We assess the feasibility of a collective district heating and cooling network based on a foundation pile heat exchanger in a new urban area in Vejle, Denmark. A thermogeological model for the area is developed based on geophysical investigations and borehole information. In tandem with a building energy demand model, the subsurface thermal properties serve as the input for a newly developed computational temperature model for collective heating and cooling with energy piles. The purpose of the model is to estimate the long-term performance and maximum liveable area that the energy piles are able to support. We consider two case studies where residential and office buildings dominate the building mass. We find that three to four floors can be supplied with heating and cooling from the energy piles, depending on the use and design of the buildings.