Effects of operation parameters on the ventilation performance for a floor-standing air conditioner

Abstract

Floor-standing air conditioners (FSAC) have been widely used in civil and office buildings due to the advantages of high cooling/heating capacity and easy installation. The major challenge of FSAC is to lower energy consumption while meeting the requirements of thermal comfort (TC) and indoor air quality (IAQ). Using the validated computational fluid dynamics (CFD) method, this study extensively examines the effects of some key operation parameters on the FSAC performance. The operation parameters include controllable supply vane angle, supply air velocity, supply air temperature, and uncontrollable outdoor weather condition. The main ventilation performance is assessed by indices such as predicted mean vote (PMV), predicted percent dissatisfied (PPD), draught rate (DR), local mean age of air (LMAA), and energy consumption (Psystem). The relative importance of the operation parameters for each ventilation performance index is identified by evaluating the individual effects of the operation parameters on such performance. Comparison of the individual and combined effects of the operation parameters on the ventilation performance reveals that the corresponding most important operation parameters account for 90.6%, 97.4%, 77.1%, 95.1%, and 79.2% of the variations in PMV, PPD, DR, LMAA and Psystem caused by the combined effects, respectively. Additionally, the outdoor weather conditions do not significantly affect DR, PPD and LMAA, but can shift PMV to uncomfortable levels. Finally, the constant-air-volume (CAV) system is recommended for FSAC during the steady stage and a simplified operation strategy is proposed.