The invention relates to a plate package for a heat exchanger device including a tank with an inner space and an inner wall surface. A sectional plane (p) extends vertically through the inner space. The tank has an inlet for the supply of a liquid medium and an outlet for discharging the medium in a gaseous state. The inner space defines a lower part space and an upper part space. The plate package (10) with heat exchanger plates (11) is provided in the inner space. Each heat exchanger plate has an extension plane perpendicular to the sectional plane. The heat exchanger plates form first plate interspaces that are open towards the inner space for recirculation of the medium, and second plate interspaces, which are closed towards the inner space for the recirculation of a fluid for evaporating the medium. Each heat exchanger plate includes a first porthole (14) and a second porthole (15). Furthermore, each heat exchanger plate includes an elongated distribution element (25) which extends into the adjacent second plate interspace and substantially transversally to the sectional plane (p).