Thermodynamic analysis of absorption chillers: Internal dissipation and process average temperature

K. C. Ng*, K. Tu, H. T. Chua, J. M. Gordon, T. Kashiwagi, A. Akisawa, B. B. Saha

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


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 high-lighted. 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.

Original languageEnglish (US)
Pages (from-to)671-682
Number of pages12
JournalApplied Thermal Engineering
Issue number8
StatePublished - 1998
Externally publishedYes


  • Absorption chiller
  • Ammonia-water binary mixture
  • Process average temperature
  • Thermodynamic modeling

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Industrial and Manufacturing Engineering


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