Conventional air conditioning system using mechanical compressor consumes more power. Alternative for this is use of vapor absorption refrigeration system which uses the chemical compression instead of mechanical compression which requires less power .As generator and pump are the only components consuming power in such system, such systems are more efficient. Implementing such system in car will increase the efficiency of car. Only part consuming energy is generator where heat is absorbed by the solution.Here heat of the exhaust gases can be used to heat up the solution.
System works as follows weak solution in generator is heated up in generator by means of exhaust gases.Here solution becomes concentrated(strong solution) this solution is then send to condenser where it condenses by means of air(or radiator liquid) .This strong solution then goes to evaporator after losing temp and pressure. In the evaporator it evaporates, here air (cooling air circulated to cabin) enters the evaporator loses heat(consequently temp ) and get cooled down and supplied to cabin. The solution in the evaporator is then sent to absorber where it get weakened. This weakened solution is then again pumped to generator by means of pump which operated by engine(or battery) and cycle gets completed.
As this system uses the heat energy of the exhaust gases which is anyway wasted the efficiency of the system is more and efficiency of car also increases.
Currently used absorber are not practical due to their large size however with help of modern technology it can be reduced in size. Further with use of sensors it is possible to control temperature and quantity of air entering the cabin.