A transport refrigeration system for an interior space of a cargo container, wherein the cargo container comprises opposed side walls, a front wall, a top wall, a bottom wall and at least one door attached on hinges at a rear wall, the transport refrigeration system being configured to be integrated into the cargo container at a front and a top interior cavity (200, 245) and comprising: an evaporator coil and an evaporator fan residing within the interior space, the evaporator coil being configured for refrigerating the interior space, the evaporator fan being positioned to receive air flow from the interior space along a path at the top wall and to direct the air flow over the evaporator coil to the interior space along another path at the bottom wall; an evaporator fan motor coupled to the evaporator fan along an axial shaft, the evaporator fan motor residing within a first interior cavity, the first interior cavity being in fluid communication with an ambient environment; a condenser coil and a condenser fan disposed adjacent to the evaporator fan motor; an insulation panel that separates the evaporator fan motor from the evaporator fan; another insulation panel located between the first interior cavity and the interior space, the other insulation panel being configured for thermally separating the interior space from the first interior cavity; at least one perforated panel located between the first interior cavity and the ambient environment, the at least one perforated panel being configured for causing ambient air to enter the first interior cavity; wherein the condenser coil and condenser fan reside within a second interior cavity, the second interior cavity being in fluid communication with an ambient environment; wherein the first interior cavity is a top cavity formed by the top wall of the cargo container and the perforated panel and the second interior cavity is a front cavity formed at the front wall of the cargo container. an evaporator coil and an evaporator fan residing within the interior space, the evaporator coil being configured for refrigerating the interior space, the evaporator fan being positioned to receive air flow from the interior space along a path at the top wall and to direct the air flow over the evaporator coil to the interior space along another path at the bottom wall; an evaporator fan motor coupled to the evaporator fan along an axial shaft, the evaporator fan motor residing within a first interior cavity, the first interior cavity being in fluid communication with an ambient environment; a condenser coil and a condenser fan disposed adjacent to the evaporator fan motor; an insulation panel that separates the evaporator fan motor from the evaporator fan; another insulation panel located between the first interior cavity and the interior space, the other insulation panel being configured for thermally separating the interior space from the first interior cavity; at least one perforated panel located between the first interior cavity and the ambient environment, the at least one perforated panel being configured for causing ambient air to enter the first interior cavity; wherein the condenser coil and condenser fan reside within a second interior cavity, the second interior cavity being in fluid communication with an ambient environment; wherein the first interior cavity is a top cavity formed by the top wall of the cargo container and the perforated panel and the second interior cavity is a front cavity formed at the front wall of the cargo container.