ThermoTilt: a smart thermoregulating garment

One of the functions of garments is to protect humans from heat and cold. Garments for cold weather typically have a thick insulation layer which serves to separate the warmth of the body surface from the cold outside and thus keep the body warm and comfortable as long as possible. For that reason we put our coats on when going outside and take them of when returning home.

In the current project we explored the possibility that the garment itself takes care of the thermoregulation by automatically increasing and decreasing its insulation layer thickness. We realized this by designing a construction consisting of a series of parallel ribs which can shift between a flat and an actuated configuration and thereby create an air pocket layer of about 20 mm. The actuation is done with shape memory alloy (SMA) wires in combination with an elastic textile band. In cold conditions the SMA wires are in their non-actuated state and the ribs are pulled upwards by the elastic band. When entering a warmer environment the SMA wires are actuated, resulting in a contraction which pulls the ribs in their flattened configuration. In this configuration the smart thermoregulating garment intrinsically reacts to changing environmental conditions and thus does not need and external control system with sensors and energy supply to function. As an alternative (and for demonstration purposes) the system may be actuated by Joule heating using a small electrical current and equipped with temperature sensors and a control system.