Abstract
Absorption chillers operate well below their reversible or endoreversible limits because their thermodynamic behavior is dominated by internal dissipation, a significant part of which occurs in the chiller’s heat exchangers. This fact has summarily been omitted from earlier analyses. It translates into incorrect values for the refrigerant process-average temperature (PAT), and leads to noticeable errors in chiller diagnostics and optimization. Using experimental measurements from an absorption chiller, in concert with a computer simulation code and an analytic thermodynamic model, we fortify these claims with quantitative examples. The correct PAT is derived and its significance in chiller analysis is highlighted. Aspects of chiller optimization that are unique to absorption technology, as opposed to conventional vapor-cycle reciprocating chillers, are also illustrated. We also substantiate that commercial absorption chiller technology has empirically evolved to close to optimal operating conditions.