Navigating Corporate Cultures From Withinoffers a unique perspective on the management of headquarter-subsidiary-host market relationships with important insights on how to align corporate values ...with a localized mindset among culturally diverse employees and across a global enterprise.
•The extent to which bifacial spectral effects are dependent on the albedo, sky conditions, and mounting structure are quantified.•Backside spectral mismatch can be reasonably approximated using ...spectral albedo measurements with just 5–8 narrow band channels.•The normalized difference vegetation index is a good predictor of the backside spectral effects present in bifacial systems.•An open access spectral dataset consisting of spectral albedo, spectral global horizontal irradiance, and spectral beam measurements is made freely available.
This paper analyzes 15-months of spectral albedo measurements collected at the Technical University of Denmark (55.6°N, 12.1°E). High-resolution spectroradiometers are used to monitor four albedo scenarios, which include green vegetation, dry vegetation, gravel, and snow. Spectral mismatch and spectral impact are calculated for the front and backside of three different bifacial cell concepts mounted on horizontal single axis trackers and fixed-tilt substructures. The spectral nature of albedo is shown to have significant influence on bifacial photovoltaic performance wherein backside spectral impact as high as 1.20 is observed for fixed-tilt systems above green vegetation and as low as 0.98 for systems above snow. The results reveal that spectral impact is always lower on tracked than fixed-tilt systems because a greater fraction of sky diffuse light reaches the backside of tracked systems. Given the variety of albedos tested here, we find that the normalized difference vegetation index is a good predictor of backside spectral effects. When the high-resolution measurements are truncated to 4 to 8 carefully selected wavelengths, we find that this limited measurement resolution sufficiently captures the seasonal spectral albedo fluctuations that influence bifacial photovoltaic energy production. Finally, to alleviate the dearth of spectral datasets presently available to the PV community, the spectral irradiance and albedo measurements are made freely available in open access format (https://doi.org/10.11583/DTU.14695437.v1).
Potential glare through reflected sunlight can be a significant hindrance factor for photovoltaic (PV) installations, especially for building-integrated PVs with atypical orientations and tilt angles ...present. Structured glass surfaces or antireflective (AR) coatings are often used as a solution, however, there is currently no universally recognized method or metric to estimate their impact on glare. This article presents an evaluation of the glare potential of different surface glasses for use in PV modules based on their bidirectional reflectance distribution functions (BRDF). BRDF threshold values for retinal burn damage, flash blindness, and discomfort glare are calculated based on retinal irradiance thresholds from literature. Subsequently, gonioreflectometric measurements on PV minimodules are used to characterize the reflectance profiles of eight different glass surfaces. Results for all measured structured glasses, both satinated and macrotextured, show significant reductions in BRDF compared with smooth glass, largely eliminating the potential for flash blindness as well as discomfort glare at low incidence angles. At high incidence angles, increased potential for discomfort glare as well as forward scattering along the glass surface can be observed. AR coatings, however, are shown to be insufficient to eliminate glare causing flash blindness.
Discussing modes of political and/or economic decoupling in an era of economic globalization seems almost contradictory as the dominating keywords in the latter are increasing integration, ...interdependency and harmonization. For example, when looking towards the political realm it seems problematic to suggest that a nation-state can opt for a withdrawal from the global community in order to nurture its domestic potential. Likewise, when looking towards the economic realm, it seems even more problematic to suggest the possibility of a national economy withdrawing from the global economy, taking an increasing internationalization of domestic markets into account. Nonetheless, there is a discourse devoted to just that, namely whether or not to decouple economically and politically from the global community. The present article explores this discourse by first taking a critical look at the concept of decoupling. It then proceeds by presenting a different approach towards the study of the relationship between the global and national level by introducing the notion of triangulation. It is argued that the relationship between economic globalization, national economics and a given societal context in which the two former are embedded, is governed by various layers of interdependency. This means that one cannot solely focus on one point in the triangle and thus decouple, so to speak, the other two in order to understand, for example, the political or economic forces at play there. According to the argument forwarded in this article, one has to take all three points in the triangle into account in order to disentangle and thus understand the complex web of interdependency among the three. To illustrate the workings of this approach, a case study of the ramifications of a newly initiated national economic development plan in Malaysia is introduced. The article ends by returning to the decoupling discourse to re-examine it in the light of the findings from the case study.
While colored photovoltaics are gaining popularity in the market for building-integrated photovoltaics (BIPV), several specific properties are not accounted for in standard PV performance models. ...This work shows how relying on the coloration efficiency alone can lead to significant errors regarding module temperatures. By comparing measured temperature data from a test installation featuring BIPV façade elements in multiple colors, little correlation is found between total optical losses (reflection and absorption losses) and module temperature. Instead, better correlation is found with total reflectance. This is attributed to the light absorbed in the pigment-based colored layers contributing to module heating, whereas reflected light does not. This is especially relevant for colors with high lightness, such as gray or beige, for which reflection losses are dominating absorption losses. When modelling colored BIPV products, it is therefore recommended to only consider reflection losses for the irradiance contributing to module heating, while continuing to also include absorption losses for the effective irradiance used in electrical performance modelling.
This paper presents the results from an extensive interlaboratory comparison of angular‐dependent measurements on encapsulated photovoltaic (PV) cells. Twelve international laboratories measure the ...incident angle modifier of two unique PV devices. The absolute measurement agreement is ±2.0% to the weighted mean for angles of incidence (AOI) ≤ 65°, but from 70° to 85°, the range of measurement deviations increases rapidly from 2.5% to 23%. The proficiency of the measurements is analysed using the expanded uncertainties published by seven of the laboratories, and it is found that most of the angular‐dependent measurements are reproducible for AOI ≤ 80°. However, at 85°, one laboratory's measurement do not agree to the weighted mean within the stated uncertainty, and measurement uncertainty as high as 16% is needed for the laboratories without uncertainty to be comparable. The poor agreement obtained at 85° indicates that the PV community should place minimal reliance on angular‐dependent measurements made at this extreme angle until improvements can be demonstrated. The cloud‐based Daidalos ray tracing model is used to simulate the angular‐dependent losses of the mono‐Si device, and it is found that the simulation agrees to the median measurement within 0.6% for AOI ≤ 70° and within 1.4% for AOI ≤ 80°. Finally, the impact that the angular‐dependent measurement deviations have on climate specific energy rating (CSER) is evaluated for the six climates described in the IEC 61853‐4 standard. When one outlier measurement is excluded, the angular‐dependent measurements reported in this work cause a 1.0%–1.8% range in CSER and a 1.0%–1.5% range in annual energy yield, depending on the climate.
This paper presents the results from an interlaboratory comparison of incident angle modifier measurements performed on encapsulated PV devices by 12 international laboratories. It is found that most of the angular‐dependent measurements are reproducible for angles of incidence ≤80°, but measurement agreement suffers at 85° with deviations as high as 23%. The uncertainty that the angular‐dependent measurement deviations contribute to the IEC 61853 climate‐specific energy rating (CSER) is calculated as 1.0%‐1.8%, depending on the climate.
PDF
