ABSTRACT
This does require some careful engineering. The air flow rates of the mechanical ventilation system are specified to ensure good indoor air quality. At the same time, the air flow rate must be adequate to deliver the needed heating power for design conditions. Ventilation losses occur between the heat exchanger (HE) and the room air outlet. Therefore, the heating power supplied by the air must exceed the demand of the rooms (see Figure 11.1.1). Some of the heat lost from the ducts may be ‘lost’ into rooms along the duct path, as well as in the room being heated.
