An accumulator is used with fixed orifice tube systems and a receiver drier is used with the TXV or thermostatic expansion valve type system. They both contain a desiccant bag. The desiccant absorbs and stores any moisture that would contaminate the refrigerant. HVAC Depot carries the highest-quality accumulators from leading manufacturers such as Carrier, Emerson, Lennox, Nordyne, Trane, and many, many more.