Heat exchanger with flat tubes and flat heat exchanger tube

The heat exchanger has bundles of tubes (10) with fins (15,90) surrounding fluid channels (51). The heat exchanger works on the counterflow principle and there are spaces with distancing projections (15,40) between the tubes to form channels for the cooling fluid. The tubes are surrounded by a casing (3) with profiled sheet metal walls (1a,1b). The tubes may be soldered in place.