Energy efficiency of ecological buildings in Tunisia: Natural fiber composites and passive strategies impact.

This article focuses on evaluating the impact of ecological additives—specifically treated Alfa and Posidonia-Oceanica fibers—and passive strategies on the thermal performance and energy efficiency of buildings under the Tunisian climate. Experimental characterization of cement and gypsum composites incorporating these natural fibers showed significant reductions in thermal conductivity and density, leading to improved insulation properties. Numerical simulations using TRNSYS software compared three building configurations: a reference building with conventional materials, and two ecological buildings using Alfa fibers (BAF) and Posidonia-Oceanica fibers (BPOF). Results demonstrated that ecological buildings reduced annual heating and cooling energy demands by approximately 43–48% and 42–46%, respectively, and lowered CO2 emissions by up to 48%. The integration of passive strategies—including Trombe walls (TW), movable solar overhangs (OV), and natural night ventilation (NV)—further enhanced energy savings, achieving heating reductions up to 83%, cooling reductions over 60%, and CO2 emission decreases exceeding 80%. These findings suggest that combining bio-based insulating materials with passive design techniques can substantially improve building energy efficiency and environmental sustainability in Mediterranean climates.