The purpose of this DTO is to test the effectiveness of a portable heat exchange unit that uses the vacuum of space to chill nearby items by controlling the vaporization rate of water. The objectives of the DTO are to demonstrate the technology in microgravity, identify potential shuttle applications, and measure the chilling capacity of the unit.
This commercial portable heat exchanger uses water as the refrigerant. It chills items by evaporating water in the reduced-pressure environment created by the vacuum of space. The unit, which is smaller than a beverage can (a cylinder 1.75 inches in diameter and 5 inches long), has the potential for extensive chilling capacity from two abundant resources aboard the Shuttle, water and vacuum. The heat exchanger has a unique internal feature that controls the water vaporization rate while maximizing heat exchange during the process. Since chilling occurs on the outer surface of the unit, items to be chilled (such as beverages or ice cream) are simply exposed to this outer surface.
The exchange unit, which is designed to connect to the orbiter waste control system vacuum port (TP126) or the wastewater overboard dump system, is equipped with quick disconnects that interface with the overboard dump system. The system performed well in demonstrations on Earth; theoretically, it should perform just as well in microgravity.
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