Experimental investigation into the thermal performance of a residential hybrid ventilation system

The thermal performance of a new type of residential hybrid ventilation system was investigated experimentally. The novelty of the system is that it is able to provide filtered and tempered fresh air, either to residences or small commercial buildings such as classrooms, using a combination of natural and/or mechanical driving forces. Fresh air passes through a wall-mounted convector unit. Inside the convector unit is a water-to-air heat exchanger, plumbed into the hydronic central heating system of the building. The heat exchanger is used to warm the ventilation air. Also contained within the convector unit is a mechanical damper used to prevent over-ventilation. An extract fan can be used to drive air through the unit at times of low natural driving forces in order to prevent under-ventilation. Experimental investigation was used to characterise the thermal performance of the system, and to assess its potential to be used as a cool-air ventilation device. It was found that the hybrid system was capable of operating effectively to such a purpose. The system was able to provide an indoor/outdoor air temperature difference of 10 K across a range of air flows up to 120 L/s, in either heating or cooling mode.