The present experimental investigation focuses on the effect of symmetric (beta similar to 30 degrees/30 degrees and 60 degrees/60 degrees) and mixed (beta similar to 30 degrees/60 degrees) chevron angles in PHE on comparative energetic and exergetic performance for nanofluid-water. The particle volume concentration of selected ZnO/water nanofluid being used as coolant lies in range 0.5-2.0%. The experimental findings elucidates the detailed observations of the effect of different chevron angles in PHE on heat transfer rate ratio, heat transfer coefficient ratio, overall heat transfer coefficient ratio, pumping power ratio, performance index ratio, exergy loss, non-dimensional exergy loss, qualitative response of system by exergetic efficiency, total entropy generation and contribution of irreversible heat transfer arises due to frictional losses by Bejan number. Experimental observation confirm that optimum enhancement in heat transfer rate ratio, heat transfer coefficient ratio and optimum reduction in exergy loss are obtained at beta similar to 60 degrees/60 degrees for 1.0% particle volume concentration of ZnO/water nanofluid. Total entropy generation also minimized for this configuration, which is 41.78% and 26.94% for beta similar to 60 degrees/60 degrees as compared to beta similar to 30 degrees/30 degrees and beta similar to 30 degrees/60 degrees in PHE respectively. Bejan number is the highest for beta similar to 60 degrees/60 degrees in PHE indicates reduction in irreversible heat transfer due to frictional losses, thus improving the qualitative response of the system. (C) 2016 Elsevier Ltd. All rights reserved.