Thermodynamic comparison of water-based working fluid combinations for a vapour absorption refrigeration system

Thermodynamic analysis of a water-based vapour absorption refrigeration system with four binary mixtures [H2O-LiBr, H2O-NaOH, H2O-LiI and H2O-LiCl], five ternary mixtures [H2O-LiBr + LiI (salt mole ratio 4:1), H2O-LiCl + LiNO3 (2.8:1), H2O-LiBr + LiNO3 (4:1), H2O-LiBr + ZnBr2 (2:1) and H2O-LiBr + LiSCN (1:1)] and seven quaternary mixtures [H2O-LiBr + LiCl + ZnCl2 (3:1:4), H2O-LiBr + ZnCl2 + CaBr2 (1:1:0.13), H2O-LiBr + ZnBr2 + LiCl (1:1.8:0.26), H2O-LiBr + LiI + C2H6O2 (3:1:1), H2O-NaOH + KOH + CsOH (4.3:3.6:2.4), H2O-LiNO3 + KNO3 + NaNO3 (5.3:2.8:1.9) and H2O-LiCl + CaCl2 + Zn(NO3)(2) (4.2:2.7:1)] has been carried out by computer simulation. Variations of performance parameters (cut-off temperature, circulation ratio, coefficient of performance and efficiency ratio) of these aqueous solutions are compared with operating temperatures (generator, evaporator, condenser and absorber temperatures) and heat exchanger effectiveness as parameters. Correlations for the performance parameters are obtained in terms of operating temperatures and heat exchanger effectiveness from the regression analysis. It has been concluded that the H2O-LiCl combination is better from the cut-off temperature and circulation ratio points of view and H2O-LiBr + LiCl + ZnCl2 combination is better from the coefficient of performance and efficiency ratio points of view. (C) 1998 Elsevier Science Ltd. All rights reserved.