  Multi Layer Capacitors MLCs are considered as the most promising refrigerant
elements to design and develop electrocaloric cooling devices. Recently, the
heat transfer of these MLCs has been considered. However, the heat exchange
with the surrounding environment has been poorly, if not, addressed. In this
work, we measure by infrared thermography the temperature change versus time in
four different heat exchange configurations. Depending on the configurations,
Newtonian and non-Newtonian regimes with their corresponding Biot number are
determined allowing to provide useful thermal characteristics. Indeed, in case
of large area thermal pad contacts, heat transfer coefficients up to 3400 W m-2
K-1 are obtained showing that the standard MLCs already reach the needs for
designing efficient prototypes. We also determine the ideal Brayton cooling
power in case of thick wires contact which varies between 3.4 mW and 9.8 mW for
operating frequencies varying from 0.25 Hz to 1 Hz. While only heat conduction
is considered here, our work provides some design rules for improving heat
exchanges in future devices.
