[Zogthetroll]

well, in your case antifreeze is needed to help prevent galvanic corrosion since you've got mixed metals in your system, aluminum and copper. adding glycol (alcohol based) will LOWER the boiling point as well as the freezing point of the coolant, but again, neither is a concern since even in a well-designed system (unlike your demo unit there), you will never see either of those extremes in temp, unless you use refrigeration.