Insulation System and Thermal Design of a Hermetically Sealed Turbo-Generator Operating in a Small-Power CHP Plant

Small CHP plants within the range of one megawatt electric power and a few megawatts thermal power might be well suited in supplying heat and electricity for small communities. Hermetically sealed turbo-generator improves the cost-effectiveness of such small-power CHP plants. In such a structure, the low pressure, low temperature steam from the turbine flows through the air-gap of the generator. On the other hand, a hermetically sealed turbo-generator sets very high demands for the generator design. Steam in the air-gap is a substance, which traditional insulating materials cannot tolerate. Also, the thermal design of the machine requires special attention. This paper introduces a turbo-generator design with steam-resistant insulation system and proper thermal design to operate in a hermetic small-power CHP plant.