CFD analysis of the effect of self-regulating devices on the distribution of naturally supplied air

Thermal comfort in living rooms or bedrooms is among others determined by the spatial distribution of the supplied ventilation air. In this work, the performance of a self-regulating (pressure-sensitive) air transfer device, in terms of air flow rate and human comfort, was investigated by means of CFD. Self-regulating ventilators limit the air supply rate according to the pressure difference across the ventilator as to reduce draught risks. The CFD analysis was carried out as much as possible according to the experimental method for evaluating such devices, described in the European Standard EN 13141-1. Pressure differences across the air transfer device of 2 and 10 Pa were studied, at a temperature difference between inside and outside climate of 20 C. Results revealed that self-regulating air transfer devices are able to achieve a uniform flow rate for the pressure differences under investigation. Besides, they decrease the risk on draught compared with non-regulating devices.