Question

Why is it preferable to allow cold water to enter at the bottom of a condenser and exit at the top?

Answer 1

In a distillation model, it is better to let the cold water enter the bottom of the condenser and exit at the top because this can lead to a better cooling effect.
When water enters from the bottom, they will stay longer in the condenser, thus the vapor in the condenser can be cooled back into liquid faster.
In addition, this method can also save the amount of water used, since they water can stay longer in the condenser.