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

[Display omitted] ► A PID mechanical ventilation controller coupled with a space model is developed for indoor comfort. ► Use of natural materials in the building walls for the effective use of mechanical ventilation. ► Validation of the integrated model with TRNSYS. ► A case study is conducted for Lebanon to lower both the operational and embodied energy. This paper investigates design features that can potentially reduce the energy consumed in attaining appropriate thermal comfort levels in typical residential buildings. 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 a typical residential apartment located in the city of Beirut, Lebanon, which is characterized by mild coastal climatic conditions. 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 5cm layer of insulating strawboard sandwiched between a 2cm×10cm wall made of masonry units consisting of Hempcrete (mixture of Portland cement, aggregates, and industrial hemp fibers) for the living zone, whereas the wall for the bedroom zone consists of a 10cm of Hempcrete.