Abstract: An accumulator for an air-conditioning (refrigeration or heat pump) system is designed to reduce flooding due to greater effective internal volume while at the same time incorporating an internal heat exchanger for better system performance, and providing better evaporation and controlled thermal properties. The accumulator embodies an outer housing that co-axially surrounds an inner liner. The inlet directs the refrigerant into the inner volume formed by the liner, wherein the liquid refrigerant and compressor oil are contained and insulated from the wall of the outer housing. A heat exchanger is arranged in the annular space between the outer housing and the inner liner and circulates a flow of condensate therethrough before delivering it to the expansion device. In this way the condensate is cooled for higher performance and at the same time refrigerant passing out of the accumulator is vaporized more completely.