Heat and mass transfer studies in a finned tube heat exchanger employed with evaporative cooling technique

Abstract

Fin and tube heat exchangers are air cooled, cross flow heat exchangers, which have shown broad prospects in places where there is lack of water resources. Research is focused on improving the heat rejection capacity of these exchangers and various enhancement techniques have been studied. Evaporative cooling is one of the techniques employed to improve the performance. Air cooled heat exchangers with evaporative cooling techniques perform better compared to conventional fin and tube heat exchangers. In the present work, a numerical simulation has been developed to investigate heat transfer enhancement in a fin and tube heat exchanger incorporated with evaporative cooling technique. An experimental setup has been built to test the modified heat exchanger and to validate the numerical results. Results indicate 40 to 60% increase in heat duty and effectiveness of enhanced heat exchanger, for cooling water flow rates in the range of 150 to 450 LPH and air flow rate of 300 CFM. Experimental values of heat transfer rate and outlet temperatures of hot water and air are compared with those of numerical simulation and the agreement is generally good.