A thermosiphon system includes a condenser, an evaporator, and a condensate line fluidically coupling the condenser to the evaporator. The condensate line can be a tube with parallel passages can be used to carry the liquid condensate from the condenser to the evaporator and to carry the vapor from the evaporator to the condenser. The evaporator can be integrated into the tube. The condenser can be constructed with an angled core. The entire assembly can be constructed using a single material, e.g., aluminum, and can be brazed together in a single brazing operation.