Performance simulations of hybrid ventilation systems in a five-story office building

This study is a part of the Finnish contribution to the HYBVENT project (Annex 35 of IEA). Two 'hybrid' ventilation concepts designed for northern climates were evaluated for a 4300 m2 office building in Helsinki : one of them is low pressure mechanical exhaust with CO2-controlled air inlets ; the other uses mechanical air supply through coils and two parallel exhaust circuit with and without fan and heat recovery. They were compared with conventional systems in Finland (mechanical supply and exhaust with constant or variable air volume). Numerical simulation of the building show that it is possible to achieve acceptable CO2 levels with hybrid systems, even if their performance is more influenced by weather conditions.