Comparative Evaluation of Bio-Based Materials for Enhancing Thermal Comfort in Low-Income Housing in Egypt Under Future Climate Scenarios

With the continuous rise in global temperatures, particularly within arid regions, maintaining thermal comfort in naturally ventilated buildings presents a significant challenge. This study investigates the effectiveness of biomaterial-infused bricks in mitigating indoor overheating in low-income residential buildings. The findings indicate that all tested bio-brick families contribute to a notable reduction in unmet thermal comfort hours compared with conventional clay bricks. The best-performing composition in both periods was 10% date palm pit polyhydroxybutyrate (DPP PHB). Compared with conventional clay brick, it removed 284 unmet comfort hours in 2024, equal to 5.5 percentage points of summer hours or a 10.5% reduction relative to the base case, and 389 h under the 2080 scenario, equal to 7.6 percentage points and a 10.4% relative reduction. Peak operative temperature fell by 2.49 °C and 2.11 °C. The research integrates both empirical field measurements and simulation-based analyses using Design-Builder software (7.3.0.046) to assess the thermal behavior of various bio-brick compositions incorporating paper waste, tea waste, rice husk, sugar bagasse, corn cob, and date palm pit with polyhydroxybutyrate. Thermophysical properties for all compositions were taken from previously published experimental studies. No specimens were manufactured or tested in this work. The simulations employed weather data for 2024 alongside future climate projections based on the IPCC 2080 (Intergovernmental Panel on Climate Change) A2 high-emission scenario. Even under the best-performing composition, operative temperature stayed outside the adaptive comfort boundaries for 47.3% of summer hours in 2024, rising to 65.4% under the 2080 scenario. While bio-bricks alone cannot eliminate discomfort hours, their demonstrated effectiveness highlights their potential as a key component within broader passive cooling strategies.