Ammonia/ionic liquid absorption in a plate heat exchanger

Abstract

Negative transport properties have always been pointed out as the key factors that hinder the application of ammonia/ionic liquids (NH3/ILs) in the absorption cycles, while heat and mass transfer of these new fluids in components have been rarely reported. The authors selected corrugated plate heat exchangers as the geometry to explore the absorption of the proposed working fluids. In this paper, a modeling method and a continuous absorption-desorption setup are introduced. Absorption process is modeled with the two-resistance theory by introducing a gas-liquid interface. Analytical heat transfer results and mass transfer from penetration theory are applied. With the model, distribution of local parameters and overall heat and mass transfer characteristics of an absorber in a cooling application are obtained. The overall heat transfer coefficient of an absorber for a refrigeration application is around 1350 W/(m²K) for the studied NH3/IL working fluids. An experimental setup is developed for further model improvement.