A generalized coefficient of performance for conditioning moist air

Ehab M. Mina, Ty A. Newell, Anthony M. Jacobi

Research output: Contribution to journalArticlepeer-review


The psychrometric chart is a useful tool for calculating the energy change between any two states and visually identifying the contribution of 'sensible' and 'latent' effects. However, the amount of work needed to move from one state to another is not read directly from the chart. In this paper, temperature and vapor pressure changes are cast into terms of minimum work relative to a dead state, and work contours are plotted on the psychrometric chart. These contours show the minimum work needed to move the state of the air further from the ambient conditions or the maximum work produced by letting a state approach the ambient conditions. A dividing line between heat pump and refrigeration operation is set on the basis total energy of the conditioned space relative to the ambient. Finally, an example is used to illustrate the implementation of the analysis.

Original languageEnglish (US)
Pages (from-to)784-790
Number of pages7
JournalInternational Journal of Refrigeration
Issue number5
StatePublished - Aug 2005


  • Air conditioning
  • COP
  • Calculation
  • Humid air
  • Performance
  • Process

ASJC Scopus subject areas

  • Building and Construction
  • Mechanical Engineering


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