THERMODYNAMICES

1. THERMODYNAMICES Presented by MUNASALA ANUSHA M.Tech, Assistant Professor DEPARTMENT OF MECHANICALENGINEERING VISAKHA INSTITUTE OF ENGINEERING & TECHNOLOGY

2. THERMODYNAMICES • THERMO--- HeatReleased • DYNAMICS ----- Mechanical Action For doingwork • The study of the effects of work, heat flow, and energy on a system • Movement of thermal energy • Engineers use thermodynamics in systems ranging from nuclear power plants to electricalcomponents. • Thermodynamics is the study of the effects of work, heat, and energy on asystem • Thermodynamics is only concerned with macroscopic (large- scale) changes andobservations

3. SYSTEM, SURROUNDING ,UNIVERSE • SYSTEM-Area under thermodynamicstudy • SURROUNDING – Area outside thesystem • Surface/Layer/Partition • UNIVERSE – System & together is calledUniverse Surroundings put

4. ISOLATED, CLOSED ANDOPEN SYSTEMS 4 Open System Both energy andmass can beexchanged. E.g. Gas turbine,I.C. Engine Isolated System Neither energynor mass can be exchanged. E.g. Thermoflask Closed System Energy, but not mass can beexchanged. E.g. Cylinder filled with gas &piston

5. THERMODYNAMICPROPERTIES • Thermodynamic Properties – It is measurable & Observable characteristics of thesystem. • Extensive: Depend on mass/size of system (Volume [V]),Energy • Intensive: Independent of systemmass/size (Pressure [P], Temperature[T]) • Specific: Extensive/mass (Specific Volume[v])

6. PRESSURE PRESSURE PRESSURE • P =Force/Area • Pa, Kpa,Bar,N/m2 • Types: • Absolute • Gage (Vacuum) • Atmospheric • Pabs =Patm +/-Pgauge

7. Volume Volume Volume • Three dimensional space occupied byan object • Unit- M3 , Liter 1m3 = 103 lit

8. Temperature Temperature TemperatureScale • Quantitative indication of Degree of Hotness & coldness of thebody. • Unit- 0C , K ,F • Thermometer • Thermometry

9. Internalenergy InternalEnergy Internal Energy[U] • Internal energy (also called thermal energy) is the energy an object or substance is due to the kinetic and potential energies associated with the random motions of all the particles that make itup. • Internal energy is defined as the energyassociated with the random, disordered motion of molecules. • Unit- KJ ,Joule

10. Enthalpy Enthalpy Enthalpy • Total Heat content of Body • Heat supplied to the body Enthalpy increases & decreases when heat is removed • Enthalpy is a measure of thetotal energyof a thermodynamic system.

11. Work • Work = Force x Displacement (Nm) (Joule) • Energy inTransient • Pathfunction • High gradeenergy • Workdonebythesystemonthesurrounding • -Positivework • Work doneonthesystembysurrounding– Negativework

12. HEAT • Energy transfer by virtue oftemperature difference • Transient form ofenergy • Pathfunction • Low gradeenergy • Negativeheat- heat transferred from thesystem ( heatrejection) • Positive heat – heat transferred fromsurrounding to system (heatabsorption)

13. HEAT HEAT CONCEPT • Energy transfer by virtue of temperaturedifference • Transient form ofenergy • Path function • Low gradeenergy • Negativeheat- heat transferred from the system ( heatrejection) • Positive heat – heat transferred from surrounding to system (heatabsorption) hot cold heat 26°C 26°C

14. Work &Heat WORK WORK • Work is the energy transferred between a system and environment when a net force acts on the system over adistance. • The sign of thework • Work is positive when the force is in the direction of motion • Work is negative when the force is opposite to the motion

15. LAWS OFTHERMODYNAMICS • FIRST LAW OFTHERMODYNAMICS (LAW OF ENERGYCONSERVATION) • SECOND LAW OFTHERMODYNAMICS • ZEROTH LAW OFTHERMODYNAMICS

16. Zeroth law ofthermodynamics

17. FIRST LAW OF THERMODYNAMICS • CONSERVATION OFENERGY • ALGEBRAIC SUM OF WORK DELIVERED BY SYSTEM DIRECTLYPROPOTOPNAL TO ALGEBRAIC SUM OF HEAT TAKEN FROMSURROUNDING • HEAT & WORK ARE MUTUALLYCONVERTIBLE • NO MACHINECAPABLEOFPRODUCING WITHOUT EXPENDITURE OFENERGY • TOTAL ENERGYOFUNIVERSE ISCONSTANT WORK

18. LIMITATIONS OF FIRST LAW OFTHERMODYNAMICS • Can’t give the direction of proceed can proceed- transfer of heat from hot body to coldbody • All processes involved conversion of heat into work & vice versa notequivalent. • Amount heat converted into work & vice versa • Insufficient condition for process tooccurs

19. HEAT RESERVOIR, HEAT SOURCE, HEATSINK • HEAT RESERVOIR- Source of infinite heat energy & finite amount of heat addition & heat rejection from it will not change itstemperature • E. g. Ocean, River, Large bodies of waterLake • HEAT SOURCE- Heat reservoirs which supplies heat to system is called heatsource • HEAT SINK- Heat reservoir which receivesabsorbs heat from thesystem

20. 2ND LAW OFTHERMODYNAMICS KELVIN –PLANCK’SSTATEMENT It is impossible to construct a machine whichoperates in cycle whose sole effectisto convert equivalent work heatinto amountof

