How to model earth-pipe as natural ventilation strategy for a room?

edit

We have used a 4 inch PVC pipe with 30 meters length and 2 meters deep underground as a natural ventilation strategy for a room in desert conditions. We have collected data from the room (temperature, humidity, solar radiation and I already know the construction details). I need to model this in EnergyPlus + Design-Builder. How can I model earth pipe?