Refrigerant circuit and method for operating it

Abstract

The present invention relates to a refrigerant circuit (10) and a method for operating such a circuit. A refrigerant circuit (10) of the generic type comprises a high-pressure section arranged downstream of a compressor (20) with a first line section (11A) and a second line section (11B), which in a first operating mode are traversed in parallel between a junction (12) and a connection point (13), wherein a heating heat exchanger (30) with an upstream first expansion valve (15A) is arranged in the first line section (11A) and an outdoor heat exchanger (40) with an upstream second expansion valve (15B) is arranged in the second line section (11B).The refrigerant circuit (10) according to the invention is characterized in that a fourth expansion valve (15D; 15E; 15H) is arranged in the first line section (11A) downstream of the first expansion valve (15A) or in the second line section (11B) downstream of the second expansion valve (15B). The method according to the invention is based on an opposing control of the opening degrees of the first expansion valve (15A) and the third expansion valve (15C) according to a target value of a first thermal parameter at the heat exchanger (30), as well as a simultaneous control of the opening degrees of the first expansion valve (15A) and the third expansion valve (15C) in response to a vertical temperature difference at the heat exchanger (30).

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