Solar power augmented heat shield systems

A dual air cavity roof has a continuous upper cavity which is cooled by fans, while the lower cavity is generally sealed. Preferably the cavities are separated by a radiant barrier. The fans are preferably powered by one or more photovoltaic cells that are also disposed on the roof. The roof can be pre-cooled with cooler night air and fans only activated when necessary to remove heat from the solar load on the upper cavity. When it is desirable to remove heat, the fan speed is optimized in each zone of the roof to enhance the natural convective flow to the optimum level. A radiant barrier can also cover the roof substrate, which is optionally an existing roof that is in need of repair. The roof structure is preferably assembled in parallel modules using insulating support brackets that support the outer surface and the barrier that separates the upper and lower cavity.