Integrated Optimization on Thermal and Aeroacoustic Performance of Room Air Conditioner by Simulation

Room air conditioners are widely applied for thermal comfort in residential and commercial buildings. The thermal performance determines the thermal comfort and the energy consumption, while the noise level is more distinguishable to customers. The optimization process of the air conditioner by integrating the thermal performance and the noise level is presented and carried out by the computer simulation with the developed simulation model. The air flow is calculated with the computational fluid dynamics (CFD) method. With the air distribution, the refrigeration cycle simulation is carried out with the distributed-parameter model of heat exchangers. The aeroacoustic pressure is calculated by Ffowcs-Williams and Hawkings equation. The air velocity distribution is used to calculate the performance of the evaporator and the condenser in the air conditioners, which are the main part of the thermal performance simulation of the refrigeration cycle. This integrated process can be used for system design, components selection to meet the design target such as cooling/heating capacity, energy efficiency ratio (EER), and noise level. With above method, a room air conditioner is designed, whose cooling capacity, EER and noise all meet the design requirements and the size is much decreased. Furthermore, the simulation data agree with the experiment results well, the difference of indoor noise, outdoor noise, cooling capacity and EER are -5.55%, -1.25%, 1.85% and -2.41% respectively. These results show that it can be used as an effective tool for thermal and acoustic performance analysis, product development, and system optimization of room air conditioners.