140 likes | 293 Views
Realization of A Cycle. P M V Subbarao Professor Mechanical Engineering Department I I T Delhi. How to Create Temperature and Pressure…..?. Power Generation Cycle. Goal: To generate Mechanical Power through from heat input !!! Question: What is the Upper Limit of Cycle Performance?
E N D
Realization of A Cycle P M V Subbarao Professor Mechanical Engineering Department I I T Delhi How to Create Temperature and Pressure…..?
Power Generation Cycle Goal: To generate Mechanical Power through from heat input !!! Question: What is the Upper Limit of Cycle Performance? Can You Predict? Is it essential to try and find out using only on the field Test?
expansion Heat Addition Heat Removal A Mathematical Model for (James Watt’s) Steam Engine
Carnot’s Model for Power Cycle s 1 – 2 : Compressor : Isentropic Compression : s2 = s1 2 – 3 : Boiler: Isothermal Heating : T3 = T2 3 – 4 : Turbines : Isentropic Expansion : s4 = s3 4 – 1 : Condenser: Isothermal Cooling : T1 = T4
The Carnot Cycle Vs The Natural Cycles Ability to Perform Ecological Nuisance
Realization of A Cycle • Heat Addition in Steam Generator, qin • Creation of Parameters of A Cycle • Resource: Sources of Energy • Mean Effective Temperature of heat addition : Entropy averaged Temperature.
Efficiency, Analysis of A Cycle • Net work out put = • Heat Input =
The selection of working fluids and operation conditions are very important to system performance. • The thermodynamic properties of working fluids will affect the system efficiency, operation, and environmental impact. • Basically, the working fluid can be classified into three categories. • Those are dry, isentropic, and wet depending on the slope of the T–S curve (dT/dS) to be positive, infinite, and negative, respectively. • The working fluids of dry or isentropic type are more appropriate for power generation. • This is because dry or isentropic fluids are superheated after isentropic expansion, thereby eliminating the concerns of impingement of liquid droplets on the turbine blades. • Moreover, the superheated apparatus is not needed.
Organic Substances must be selected in accordance to the heat source temperature level (Tcr < Tin source)
Selection of Fluids • RC (Single Componant Working Fluid) • Evaporation and condensation at fixed temperatures • Fluid must be selected in accordance to the temperature level of the heat source • Pinch point is limiting factor for heat transfer • Environmental impacts and restrictions by using organic substances • Inflamable and/or toxic and/or GWP (Global Warming Potential) and/or ODP • (Ozone Depletion Potential)