Its a differance in design depending how the car maker designs the a/c system. To protect the A/C compressor from any liquid slugging, an A/C accumulator is used in this A/C system to retain any refrigerant that may exit from the evaporator in a liquid state. The accumulaor typically has a drier material bag inside it to absorb moisture. Systems that have a reciver drier are located at condensor and has a basic purpose to absorb moisture only. I think the Dodge Caliber uses the accmulator design system.