During the last decade there have been significant advances in the development and application of metal versions of compact heat exchangers. In parallel with this trend, high performance polymer films have become commercially available. These materials (eg, polyether ether ketone and polyimide) have working temperatures in excess of 250-degrees-C and exhibit excellent resistance to most process fluids. It was therefore recognised that this new generation of polymers could play a key role in fostering the development of a new class of compact heat exchangers which could be cheaper, lighter and more corrosion resistant than their metal equivalents. It is envisaged that the heat exchange matrices would be comprised of crossed corrugated films, which are easily manufactured but for which heat transfer and pressure drop performance data is lacking. The work described below attempts to remedy this deficiency and provide design data which will promote the wide application of polymer films in compact heat exchangers.