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Your search keyword '"Ghaddar, Nesreen"' showing total 255 results
Start Over Author "Ghaddar, Nesreen" Publication Type Academic Journals
255 results on '"Ghaddar, Nesreen"'

15. Impact assessment of climate change on naturally ventilated residential buildings in Lebanon — Overheating risk under future climate scenarios

Author

Younes Jaafar, Ghaddar Nesreen, and Ghali Kamel

Subjects
Environmental sciences, GE1-350
Abstract

In light of current climate change and global warming, indoor overheating poses a significant risk. Buildings in the Mediterranean climate heavily rely on natural ventilation to maintain acceptable indoor thermal conditions. This reliance poses an increased risk to built environments in this region, particularly those occupied by low-income populations who cannot afford conditioning systems. This study assesses the thermal performance of typical residential buildings in Lebanon in response to future climate change, considering various emission scenarios and climate zones. The study uses morphed future weather data and dynamic building simulations to assess indoor overheating and the potential for natural ventilation to establish comfortable indoor conditions. Findings indicate that indoor overheating occurrences in naturally ventilated apartments are expected to increase in both frequency and intensity in the future, across different emission scenarios, varying by climate. The risk of overheating was highest in inland region, followed by coastal then mountain regions. Regarding natural ventilation comfort hours, coastal climates saw a significant decrease (40% to 26% in the worst case), inland climates witnessed a slight reduction (27% to 23% in the worst case), and mountain climates observed a marginal increase (1% to 3%), accompanied by an increased risk of overheating during peak periods.

Published
2024
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49. Resilience of Personalized Ventilation in Maintaining Acceptable Breathable Air Quality When Combined with Mixing Ventilation Subject to External Shocks.

Author

Karam, Jennifer, Ghali, Kamel, and Ghaddar, Nesreen

Subjects
VENTILATION, INDOOR air quality
Abstract

This work evaluates the ventilation resilience of the combined personalized ventilation (PV)-mixing ventilation (MV) system when implemented in a typical office space. This resilience is first evaluated by monitoring the ability of the PV devices when designed at different supply flow rates to maintain acceptable levels of CO2 at the occupant's breathing zone when the MV system is subjected to a shock. The shock considers a malfunction of the MV system for periods of 3 h and 6 h, and at shutoff percentages of MV fan flow of 100% and 50%. This is followed by evaluating the resilience of the MV system when the PV air handling unit is shutoff for short periods. The following three aspects of resilience were calculated: the absorptivity, the recovery, and the resilience effectiveness. To monitor the CO2 temporal variation at the breathing zone, a computational fluid dynamic model was developed and validated experimentally. It was found that the resilience effectiveness varied between 0.61 (100% MV shutoff for 6 h and PV at 4 L/s) and 1 (50% MV shutoff for 3 h and PV at 13 L/s). Additionally, CO2 build-up and recovery took minutes during MV malfunctions and seconds during PV malfunctions. [ABSTRACT FROM AUTHOR]

Published
2024
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