A device, including a heat exchanger plate and a plate package (2) of heat exchanger plates (1) which are provided beside each other to form a plate interspace between adjacent plates. The plate interspaces form, in an alternating order, first passages (3) for a first medium and second passages (4) for a second medium which cools the first medium. Each heat exchanger plate has at least two portholes forming a first inlet port channel and a first outlet port channel (7), which extend through the plate package to a first inlet and a first outlet, respectively, for the first medium to and from the first passages (3). The first outlet forms a gas outlet (31) for discharging a gaseous portion of the first medium and a liquid outlet (32) for discharge of liquid of the first medium. The liquid outlet (32) is separated from the gas outlet (31) to permit separate discharge of the liquid and gaseous portions.