There is a tutorial on Adafruit[1] that makes use of that library to build a sous-vide cooker using a rice cooker or crockpot. I built one a little over a year ago. It was a great learning exercise. The real issue with it is that (at least with my setup) it takes forever to preheat (~1 hour to get to 130°F). I speed this up using boiling water. At higher temperatures (170°F+) it still takes a long time to heat, even with this method. I also use a pump to improve the temperature consistency, which is not mentioned in the tutorial. I recently got an Anova Immersion Circulator, which is much easier to use.

[1] https://learn.adafruit.com/sous-vide-powered-by-arduino-the-...