Heat Capacities of Four Promising Alternatives to Lithium Bromide Aqueous Solution in Absorption Refrigerators

Properly choosing additives to conventional lithium bromide aqueous solution to improve the performance is an important part in lithium bromide absorption refrigeration studies. Mixtures consisting of lithium bromide + triethylene glycol + water, lithium bromide + propylene glycol + water, lithium bromide + sodium formate + water, and lithium bromide + potassium formate + water were thought to be four promising alternatives to lithium bromide aqueous solutions. In the study, heat capacities of the four kinds of solutions were measured using a calvet type calorimeter at temperatures from 308.15 K to 348.15 K. The experimental data were regressed using a stepwise statistical method, and the corresponding equations for each kind of solution were given. The average absolute deviations between experimental and calculated values were no more than 0.12 % for all of the systems.