Performance of demand-controlled heat recovery ventilation systems with central and zonal control in a single-family house

Improving ventilation efficiency in residential buildings is crucial to reducing energy consumption while maintaining indoor air quality. This study investigates three demand-controlled ventilation (DCV) strategies compared to a traditional constant airflow (CAV) system in a single-family house. The DCV strategies evaluated include central CO₂ control using a sensor in the exhaust duct, central CO₂ control using the highest reading from individual rooms, zonal CO₂ control with two zones prioritized by the highest CO₂ level in each, and constant airflow as the baseline system. Dynamic energy simulations were performed using a calibrated model based on Estonian climate conditions and a typical residential occupancy profile. Each control strategy was simulated in combination with three types of heat recovery ventilation units: rotary heat exchanger (RHE), energy recovery ventilator (ERV), and heat recovery ventilator (HRV). Results show that energy saving of demand-controlled system with dual-zone control was 33% while maintaining indoor air quality, but central control with exhaust sensor resulted in negligible saving. Notably, the dual-zone strategy with enthalpy recovery plate achieved the lowest overall energy consumption, reducing both space heating and fan electricity demand. The findings highlight the importance of sensor placement, control logic, and heat recovery selection in optimizing ventilation energy performance in residential buildings.