Multi-room type air-conditioning device

Abstract

The present invention provides a multi-chamber air conditioner which can make a plurality of indoor units (2n) are respectively operated or stopped to operate, and the mulit-chamber air conditioner executes the following oil-return controlling steps: first detecting out the heat exchanger temperature Tc-n of each indoor unit (2n) no matter whether the air conditioner is operated or not operated in the heating operation; then calculating the highest temperature Tc-max of the heat exchanger in the heat exchangers which is operating the indoor units and the largest heat exchanger temperature difference delta Tc-max in the heat exchanger temperature difference delta Tc-n between the heat exchanger temperature of each stopped indoor unit; adjusting the opening of the indoor expansion valve of the prescribed stopped indoor unit and executing oil-return controlling at the condition that the largest heat exchanger temperature difference delta Tc-max is larger than or equal to the prescribed threshold value delta-S.

Description

technical field [0001] The present invention relates to a multi-chamber air conditioner which connects a plurality of indoor units together to form a refrigeration cycle circuit and then performs heating operation. Background technique [0002] In the conventional multi-room air conditioner, when the compressor is started for heating operation in the presence of a stopped indoor unit, the amount of refrigerating machine oil flowing out of the compressor must first be judged based on the temperature of the compressor casing. How much, and when it is judged that the outflow is too much, the opening of the expansion valve of the indoor unit that is stopped is corrected (for an example, refer to Japanese Patent Laid-Open Publication No. 2003-287312). [0003] FIG. 6 shows a flow chart of operations in the multi-room type air conditioner in the above-mentioned Japanese publication. As shown in Fig. 6, when the compressor is started due to a certain indoor unit performing a heati...

AI Technical Summary

Problems solved by technology

[0004] However, in the above-mentioned conventional air conditioner, when the compressor is started in the heating operation state, the refrigerant in the stopped indoor unit also flows and releases heat, which hinders the increase of the condensing temperature in the initial stage of the heating operation.

Moreover, since the opening of the expansion valve will be corrected at the same time when starting, it is impossible to correct the difference in installation conditions such as the difference in the easy accumulation of refrigerating machine oil caused by the difference in the distance between the indoor unit and the outdoor unit, and the Considering the ease of storage of refrigerating machine oil due to the difference in height between units, the difference in room temperature of each indoor unit, the difference in the elapsed time after the start of operation, and the state of refrigerating machine oil stored in the indoor unit, there will be relatively close Although the refrigerating machine oil in the remote indoor unit can be recovered smoothly, it is difficult to recover the refrigerating machine oil in the remote indoor unit, or the oil cannot be recovered when the refrigerating oil must be recovered during operation

In such a case, the compressor is likely to fail

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