Co2 In room with people

Hi All,

I am trying to simulate the room with people, to monitor co2 distribution in a room with supply and exhaust air, i created a Internal flow volume and assigned supply, exhaust to the faces in flow volume.

in passive scalar source I selected parts as cubes for co2 generation and selected faces of people parts for heat flux in boundary conditions.

can someone explain me where i am doing wrong? if i assigned whole room as boundary conditions i am getting more errors, thanks

regards,

VR