A study of parameters affecting the dirtiness on the performance signals of a room air conditioning unit.

To maintain a good performance, a room air conditioning unit is generally recommended to be cleaned twice a year, regardless of operating hours or concentration of airborne particles. With less operating hours or under clean ambience, the maintenance cost could be postponed under common energy efficiency. If a cleaning signal could be sent from the unit, itself, to the owner, a proper cleaning schedule could be provided. A dirtiness monitoring factors are aimed to be investigated from this study. Under varied degree of dirtiness simulated on the fan coil unit, system operation behaviors and thermodynamic properties were investigated. An experimental apparatus was installed under the actual indoor and outdoor conditions, in order to follow up related factors on real-time vapor compression cycle. [ABSTRACT FROM AUTHOR]