  We numerically implement the concept of thermal radiation pumps in realistic
photonic circuits and demonstrate their efficiency to control the radiation
current, emitted between two reservoirs with equal temperature. The proposed
pumping scheme involves a cyclic adiabatic modulation of two parameters that
control the spectral characteristics of the photonic circuit. We show that the
resulting pumping cycle exhibits maximum radiation current when a cyclic
modulation of the system is properly engineered to be in the proximity of a
resonance degeneracy in the parameter space of the photonic circuit. A
developed Floquet scattering framework, which in the adiabatic limit boils down
to the analysis of an instantaneous scattering matrix, is offering an
engineering tool for designing and predicting the performance of such thermal
pumps. Our predictions are confirmed by time-domain simulations invoking an
adiabatically driven photonic cavity.
