The HyperChiller lets you cool a cup of hot coffee so you can drink it cold, which its manufacturers claim is “perfect iced coffee.” This is, of course, untrue. It will taste like coffeemaker coffee which you’ve neglected.
The reason that real iced coffee tastes good is because it’s brewed as toddy – cold water is used, and the flavors are extracted from the coffee grounds over 24 hours, yielding a coffee that tastes better and has a lower acid content. (You can use an actual “toddy maker” to do this if you want, but you can also mix the grounds and water into a plastic pitcher, and filter them into a second pitcher the next day with a regular coffee filter.)
If you’re wondering why regular brewed coffee tastes okay when it’s hot, but not cold, it’s because the bitter compounds extracted in the brewing process are less detectable by your taste buds when the coffee’s hot. Coffee also releases more aromatic compounds when it’s hot, causing the pleasant smell of the coffee to become proportionally stronger in comparison to its bitterness. The HyperChiller, in other words, has been specifically designed to ruin coffee.