Abstract: A method and system are provided for cooling a medium. A fluid is moved tugh the medium and bubbles are induced in the fluid as it moves through the medium. The bubble formation is induced by applying an acoustic field to the fluid as it moves through the medium. A heat sink can be thermally coupled to the fluid downstream of the medium so that heat rejected during bubble contraction and collapse is passed to the heat sink. The pressure of the fluid, i.e. the velocity of the fluid, can also controlled so that the bubbles contract and collapse in the region of the heat sink.

Abstract: Temporarily insulating frozen surfaces, such as ice rinks, from the ambient air by spreading a metastable liquid foam over the ice surface to remain thereon when the ice surface is not in use, then prior to the next use period, removing the aged, partially frozen foam. Fire fighting foam liquids are preferred embodiment foaming agents.