Experimental studies on thermosyphon solar water heating system using twisted tape inserts

Abstract

Experimental studies on heat transfer friction factor and thermal newlineperformance of solar water heater fitted with helical Left Right Kenics and customized twists with a twist ratio of 3 and its modified forms with rod and spacer of various lengths are studied under identical operating conditions using water as working fluid and the results are presented newlineThe heat augmentation friction factor for plain tube collector is newlinecomparatively lower than the other collectors The highest improvement in overall thermal performance observed in the system with Kenics twisted tape is 71 2 The use of rod and spacer of various lengths reduced the friction factor significantly between 9 and 49 newlineCorrelated results for Nusselt number and friction factor for twisted newlinetape systems are compared with the corresponding experimental results and the deviation is within 19 and 15 respectively Simulated results using CFD are compared with theoretical values for plain tube system and the deviation is within and#61472;4 61 for Nusselt number and and#61472;and#61472;3 21 for friction factor For twisted tape collectors the deviations between experimental and simulated values are and#61472;13 11 and and#61472;11 23 respectively for Nusselt number and friction factor Based on the results Kenics twist with 125 mm rod offered good thermal performance with significant reduction in friction factor newline