Supercritical carbon dioxide (SCO2) is primarily used in space reactors and underwater unmanned nuclear power plants, and its heat dissipation capability is a critical consideration. To accurately predict the heat load of the cabin in the nuclear power plant, this paper establishes a heat dissipation model for the pipe network, performs precise calculations of the heat dissipation, and explores the factors influencing it. The results indicate that heat dissipation decreases with the cabin air temperature; as the temperature of SCO2 increases, the heat dissipation of the pipe network also increases; and as the thickness of the interstitial material and the thickness of the metal-type thermal insulation layer increase, the heat dissipation of the pipe network gradually decreases. Compared to water, supercritical carbon dioxide exhibits a faster flow rate at the same mass flow rate, and friction heat cannot be overlooked. To investigate the impact of friction heat on the pipe network simulation, this paper establishes a calculation model for friction heat in the pipe network, calculates the friction heat, and further analyzes the influencing factors. It concludes that the friction heat is primarily determined by the mass flow rate and density of the work material. The heat generated by friction is mainly influenced by the mass flow rate and density. The developed model for frictional work heat generation can yield more accurate results for the simulation of the supercritical carbon dioxide pipeline network, while the pipeline network heat dissipation model can serve as a reference for optimizing the design of the cabin heat dissipation system and controlling heat dissipation in nuclear-powered deep-space exploration and unmanned submersible vehicles.