Numerical study on heat and mass transfer characteristic of plate absorber

Abstract

A model of simultaneous heat and mass transfer process in absorption of refrigerant vapor into a lithium bromide solution of water-cooled vertical plate absorber was developed. The model can predict temperature and concentration profiles as well as the absorption heat and mass fluxes, the total heat and mass transfer rates and the heat and mass transfer coefficients. The temperature is the highest at the interface and decreases to the lowest at the wall. In contradiction with the temperature profiles, the concentration is the lowest at the interface and increases to the highest at the wall. The absorption heat and mass fluxes, the total heat and mass transfer rates and the heat and mass transfer coefficients get high values at the inlet region but decrease at the outside of the inlet region. Besides, the effect of operating condition has been investigated and found that the absorption mass flux increases as the inlet cooling water temperature decreases, the system pressure increases, the inlet solution concentration increases, and the inlet solution temperature decreases. An analysis for the constant wall temperature condition has also been carried out to investigate the reliability of the present numerical method through comparing with previous investigations.