Performance analysis on a multi-type inverter air conditioner

An analysis was conducted for a multi-type inverter air conditioner with a linear electronic valve as the expansion device and a variable speed compressor. The system performance was analyzed with variations of operating frequency of the compressor, cooling load imposed on the system and cooling load fraction (i.e. load ratio) between rooms in which is installed an evaporator. The optimum opening of the electric expansion valve (EEV) was calculated when the compressor operating frequency was specified at a given cooling load. As compressor operating frequency increased with cooling load increment, the EEV should have adjusted to get wide openings to get an optimum COP of the system. While total cooling load of the system was constant, the cooling load fraction changed due to the cooling load differences between each room in the multi-type air conditioning system with a number of evaporators and EEVs. The operating frequency of the compressor was increased with increment of the load ratio, and consequently, the power consumption of the compressor increased. The increment of the load ratio, which means increasing the load difference between each room, causes a reduction of the system performance (COP), although the total cooling capacity was constant. (C) 2001 Elsevier Science Ltd. All rights reserved.