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Residential photovoltaic systems often experience partial shading from chimneys, trees or other structures, which can induce hot-spots in the modules. If the temperature and frequency of these hot-spots are high, the module's reliability and safety may be at risk. IEC 61215-2:2021 hot-spot endurance test is utilized to evaluate the materials' ability to withstand partial shading. Since modules in residential systems can be subjected to higher temperatures than those in the open field, IEC TS 63126:2020 recommends adjusting the module temperature for the hot-spot endurance test according to the module's operating temperature. This study tested the hot-spot endurance of PERC, IBC and HJT modules under standard (55 °C) and more severe (75 °C, Level 2 condition in IEC TS 63126:2020) test conditions, as well as outdoor accelerated-ageing tests were performed with shadow masks. The results demonstrated that irrespective of environmental conditions, hot-spots can form at lower temperatures, with more shading-tolerant cells (i.e., cells with lower breakdown voltage) or with shorter strings. We also show that it is possible to shorten the effort- and time-consuming hot-spot endurance test described in the standard and obtain similar results. In addition, the hot-spot endurance test for residential PV systems was evaluated in terms of module temperatures and duration. In this respect, we propose to increase the testing temperatures of the hot-spot endurance testing for modules operating at high temperatures in IEC TS 63126:2020. more...

Building integrated photovoltaics (BIPV) is progressively achieving an advanced level of technical maturity and considerable market penetration. In the last kilometre for considerable market implementation, major challenges are today mostly related to improving cost‐effectiveness and product reliability. BIPV multifunctional products are still framed in complex and sometimes unclear qualification processes, in the grey area between electrotechnical and construction sectors, impacting commercialization and users' confidence. The EN 50583 part 1 and part 2 standards today represent the main regulatory framework in Europe for BIPV. However, acts in force for product certification, in the construction and electrical sectors, in most national and local contexts are not yet harmonized for BIPV and imply wide margins of interpretation. The product's qualification in the EU is therefore based on electrical standards for photovoltaics modules or, on the other hand, on standards for construction products. To overcome some of these barriers and challenges, the authors propose a newly developed procedure for testing the impact resistance of BIPV products, introducing a performance‐based approach with the goal of combining building and electrical‐related limit states and responding to the need for a harmonized assessment to ensure the product's safety in use. The methodology and preliminary findings resulting from the application of real test cases, taking also into account the effect of temperature, are presented and analysed. As a result, it is envisaged that the implementation will help operators and prospective normative upgrades, ensuring more outstanding product quality for BIPV's market and driving towards a drop in life cycle costs. [ABSTRACT FROM AUTHOR] more...

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. [ABSTRACT FROM AUTHOR] more...

Because building-integrated photovoltaic (BIPV) modules are fully integrated into a building envelope, the back of the module can be exposed to little or no ventilation, resulting in increased operating temperatures. As the temperature increases, the performance of the modules decreases, and the durability of the module and its polymeric components (e.g., encapsulant and backsheet) may be impacted. Over the years, three different PV test stands were monitored in Canobbio (southern Switzerland) in different configurations: open-rack, BIPV partially-ventilated and BIPV insulated (non-ventilated) to investigate the effect of the operating temperatures on the long-term energy performance of the different BIPV module types. In this study, the PV modules installed in these test stands were thoroughly examined by: (i) evaluating the long-term performance of the modules, and (ii) establishing a correlation between the electrical performance and changes in the properties of the polymers used in the laminate. In general, we observe that: (i) for some bill of materials (BOM), the higher thermal stress of BIPV configurations can accelerate the degradation, particularly of the encapsulant, leading to current losses attributed to the polymer (discolouration); (ii) in some cases, the higher thermomechanical stress can lead to a higher rate of damaged cells and cell interconnects, resulting in fill factor losses; (iii) on the other hand, a careful selection of the BOM and system design (with adequate rear ventilation) may mitigate the issues related to higher thermal and thermomechanical stresses. [ABSTRACT FROM AUTHOR] more...