An apparatus for heat exchange with radial mixing comprises a trough with two rotatably arranged shafts extending alongside each other, which shafts are each provided with paddles spaced apart in an axial direction with an intermediate distance. The paddles extend substantially in a radial plane with respect to the shafts, and extend in a circumferential direction over at least a part of the circumference. In the circumferential direction, the paddles are at least partly wedge-shaped. Upon opposite rotation of the shafts, successive paddles mesh alternately, thereby forming a gap narrowing again and again. Per shaft, successive paddles in an axial direction are staggered relative to each other in circumferential direction through an angle.