents a good cross section of the instrumentation for solar spectrum measurements available to date. The instruments were calibrated by each partner prior to the intercomparison following their usual procedure and traceability route in order to verify the entire measurement and traceability chain. The difference in measured spectral irradiance showed to have an impact on the calibration of a set of Iso-Type cells varying from ±2% to ±14% for middle and bottom cell, respectively. Copyright © 2014 John Wiley & Sons, Ltd
Spectroradiometry in PV: How inter-laboratory comparison may improve measurement accuracy
No full textSpectroradiometry is a key metrological topic for accurate testing of photovoltaic (PV) devices, particularly relevant both for indoor testing on solar simulators and for outdoor testing. The relevance of accurate measurements of solar spectral irradiance has led the most renowned European solar PV test centres to take part to a series of International Spetroradiometer Intercomparisons that has taken place every year so far since 2011 in various localities in the Mediterranean Basin. This paper revisits the performance of participant laboratories and highlights the importance of inter-laboratory comparisons, showing the possible improvements in measurement reproducibility. © 2018 IEEE
Set of protocols for overall testing for CPV
No full textThe success of a new CPV prototype depends on modules quality and assembly compliance with existing Standards, such as IEC 62108, 62670, 62787, and others still under development/approval for performance evaluation. The overall CPV system reliability is based on the quality of the subcomponents such as the optics, the cells, the electronics and the assembly of the whole system, but there is a dramatic lack of technical specifications for new prototypes to comply with. The Italian project SCOOP (SOLAR CONCENTRATION TECHNOLOGIES FOR PHOTOVOLTAIC SYSTEMS) was aimed at developing an Italian network of laboratories and industrial facilities to enter the CPV market. The project, funded by the Ministry of Industry, started in 2009 and ended at the end of 2013. SCOOP addressed the development of solar cells, optical systems and inverters, to be used in four different CPV prototypes. The development of a network of laboratories specialized to test, verify and check components such as plastic materials, optics, cells, electronics and module/assembly at prototype and industrial scale has been one of the main targets of the project. Within the project a set of protocols for the testing of subcomponents, components, modules and the final systems have been defined and validated. © 2014 IEEE
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Rating of CPV modules: Results of module round robins
No full textThe results of three CPV module round robins are presented. Ten test labs around the world participated to the round robins in total. Each round robin used a different CPV module technology (Daido Steel, Soitec, Suncore). The data gathered at the test labs was used to test CSOC power rating procedures as basis for the IEC draft standard 62670-3. The deviation between the minimum and the maximum power output rated at the test labs was in average 4.4 % with a standard deviation of 1.8 %abs. This underlines that power ratings or CPV modules are reliable and reproducible. © 2016, American Institute of Physics Inc. All rights reserved
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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