Inner courtyards have been traditionally used as passive strategy in vernacular buildings in desert climates. This paper presents a study conducted to investigate indoor and outdoor thermal comfort of two vernacular buildings in the hot arid climate of Upper Egypt and proposes an improved solution for courtyards to achieve sustainable development of current vernacular houses and apply the same in the arid climate zone of Egypt. The thermal comfort of vernacular building spaces was evaluated based on using field measurements during the hot season and improvement for courtyards based on ENVI-met V5.6.1 simulation model using three scenarios. Two vernacular buildings (Hassan Fathy and Nubian house) were selected to represent the traditional buildings south of Egypt. The study found that using adobe bricks with high thermal mass in vernacular buildings maintained lower indoor temperature with a range of 2.7 °C to 6.7 °C compared to outdoor temperature; this is considered effective thermal insulation. Meanwhile under extreme hot conditions, courtyard temperature inside the vernacular house was 0.3 K higher than the outdoor. This is not sufficient to maintain indoor thermal comfort without integrating passive solutions inside courtyards. In addition, applying the hybrid solution with big dense trees in the courtyards achieved a significant reduction in PET ranging from 4.2 °C and 5.7 °C; shading the widest area of courtyards and allowing for family activities. The study provided techniques and methodology for the middle courtyard of vernacular buildings, demonstrating how improvement achieves thermal comfort and sustainable development required in the 21st century in Upper Egypt, and can be applied to other vernacular houses in different desert cities in southern Egypt.

This paper proposes a time-based no-cost category of energy conservation measures (ECMs) enabled by audit-driven building energy modeling. The study presents an audit-to-simulation framework applied to an academic building (Electrical Engineering Department, Assiut University, Egypt) following the audit levels and requirements of ASHRAE Standard 100-2024. The building operation is characterized via audit findings, high-resolution electrical monitoring, and occupancy profiling, then translated into a calibrated building energy model (BEM) developed using SketchUp, OpenStudio, and EnergyPlus. The validated BEM serves as a decision-support testbed to evaluate the proposed ECMs prior to implementation, enabling quantification of their impacts on annual and daily energy use, peak reduction, and load-profile shape. The proposed ECMs are classified into two subcategories: working-day ECMs and time-slot-modification ECMs. The first category involves adjusting the number of working days per week. The second category includes several scheduling-based strategies, namely seasonal time shifts, modification of lecture and tutorial session durations, rearrangement of lectures and tutorial sessions, and shifting peak-demand time slots. The simulation results show that modifying lecture and tutorial durations (ECM3) is the most effective measure, achieving 6.2% annual energy savings, followed by seasonal time shifts (ECM2) with 5.8%. For peak demand, reducing operation during peak periods (ECM5) lowers the daily peak load by 25.9%. The combined implementation of the proposed ECMs reduces annual energy consumption by up to 16% and daily peak demand by 29.4%. The findings highlight the substantial potential of structured audit-informed operational strategies in university buildings, emphasizing their role as low-risk, high-impact interventions for peak management and energy performance enhancement.