LR3/Disco 3
The cool box is an open topped container with an aluminum liner and an insulating outer layer. A thermoelectric cooler is
installed in the front of the container. The top of the container is covered by the cubby box tray and the cubby box lid. An
electrical connector on the front of the cool box connects the cool box to the console harness.
Operation of the thermoelectric cooler is controlled by an on/off switch on the top front edge of the container. A permanent
battery feed is supplied to the on/off switch from the central junction box (CJB). A light emitting diode (LED) in the on/off
switch is illuminated while the cool box is selected on.
The thermoelectric cooler is a solid state heat pump that uses the Peltier Effect to cool the inside of the cool box. The
Peltier Effect occurs when a direct current is passed through a circuit of two dissimilar conductors, which are connected
together at two junctions; this causes one junction to become cold and one junction to become hot. The potential
difference between the two conductors creates an electric field at each junction; when a current is then applied to the
circuit the charge flows against the direction of the electric field at one junction, causing it to absorb heat, and with the
direction of the electric field at the other junction, causing it to release heat. In thermoelectric coolers, a number of these
circuits (known as couples) are connected together, in series, and sandwiched between ceramic plates, then connected
to a heatsink and fan. On the cool box, the cold side of the thermoelectric cooler is attached to the aluminum liner and the
heatsink and fan are installed on the insulating outer layer.
Peltier Effect Circuit
Item Part Number
Description
1
Cubby box lid
2
Cubby box tray
3
Container
4
On/Off switch
5
Thermoelectric cooler heatsink
6
Fan
7
Electrical connector
