A heat transport device with a diphasic working fluid contained in a general closed circuit, includes an evaporator having a microporous body suitable for providing capillary pumping of liquid phase fluid; a condenser; a tank having an inner space, with a liquid portion and a gas portion; and an inlet/outlet arranged at the liquid portion, wherein the volume of the liquid portion can vary between a minimum volume and a maximum volume. The gas portion of the tank contains the vapor phase of the working fluid, at a first partial pressure, and a noncondensable auxiliary gas at a second partial pressure, wherein the second partial pressure is greater than the first partial pressure, at least when the liquid portion is at the minimum volume thereof.