Entropy production analysis and experimental confirmation of absorption systems

Absorption chillers, heat pumps and heat transformers exploit thermal power input to satisfy a variety of refrigeration and heating applications, as well as to boost the temperature of low-grade heat. Can one arrive at accurate predictions of system performance with a simple analytic irreversible thermodynamic model? In capturing the essential physics of the problem, that model would be required to provide a predictive and diagnostic tool and to permit determination of optimal absorption system operating conditions. We derive such a model and check its validity against experimental data and computer simulation results from a variety of commercial absorption units. We reinforce the observation that commercial units appear to have evolved empirically such that maximum efficiency is realized under design conditions. The failure of a host of previously-published endo-reversible thermodynamic models to account for fundamental qualitative features and accurate predictions of system behavior is documented with computer simulation results and experimental performance data. (C) 1997 Elsevier Science Ltd and IIR.