  We pose an engineering challenge of controlling an Ensemble of Energy Devices
via coordinated, implementation-light and randomized on/off switching as a
problem in Non-Equilibrium Statistical Mechanics. We show that Mean Field
Control} with nonlinear feedback on the cumulative consumption, assumed
available to the aggregator via direct physical measurements of the energy
flow, allows the ensemble to recover from its use in the Demand Response
regime, i.e. transition to a statistical steady state, significantly faster
than in the case of the fixed feedback. Moreover when the nonlinearity is
sufficiently strong, one observes the phenomenon of "super-relaxation" -- where
the total instantaneous energy consumption of the ensemble transitions to the
steady state much faster than the underlying probability distribution of the
devices over their state space, while also leaving almost no devices outside of
the comfort zone.
