HVAC&R Equipment Performance Group
Publications
A Curve Based Mixed System Rating Method for Unitary Air Conditioners
A Curve-Based Mixed System Rating Method for Unitary Air Conditioners (2.43 MB)
W. Vance Payne and Piotr A. Domanski
NISTIR 7225
Keywords:air conditioner, cooling capacity, cyclic degradation coefficient, mixed system, rating procedure, SEER
Abstract:The curve-based method was evaluated based on performance predictions and independent laboratory testing for nine mixed systems. Capacity predictions were within ±5% of the tested values for six of the mixed systems, and four of the SEER predictions were within ±5% of the tested SEERs. Predictions for SEER showed an under prediction 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. This report includes detailed measurement data for the tested evaporators and an uncertainty analysis of the rating methodology.
