The effect of shape memory alloys (SMA), is based on a thermo-elastic conversion of the mesh effect occurring only in some of the alloy systems as e.g. Ni-Ti. If a SMA component is deformed below a certain temperature, a reversible change in shape is taking place. As soon as the component is heated up again beyond conversion temperature, it takes again its austenitic mesh effect und gets thus back its original shape. Shape memory alloys are caracterized by their considerable power density that enables the application of silent actuators with a simple structure.
By using different SMA components, two development projects are currently promoted.
1. Return Temperature Limiters
Return temperature limiters are applied to limit temperature in floor heating and to thus prevent damages. A pretensioned SMA spring closes a gate valve as soon as a defined temperature limit is reached.
2. Thermo-electric Actuator:
By supplying a resistance wire with current, a displacement based on the resulting heating and the change in length of the SMA wire is generated.