Thermoelectric
Cooling
Thermoelectric
cooling uses the Peltier
effect to create a heat flux between the junctions of two
different types of materials. A Peltier cooler, heater, or thermoelectric heat pump is a solid-state active heat pump which transfers heat from one side of the
device to the other, with consumption of electrical, depending on the direction
of the current. Such an instrument is also called a Peltier device, Peltier
heat pump, solid state refrigerator, or thermoelectric cooler (TEC). They can
be used either for heating or for cooling (refrigeration), although in practice
the main application is cooling. It can also be used as a temperature
controller that either heats or cools.[1]
This technology is far less commonly
applied to refrigeration than vapor-compression
refrigeration is. The main advantages of a Peltier
cooler (compared to a vapor-compression refrigerator) are its lack of moving
parts or circulating liquid, and its small size and flexible shape (form
factor). Its main disadvantage is that it cannot simultaneously have low cost
and high power efficiency. Many researchers and companies are trying to develop
Peltier coolers that are both cheap and efficient.
A Peltier cooler can also be used as a thermoelectric generator. When operated as a cooler, a voltage
is applied across the device, and as a result, a difference in temperature will
build up between the two sides.[2] When operated as a generator, one side
of the device is heated to a temperature greater than the other side, and as a
result, a difference in voltage will build up between the two sides. However, a
well-designed Peltier cooler will be a mediocre thermoelectric generator and
vice-versa, due to different design and packaging requirements.
Thermoelectric junctions are generally
only around 5–10% as efficient as the ideal refrigerator compared
with 40–60% achieved by conventional compression cycle systems. Due to the
relatively low efficiency, thermoelectric cooling is generally only used in
environments where the solid state nature Peltier (thermoelectric) cooler
performance is a function of ambient temperature, hot and cold side heat
exchanger (heat sink) performance, thermal load, Peltier
module (thermopile) geometry, and Peltier electrical parameters.
