  An improved thermodynamic cycle is proposed, where the cooling effect of an
electrocaloric refrigerant is enhanced by applying a reversed electric field.
In contrast to conventional adiabatic heating or cooling by on-off cycles of
the external electric field, applying a reversed field is significantly
improving the cooling efficiency, since the variation in configurational
entropy is increased. By comparing results from computer simulations using
Monte-Carlo algorithms and experiments using direct electrocaloric
measurements, we show that the electrocaloric cooling efficiency can be
enhanced by more than 20\% in standard ferroelectrics and also relaxor
ferroelectrics, like Pb(Mg$_{1/3}$/Nb$_{2/3}$)$_{0.71}$Ti$_{0.29}$O$_3$.
