In an active heat switch a small external gas absorber pod is connected by a gas tube to the foot of the switch. Gas is released into the switch by electrically heating the pod under user control. The thermal conductance in ON and OFF states depend on material properties of the gas and the heat switch shell, and on the temperatures at the ‘hot’ and ‘cold’ ends.
An ideal heat switch would have high on-state conductance and very low off-state conductance. In practice it is very challenging to manufacture a gas-gap heat switch that meets both criteria. The space available to accommodate the heat switch is an additional constraint.
To find out whether we can provide a heat switch for your particular requirements, use our Heat Switch Questionnaire to let us know more about your intended application.