Performance Enhancement of Air-cooled Condensers

Heat transfer by convection in air cooled condensers is studied and improved inthis work. In order to enhance the performance of air cooled condensers, it is important totake into consideration both of condensation inside condenser tubes and convectionoutside, where the enhancement in convection side is the dominant one. Aluminum extrudedmicro-channel flat tubes improve the performance of condensation more than conventionalcircular tubes but still has potential for air side improving. So the enhancement ofconvective heat transfer in air side is achieved in this study by inclination of the flat tubesby a certain angle with respect to horizontal in two cases. The first proposed case is tomake convergent and divergent channels for air flow (case 1), while the second case istilting all tubes in parallel to each other (case 2). A parametric study is performed toinvestigate the optimum inclination angle (β) and aspect ratio (Ar). Mathematical modelingfor air cooled condensers was applied to aluminum flat tubes to study and evaluate theseproposed two cases. A computational fluid dynamic software (CFD) is used to solve theproblem. Theoretical results show that the optimum angle for the proposed two cases isabout 4 deg. With corresponding aspect ratio of 0.58. This leads to enhancement of heattransfer coefficient by factor (Kh) of 1.469 and 1.46 against increase in pressure dropfactor (KP) of 2.12 and 1.95 for case 1 and case 2 respectively.