The goal of this thesis is to model a laboratory-scale district heating system to help test its performance and simulate diJerent scenarios and configurations. The experimental system in question is located inside the Politecnico di Torino laboratories and it was built to replicate in a smaller scale the characteristic behaviour of a district heating system. Heat generation is accomplished with a natural gas water heater. The primary circuit is composed of a small network of steel pipes which distributes hot water to two secondary circuits. Each of the two secondary circuits features a substation, composed of a plate heat exchanger and a circulation pump, and an air heater to simulate heat load.