A system for maintaining an IC-chip near a set-point temperature while electrical power dissipation in the IC-chip is varied includes a container having an open end with a seal ring. Located in the container is at least one nozzle for spraying liquid coolant droplets on a portion of an IC-module which holds the IC-chip. This spraying of the liquid coolant occurs while the seal ring is pressed against the IC-module. Further, at least one window is provided in the container such that it passes energy by electromagnetic radiation from a radiation source to the IC-module, but blocks the liquid coolant.