1. An automobile air conditioning system comprising generally a regenerator, a segregator, a condenser, an evaporator, and absorber, a heat exchanger and a plurality of conducts inter-communicated thereinbetween to form a cool air production system thereof, the improvement being characterized in adaptation of a coil tube helically wound on the outer periphery of the main portion of an exhaust pipe and utilizing the residual heat of the waste gas generated by engine to vaporize the liquidized refrigerant NH.sub.3 for said system instead of a compressor; said system further comprising: a pair of first and second capillary tubes, said first capillary tube being connected in-between said segregator and said condenser; said second capillary tube being connected in-between said condenser and said evaporator; a tubular network, said tubular network being disposed beneath the roof panel and the bonnet of an automobile and connected respectively with said segregator and said condenser; a three way tube, said tube being adapted to join the vapors from said segregator and said tubular network and lead them to said condenser; a control valve, said valve being adapted to control the heat vapor from said segregator to said evaporator; A check valve, said valve being adapted to lead the mixture of liquidized refrigerant NH.sub.3 to said regenerator and prevent said refrigerant NH.sub.3 from retaining to the absorber; When said liquidized refrigerant NH.sub.3 supplied from said regenerator having been vaporized by heat from said exhaust pipe and flows upwards into said segregator via said coil tube for a process of separation, then a separated hot vapor flows via said first capillary tube and joins at said three way tube with the vapor coming from said tubular network together into said condenser, said hot vapor being condensed therein prior to becoming drops to enter into said evaporator via said second capillary tube for vaporization and producing cooled air therein; said vapor inside said evaporator having further been absorbed into said absorber and mixed therein with NH.sub.3 which is separated out of said segregator via said heat exchanger; a mixture of said liquidized refrigerant NH.sub.3 inside said absorber being led to said regenerator via said check valve for continuous supply to said coil tube, circulation for cool air production being therefore completed.