Utilizing your understanding of the First Law of Thermodynamics, consider two tu
ID: 2078583 • Letter: U
Question
Utilizing your understanding of the First Law of Thermodynamics, consider two turbines: one open flow and one closed flow. Superheated water (a pure substance) is demonstrated throughout each individual turbine.
The initial pressure is 0.40MPa and the initial temperature is 700C in both systems.
The heat loss from the closed system is half that of the open system.
The temperature for the open system is reduced by 100C and pressure is reduced by 25% at the second point value.
The pressure increases to 0.60MPa at the second point value for the closed system.
This increase in pressure compensates for the heat loss allowing the temperature to remain constant throughout the closed system.
1. Using the Superheated Water Tables, consider that the superheated water used in both systems is an ideal gas, what is the specific volume of the two systems at the second point value for each system.
2. Which of the systems is isothermal?
3. Calculate the coefficient of pressure for the adiabatic system.
Explanation / Answer
1. For open system: W=-integral(v.dp)
=> h1-h2 = v×(p1-p2)
=> 2857-2639= v× (1-.75)×0.4×E-6
=> v= 0.013 kg/m3.
for closed system v2/v1= (p2/p1)^(1/1.013)
2. closed system is isothermal as internal energy will remain constant.
3. efficiency will be 1-(T2/T1) = 1-(873/973) = 10.27%
4. COP will be higher if it is operated as a heat pump and it will be 973/(973-873) = 9.73 compared to 8.73 COP of refrigerator.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.