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 74% savings in fan energy consumption relative to the reference constant air-volume system. The simulations indicated the need for less-resisting 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. (paper)