Modeling of Local Measured Heat and Mass Transfer Variations in a Microchannel Ammonia-Water Absorber

This paper presents the results of an experimentally validated model for the prediction of heat and mass transfer rates in a novel microchannel absorber for residential and light-commercial applications. The detailed temperature, concentration, and mass flow rate profiles through the absorber are predicted with this model. A surface area effectiveness ratio is defined to account for potential solution distribution and surface wetting problems, which results in excellent agreement between the predictions of the model and the measured data. These experimentally validated analyses show that the novel microchannel falling-film absorber geometry can yield significantly compact absorbers that would facilitate the implementation of absorption cycles in small capacity heat pumps. With improvements in solution distribution, it is expected that an extremely compact, 0.104 × 0.104 × 0.505 m absorber will readily transfer the duty that corresponds to a residential heat pump.