Cryostasis Chamber

The Cryostasis Chamber is a machine designed to place a subject into suspended animation by lowering his temperature to the point of freezing.

The Winter Soldier
HYDRA placed the Winter Soldier in one of these chambers to keep him under control. They would only unfreeze him when they had a mission ready, that way he could last the decades, and not succumb to age and become wasted. Also so he could not reactivate his lost memories. As soon as the mission was over, HYDRA would return him to this chamber.

Carl Creel
Carl Creel was placed in a cryostasis chamber after Phil Coulson incapacitated him with a modified version of the Overkill Device.

Coulson delivered Creel in the chamber to Glenn Talbot inside a van. He warned Talbot that the chamber's power had less than an hour before it deactivated because it needed a more stable power source.