The model validation test can be divided into two parts: the
winter period test and the summer period test. In the two periods,
the water supply pump worked with different schedules. During
the winter testing period, the pump operated in the mid-night for
3 h to have the water in the system totally replaced everyday. The
water temperatures in the two storage tanks were then the same
in the early morning. And in summer, the pump operated 3–4 days
a time and the water was replaced totally in the system. Therefore,
the temperature curves for the two test periods were different.
Fig. 6(a) and (b) shows the results of experimental validation of
the single-phase open thermosyphon system model, and Fig. 7(a)
and (b) shows those of the two-phase closed thermosyphon system
mode. It can be seen that the two numerical models did give good
representation of the real situations.