Component submodels for a room air conditioner computer simulation were developed and validated using data from a 1.5 ton (5.3 kW) room air conditioner. The room air conditioner was tested over an extremely wide range, indoor and outdoor temperatures from 67°F to 115°F (20°-46°C). During the validation, the problems associated with modeling room air conditioners were addressed: nonuniform evaporator and condenser airflow, recirculation, and the capillary tube. The evaporator, condenser, capillary tube, and compressor power models are accurate and suitable for system simulation. However, the RMS error for the compressor mass flow submodel was 7%, an inaccuracy that must be corrected before accurate system simulation can be achieved.

The entire validation procedure was made easier because the simulation model and solver routine are kept separate by using the Newton-Raphson solution method to solve the equations. This separation allows the user to easily "swap" parameters with variables as long as the equations remain independent. The inherent problems associated with the use of the Newton-Raphson routine-highly nonlinear and discontinuous equations-were overcome by developing automatic-relaxation, variable-checking, and equation-switching methods.

Units: Dual