A heat collector includes a heat sink. A recess in the heat sink either forms or receives internal gas and liquid phase lines. A manifold may be integrally formed in the heat sink or may be added on. The manifold combines separate input and output connections into a composite input and output connection. An internal composite line may include the internal gas and liquid phase lines and may be connected to the composite connection of the manifold. The internal liquid phase line is fluidly connected to the internal gas phase line in a transition region of the composite line. Advantageously, the internal liquid phase line may be disposed inside the internal gas phase line for protection and positive heat transfer effects. A cover may hold the composite line in the recess and provide good thermal contact between the lines and the heat sink.