Compressor power modeling: Part 1 thermodynamic efficiency determination from manufacturer's performance curves

Manohar R. Kulkarni*

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review


Compressor is at the heart of any refrigeration system and it is also the largest consumer of energy. Thus for an energy efficient operation of a refrigeration system it is imperative that compressor performance be understood and closely monitored. Further, as the current trend of the integrated electromechanical control becomes a common place there will be opportunities to utilize a switchover control strategy (or strategies), especially for the off-design or part-load system operations. Hence a compressor power model approach based on the manufacturer's data is proposed. Compressor performance curves are usually provided by the manufacturers. These curves give full load compressor power and the cooling capacity as a function of saturation evaporator and condenser temperatures for a specified amount of subcooling and for either a specified amount of superheat or for a specified compressor return temperature. The proposed modeling approach will work equally well with either compressor performance curves; however the efficiency determination procedure will be slightly different in each case. From the performance curves the rated compressor power and rated capacity are determined at specific saturation evaporator and condenser temperature. These values, the compressor specifications and the other thermodynamic property information are utilized to compute the volumetric and isentropic efficiencies. It is then assumed that these efficiencies remain invariant with respect to the amount of superheat and the amount of subcooling. Next, using a linear multi-variate regression analysis, curve-fits for the efficiencies as a function of saturation and condenser temperatures are developed.

Original languageEnglish (US)
Pages (from-to)721-726
Number of pages6
JournalProceedings of the Intersociety Energy Conversion Engineering Conference
StatePublished - 2001
EventProceedings of the 36th Intersociety Energy Conversion Engineering Conference, IECEC - Savannah, GA, United States
Duration: Jul 29 2001Aug 2 2001

ASJC Scopus subject areas

  • Fuel Technology
  • Electrical and Electronic Engineering


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