Mechanical Ventilation and Indoor Environmental Quality: Experimental Comparison Between Two Decentralised Systems in School Classrooms

This paper presents a comparison between two types of controlled mechanical ventilation (CMV) decentralised systems in school classrooms: one with an internal unit within the classroom (I), and one with ducts located in the ceiling (C). The main results show that, in terms of indoor air quality evaluation, CO2 levels in classrooms are influenced by both the opening or closing of doors and windows, as well as by the mechanical ventilation system. Only the classroom with the ceiling-hosted system (C) maintains acceptable CO2 levels solely through the system’s contribution, without the need to open the windows. The three-dimensional comfort mapping demonstrates a uniform microclimatic condition in the C classroom, while the I classroom records localised discomfort.