Carbon dioxide soil efflux modelling in closed dynamic respiration chambers is a challenging task. This is attributed on many occasions to the very small concentrations of carbon dioxide being transported between soil and the atmosphere. This paper describes a portable device which was made exclusively to accurately measure carbon dioxide efflux from soil locations. The blowing fan creates a forced convective flow to occur in the chamber making the K-Epsilon turbulence model a necessity to model the occurring flow in the respiration chamber gas domain. Furthermore the Darcy model is applied on the porous domain to model the flow pattern within the soil. The measurement process was achieved through measuring carbon dioxide concentration, temperature and relative humidity inside the chamber in relation to time. Simulation and experimental data is obtained using ANSYS and MATLAB. A significant agreement between the experimental and numerical results was achieved.