A spiral heat exchanger includes a spiral body formed by at least one spiral sheet wound to form the spiral body forming at least a first spiral-shaped flow channel for a first medium and a second spiral-shaped flow channel for a second medium, wherein the spiral body is enclosed by a substantially cylindrical shell being provided with connecting elements communicating with the first flow channel and the second flow channel, where the at least one spiral sheet comprises a corrugated heat transfer surface with corrugations for increasing the heat transfer and supports for spacing the wounds of the at least one spiral sheet in the spiral body.