AC-2746 -- Development and Validation of a Reciprocating Chiller Model for Hourly Energy Analysis Programs

This paper describes the development of a reciprocating chiller model for use in hourly building energy analysis computer simulation programs. The model and its development are described, along with a procedure for getting the model parameters from the manufacturer's catalog data. The paper shows that the normalization used for the model parameters will allow one set of parameters to accurately reproduce the catalog data (+/-3%) for a wide range of chiller sizes. The paper considers chillers ranging from 10 to 50 tons, chilled water temperatures ranging from 4.40 to l0.0°C, and condensing water temperatures ranging from 23.9 to 35.0°C.

The chiller model is validated against measured performance data taken on a 20-ton reciprocating chiller operating in an experimental facility designed to simulate a conven­tional four-zone HVAC system. The agreement between the measured chiller performance and the model was less than 5.4% for all operating points. This is within the experimental accuracy of the measured data.

The paper also presents a test of a Fortran implementation of the model. The output of the Fortran code, using the default parameters, is compared to the experimental and catalog data.