A wind turbine generator (10) includes a tower (12), a nacelle (14) rotatably mounted to the tower (12), the nacelle having a longitudinal axis and being configured to align the longitudinal axis with the direction of the incoming wind during operation of the wind turbine generator (10), one or more heat-generating components (22) housed in the wind turbine generator (10), and a containerized HVAC module (26) mounted on a roof (31) of the nacelle (14) and operably connected to the one or more heat-generating h components (22) for cooling the heat-generating components (22). The module (26) includes a shipping container (30) having a floor (32), a roof (34), a pair opposed longer side walls (36), a pair of opposed shorter end walls (38), and a longitudinal axis, the longitudinal axis of the shipping container (30) being oriented generally perpendicular to the longitudinal axis of the nacelle (14), the shipping container (30) having at least one heat exchanger (40) therein.

A set of units for assembly to form a wind turbine nacelle. The nacelle comprises a rotor-supporting assembly and generator, and a power conversion assembly and the set of units comprises a main unit arranged to be connected to a wind turbine tower and housing the rotor-supporting assembly and the generator, and at least two different auxiliary units each housing an operative component forming part of the power conversion assembly. To allow different wind turbine configurations, one of the auxiliary units can be selected from the at least two auxiliary units and assembled with the main unit to form the nacelle.