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A Curve-Based Mixed System Rating Method



Piotr A. Domanski, William V. Payne


The curve-based method was evaluated based on performance predictions for nine mixed systems, which were also tested by an independent testing laboratory. Capacity predictions were within 5% of the tested values for six of nine mixed systems, and four of nine SEER predictions were within 5% of the tested SEERs. Predictions for SEER showed an underprediction bias due to the wide variation of possible values for the cyclic degradation coefficient (CD) and the necessity of assuming a conservative value of CD in mixed system rating calculations. The report includes detailed test data for tested evaporators and an uncertainty analysis of the rating methodology.
Journal of Research (NIST JRES) - 7225
Report Number


air conditioner, cooling capacity, cyclic degradation coefficient, mixed system, rating procedure, SEER


Domanski, P. and Payne, W. (2005), A Curve-Based Mixed System Rating Method, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed April 23, 2024)
Created May 4, 2005, Updated October 12, 2021