Ammonia soaks up heat energy like a sponge soaks up water.
The analogy is not perfect. yet it presents an irony.
At the distance Saturn is from the Sun, pure water should
freeze solid and become as hard as steel.

But....An ammonia-water mix, plus feeble heat-energy
generated by tidal energy generated on Enceladus by all the remaining moons of Saturn, plus the tidal energy kicked in by the sun, maybe just enough to keep that mix a liquid or slushy state at those cyrogenic
temps.

BUT!...The bad news?...Enceladus is getting gradually colder.
That's an indisputable conjectural fact.
The bodies of liquid or slush beneath its surface will freeze
solid in the future.
Let's get there soon!