Due to the climatic change an increase of the ambient temperature correlates with the room air cooling demand. To reach the comfort range for humans regarding air temperature and air humidity in a room both these parameters have to be reduced. Compared to electric energy from fossil fuel power stations emitting carbon dioxide solar PV driven cooling machines are an alternative and sustainable technology to tackle the comfort demand. To reduce the electric energy demand in the room air cooling and air distribution process a duct containing capillary mattress is suitable. Due to its shape – the duct acts as a gravimetric cooling and dehumidification element without an electric energy consuming ventilator i.e. as a noise free convection driven air distribution. In cases where the planned building renovation comprises an increase of office (room air) comfort these capillary mattress containing ducts are an economic solution and an alternative to a split cooling system. To reach the comfort zone of air temperature and relative air humidity in an office for example the number, size and position of a ducts containing capillary tube mattress can be determined through a multi-parameter simulation. In our paper we present a study of versions in which air temperature, air humidity, air flow distribution and air pressure in an office room interacting with ambient air of a tropical savanna climate (through the controlled windows) are determined. Regarding the cooled (and uncomfortable) air flow distribution the positioning of the desks and the cooling duct can be optimized.