The invention relates to a thermal conditioning circuit (1) comprising a condenser (4), a compressor (2), an internal heat exchanger (6), an evaporator (10), and a pressure reducer (8) arranged upstream of the evaporator (10). According to the invention, the internal heat exchanger (6) is oversized such that the cooling fluid (FR) is overheated at the outlet of the internal heat exchanger (6) and not at the outlet of the evaporator (10).