Use of DCV for heating and the influence on IAQ in passive house buildings

Measurements were performed in a test room at SINTEF building and infrastructure, Oslo. The test room is 16 m2 and built according to NS-EN 442-2.  Measurements of various air flow rates (9 l/s, 18 l/s, 34 l/s and 50 l/s) and different supply air temperatures (2, 4, 6 and 10 degrees over room temperature) were performed. Tracer gas (SF6) measurements were performed to evaluate ventilation effectiveness and age of air in occupied zone.

These tests were performed with 2 different exhaust positions (down by the floor and up under the ceiling) to check if the position of the exhaust influence the ventilation efficiency and age of air in the occupied zone.

The test room used an Active supply air diffuser from Lindinvent, designed to keep a constant air velocity with various air flow rate.

The results show variable local air change index in the breathing zone based on air flow rate and the difference between room temperature and supply air temperature. The heating demand that’s needed can be delivered without influencing the IAQ in passive house buildings.

Results show the different local air change index in the breathing zone for the different exhaust positions.

There are preformed measurements with heat sources, and they appear to increase mixing, and measurements done without heat sources are a worst case scenario.