Indoor air quality and ventilation requirement in residential buildings: A case study of Tehran, Iran

The ventilation system is a key device to ensure both healthful indoor air quality (IAQ) and thermal comfort in buildings. The ventilation system should make the IAQ meet the standards such as ASHRAE 62. This study deals with a new approach to modeling the ventilation and IAQ requirement in residential buildings. In that approach, Elite software is used to calculate the air supply volume, and CONTAM model as a multi-zone and contaminant dispersal model is employed to estimate the contaminants' concentrations. Amongst various contaminants existing in the residential buildings, two main contaminates of carbon dioxide (CO2) and carbon monoxide (CO) were considered. CO and CO2 are generated mainly from combustion sources such as gas cooking and heating oven. In addition to the mentioned sources, CO2 is generated from occupants' respirations. To show how that approach works, a sample house with the area of 80 m(2) located in Tehran was considered as an illustrative case study. The results showed that CO2 concentration in the winter was higher than the acceptable level. Therefore, the air change rate (ACH) of 4.2 was required to lower the CO2 concentration below the air quality threshold in the living room, and in the bedrooms, the rate of ventilation volume should be 11.2 ACH.