A system having a sub-system that is configured to change a thermal condition of a physical component from a set-point to a new set-point, wherein the sub-system includes: a mixer operative to receive a first conditioning fluid having a first temperature and a second conditioning fluid having a second temperature different from the first temperature, and operative to supply to the physical component a mix of the first conditioning fluid and the second conditioning fluid; and a controller configured to control the mixer in dependence on the new set-point. Also a method of operating a lithographic apparatus as well as a device manufactured using the system described herein or according to methods described herein.