A unified global investigation on the spectral effects of soiling losses of PV glass substrates: preliminary results

This is the author accepted manuscript. The final version is available from IEEE via the DOI in this recordThe present work reports on the initial results of an international collaboration aiming to investigate the spectral effects of soiling losses. Identical glass coupons have been exposed outdoors for eight weeks in different locations worldwide, and weekly direct and hemispherical transmittance (T%) measurements are compared. Maximum losses as high as 7% and 50% in hemispherical and direct transmittance, respectively, have been found during the 8-week outdoor exposure. At the end of the data collection, a preliminary analysis of the spectral impact of soiling has been performed. The results show that the blue end of the spectrum is more affected and that lower hemispherical T% correlate to larger area covered by particles.Engineering and Physical Sciences Research Council (EPSRC)US Department of Energ

Application of atmospheric transport models at the new atmospheric Ebre Delta station (ClimaDat Network) in Eastern Spain

The Ebre Delta atmospheric station (DEC3) was installed in Eastern Spain, within the framework of the ClimaDat project of the Institut Català de Ciències del Clima (IC3). This station offers continuous measurements of greenhouse gases and tracers concentrations (CO2, CH4, CO, N2O and SF6), along with atmospheric concentrations of the natural radioactive gas 222Rn. Meteorological parameters, such as humidity, temperature, wind speed and wind direction are also measured at DEC3 site. This qualitative analysis aims to use the FLEXPART and the HYSPLIT models, with meteorological input of ECMWF and with spatial resolution of 0.2 degrees, to perform back trajectories at DEC3 station and qualitatively analyze how different air masses coming from the Northern Western Europe or from the Mediterranean Sea influence observed gases concentrations.Postprint (published version

Application of Atmospheric Transport Models at the new atmospheric Ebre Delta station (ClimaDat network) in Eastern Spain

Abstract: The Ebre Delta atmospheric station (DEC3) was installed in Eastern Spain, within the framework of the ClimaDat project of the Institut Català de Ciències del Clima (IC3). This station offers continuous measurements of greenhouse gases and tracers concentrations (CO 2 , CH 4 , CO, N 2 O and SF 6 ), along with atmospheric concentrations of the natural radioactive gas 222 Rn. Meteorological parameters, such as humidity, temperature, wind speed and wind direction are also measured at DEC3 site. This qualitative analysis aims to use the FLEXPART and the HYSPLIT models, with meteorological input of ECMWF and with spatial resolution of 0.2 degrees, to perform back trajectories at DEC3 station and qualitatively analyze how different air masses coming from the Northern Western Europe or from the Mediterranean Sea influence observed gases concentrations

Comparison of the diagnostic accuracy of commercial NS1-based diagnostic tests for early dengue infection

<p>Abstract</p> <p>Background</p> <p>We compared the diagnostic accuracy and reproducibility of commercially available NS1-based dengue tests and explored factors influencing their sensitivities.</p> <p>Methods</p> <p>Paired analysis of 310 samples previously characterized as positive (n = 218) and negative (n = 92) for viral isolation and/or RT-PCR and/or IgM seroconversion. Masked samples were tested by two observers with Platelia™ Dengue NS1 Ag, second generation Pan-E™ Dengue Early ELISA, SD Dengue NS1 Ag ELISA, Dengue NS1 Ag STRIP™, and SD BIOLINE™ Dengue Duo (NS1/IgM/IgG).</p> <p>Results</p> <p>SD BIOLINE™ NS1/IgM/IgG had the highest sensitivity (80.7% 95%CI 75-85.7) with likelihood ratios of 7.4 (95%CI 4.1-13.8) and 0.21 (95%CI 0.16-0.28). The ELISA-format tests showed comparable sensitivities; all below 75%. STRIP™ and SD NS1 had even lower sensitivities (<65%). The sensitivities significantly decreased in samples taken after 3 days of fever onset, in secondary infections, viral serotypes 2 and 4, and severe dengue. Adding IgM or IgG to SD NS1 increased its sensitivity in all these situations.</p> <p>Conclusions</p> <p>The simultaneous detection of NS1/IgM/IgG would be potentially useful for dengue diagnosis in both endemic and non endemic areas. A negative result does not rule out dengue. Further studies are required to assess the performance and impact of early laboratory diagnosis of dengue in the routine clinical setting.</p

Tables for the estimation of the internal rate of return of photovoltaic grid-connected systems

