Refrigerant Circuit And Method Of Controlling Such A Circuit

A refrigerant fluid circuit for thermally conditioning a cabin of a vehicle, comprising:

• a first branch in which are installed in series at least one compressor and an interior exchanger designed to ensure thermal exchange between the refrigerant fluid and an interior air stream, to be dispatched into the cabin,
• a second branch in which are installed in series at least one first means of control of the circulation of the refrigerant fluid in said second branch, a first expansion member and an evaporator,
• a third branch in which are installed in series at least one second expansion member and an exterior exchanger designed to ensure thermal exchange between the refrigerant fluid and an exterior air stream, arranged outside the cabin,
• said first branch being in series with the second branch and the third branch, said second branch being in parallel with said third branch,
• a means for placing the third branch in communication with the second branch, said means being installed between a sector of the third branch situated downstream of the exterior exchanger and a portion of the second branch situated upstream of the first expansion member.