The two elements of thermal load in thermoelectric
refrigeration systems include active and passive loads.
Active load is considered whenever part of the load
actually produces heat. For example in an electronic
circuit the circuitry would dissipate wattage depending
upon its voltage and current requirements. Many TE
applications don’t have an active load and this term can be
entirely discarded in these cases. To maintain a
temperature difference between the thermal load of the
system and the ambient environment, a small amount of
energy must be continually moved into or out of the load.
The rate at which this energy is moved is the passive load.