Phase change material evaporator charging control

A method (300) of controlling an air conditioning compressor in a heating ventilation and air conditioning system having an evaporator (10) including a phase change material is presented. The method (300) includes the steps of measuring an evaporator (10) output air temperature (312), determining a state of charge value (106) by calculating a difference between an estimated refrigerant temperature based on the evaporator (10) output air temperature and a phase change material freeze temperature and integrating this difference over time (316) and operating the air conditioning compressor to maintain the state of charge value (106) between an upper and lower limit (324, 328). A method (200) of recovering braking energy in a vehicle containing a heating ventilation and air conditioning system having the evaporator (10) including the phase change material is also presented.