Airflow network modelling of a virtually renovated school to study the optimal design and regulation of ventilation systems in Iceland

¹ Department of Civil- and Architectural Engineering, Aarhus University, Inge Lehmanns Gade 10, 8000 Aarhus C, Denmark.
² Efla Consulting Engineers, Lyngháls 4, 110 Reykjavík, Iceland.

Abstract

Properly ventilated classrooms to ascertain the indoor air quality (IAQ) are key to healthy schools. In Iceland, some projects of renovating schools are being carried out to provide proper IAQ and thermal comfort. This study was to utilize airflow network modelling, CONTAM, to simulate the IAQ at a school in Iceland before renovation. To assess the IAQ, the concentrations of CO2, formaldehyde (HCHO) and total volatile organic compounds (TVOC) were simulated and the exposure to those gaseous concentrations was examined. The simulation of CONTAM was first validated by employing a case study with well documented experimental data found in literature. The simulation results of our CONTAM modelling agreed well with the experimental data as well as the simulation results obtained by the same authors of the experimental study. The program of CONTAM was then further applied to simulate 13 scenarios designed for our study on the school building in Iceland. The results indicated that pure natural ventilation system might not be able to maintain CO2 concentration lower than 1000 ppm during the entire period and thus mechanical ventilation system is needed in such a building. The simulation results also support that the ventilation rate of 15 l s^-1 person^-1 is needed with current occupant numbers in classrooms. The concentrations of HCHO and TVOC could be maintained to be reasonable with air exchange rate of 0.5 h^-1 if the doors of classrooms could be open during the night. The results achieved from this study provide guidance for the renovation of the school and design/regulation of the ventilation system after renovation.