Douwe Egberts Cafitesse 100, Service Manual

Page: 168 / 210

07.2004
5F - 6
Functions - Cooling System Service Manual Cafitesse 100
The principle of thermoelectric cooling
• For cooling the flexi-packs, the dispenser is
equipped with a thermoelectric cooling
system. The element in such a system is
called Peltier element (1). (Fig. 1)
• The Peltier element (1) consists of a series
of thermoelectric cooling cells. The
elements of the cooling cells consist of 2
bismuth semiconductor bridges made from
tellurium with different doping. (Fig. 1)
• The amount of heat that is transferred is
proportional to the electric current and to
the amount of cooling cells contained in the
Peltier element.
F.3.2 Function: Cooling System
• Cells are electrically connected in series in
the Peltier element.
Viewed thermally, these cells are connected
in parallel.
The typical electric current (in a stable,
cooled state of the system) is approx.
3.5 A.
• The Peltier element (1) acts as a heat
pump and transfers the heat energy from
the cold cooling compartment side to the
warm heat sink side. In addition to the
cooling power (typically 10 W) from the
cooling compartment, the electric loss of
the element (typically 35 W) is also
transferred to the warm side. (Fig. 1)
Fig. 1
1
2