Solid state relay heatsinks are devices that provide solid state relays with a means of dissipating heat and maintaining safe operating temperatures. All solid state relays generate heat and failure to manage this can result in the relay's failure or destruction.
Solid state relay heatsinks are made of high thermal conductive materials such as silver, gold, copper or aluminium. Aluminium is commonly used for its availability and low cost, typically with a black anodized finish to provide additional radiant heating dissipation. The heatsink is firmly attached to the solid state relay.
Heatsinks have vertical fins through which hot air flows, normally assisted by a fan. The fins provide a large surface area that cools the air. Once cooled, the air is expelled into the environment, so ventilation is crucial. A heatsink's performance is measured by its thermal impedance (resistance to the transfer of thermal energy). A lower numerical thermal impedance rating means more efficient heat transfer.
When choosing solid state relay heatsinks you should bear in mind coordinating size, form factor, thermal impedance rating and mounting.