|
1 A thermoelectric cooler (TEC),
sometimes called a thermoelectric module or Peltier, is
a semiconductor-based electronic component that functions
as a small solid-state heat pump. By applying a low voltage
DC power source to a TEC, heat will be moved through the
cooler from one side to the other. One cooler face, therefore,
will be cooled while the opposite face simultaneously is
heated. Consequently, a thermoelectric cooler may be used
for both heating and cooling by reversing the polarity (changing
the direction of the applied current).
2 Peltier effect, first observed in 1834 by Jean
Peltier, the cooling of one junction is known as the Peltier
effect and occurs when a current is passed through two dissimilar
semiconductors (n-type and p-type) that are connected to
each other at two junctions (Peltier junctions). The current
drives a transfer of heat from one junction to the other.
3 N-type material, is a kind of semiconductor material
that is doped so as to have an excess of electrons. A semiconductor
with extra electrons is called N-type material, since it
has extra negatively charged particles. In N-type material,
free electrons move from a negatively charged area to a
positively charged area.
4 P-type material, is a kind of semiconductor material
that is doped so as to have a deficiency of electrons. A
semiconductor with extra holes is called P-type material,
since it effectively has extra positively charged particles.
Electrons can jump from hole to hole, moving from a negatively
charged area to a positively charged area. As a result,
the holes themselves appear to move from a positively charged
area to a negatively charged area.
5 Current carriers: Metals conduct electricity
via delocalised electrons within the metal lattice - in
a metal, the atoms lose valence electrons to form a lattice
of positively-charged cations. The valence electrons are
then delocalised throughout the lattice, and are free to
move between the cations - these electrons are the current
carriers.
6 Thermoelectric material, an alloy of materials
that produce thermoelectric properties, was composed by
N-type material and P-type material.
7 A heat pipe is a simple device that can quickly
transfer heat from one point to another. They are often
referred to as the "superconductors" of heat as
they possess an extra ordinary heat transfer capacity &
rate with almost no heat loss. It consists of a sealed aluminum
or copper container whose inner surfaces have a capillary
wicking material. Inside the container is a liquid under
its own pressure, that enters the pores of the capillary
material, wetting all internal surfaces. Applying heat at
any point along the surface of the heat pipe causes the
liquid at that point to boil and enter a vapor state. When
that happens, the liquid picks up the latent heat of vaporization.
The wick provides the capillary driving force to return
the condensate to the evaporator. The quality and type of
wick usually determines the performance of the heat pipe,
for this is the heart of the product. Different types of
wicks are used depending on the application for which the
heat pipe is being used.
|
