A heat transfer system comprising: at least one evaporator comprising: a cylindrical barrier wall defining a central axial opening and an outer cylindrical surface, the cylindrical barrier wall having a length, a first axial end, and a second axial end; a cap that fits at an end of the cylindrical barrier wall, the cap including an outer surface that is external to the central axial opening and an inner surface that abuts the central axial opening; a cylindrical wick disposed within the central axial opening, having an inner surface defining a central axial channel and extending substantially along the entire length of the cylindrical barrier wall from the first axial end to the second axial end; the heat transfer system characterized by: a portion of the outer cylindrical surface defining a liquid inlet port extending through the outer cylindrical surface of the cylindrical barrier wall and through the cylindrical wick to the central axial channel defined by the inner surface of the cylindrical wick; a liquid outlet port extending through the cylindrical barrier wall and through the cylindrical wick to the central axial channel defined by the inner surface of the cylindrical wick; and a vapor port extending through the cylindrical barrier wall to a vapor removal channel that is defined at an interface between the cylindrical wick and the cylindrical barrier wall. at least one evaporator comprising: a cylindrical barrier wall defining a central axial opening and an outer cylindrical surface, the cylindrical barrier wall having a length, a first axial end, and a second axial end; a cap that fits at an end of the cylindrical barrier wall, the cap including an outer surface that is external to the central axial opening and an inner surface that abuts the central axial opening; a cylindrical wick disposed within the central axial opening, having an inner surface defining a central axial channel and extending substantially along the entire length of the cylindrical barrier wall from the first axial end to the second axial end; a cylindrical barrier wall defining a central axial opening and an outer cylindrical surface, the cylindrical barrier wall having a length, a first axial end, and a second axial end; a cap that fits at an end of the cylindrical barrier wall, the cap including an outer surface that is external to the central axial opening and an inner surface that abuts the central axial opening; a cylindrical wick disposed within the central axial opening, having an inner surface defining a central axial channel and extending substantially along the entire length of the cylindrical barrier wall from the first axial end to the second axial end; a portion of the outer cylindrical surface defining a liquid inlet port extending through the outer cylindrical surface of the cylindrical barrier wall and through the cylindrical wick to the central axial channel defined by the inner surface of the cylindrical wick; a liquid outlet port extending through the cylindrical barrier wall and through the cylindrical wick to the central axial channel defined by the inner surface of the cylindrical wick; and a vapor port extending through the cylindrical barrier wall to a vapor removal channel that is defined at an interface between the cylindrical wick and the cylindrical barrier wall.