Browsing by Subject "LCZ"

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    Human thermo-physiological comfort assessment in Lisbon by local climate zones on very hot summer days
    (Frontiers Research Foundation, 2023-05-17) Reis, C.; Nouri, Andre Santos; Lopes, A.
    Extreme heat is a current and future issue on urban areas, with negative impacts on health and quality of life (increasing morbidity and mortality rates). This paper analyses day (12:00–15:00 h) and nighttime (00:00–03:00 h) thermo-physiological comfort (TC) conditions by Local Climate Zones (LCZ) in Lisbon during a particular Local Weather Type (LWT), very hot summer days. For this, 13 different microscale sample areas were chosen covering urban and non-urban land cover classes (LCZs 1–3, 4–6, 8, 9, A and B). Universal Thermal Climate Index (UTCI) and Mean Radiant Temperature (MRT) were modeled on SkyHelios software for 163 days between 2008 and 2014. Results show that during the day all urban LCZ samples depict the same average TC conditions (average UTCI of 34°C—strong heat stress) and densely wooded areas are 2°C cooler (average UTCI of 32°C—moderate heat stress). However, compact areas (LCZs 1–3) with low sky view factor and some vegetation (street trees) display lower percentages of area with higher thermo-physiological discomfort (TD) levels (83% with strong heat stress against 98% in LCZs 8 and 9 and 100% in LCZs 4–6). When considering the hottest days (air temperatures equal or above 35°C—75th percentile), the moderate heat stress class disappears in all samples and the very strong heat stress class appears only on urban areas, occupying between 12% and 16% on LCZs 1–3, 10%–22% on LCZs 4–6, 16%–22% on LCZs 8 and 9 on LCZ 9. During the nighttime period all samples show no thermal stress, favoring nocturnal physiological recovery. TC conditions in Lisbon are strongly influenced by solar radiation and wind, which explains the need to increase the shading area, preferably by trees, and to promote and preserve ventilation paths.
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    Key factors impacting performance of a salinity gradient solar pond exposed to Mediterranean climate
    (Elsevier Ltd, 2017) Torkmahalleh, M. A.; Askari, M.; Gorjinezhad, S.; Eroğlu, D.; Obaidullah, M.; Habib, A. R.; Godelek, S.; Kadyrov, S.; Kahraman, O.; Pakzad, N. Z.; Ahmadi, G.
    Solar ponds are low cost pools of brine solutions with integrated storage zones that harvest incident solar energy and store it as thermal energy. The current study examined the performance of a salinity gradient solar pond under the Mediterranean climatic condition for ten consecutive months of operation, from October 8, 2014 to July 31, 2015. The presented results are based on the experimental data of a small-scale circular pond, 61�cm in diameter a height of 55�cm, constructed and operated at Middle East Technical University, Northern Cyprus Campus (METUNCC). The study showed the necessity of regular surface washing and having excess undissolved salt at the lower convective zone (LCZ) to maintain the pond stability. The variations in the temperature of the non-convective (NCZ) and lower convective zones (LCZ) are found to be a function of both ambient temperature and solar irradiation (insolation). The variation of the overall pond's temperature strongly follows the changes in ambient temperature while solar insolation directly affects the increase in temperature gradient by depth. During the period of this study, the pond reached the highest average temperature of 48��C in July 2015 while the average ambient temperature for this month was 30��C. � 2016 Elsevier Ltd