shows the effect of the heat transfer coefficient at the condenser region on the heat pipe thermal resistance for different
heat inputs (3rd Kind boundary condition). The thermal resistance decreases as the heat transfer increase is quickly rejected at the heat sink. As heat input increases, thermal resistance increases for
lower heat transfer coefficients levels. In this case, for achieving high heat transfer coefficient fins can be attached to the condenser area to increase its effective surface area or increasing heat transfer coefficient. Note that more other studies are needed to examine other parameters affecting heat pipe thermal resistance such as wicks parameters, fill charge, heat pipe surface areas and lengths. Such studies can be useful for further heat exchanger thermal performance improvement.