HEAT PIPE WITH CONTROLLED FLUID CHARGE AND HYDROPHOBIC COATING

The present invention is a heat pipe having a specified volume of working fluid determined in relation to the interior volume of the heat pipe and a target temperature TT, to provide self-temperature regulation and pressure management. The heat pipe comprises at least a evaporator region and a condenser region having a known interior volume V and a mass of working fluid given by the relationship Mwf=Dwf at TT×V where Dwf is the density of the saturated vapor of the fluid at temperature TT plus an amount of additional working fluid sufficient to have the rate of evaporation about equal to the rate of condensation for the particular heat pipe configuration. The heat pipe has at least the condenser region having an interior coating of a hydrophobic material.