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Highlights • Mass fraction difference as the driving force for the mass transfer. • New variable to fit experimental data for absorption chillers. • Linear relation of cooling capacity to mass fraction difference. • Less deviation compared to characteristic temperature function. Abstract Absorption chillers are considered as heat transfer devices and hence most commonly modeled as heat transfer processes. The absorption of the refrigerant vapor though inherently involves mass transfer into the absorbent, which in comparison to the heat transfer usually is a slow transport process. Modeling absorption chillers, however, usually does not include this mass transfer process. This in fact neglects the dominant process in absorption chillers which is addressed in the present paper. [ABSTRACT FROM AUTHOR]

A comparison of absorption and desorption is conducted using a detailed model describing heat and mass transfer. First, the influences of various assumptions have been evaluated. Second, typical conditions for both absorption chillers and heat transformers have been defined. The performance of absorption and desorption processes have been analysed for a flow length of 0.1 m. In an absorption chiller, during desorption, the viscosity is lowered and the mass diffusivity is increased. These circumstances cause a 46% higher transfer rate as compared to absorption. Thus, the overall performance of the process is determined by the absorber component. In a heat transformer, during absorption at an elevated pressure and temperature level, the viscosity is lower and mass diffusivity is higher as compared to desorption. Therefore, the transfer rate of during absorption is 10% higher as compared to desorption. Hence, the desorber performance is somewhat more influential to the overall system performance. [ABSTRACT FROM AUTHOR]