This is a discussion about the completion of the crash course in steam (http://openfarmtech.org/wiki/Crash_Course_in_Steam)

question:
Tell me how much energy is required to convert water to steam at a certain temperature and pressure:

Answer:

Starting with 1 kg of water @ 25°C, 0.1 Mpa to steam @ 400°C 1.5 Mpa*(400°C may be to high, but...)

enthalpy of 1 kg of water @ 25 C 0,1Mpa ( H1) = 104.86 kj

enthalpy of 1 kg of saturated steam @ 198 C 1,5Mpa ( H2) = 2789.88kj

Energy necessary to raise the temperature of the steam to 198 to 400 C = (400-198) x 2.819 = Q1 = 570Kj


energy required is: (H2 - H1) + Q1= 3255 kj = 0,57kwh


1. How much steam (400°C 1.5 Mpa) can be generated from a given energy ?

= (1/0,57)kg/kwh = 1,75kg/kwh


2. How much time it will take to do #1 if you know the rate of energy input (power input)

(1,75 x P) kg/h, where P = power in kw


3. How much solar steam you should generate from a certain rate of solar power input

depends on the termal eficiency of the solar boiler >>. Let's assume 80%

so, 0.8 x (1,75 x P) kg/h


4. How much power is obtained from the steam you generate when running through the engine.

Depends on a lot of parameters for the engine, but let's assume a 10% eficiency.


resulting power is 0.1 x 0.8 x Sp; where Sp =solar power in kw


comments?