[en] A suction-liquid heat exchanger for a heat pump is provided by utilizing an inner vessel as a suction line accumulator together with a surrounding high pressure outer vessel which is utilized as a receiver in the liquid line. Heat from the liquid refrigerant in the outer vessel is transferred to the cooler liquid accumulated in the inner vessel to vaporize it, preventing slugs of liquid refrigerant from entering the compressor. The exit and entry ports of the outer vessel are at different levels. This causes a greater amount of liquid refrigerant to remain in the outer vessel on heating mode operation than on reverse flow for cooling, thereby increasing the heat transfer to the accumulator as required for the greater volume of liquid in the suction line gas and compensating for the decreased quantity of refrigerant needed for heating