Abstract: The performance of a thermal insulation for a building surface 6, subject to a thermal gradient emitting from the building interior, is enhanced by a neutral thermal gradient. For this purpose an electrical heating element 1 is adapted to release very low Wattages of thermal energy and is contained within an inner layer 4 and an outer layer 5 of thermal insulation. Adjusting the thermal efficiency of the insulation layers controls the magnitude of the thermal energy required to maintain the temperature of the element 1 at the equivalent temperature level to the building interior. The element 1 may be provided with a moisture controller and discharge sizeable quantities of thermal energy to dry moisture from the thermal insulation materials of the assembly.

Abstract: The performance of a thermal insulation for a building surface 6 (FIG. 1), subject to a thermal gradient emitting from the building interior, is enhanced by a neutral thermal gradient. For this purpose an electrical heating element 1 has means for releasing very low Wattages of thermal energy and is contained within an inner layer 4 and an outer layer 5 of thermal insulation. Adjusting the thermal efficiency of the insulation layers controls the magnitude of the thermal energy required to maintain the temperature of the element 1 at the equivalent temperature level to the building interior. The element 1 may be provided with a moisture controller and discharge sizeable quantities of thermal energy to dry moisture from the thermal insulation materials of the assembly.

Abstract: The performance of a turbine in a duct having a convergent and a divergent surface is enhanced by controlling the fluid flow pattern along the inner duct surface. For this purpose a free rotor redistributes part of the inner fluid stream through a ring into the outer stream to prevent premature separation of the inner stream from the divergent duct surface. The turbine and rotor are driven by distinct fluid streams that are separated by a duct.

Abstract: The preformance of a turbine (3) for harnessing energy from a fluid stream is enhanced by increasing the speed of fluid flowing over the blades of the turbine. For this purpose a rotor (9) is driven by the fluid stream and has means for extracting fluid from the downstream side of the turbine. The turbine (3) and rotor (9) are driven by distinct fluid streams, which are separated by a duct (1).