A numerical modeling approach to evaluate energy-efficient mechanical ventilation strategies

Abstract

This thesis investigates design features that can potentially reduce the energy consumed in attaining appropriate thermal comfort levels in typical residential buildings in urban and rural settings. A numerical model coupled with a PID controller is developed to predict the indoor air temperature that is adjusted via mechanical ventilation. The model is used to simulate and evaluate various scenarios of building wall layouts and materials. From the various simulation runs, the wall configurations and materials were refined to combinations that rendered the mechanical ventilation a feasible option for attainment of comfort for the largest number of hours per year. The runs were conducted for two typical residential apartment located in the city of Beirut, Lebanon, representative city for the urban settings, and for the Bekaa region, representative city for the rural settings. The same wall configurations were examined both settings. Different wall configurations were assumed for each of the living zone and the bedroom zone of the apartment. The simulation results suggest an optimal wall configuration comprised of a 5 cm layer of insulating strawboard sandwiched between a 2 × 10 cm wall made of masonry units consisting of Hempcrete (mixture of Portland cement, aggregates, and industrial hemp fibers) for the living zone for both location the rural and urban areas, whereas the wall for the bedroom zone in the urban setting consists of a 10 cm of Hempcrete and in the rural setting consists of a 10 cm of Hempcrete in addition to 5 cm layer of insulating strawboard.