Simulations of a novel demand-controlled room-based ventilation system for renovated apartments

The study simulated and assessed a novel control algorithm for an innovative room-based ventilation system for renovated apartments. The novel system is a manifold of fans that connects to an air-handling unit to control the supply of airflow to each room in an apartment. The exhaust side has a 3-way damper to control the division of extract airflows. The simulation required demand-control of ventilation airflows in each room. This included CO₂- and temperature-based control of supply to dry rooms and humidity- and temperature-based control of exhaust from wet rooms. The object-oriented software IDA-ICE includes a graphical interface for assembling the controls, which enabled custom simulations. The controls efficiently maintained sufficient air quality in each room and ensured balance of supply and exhaust. The room-based demand-controlled ventilation system achieved 64% savings in fan energy consumption relative to the reference constant air-volume system. The simulations indicated the need for less limiting overflow vents in doorways to prevent infiltration heat loss when supplying bedrooms with greater airflow. Infiltration heat losses increased by 18% with closed doors despite the use of acoustic vents to assist overflow. Future measurements will aim to validate the demand-control algorithm and the performance of the novel system in real apartments.