Alternative Fluids for Power Generation

In the search for an alternative fluid to water for large power plant, examination of basic properties discloses no other single fluid which advantageously covers the entire range of temperature from 1050° to 80°F, offers so high a heat drop per pound, or so low a boiler feed debit. Most alternative fluids have a lower sonic velocity. Discussion is therefore confined to three cases of substitution:(a)In a binary superposition cycle above steam.(b)In a binary subposition cycle below steam.(c)In low temperature recuperation applied to process heat or gas turbine exhaust heat.