engine statement of 2nd Law: - Impossible for sup to have n= = (100% off (Kelvin's) - Imp for any process to have Usas its site a result the transfer of heat from cooler object to warmer object (Claussius) Energy offi ciency of Cycle is independent of working subs. Any cyclic process that absorbs heat at reversible one temp Cy rejectes heat at another temp. Cy is has energy efficiency of carnot cycle. Thermal devices or thermal machines are me of the application Heat pumps to produce heating Refrigerators to produce corling Steam turbines used in ships. Compustion engines of combustion vehicles Rxn turbines of aircraft. Refrigeration, ACs Cy Heat Pump Heat engines operating in reverse By dring work, heat extracted from old reservoir up exhausted to hit reservoir
Intensive, temp, brilling pt. Extensive, weight, length State ) Tmp,P, U(int 6), H(enthalpy) etc. Path W(workdone), , q(heat transf.) etc. fun U . State the Cy extensive prop. of system Changes when Eis transferred ents or out the s ps. in form of heat/work WD dW when system expands by dv against Per dw= - Pex dv Vf W2 - Pender Systemdring vi work on surrounding Thermo process is reversible. if process can be turned back such that both system Cy surroundings return to their og states, with no change anywhere else in universe. In reality, no such process exist. A change can be reversed by in finitisinal modification of a variable.
dg. Thermal eg. of 2 systems with same temp. If temp of either system is lowened intiniterially then energy Hours ink the system with lower temp. raised, flows out of hotter eg Reversible expansion Suppose gas is contined by piston, Per P of confined gas its surroundings 'cause an infinitesimal such a system is in mechanical eg. with change in ext. P in either direction causes changes in V in opp. directions dw 2 -Pex dV= -pdv W2 - p dv Vi 2 systems in thermal eq. if no net when flow of heat(themal energy) between them they are connected by a path permeable to heat. Zeroth Law Two systems use Third the two with each other