A: What is the working theorem for heat pipe heat sinks? Heat pipe heat sinks work in a way that a heat pipe is hollow inside and it contains fluid that has a very low boiling point. Therefore, the fluid’s liquid-vapor phase changes within the completely sealed vacuum tube are utilized for transmitting heat. A heat pipe has very high thermal conductivity and is almost 100 times higher than that of pure copper. Due to its high thermal conductivity, it is representative for high-end heat sinks. There are three types of techniques for manufacturing heat pipes and they include groove-type, mesh-type, and sintered-type heat pipes. The commonly used materials include red copper or brass. The heat pipe manufacturing technique or material to be used on heat sinks should depend on different design requirements.