An application of fuzzy logic to control the refrigerant distribution for the multi-type air conditioner

Single type air conditioners (STAC) consist of one outdoor unit and one indoor unit. Multi-type air conditioner (MTAC) consist of one compressor in outdoor unit and some indoor units. In this paper, we use the free joint MTAC which can joint six indoor units to one outdoor unit. In the control of the refrigerant distribution, there are three procedures: to measure the pipe pressure of indoor unit; to calculate the amount of the refrigerant for each indoor units accurately, and to analyze the relation between the room temperature and outdoor temperature of the system. In the conventional refrigerant distribution control, the cooling load are estimated by using a experimental relation between evaporating coil target temperature and present temperature. In this paper, we apply the fuzzy logic control method to the linear valve control for the stable refrigerant distribution in the presence of operating condition change.