A continuous decrease trend in PV costs together with a wide variety of supporting measures have turned photovoltaic grid-connected systems (PVGCS) into a profitable investment when some economic conditions are met. The internal rate of return (IRR) is a meaningful parameter for prospective owners of these PV systems. Nevertheless, this parameter has to be estimated by means of non-analytical methods. This paper presents some easy-to-use tables addressed to estimate the IRR avoiding cumbersome calculations, which is an attractive feature for owners, marketers and designers. Firstly, current and near-term costs of PVGCS are reviewed, together with some financial incentives available at present. This introduces the economic scenario, where the tables are to be used. A short introduction to the economic analysis of these systems provides a solid ground to eventually present the tables intended to the estimation of the IRR. Lastly, three examples demonstrate the use of the tables.Economic analysis Grid-connected Financing

Solar Spectral and Module Temperature Influence on the Outdoor Performance of Thin Film PV Modules Deployed on a Sunny Inland Site

This work aims at analysing the influence of both module temperature and solar spectrum distribution on the outdoor performance of the following thin film technologies: hydrogenated amorphous silicon (a-Si:H), cadmium telluride (CdTe), copper indium gallium selenide sulfide (CIGS), and hydrogenated amorphous silicon/hydrogenated microcrystalline silicon hetero-junction (a-Si:H/μc-Si:H). A 12-month experimental campaign carried out in a sunny inland site in which a module of each one of these technologies was tested and measured outdoors has provided the necessary empirical data. Results show that module temperature exerts a limited influence on the performance of the tested a-Si:H, CdTe, and a-Si:H/μc-Si:H modules. In contrast, the outdoor behaviour of the CIGS module is the most affected by its temperature. Blue-rich spectra enhance the outdoor behaviour of the a-Si:H and a-Si:H/μc-Si:H modules while it is the other way round for the CIGS module. However, the CdTe specimen shows little sensitivity to the solar spectrum distribution. Anyway, spectral effects are scarcely relevant on an annual basis, ranging from gains for the CIGS module (1.5%) to losses for the a-Si:H module (1.0%). However, the seasonal impact of the spectrum shape is more noticeable in these two materials; indeed, spectral issues may cause performance gains or losses of up to some 4% when winter and summer periods are considered

Outdoor characterization of CdTe technology and seasonal performance analysis at different latitudes in Europe.

: The aim of this work is to improve knowledge about the observed seasonal behavior of CdTe modules under real op-erating conditions. The study consists of a characterization of the CdTe photovoltaic (PV) technology based on the ap-plication of the Sandia Array Performance Model (SAPM) to two PV fields in Italy (Viterbo and Bolzano) and two PV test modules in Spain (Madrid and Jaén). SAPM is a semi-empirical power estimation model that takes into account the four main phenomena that affect the Performance Ratio (PR) of PV plants or modules: temperature, angle of incidence, irradiance and spectral effects. New outdoor experimental procedures were set up at the ESTER station of University of Rome Tor Vergata to validate the temperature coefficients, the angle of incidence coefficients and the spectral mismatch coefficients of CdTe modules to be used in the SAPM model implementation. A detailed analysis of the deviation be-tween the experimental PR data and the modeled PR estimated by SAPM reveals that it is possible to characterize the re-siduals and attribute them to phenomena not considered by the model

Empirical model to predict the operating temperature of the modules of a photovoltaic system

The aim of this work is the validation of a regression model to forecast the cell temperature of a photovoltaic module under different conditions from those for which it was fitted. In a previous article, a model which uses as inputs the air temperature, the incident irradiation and the wind speed was proposed to forecast the cell temperature. To know if this model could be universally used, the cell temperature of a module of the same technology installed in another location with different weather conditions has been computed using the coefficients estimated previously. From the obtained results, it can be concluded that the model is able to predict the operating temperature of the generator of a power plant and could be applied to this technology at any location regardless of the weather conditions.

Procedure to carry out quality checks in photovoltaic grid-connected systems: Six cases of study

Assessing the correct operation of PV grid-connected systems (PVGCS) is paramount not only for mere energy and profitability concerns but also for safety reasons. Intended to this purpose, the IEC 62446 standard is open to some tests to be required in some circumstances, in addition to those stated in this document. Our work proposes a procedure to carry out quality checks in PVGCS complying with this standard and dealing with some tests not mentioned in it - namely, PV generator peak power measurement, inverter response and earth electrode measurement - so that the verification of the system gets more comprehensive. This procedure was carried out in six PV plants sited in different locations with a Mediterranean climate in Spain. The most remarkable results of this experimental campaign may be summarized as follows: an excellent on-site behavior of the inverters, in general very good figures for the isolation and earth electrode resistance and a scarcely relevant existence of hot spots. On the down side, some figures for the peak power of the tested PV generators well below their nominal value were found. The procedure described in this paper has proved to be a useful tool to assist in the verification of a PVGCS after installation and for subsequent re-inspection or maintenance.Grid connected systems Test & measurement Electricty yield Safety