1. Field of the Invention
The present invention relates to a multi-type air conditioning apparatus for air-conditioning a plurality of rooms.
2. Description of the Related Art
In buildings with many rooms, use is made of a multi-type air conditioning apparatus in which a plurality of indoor units are connected to a single outdoor unit.
This type of air conditioning apparatus is equipped with an variable-capability compressor and an outdoor heat exchanger in the outdoor unit, and an indoor heat exchanger in each of the indoor units, the variable-capability compressor, the outdoor heat exchanger and the indoor heat exchangers constituting a refrigerating cycle.
Each indoor unit is arranged to sense its air-conditioning load based on indoor temperature and inform the outdoor unit of the sensed air-conditioning load. The outdoor unit controls the capability of the variable-capability compressor in accordance with the sum of the air-conditioning loads on the indoor units.
Examples of this type of air conditioning system are disclosed in U.S. Pat. Nos. 4,926,652, 4,932,220, and 5,074,120.
With such an air-conditioning apparatus, the pipe coupled to each indoor heat exchanger is made large in bore diameter so as to allow a sufficient amount of refrigerant to flow through the indoor heat exchanger.
However, when the air-conditioning load is so light that the amount of refrigerant flowing through the indoor heat exchanger is small, the heat loss of the refrigerant in the pipe increases. Further, the longer the pipe is, the further the heat loss increases.
The heat loss is represented by the product of the actual amount of heat loss and the capability of the variable-capability compressor. When the heat loss is great, the indoor unit becomes poor in air-conditioning capability, particularly in heating capability.