Advanced Working Fluid Properties in Heat Pump and Absorption Cooling Operations. Annual Report December 1, 1987-November 30, 1988

摘要

A theoretical correlation formula based on the mean-spherical approximation solution for the primitive model of electrolytes is developed for accurate description of the osmotic, activity coefficients and vapor pressures of single-salt, mixed-salt, single-solvent and multisolvent salt solutions. Both aqueous and ammoniac systems are investigated. Vapor-liquid equilibria of water-ammonia mixtures are correlated with a local composition model for polar solvents. The systems studied have bearing on gas-fired absorption cooling cycles. Salt systems such as LiBr-water-ethylene glycol, and ammonia-NaSCN are well predicted by the present method for thermodynamic properties. Input data involve the minimum number of necessary characterization parameters such as valences, ion sizes, dielectric constant, plus state conditions: temperature, density, and composition. The only 'adjustable' quantity is the cation size, which reflects the degree of hydration at various concentrations.