A power cycle concept uses water as a working fluid and the

A power cycle concept uses water as a working fluid and the heat source is hot water in a geologically active area. The rock and fluid around the boiler is at a temperature of 320 C and the waste heat is discharged to the atmosphere at 25 C. If the net work required by the power plant is 40 MW, do the following:

1. What is the maximum efficiency that could be expected of the plant?

2. What energy input is needed from the geological source?

3. What is the mass flow rate of the working fluid (water) required for the cycle if the process in the boiler serves to change saturated liquid to saturated vapor at 320 C?

4. Is this mass flow rate lower or higher than would be needed to achieve the phase change at 320 C in an actual power plant?

A power cycle concept uses water as a working fluid and the heat source is hot water in a geologically active area. The rock and fluid around the boiler is at a temperature of 320 C and the waste heat is discharged to the atmosphere at 25 C. If the net work required by the power plant is 40 MWdo the following: 1. What is the maximum efficiency that could be expected of the plant? 2. What energy input is needed from the geological source? 3. What is the mass flow rate of the working fluid (water) required for the cycle if the process in the boiler serves to change saturated liquid to saturated vapor at 320 c? 4. Is this mass flow rate lower or higher than would be needed to achieve the phase change at 320 C in an actual power plant? The = 25 C Turbine We= 40 MW Condenser NF (Pump Boiler Tource = 320 C

Solution

solution

maximum efficiency = 1 - Ta / Ts

= 1 - { ( 25 + 273) / ( 320 + 273) }

   = 49.75 %