Assessment of Indoor Air Quality and Ventilation Rate in Residential Dorms After Net-Zero Retrofit

Buildings currently consume approximately 40% of the world's energy, with a significant portion of that energy coming from coal and natural gas sources. This demand is expected to rise further because of climate change. To address the impact of climate change on building energy usage and environments, there is a growing trend worldwide where governments are supporting the retrofitting of older homes. As part of this effort, a residential dorm in Syracuse, New York, USA, underwent a retrofit. Changes included altering the size of the windows (fenestrations), replacing the old electric baseboard heater with a new split heat pump system, and introducing heat recovery ventilation. However, assessing indoor air quality (IAQ) and ventilation rates in residential dorms post-retrofit posed challenges. The purpose of this research was to use computational fluid dynamics (CFD) simulations to assess the ventilation in the living room and compare it with collected data during the winter season. We first built a geometric model based on the actual room dimensions and HVAC equipment both before and after the retrofit. We conducted CFD simulations for a typical winter day and determined the airflow rates based on the simulation results. To validate our simulations, we collected data within the dorm for nine months before and after the retrofit. This data included various thermal and IAQ parameters such as indoor air temperature, concentrations of CO₂ and TVOC using multiple sensors. The actual ventilation rate was calculated based on the CO₂ concentration before and after the retrofit within the dorm. The results showed a strong agreement between the test data and the simulation, demonstrating the suitability of CFD for evaluating IAQ and ventilation following a retrofit. Furthermore, questionnaire survey of the dorm residents yielded positive feedback regarding the improved IAQ and ventilation. These findings highlight the effectiveness of the retrofit design we implemented.