Homework 4 Consider a steam power plant operating on the ideal regenerative Rankine cycle with one open feedwater heater. Steam enters the turbine at 15 MPa and 600C and is condensed in the condenser at a pressure of 10 kPa. Some steam leaves the turbine at a pressure of 1.2 MPa and enters the open feedwater heater. Determine the fraction of steam extracted from the turbine and the thermal efficiency of the cycle. 2 Boiler Open FWH 3 Pump II Pump I Turbine Condenser 4 5

a. Calculate the thermal efficiency and turbine-exit quality for an Ideal Rankine Cycle where the steam exits boiler at 5MPa, 450C and the condenser pressure is 15 kPa. Draw the systems and the Ts diagram for the process. b. Calculate also the thermal efficiency and turbine-exit quality if the system is modified to an Ideal Reheat Rankine Cycle where the reheat takes place at 1 MPa and the steam leaves the reheater at 500C. Draw the systems and the Ts diagram for the process and discuss your findings of these two systems.

show complete and step by step solution with ts diagram illustration. REGENERATIVE CYCLE AN ENGINE

It has been decided to operate a steam power station on a Rankine Cycle with a relativelyhigh condenser pressure of 8 bar so that the condenser cooling water can be used for adistrict heating scheme. The steam pressure and temperature at exit from the boiler are100 bar and 500 °C respectively. Neglect the power needed for the feed pump and assume the turbine operates isentropically. a) If 400 MW of power are required for the district heating, calculate the rate of steamrequired to flow through the condenser.b) What would be the net power (work rate) output from the plant? c) Calculate the cycle efficiency and comment on your result.

In a Rankine cycle, steam leaves the boiler and enters the turbine at 4 MPa and 400◦C. The condenser pressure is 10 kPa. Determine the cycle efficienc

It has been decided to operate a steam power station on a Rankine Cycle with a relativelyhigh condenser pressure of 8 bar so that the condenser cooling water can be used for adistrict heating scheme. The steam pressure and temperature at exit from the boiler are100 bar and 500°C respectively. Neglect the power needed for the feed pump and assume the turbine operates isentropically. a) If 400 MW of power are required for the district heating, calculate the rate of steamrequired to flow through the condenser.b) What would be the net power (work rate) output from the plant?c) Calculate the cycle efficiency and comment on your result.

a b

SITUATIONAL PROBLEM NO II In a reheat cycle steam at 8.0MPA and 485degC enters the turbine and expands to 1.4MPA. At this point, the steam is withdrawn and passed through a reheater. It reenters the turbine at 1.3 MPa and 720degC. Expansion now occurs to the condenser pressure of 0.0006MPa. For the cycle and 1kg of steam determine: 4. Heat added 5. Work Turbine 6. Work Net Thermal Efficiency 7.

An Ideal Reheat Cycle , steam enters the high pressure turbine at 750 psia and 800F and leaves at 100 psia. It is then reheated to 800F, passes through the low pressure turbine and exhausts to a condenser at 1 psia. Find the thermal efficiency of the cycle in %. From Steam Table h1 =1401.5 Btu/lb  h2 =1189.96 Btu/lb h3 =1429.8 Btu/lb h4 = 1031.13 Btu/lb h5 = 69.72 Btu/lb h6 = 72.09 Btu/lb (include the diagram)

AN ELECTRIC POWER PLANT OPERATES BASED ON A RANKINE CYCLE IDEAL STEAM REGENERATIVE WITH TWO FEED WATER HEATERS AND OVERHEATING. STEAM ENTERS THE TURBINE AT 15 MPa AND 600 C AND ESCAPE TOWARDS CONDENSER AT 6 kPa. THE STEAM IS SUPERHEATED TO 0.8 MPa AND 500C. ONE IS MADE STEAM EXTRACTION FROM THE TURBINE AT 1.4 MPa TO A CLOSED WATER HEATER FEED AND CONDENSATE FROM THIS HEATER IS THROTTED AND DELIVERED TO OPEN FEEDWATER HEATER; STEAM EXTRACTION OF THE TURBINE TO THE OPEN FEEDWATER HEATER IS CARRIED OUT AT 0.4 MPa. THE TURBINE DEVELOPS A POWER OF 100 MW. DETERMINE: a) DRAW THE T-s AND EQUIPMENT DIAGRAMS b) THE THERMAL EFFICIENCY OF THE CYCLE. c) THE FLOW OF WATER NECESSARY TO CONDENSE THE STEAM THAT ENTERS THE CONDENSER, IF THE WATER FOR IT ENTERS AT A TEMPERATURE OF 22C AND SALE WITH AN INCREASE OF 10 DEGREES. d) THE MASS FLOW OF STEAM THROUGH THE STEAM GENERATOR FOR AN OUTPUT OF POWER IN THE TURBINE OF 100 MW.