Evaluating Hybrid Ventilation Effects on Indoor Air Quality and Particulate Matter Levels in Cold Climate Mixed-Mode BUILDINGS

Abstract

This study investigates the quality of outdoor air in cold-climate countries such as Norway, focusing on the concentration of particulate matter (PM), and examines the impact of changes in PM concentrations on the operation of hybrid ventilation systems. This is achieved by developing a custom macro to control window openings based on the concentration of PM inside and outside the building and integrating it into the hybrid ventilation system, which also relies on temperature, CO₂ concentration, and night ventilation in its operation. The study utilizes the IDA-ICE program and data from the Norwegian air quality website.

Research gaps in previous projects primarily focused on energy conservation and indoor CO₂ concentration, with few projects addressing the integration of PM concentration with hybrid ventilation systems. This motivated the development of the PM control macro, which aims to enhance indoor air quality and achieve optimal indoor comfort, directly impacting work quality, continuity, employee comfort, and performance. A case study was utilized as a building model representing a mixed-mode office.

Simulations were conducted for specific days in February and May, using two hybrid ventilation scenarios: one without PM control and one with PM control. No significant differences in window opening signals were recorded between the two scenarios during these days, which can be attributed to the low PM concentrations in the external environment during this period, indicating clean air and low pollution levels in Norway. Subsequently, a simulation was conducted for a day in July, considered a critical day in terms of PM concentration in the external environment. The results showed significant adjustments to the window opening signals to align with PM control.

Therefore, this study highlights the importance of taking indoor air quality into account when using hybrid ventilation systems through the developed control strategy, where PM control plays a crucial role alongside CO₂ control, temperature control, and night ventilation cooling.