Selective emittance materials show high technical potential for use as radiative cooling heat exchangers for buildings. This paper presents the thermal modeling of the photonic radiative cooler and the simulation of a system that integrats the photonic radiative cooler with radiant floor cooling in a medium office building. The system was simulated with EnergyPlus and the extensive use of its energy management system module. Our simulation results show that the radiator surface temperature remains well below the ambient air temperature even during summer in Las Vegas. The radiative cooler was sufficient to meet the cooling load for five months of the year and addressed at least 17% of the total hydronic loop load in the peak summer months.