A refrigeration system includes a compressor for driving a refrigerant along a flow path in at least a first mode of system operation; a first heat exchanger along the flow path downstream of the compressor in the first mode; a second heat exchanger along the flow path upstream of the compressor in the first mode; and an expansion device in the flow path downstream of the first heat exchanger and upstream of the second heat exchanger in the first mode, wherein the second heat exchanger includes a combined header and accumulator for collecting liquid and vapor refrigerant.
