Liquid Cooling and Ventilation Garment

A Liquid Cooling Garment (LCG) is a form-fitting garment that is used to remove body heat from the wearer in environments where evaporative cooling from sweating and open air convection cooling does not work, or the wearer has a biological problem that hinders self-regulation of body temperature.

A Liquid Cooling and Ventilation Garment (LCVG) has additional crush-resistant ventilation ducts, which draw moist air from the wearer's extremities, keeping the wearer dry. In a fully enclosing suit where exhaled breathing air can enter the suit, the exhaled air is moist and can lead to an uncomfortable feeling of dampness or wetness.

While this technology is most commonly associated with space suits, it is also used in a wide range of Earth-bound applications where open-air cooling is difficult or impossible to achieve, such as fire fighting, working in a steel mill and increasingly by surgeons during long or strenuous procedures.

There are typically two parts to a liquid cooling garment:

The garment is typically a close-fitting non-stretching fabric or a tight-fitting elastic fabric, with flexible tubing sewn onto the fabric. A single-layer of fabric may be used, with the tubing either on the inside directly contacting the wearer's skin, or on the outside separated by the fabric. If two layers of fabric are used, stitched channels can be formed which enclose the tubing between the two fabric layers. Where flame resistance is needed, the garment may be constructed out of materials such as nomex.

The tubing is typically a few millimeters in diameter, and may be made out of any number of flexible plastics such as polyvinyl chloride (PVC) or silicone. Smaller diameter tubing permits a higher degree of garment flexibility, but at a cost of lower heat absorption capacity, and increased pressure needed to push liquid through the tubing.

When a large area needs to be cooled or the external environment also heats the tubing, a single long tube may not be enough because the liquid becomes saturated with heat and can not cool any further. Making the liquid much colder is not an option since it leads to uncomfortable coldness where the liquid enters the tubes. Instead, multiple parallel tubes are used to increase the volume of liquid available to absorb heat.

...
Wikipedia