Performances of DAHT connected to building airthightness and indoor hygrothermal climate

As building insulation level increases, the coupling of ventilation systems with building
enveloppe airtightness becomes an important issue in order to improve buildings energy
performances. A building ventilation model can be built on a set of resistances and generators
in order to handle infiltration, natural ventilation as well as fan driven air flows. The model is
able to assess the indoor air humidity level and the building energy balance.
Double flow ventilation can be handled through decentralized air handling terminals (DAHT),
integrated in window ledges. A model of DAHT can be combined with the model of a whole
building envelope, including infiltrations as well as dynamic behaviour, allowing comparisons
with classical ventilation systems, such as natural or hybrid systems, or with centralized
double flow systems. Results regarding energy consumptions, air humidity levels and
superficial condensation risks can be analysed. Fresh air flow can be calibrated in order to
meet air quality standards related to indoor humidity level and CO2 concentration.
The modelization of buiding indoor hygro-thermal climate allows a complete assessment of
the seasonal heat exchanger efficiency, including heat recovery through the condensation of
indoor air humidity when it flows through the exchanger.