A transport refrigeration unit comprising: a compressor configured to compress a heat transfer fluid; a condenser disposed downstream of the compressor, the condenser configured to condense the heat transfer fluid from a gaseous state to a liquid state; an expansion device disposed downstream of the condenser, the expansion device configured to release pressure of the heat transfer fluid; a first flow control device disposed downstream of the condenser, the first flow control device configured to direct the heat transfer fluid downstream of the expansion device; a first evaporator disposed downstream of the expansion device and the first flow control device; a second evaporator disposed downstream of the expansion device and the first flow control device, wherein the second evaporator includes a thermal accumulator (305, 435, 520, 660, 665, 735, 835); a second flow control device disposed downstream of the first evaporator and upstream of the compressor; characterized in that the transport refrigeration unit further comprises: a third flow control device disposed downstream of the second evaporator and upstream of the compressor, wherein the transport refrigeration unit is configured to operate in a first series mode such that the first flow control device, the second flow control device, and the third flow control device are controlled to direct the flow of heat transfer fluid from an outlet of the first evaporator to an inlet of the second evaporator, and wherein the transport refrigeration unit is configured to operate in a second series mode such that the first flow control device, the second flow control device, and the third flow control device are controlled to direct the flow of heat transfer fluid from an outlet of the second evaporator to an inlet of the first evaporator. a compressor configured to compress a heat transfer fluid; a condenser disposed downstream of the compressor, the condenser configured to condense the heat transfer fluid from a gaseous state to a liquid state; an expansion device disposed downstream of the condenser, the expansion device configured to release pressure of the heat transfer fluid; a first flow control device disposed downstream of the condenser, the first flow control device configured to direct the heat transfer fluid downstream of the expansion device; a first evaporator disposed downstream of the expansion device and the first flow control device; a second evaporator disposed downstream of the expansion device and the first flow control device, wherein the second evaporator includes a thermal accumulator (305, 435, 520, 660, 665, 735, 835); a second flow control device disposed downstream of the first evaporator and upstream of the compressor; characterized in that the transport refrigeration unit further comprises: a third flow control device disposed downstream of the second evaporator and upstream of the compressor, wherein the transport refrigeration unit is configured to operate in a first series mode such that the first flow control device, the second flow control device, and the third flow control device are controlled to direct the flow of heat transfer fluid from an outlet of the first evaporator to an inlet of the second evaporator, and wherein the transport refrigeration unit is configured to operate in a second series mode such that the first flow control device, the second flow control device, and the third flow control device are controlled to direct the flow of heat transfer fluid from an outlet of the second evaporator to an inlet of the first evaporator. a third flow control device disposed downstream of the second evaporator and upstream of the compressor, wherein the transport refrigeration unit is configured to operate in a first series mode such that the first flow control device, the second flow control device, and the third flow control device are controlled to direct the flow of heat transfer fluid from an outlet of the first evaporator to an inlet of the second evaporator, and wherein the transport refrigeration unit is configured to operate in a second series mode such that the first flow control device, the second flow control device, and the third flow control device are controlled to direct the flow of heat transfer fluid from an outlet of the second evaporator to an inlet of the first evaporator.