Epoxy coatings with good adhesion characteristics have been developed that are suitable for large-scale manufacturing and application in compact heat exchangers. Two of them, with a static contact angle for water of 105° and 79° have been tested in a finned-tube condenser comparing flat plate minichannels on the gas-side. Contrary to the expectation, the thermal efficiency of the 105° condenser is slightly less than that of the 79° one. This is due to a reduction of condensate drop size at detachment, resulting in relatively small dry paths after drainage. The finned-tube geometry is shown to be less favourable for a condenser than a compact cross-flow plate geometry with minichannels on both the gas- and coolant side.
|Journal||Experimental Thermal and Fluid Science|
|Publication status||Published - 2007|