Small capacity, air-cooled NH3-H2O absorption systems are becoming more attractive in applications where the input energy can be obtained for free, e.g. solar energy, exhaust gases of engines, etc., due to the increasing price of the primary energy. In this work, an air-cooled absorption refrigeration system for transport application is being studied. As it is well known, the absorber is the most critical heat exchanger due to its low heat and mass transfer coefficients. In this work, two types of suitable absorber are modelled: i) falling film flow; ii) bubble flow. A review of literature has been done, and a validation has been performed comparing the results of the models with the published results. The nominal working conditions of the absorber have been obtained from a thermodynamic simulation of the whole cycle. The performance of the two types of absorbers is compared for this application.
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