21. 2ND LAW OF THERMODYNAMICS CLAUSIUSSTATEMENT CONCEPT STATEMENT • It is impossible to construct a machine which operates in cycle whosesole effectis to transfer heat from LTB to HTB without consuming externalwork

22. 2nd Law: Clausius and Kelvin Statements 22 • Clausius statement(1850) • Heat cannot by itself pass from a colder to a hotter body; i.e. it is impossibleto Q1 = Q2 =Q • build a “perfect” refrigerator. • The hot bath gains entropy, the cold bath losesit. • ΔSuniv=Q2/T2– Q1/T1= Q/T2– Q/T1< • 0. M is notactive. • Kelvin statement(1851) • No process can completely convert heat into work; i.e. it is impossible to build a “perfect” heatengine. • ΔSuniv= – Q/T <0. • 1st Law: one cannot get something for nothing (energy conservation). • 2nd Law: one cannot even break-even (efficiency must beless

23. HEATENGINE HEATENGINE HEATENGINE • Thermodynamic system/Device whichoperatein cycle converts the heatintouseful work.

24. HEATENGINE Efficiency = e =W/Qs W Qhot Qcold 1 Qcold e Qhot Qhot 1 Tcold Qhot e Carnot T hot Note:Thetemperaturesmust be measuredinKelvins!!!

25. HEATPUMP • Thermodynamic system/Device which operate in cycle convertsthe heat into usefulwork. Hot Reservoir, TH QH WORK P QC Cold Reservoir,TC

26. HEAT PUMP &REFRIGERATOR • HEATPUMP Hot Reservoir,TH Hot Reservoir,TH QH QH W W P R QC QC Cold Reservoir,TC Cold Reservoir,TC

27. Reversible Engine: the CarnotCycle 27 • Stage 1Isothermal expansion at temperature T2, while theentropy rises from S1 toS2. • The heat entering the systemis • Q2 = T2(S2 –S1). • Stage 2adiabatic (isentropic) expansion at entropy S2, whilethe temperature drops from T2 toT1. • Stage 3Isothermal compressionat temperature T1, while the entropy drops from S2 toS1. • The heat leaving the systemis • Q1 = T1(S2 –S1). • Stage 4adiabatic (isentropic) compression at entropy S1, whilethe temperature rises from T1 toT2. Since Q1/Q2 =T1/T2, η = ηr = 1 –T1/T2.

28. POWER PLANTENGINEERING PROF. S. S. BABAR (MECHANICAL ENGG.DEPT)

29. POWERPLANT • HYDROELECTRIC POWERPLANT • THERML POWERPLANT • NUCLEAR POWERPLANT • SOLAR POWERPLANT • WIND POWER PLANT • GEOTHERMAL POWERPLANT • TIDAL POWERPLANT

30. THERMAL POWERPLANT • COMPONENTS • 1. STEAMGENERATOR • 2. STEAMTURBINE • 3.GENERATOR • 4.CONDENSER • 5. FEEDPUMP

31. THERMAL POWERPLANT ADVANTAGES DISADVANTAGES • Plant set up timeis more • Large amount ofwater required • Pollution • Coal & ashhandling seriousproblem • High maintenancecost • Cheaper fuelsused • Less spacerequired • Plant near the load centers so less transmissioncost • Initial investment is less than otherplants

32. HYDROELECTRIC POWERPLANT

33. HYDROELECTRIC POWERPLANT COMPONENTS HYDRO- ELECTRICPLANT • RESERVOIR • DAM • TRASHRACK • GATE • PENSTOCK • TURBINE • GENERATOR • TAILRACE

34. HYDROELECTRIC POWERPLANT

35. HYDROELECTRIC POWERPLANT ADVANTAGES DISADVANTAGES • No fuelrequired • Nopollution • Running costlow • Reliable powerplant • Simple design& operation • Water sourceeasily available • Power dependson qty of water • Located awayfrom load center- transmission cost high • Setup time ismore • Initial cost -high

36. NUCLEAR POWERPLANT

37. NUCLEAR POWERPLANT

38. NUCLEAR POWERPLANT

39. Fission controlled in a NuclearReactor STEAM ControlRods Steam Generator Connect to Rankine Cycle (Heat Exchanger) Water FuelRods Coolant andModerator Pump Pressure Vessel andShield WPUI – Advances in Nuclear2008

40. NUCLEAR POWERPLANT ADVANTAGES DISADVANTAGES • Setup cost–more • Availability offuel • Disposal ofradioactive waste • Skilled manpower required • Cost of nuclearreactor high • High degree ofsafety required • Large amount of energy withlesser fuels • Lessspace • Nopollution • Cost of power generation isless

41. WIND POWERPLANT

42. WIND POWERPLANT • AIR IN MOTION CALLEDWIND • KINETIC ENERGY OF WIND IS CONVERTED INTO MECHANICALENERGY • K.E. = (M X V2)/2 • ROTOR • GEARBOX • GENERATOR • BATTERY • SUPPORTSTRUCTURE

43. WIND POWERPLANT

44. WIND POWERPLANT ADVANTAGES DISADVANTAGES • Low energydensity • Variable, unsteady, in termittentsupply • Location mustbe away fromcity • High initialcost • Nopollution • Wind free ofcost • Can be installedany where • Lessmaintenance • No skilledoperator required

45. SOLAR POWERPLANT

46. SOLAR POWERPLANT ADVANTAGES DISADVANTAGES • Freely &easily available • No fuelrequired • Nopollution • Lessmaintenance • No skilledman powerreq. • Dilutesource • Largecollectors required • Depends on weatherconditions • Not availableat night

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