Power Conversion Systems of the 21st Century

A review of the experience with power conversion systems during the past 15 centuries provides a basis for speculating on the nature of the systems that will predominate in the 21st century. Exhaustion of our fossil fuel reserves coupled with cost considerations will overcome emotional objections and lead to the use of nuclear fission and fusion as our prime energy sources. To obtain a high thermal efficiency it appears that the power conversion systems best suited to use with fission or fusion reactors will employ a potassium or cesium vapor topping cycle operating with a turbine inlet temperature of 1,400°F - 2,000°F (760°C - 1,100°C) that will reject its heat at around 1,000°F (540°C) to a conventional steam system. The latter in turn will reject its heat at around 300°F (150°C) for use in industrial processes and district heating systems. Excess waste heat will be employed to distill sewage to provide freshwater, and to evaporate sewage sludge to dryness and sterilize it for use as fertilizer.