Abstract: The invention relates to a heating, ventilating and/or air conditioning system with a main air conditioning loop (10) for a refrigerant including at least one compressor (11), a condenser (12), an expansion device (13) and an evaporator (14), a cold storage heat exchanger (21) suitable for storing cold during operation of the compressor (11), and a secondary air-conditioning loop (20a) comprising the cold storage heat exchanger (21). The secondary air-conditioning loop (20a) is suitable to cool the evaporator (14) when the compressor (11) is out of operation. The secondary air-conditioning loop (20a) includes a fluid circulation branch disposed in parallel with a main air conditioning loop (10) common section including at least the evaporator (14). The fluid circulation branch contains a cold production element (21) able to cool the refrigerant toward the evaporator. The invention is particularly dedicated to heating, ventilating and/or air conditioning systems in “Stop and Start” cars.