1. \ ME 200 L32 Today’s Class 8.3 Exams not picked up this week may be recycled! \ ME 200 L32 Utility Power Generation Self Study Assignment 8.2 Today’s Class 8.3 Kim See’s Office ME Gatewood Wing Room 2172 Examination 3 grades are available Blackboard and Examinations can be picked up all of this week from Gatewood Room 2172 Exams not picked up this week may be recycled! https://engineering.purdue.edu/ME200/ ThermoMentor © Program Spring 2014 MWF 1030-1120 AM J. P. Gore gore@purdue.edu Gatewood Wing 3166, 765 494 0061 Office Hours: MWF 1130-1230 TAs: Robert Kapaku rkapaku@purdue.edu Dong Han han193@purdue.edurkapaku@purdue.eduhan193@purdue.edu

2. 2 Outline Rankine Cycle (with Improved Performance) –Will introduce base-line Rankine Cycle while introducing Superheating and Open feed water heating –Reheating- will mention but leave for you to explore –Supercritical- will mention but leave for you to explore –Closed feed water heating- will mention but leave for you to explore –Multiple feed water heating- will mention but leave for you to explore

3. Regenerative Vapor Power Cycle Using an Open Feed-Water Heater ► See T-s diagram: Open feed-water heater and high pressure pump move the material to 7. So heat transfer to the cycle takes place from state 7 to state 1, rather than from state a to state 1- increasing the average temperature of heat addition &  Carnot T avg (a-1) T avg (7 - 1)

4. Regenerative Vapor Power Cycle Using an Open Feed- Water Heater ►Follow a unit of mass as it moves through the cycle. The unit of mass is denoted in parentheses by (1). ► (1) enters turbine at state 1 and expands to state 2 where a fraction (y) is extracted into the open feed-water heater. ►Remaining (1-y) expands through the second turbine stage to state 3, is condensed to state 4, and then pumped to state 5 where it enters the open feed-water heater. (1)(1-y) (y)(y)

5. Regenerative Vapor Power Cycle Using Open Feed-Water Heater ► (y) and (1-y) entering the feed-water heater at states 2 and 5, respectively, mix, giving a single stream at state 6 and recovering the unit mass (1). ►Unit mass (1) at 6 is pumped to state 7 and fed to the steam generator and boiled and superheated to state 1 by external heat addition (1) (1-y) (y)(y)

6. ►With fraction y known, mass and energy rate balances applied to control volumes around the other components yield the following expressions, each on the basis of a unit of mass entering the first turbine stage. Mass, Energy, Entropy Balance Equations ►Applying steady-state mass, energy and entropy balances to the feed-water heater, the fraction of the total flow y is

7. ► For the pumps ► For the steam generator ► For the condenser ► For the turbine stages Mass, Energy, Entropy Balance Equations Apply second law to all components as a class exercise.

8. Cogeneration Systems ►Are integrated systems that simultaneously yield two valuable products, electricity and steam (or hot water) from a single fuel input. ►Typically provide cost savings relative to producing power and steam (or hot water) in separate systems. ►Are widely deployed in industrial plants, refineries, food processing plants, and other facilities requiring process steam, hot water, and electricity. ►Can be based on vapor power plants, gas turbine power plants, internal combustion engines, and fuel cells.

9. Cogeneration Systems ►An application of cogeneration based on vapor power plants is district heating – providing steam or hot water for space heating together with electricity for domestic, commercial, and industrial use. Steam exported to the community Electricity provided to the community

10. Cogeneration Systems ►Exporting useful steam to the community limits the electricity that also can be provided from a given fuel input, however. ►For instance, to produce saturated vapor at 100 o C ( 1 atm) for export to the community water circulating through the power plant will condense at a higher temperature and thus at a higher pressure. ►In such an operating mode thermal efficiency is less than when condensation occurs at a pressure below 1 atm, as in a plant fully dedicated to power production. T > 100 o C p > 1 atm