Occupant influence on residential ventilation patterns in mild climate conditions

Abstract

The air change rate per hour (ACH) inside a dwelling depends on its envelope air-tightness, ventilation devices and weather conditions. However, the occupant behaviour of residential buildings in mild climates is a key factor for the resulting ACH, influencing the indoor air quality and thermal comfort. This study was based in a one-year measurement campaign aiming at the assessment of the influence of occupants on the ventilation conditions of a dwelling located in Porto, Portugal. The master bedroom was monitored using temperature, relative humidity and CO2 sensors and air-tightness was evaluated with blower-door tests. In addition, surveys were also carried out where the occupants registered these actions and their occupation in the studied room. In this study, it was found that the main actions performed by occupants with influence in the ACH were related with windows handling and air grill extraction vents regulation. The measurements allowed to define behavioural typical patterns. The results include the typical CO2 concentration profiles in the main room and its variation in function of occupant behaviour. It was found that opening the air grill extraction vents could vary the total ACH up to 92%. Opening windows at night could increase the total ACH up to 435%. Before the morning window opening the minimum ACH obtained was 0.37h(-1) and the action of morning window opening lead to an average ACH around 4 h(-1). (C) 2017 The Authors. Published by Elsevier Ltd.