refrigerators: one to measure the air temperature inside the refrigerator and the other
to measure the water temperature inside the container. The air temperatures of the
refrigerators decrease rapidly, while the water temperatures decrease slowly. This is
due to the heat release from water being relatively slow. Consequently, the CDP of
the refrigerator is barely affected by the small passive-load.
Fig. 12 shows the temperature stability of TER-3 compared with that of the CCR.
The ‘‘wave-like’’ fluctuation in the temperature of the CCR is due to the switching
on-and-off operation. The frequency of the on-and-off operation is about 120 cycles/
day and it increases with an increase in DTab. It is estimated that the fluctuation
in temperature of the CCR due to the switching on-and-off operation is more than
0.5 K, while that for TER-3, which has an electronic temperature-control circuit,
is less than 0.2 K. Evidently, the temperature stability of control accuracy of a ther-