Air-conditioning apparatus

#This application is a U.S. national stage application of International Application No. PCT/JP2012/003078 filed on May 11, 2012, the disclosure of which is incorporated herein by reference.

#The present invention relates to an air-conditioning apparatus that performs air conditioning by using, for example, a zeotropic refrigerant mixture.

#For reasons such as enhanced operational efficiency and environmental considerations, there are air-conditioning apparatuses that perform air conditioning by using a zeotropic refrigerant mixture in which a plurality of refrigerants with different boiling points are mixed. For example, in some conventional air-conditioning apparatuses using a zeotropic refrigerant mixture such as multi-air-conditioning apparatuses for buildings, a composition-sensing bypass circuit is added to the main refrigerant circuit to sense the composition (circulating composition) of a zeotropic refrigerant mixture circulating through the refrigerant circuit. For example, the composition-sensing bypass circuit is formed by composition-sensing heat exchangers and an expansion device, with temperature and pressure sensors attached in the flow path. A part of the refrigerant discharged from the compressor is caused to flow through the composition-sensing heat exchanger (high-pressure side), the expansion device, and the composition-sensing heat exchanger (low-pressure side) in the order named, and bypassed to the suction portion (suction-side pipe) of the accumulator. At this time, the temperature of the refrigerant in a supercooled liquid state (supercooled liquid refrigerant) at the outlet of the composition-sensing heat exchanger (high-pressure side), the temperature of the refrigerant that is in a two-phase state (two-phase refrigerant) after passing through the expansion device, and the pressure (low-pressure side pressure) at the suction portion of the accumulator are detected by the temperature and pressure sensors. Then, the circulating composition is computed on the basis of the temperature of the supercooled liquid refrigerant, the two-phase refrigerant temperature, and the low-pressure side pressure (see, for example, Patent Literature 1).

#FIG. 1 is a schematic diagram illustrating an example of the apparatus configuration of an air-conditioning apparatus according to Embodiment 1 of the present invention.

#FIG. 2 illustrates a flow of refrigerant in cooling operation mode of an air-conditioning apparatus 100.

#FIG. 3 illustrates a flow of refrigerant in heating operation mode of the air-conditioning apparatus 100.

#FIG. 1 is a schematic diagram illustrating an example of the apparatus configuration of an air-conditioning apparatus according to Embodiment 1 (hereinafter, referred to as air-conditioning apparatus 100). A configuration of the air-conditioning apparatus 100 will be described with reference to FIG. 1. In the following description, when a temperature, a pressure, or the like is described as being high, low, or the like, this is not determined in relation to a specific absolute value but is determined relatively depending on the state, operation, or the like of the apparatus or the like.

#The air-conditioning apparatus 100 according to Embodiment 1 is an apparatus that performs air conditioning using a refrigeration cycle by circulating a zeotropic refrigerant mixture made up of a plurality of refrigerants with different boiling points (for example, a refrigerant in which an R32 refrigerant and an R1234yf refrigerant are mixed at mass ratios of 44 wt % (percent by weight) and 56 wt % (percent by weight)). In the air-conditioning apparatus 100 according to Embodiment 1, an outdoor unit 1 and an indoor unit 2 are connected by a refrigerant main pipe 3 to form a refrigerant circuit. As for the operation mode, it is possible to select a cooling operation mode in which the indoor unit 2 to be operated performs cooling, and a heating operation mode in which the indoor unit 2 to be operated performs heating.

#<Outdoor Unit 1>