New Advanced Condenser Mechanically Expanded Type with Oval-Flat Tubes

Mechanically expanded technology is applied since long time for manufacturing of condensers for air conditioning applications. Typical geometry consists of round copper or aluminum tubes, and flat aluminum fins. This common solution limits the global performance, specially heat rejection, so that to have more performance it is necessary to advance the brazed technology, serpentine or parallel flow type condensers. The application of oval-flat tubes with ratio between major axis/minor axis, ratio indicated as a/b, greater than 3.0 to the radiators for engine cooling systems has relaunched the mechanically expanded technology, providing performance comparable to those of brazed technology. Until today the application of the oval-flat tube to the condenser has been considered not possible owing to the heavy work conditions on the tube side, specially in terms of pressure.

The purpose of this paper is to present the development results of a new advanced condenser, named POLARIS, mechanically assembled type with oval flat tubes, the structural behaviour of the new geometry and the performance reached with respect to the other technologies.