Simulation of Room Air Conditioner Performance

A room air conditioner simulation model has been developed, and validated experimentally. This report describes the assumptions made in the governing equations along with the process used to estimate a few empirical parameters, based on experimental data. The system model uses the Newton-Raphson method to solve its governing equations. This approach allows variables to be "swapped" with parameters, for example to solve for. the condenser or evaporator area neCessary to attain a given EER. This Newton-Raphson solver also has the capability to perf011ll sensitivity and uncertainty analyses. The ACRC room air conditioner model contains governing equations based on an extensive set of experiments with a I-ton Amana test unit and a 1.5-ton Whirlpool unit. Both of these data sets were taken using power measurements and externally-mounted thermocouples. The next step in the model validation will be a data set including refrigerant-side thermocouples and pressure transducers. This will allow the effect of intrusive instrumentation to be assessed. Additionally, the accuracy of swface thermocouples can be compared to that of immersion thennocouples. Validation of the model has been perfonned on a component and system level. The prediction of each of the component models has been documented in this report. The compressor maps and charge inventory equations proved to be the primary sources of uncertainty. The accuracy of the system simulation model in several modes of operation is also reported. When subcooling and superheat are specified, the system model was found to be quite accurate in terms of evaporator capacity and EER (1 % and 5% average error, respectively). The average error in system model prediction of capacity and EER during simulation mode was larger (-5% and 6%, respectively) mainly due the uncertainty associated with the charge inventory equations. Several appendices document the component level analyses in more detail and also provide a user's guide to the model.Air Conditioning and Refrigeration Center Project [number illegible