Why is Carnot cycle more efficient than Rankine cycle?
Energy rejection The thermal efficiency of a Rankine cycle is lower then that of a Carnot cycle operating between the same temperature levels. This is primarily because of the fact that the energy transfer as heat in the boiler does not take place at constant temperature in the Rankine cycle.
What is the advantage of Rankine cycle?
To increase its power output, a reheater is used between the HP and LP turbines. Advantages: The advantages of using a reheat cycle are higher thermal efficiency, reduced feed water pump power, smaller condenser, smaller boiler, long life of the turbine and less handling of the fuel and firing requirement.
Is Carnot cycle the most efficient?
The most efficient heat engine cycle is the Carnot cycle, consisting of two isothermal processes and two adiabatic processes. The Carnot cycle can be thought of as the most efficient heat engine cycle allowed by physical laws.
What is the difference between a Rankine cycle & a Brayton cycle?
Rankine cycle is a steam engine, the water is boiled, evaporated, used for work and then condensed for re-use, thus making it a closed cycle. The working fluid undergoes a phase change in the Rankine cycle whereas in Brayton cycle there is no phase change the working fluid always remains in the gaseous phase.
What are the four process of Rankine cycle?
The four processes of an ideal Rankine cycle are as follows; Process 1-2: Isentropic compression in a pump. Here the working fluid is pumped from low to high pressure. 2-3: Constant pressure heat addition in the boiler….Thank you.
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Is a Carnot cycle reversible?
The reversible Carnot cycle provides an upper limit for the heat engine. In the Carnot cycle, the greatest possible share of the heat produced by combustion is converted into work. The Carnot process consists of two isothermal and two isentropic steps.
What is difference between Rankine and actual Rankine cycle?
The efficiency of the ideal Rankine cycle is close to the efficiency of the Carnot Cycle…. Difference Between Ideal and Actual Rankine Cycle….What is difference between Rankine and actual Rankine Cycle?
|Rankine Cycle Representation is as follows on P-v and T-s diagrams:|
|Ideal Rankine Cycle||1-2′-b-3′-4′-1|
|Actual Rankine Cycle||1-2-b-3-4-1|
Is Carnot engine 100 efficient?
In order to achieve 100% efficiency (η=1), Q2 must be equal to 0 which means that all the heat form the source is converted to work. The temperature of sink means a negative temperature on the absolute scale at which the temperature is greater than unity.
Why is Carnot cycle Impossible?
In real engines, the heat transfers at a sudden change in temperature whereas in a Carnot engine, the temperature remains constant. In our day to day lives, reversible processes can’t be carried out and there is no such engine with 100 % efficiency. Thus, the Carnot cycle is practically not possible.
Is Brayton and Rankine cycle more efficient?
Suppose that the gas turbine cycle has an efficiency of 40%, which is a representative value for current Brayton cycle gas turbines, and the Rankine cycle has an efficiency of 30%. The combined cycle efficiency would be 58%, which is a very large increase over either of the two simple cycles.
What is the ideal Rankine cycle?
The Rankine cycle is the ideal cycle for vapor power plants; it includes the following four reversible processes: 1-2: Isentropic compression Water enters the pump as state 1 as saturated liquid and is compressed isentropically to the operating pressure of the boiler.
What is Carnot cycle principle?
Carnot’s theorem, developed in 1824 by Nicolas Léonard Sadi Carnot, also called Carnot’s rule, is a principle that specifies limits on the maximum efficiency any heat engine can obtain. The efficiency of a Carnot engine depends solely on the temperatures of the hot and cold reservoirs.
What is the working principle of a Carnot cycle?
In a Carnot cycle, the working substance is subjected to a cyclic operation consisting of two isothermal and two adiabatic processes. The engine developed by Carnot has air (which is assumed to work as a perfect gas) as its working substance enclosed in a cylinder, in which a frictionless piston A moves.
What is Carnot cycle and its efficiency?
The Carnot cycle is a theoretical ideal thermodynamic cycle proposed by French physicist Nicolas Léonard Sadi Carnot in 1824 and expanded upon by others over the next few decades. It provides an upper limit on the efficiency that any classical thermodynamic engine can achieve during the conversion of heat into work, or conversely, the efficiency of a refrigeration system in creating a temperature difference by the application of work to the system. It is not an actual thermodynamic cycle but is
What does Rankine cycle mean?
The Rankine cycle or Rankine Vapor Cycle is the process widely used by power plants such as coal-fired power plants or nuclear reactors. In this mechanism, a fuel is used to produce heat within a boiler, converting water into steam which then expands through a turbine producing useful work.
What is the efficiency of a Rankine cycle?
Therm a l Efficiency of Rankine Cycle: The thermal efficiency of the Rankine cycle is the ratio between the work produced by the steam turbine that has been reduced by the pump work, with the incoming heat energy from the boiler. The heat energy from the fuel is transferred to the working fluid i.e. water.