Thermal Property Measurements and Enthalpy Calculation of the Lithium Bromide+Lithium Iodide+1,3-Propanediol+Water System

The lithium bromide+lithium iodide+1,3-propanediol+water LiBr/LiI mole ratio=4 and (LiBr+LiI)/HO(CH₂)₃ OH mass ratio=4] solution is being considered as a potential working fluid for an absorption chiller. Heat capacities at four temperatures, 283.15, 298.15, 313.15, and 333.15 K, were measured in the range from 50 to 70 mass%. In addition, the differential heats of dilution at 298.15 K were measured in the range from 45.3 to 71.8 mass%. Each individual data set was correlated with a proper regression equation with a high accuracy. A new enthalpy calculation method for the working fluids containing organics was proposed. The calculation method correlated the heat capacity (at various temperatures and concentrations) and the differential heat of dilution (at ambient temperature and various concentrations). The present method was applied for the construction of enthalpy–concentration (H–T–X) diagrams with high confidence.