Heat and mass transfer studies on a compact bubble absorber in R134a-DMF solution based vapour absorption refrigeration system

Experimental investigations have been carried out to study heat and mass transfer characteristics of Tetrafluoro ethane (R134a) in Dimethyl formamide (DMF) solution in a compact bubble absorber of vapour absorption refrigeration system of 1 TR capacity. Plate heat exchangers have been used as system components. Bubble absorption principle is employed in the absorber and hot water supplies heat to the generator. Effect of operating parameters such as circulation ratio, absorber and generator temperatures on heat and mass transfer effectiveness, overall heat transfer coefficient and volumetric mass transfer coefficient are investigated. It is found that heat and mass transfer effectiveness of absorber are better at lower circulation ratios and higher generator temperatures. Experimental results are compared with those obtained from numerical model developed earlier by the authors and the agreement is generally fair. From the experimental data, a correlation has been obtained for volumetric mass transfer coefficient, using multi-linear regression analysis.

► Heat and mass transfer characteristics are experimentally studied on a compact bubble absorber.
► A new working fluid pair Tetrafluoro ethane (R134a)-Dimethyl formamide is used.
► Effect of circulation ratio, absorber and generator temperatures are studied.
► A correlation for volumetric mass transfer coefficient is presented from the studies.
► Heat and mass transfer effectiveness are better at low circulation ratios and high generator temperatures.