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Cooling System
The cooling system removes heat from the inner chamber. It has had no change in design
and consists of a thermoelectric cooler (TEC), a self contained liquid cooler with radiator and fan
to dissipate heat to the environment, and a cold sink with fan to distribute the cold air within the
insulated chamber. The individual components were assembled with round steel bolts and are
shown below in Figure 1.
Figure 1: Assembled cooling system
Thermoelectric cooling utilizes the Peltier effect to create a temperature differential
across the junction of two dissimilar metals. In a TEC, electric power is used to generate a
temperature difference between the two sides of the device. Connecting the TEC to a direct
current causes one side to get hot and the other side to get cold. With a small, flat scrap piece of
plywood thermal paste was thinly but evenly distributed over both sides of the TEC, which then
was sandwiched between the liquid cooler and the cold sink. Thermal paste fills small voids and
crevices that are present due to the imperfectly flat and smooth surfaces of the components,
which helps heat flow and lowers the thermal resistance.
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