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During the last few decades, unheated attic spaces (so-called "cold attics") have been one of the most moisture-problematic spaces in the building practices of Europe and North America. Problems with such spaces are usually associated with condensation, frost formation, and mould growth on the lower surfaces of the roof deck. To solve these problems, a number of qualitative studies were performed. Although these studies revealed many important pieces of information, some of them are seemingly not in accordance with one another. Therefore, there has not yet been presented cold attic design which is suitable (especially moisture-safe) for the whole target region. The aim of this paper is to determine whether such a design can be determined or state the reasons why it is not possible. Based on a review of published studies, 38 cold attic designs were selected for detailed analysis. Their comparative parameters were established, quantified, and compared. The moisture-safeness of each design was evaluated using an original approach, and the designs were sorted into groups based on their similarities. Despite many uncertainties, it was found that the criteria for moisture-safe cold attic design in the target region can likely be stated. [ABSTRACT FROM AUTHOR]

Photovoltaic (PV) systems are the cheapest source of electricity in sunny locations and nearly all European countries. However, the fast deployment of PV systems around the world is bringing uncertainty to the PV community in terms of the reliability and long-term performance of PV modules under different climatic stresses, such as irradiation, temperature changes, and humidity. Methodologies and models to estimate the annual degradation rates of PV modules have been studied in the past, yet, an evaluation of the issue at global scale has not been addressed so far. Hereby, we process the ERA5 climate re-analysis dataset to extract and model the climatic stresses necessary for the calculation of degradation rates. These stresses are then applied to evaluate three degradation mechanisms (hydrolysis-degradation, thermomechanical-degradation, and photo- degradation) and the total degradation rate of PV modules due to the combination of temperature, humidity, and ultraviolet irradiation. Further on, spatial distribution of the degradation rates worldwide is computed and discussed proving direct correlation with the Köppen-Geiger-Photovoltaic climate zones, showing that the typical value considered for the degradation rate on PV design and manufacturer warranties (i.e., 0.5%/a) can vary ± 0.3%/a in the temperate zones of Europe and rise up to 1.5%/a globally. The mapping of degradation mechanisms and total degradation rates is provided for a monocrystalline silicon PV module. Additionally, we analyze the temporal evolution of degradation rates, where a global degradation rate is introduced and its dependence on global ambient temperature demonstrated. Finally, the categorization of degradation rates is made for Europe and worldwide to facilitate the understanding of the climatic stresses. [ABSTRACT FROM AUTHOR]