Modelling and comprehensive analysis of a LiBr-water compact desorber-condenser cooled by air

• A LiBr-water microchannel desorber coupled with an air-cooled condenser is studied. • Tests at different temperatures, concentrations and solution mass flow rates are done. • A heat and mass transfer model is proposed and validated with the measurements. • Errors for mass transfer are below 34% and below 20% for the temperatures predicted. • Performance maps are built for various ambient conditions and solution states. Membrane technology applied to absorption or desorption of the refrigerant in absorption systems has received increasing attention because of the compactness that can be achieved comparing to traditional heat and mass transfer devices. For LiBr-water systems, another issue is the need of a cooling tower. In this study, a new microchannel membrane based desorber heated with water, coupled with an air-cooled condenser is considered. Measurements at three different heating temperatures, solution mass flow rates and concentrations are used to validate the heat and mass transfer model proposed for the new ensemble desorber-condenser. The model is based in correlations gathered from the literature. Errors under 34% are found for the mass flow rate of vapour generated. Predicted condensing temperature and outlet temperatures of the solution are within a range error below 20%, while the error found for the outlet heating water is below 6%. The model is used to predict the system performance at different heating temperatures, mass flow rates, solution concentrations and ambient temperatures, providing a performance map of operation for the novel system that can be used as a predictive tool.