Investigation of the effects of plate patterns on effectiveness and entropy generation in plate heat exchangers

Compact plate heat exchangers (PHE) are widely used in various industry and power generation fields, especially as condenser and evaporator. Since heat rejection is an essential part of ORC systems, all improvements on heat transfer will lead higher efficiencies. There are some design criteria for such devices. Heat transfer, pressure drop, compactness, entropy generation, and effectiveness are the most essentials. The thermal performance and compactness of these devices can be increased by modifying the surface patterns of plates. However, attention should be paid to pressure drop and entropy generation since any modification on surface can easily led to pressure drop and entropy generation due to viscous effects on the plate surface which increase pumping duty eventually. Thus, there exists an optimization problem that one should take care of. This paper presents an investigation of the effect of the plate surface patterns of a standard PHE and trachea patterned compact PHE in terms of effectiveness and entropy generation. Trachea shaped fins are placed on the surface of the plate to form a trachea patterned PHE designed in accordance with the additive manufacturing method. Compactness which is heat transfer surface area scaled by the heat exchanger volume is an important design parameter for heat exchangers. In order to increase compactness, plate surface is decorated with trachea shaped fins. Consequently, compactness reached to 8150 while it is only 4280 for the standard PHE with three plates. In order to perform the thermodynamic analysis of the trachea pattern compact PHE, different flowrates were taken as 0.01, 0.03 and 0.05 kg/s. As a result of the study, the heat transfer amount was 2950 W, the efficiency was 0.282, and the entropy production was 20.370 W/K.     «

Compact plate heat exchangers (PHE) are widely used in various industry and power generation fields, especially as condenser and evaporator. Since heat rejection is an essential part of ORC systems, all improvements on heat transfer will lead higher efficiencies. There are some design criteria for such devices. Heat transfer, pressure drop, compactness, entropy generation, and effectiveness are the most essentials. The thermal performance and compactness of these devices can be increased by modi...     »