What is effectiveness of a regenerator?

The effectiveness of a regenerator is the ratio between actual heat transfer from the exhaust to the compressed air and ideal heat transfer from the exhaust to the compressed air. (26) A system with higher regeneration effectiveness naturally has greater efficiency.

How efficient are Stirling engines?

Their lower maintenance requirements make the overall energy cost comparable. The thermal efficiency is also comparable (for small engines), ranging from 15% to 30%. For applications such as micro-CHP, a Stirling engine is often preferable to an internal combustion engine.

What is the function of regenerator?

Regenerators can be used for exhaust-gas heat exchange or for intercooling in gas-turbine systems. As an exhaust-gas heat exchanger, a regenerator recovers heat from the exhaust and uses it to preheat the compressed air before the compressed air enters the combustor.

What is the working fluid in the Stirling engine?

Stirling engines are mechanical devices working theoretically on the Stirling cycle in which compressible fluids, such as air, hydrogen, helium, nitrogen, or even water vapor, are used as working fluids.

What is the effectiveness of regenerator in gas power plant?

The effectiveness of most regenerators used in practice is below 0.85. The thermal efficiency of an ideal Brayton cycle with regeneration depends on the ratio of the minimum to maximum temperatures as well as the pressure ratio.

Which cycle is more efficient for electricity generation plant?

The Brayton (gas turbine) cycle, which makes one-half of the electricity in the IFCC, is inherently more efficient than a Rankine (steam) cycle, because there is no loss of the heat of vaporization of the water to make steam in the Brayton cycle.

What is the difference between regenerator and recuperator?

In a regenerator heat from the primary medium is first stored in a thermal mass and later (next cycle) regenerated from that mass by the secondary medium. In a recuperator both media are separated by a wall through which heat is transferred directly.

When regenerator is used thermal efficiency is?

For a regenerator assumed to have an effectiveness of 80%, the adiabatic thermal efficiency of the regenerative cycle is about 40% higher than its counterpart in the simple cycle, as shown in Figure 2-13. The work output per pound of air is about the same or slightly less than that experienced with the simple cycle.

What cycle is the most efficient?

Carnot Cycle
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.

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How is the effectiveness of a regenerator determined?

The regenerator effectiveness (ε) is given by the following relationship: Figure 2-4. The regenerative gas turbine cycle. Thus, the overall adiabatic thermal cycle efficiency for this system can be written as:

How is the nose used as a regenerative heat exchanger?

The Rothemuhle regenerator is used as an air preheater in some power generating plants. The thermal design of this regenerator is the same as of other types of regenerators. We use our nose and throat as a regenerative heat exchanger when we breathe. The cooler air coming in is warmed, so that it reaches the lungs as warm air.

Which is more economical, a regenerator or a recuperator?

This makes a regenerator more economical in terms of materials and manufacturing, compared to an equivalent recuperator. The design of inlet and outlet headers used to distribute hot and cold fluids in the matrix is much simpler in counter flow regenerators than recuperators.

How are regenerative heat exchangers used in cryogenics?

Cryogenics Regenerative heat exchangers are made up of materials with high volumetric heat capacity and low thermal conductivity in the longitudinal (flow) direction. At cryogenic (very low) temperatures around 20 K, the specific heat of metals is low, and so a regenerator must be larger for a given heat load.