Experimental studies on heat and mass transfer in tubular generator for R134a-DMF absorption refrigeration system

Experimental investigations have been carried out to study heat and mass transfer during desorption of Tetrafluoro ethane (R134a) from R134a and Dimethyl formamide (DMF) solution in a tubular generator. Absorption refrigeration system has been built with brazed plate heat exchangers as condenser, absorber, evaporator and solution heat exchanger and with stainless steel concentric tubes as the generator. Effects of operational parameters viz., solution two phase Reynolds number, driving temperature ratio, driving pressure ratio, solution initial concentration on generator performance are analyzed. Desorption ratio, Sherwood number and Nusselt number increase as the solution Reynolds number, solution initial concentration, driving temperature ratio increase whereas these parameters decrease as the driving pressure ratio increases. Finally a correlation for Nusselt number and Sherwood number are proposed based on the experimental studies. Highlights: R134a desorption from R134a-DMF mixture is investigated experimentally. Stainless steel concentric tubes are used as generator of absorption system. Heat and mass transfer parameters are analyzed. Effect of non dimensional parameters on generator performance is examined. Empirical correlations for Nusselt and Sherwood numbers are proposed. © 2012 Elsevier Masson SAS. All rights reserved.