Table 4.

The merits of the MHPA [70].

Merits	Description
High heat transfer capability	Micro grooves can improve the region of heat exchange, thereby, the heat transfer capability is able to be strengthened dramatically.
Strong confined ability	The clapboards within the micro-channel play an important reinforcement influence and significantly enhance the confinement ability of MHPA.
Good reliability	One damaged micro-channel does not affect other micro-channel operating as they are all operating independently.
Small contact thermal resistance	This structure could conquer the demerits of cylindrical heat pipe and significantly decreases thermal resistance among the interface.
Low cost	One-time extrusion aluminium material is applied in the MHPA, and its price is more cost-effective compared to copper pipes.