Sage-Tips

What conditions will affect the efficiency of Stirling engine?

The Stirling engine performance depends on geometrical and physical characteristics of the engine and on the working fluid gas properties such as regenerator efficiency and porosity, dead volume, swept volume, temperature of sources, pressure drop losses, and shuttle losses.

How can you increase the efficiency of a Stirling engine?

(2) The methods in improving the performances of stirling engine includes: improving the hot end temperature, reducing the cold end temperature, increasing the average cycle pressure, speeding up the rotate speed, phase angle approximately being equal to 90 °and stro/e volume ratio approximately being equal to 1, etc.

How does an alpha Stirling engine work?

The Stirling engine uses the temperature difference between its hot end and cold end to establish a cycle of a fixed mass of gas, heated and expanded, and cooled and compressed, thus converting thermal energy into mechanical energy.

How does the Stirling cycle engine work?

A Stirling cycle engine is a closed cycle regenerative heat engine that operates by cyclically compressing and expanding a gaseous working fluid at different temperatures such that there is a net conversion of heat energy to mechanical work.

Why is hydrogen a better working fluid for the Stirling engine?

The fluid in which the proposed Stirling engine had the best performance was hydrogen. However, hydrogen is not widely used as a working fluid in Stirling engines because of its high risk of flammability. It was also found that the proposed engine had better performance at higher pressures.

Why don’t we use Stirling engines?

Stirling engines are rarely used for generating electricity. They are basically reciprocating engines and require fairly exotic alloys in their heat exchangers. Although in theory they are fairly efficient they are expensive and bulky.

What fuel do you use in a Stirling engine?

Stirling engines are an external combustion engine, where the fuel source is burned outside the engine cylinder. This energy source drives a sealed inert working fluid, usually either helium or hydrogen, which moves between a hot chamber and a cold chamber.

How does a free piston Stirling engine work?

A Stirling engine uses a working gas such as helium, which is housed in a sealed environment. When heated by the natural gas-fueled burner, the gas expands causing a piston to move and interact with a linear alternator to produce electricity. As the gas cools and contracts, the process resets before repeating again.

Why are Stirling motors not widely in use today?

Here’s the Short Answer: Stirling engines are not good for applications that need to change their power output levels quickly, like cars for example. Plus, they tend to be heavier (and more expensive) than gasoline or diesel engines of a similar power output.

How do you run a Stirling engine continuously?

To have a Stirling run continuously you need to have a hot section that gets constantly heated by some source, and a cold section that is cooled in some way. Without constantly heating the hot section and cooling the cold section eventually enough heat would be transferred between the two that you would just end up with two warm sections.

What is the first law of thermodynamics for a Stirling engine?

Equation 1: First law of thermodynamics for a Stirling engine, the first law is simply an energy balance of the system The ratio of useful work to the heat transfer into the engine is called thermal efficiency. Think of it as the ratio of what you want (useful mechanical work) divided by what costs (heat transfer into the engine).

What is the ideal thermal efficiency of a Stirling engine?

Equation 4: Ideal Stirling thermal efficiency is equal to the Carnot efficiency To have a Stirling run continuously you need to have a hot section that gets constantly heated by some source, and a cold section that is cooled in some way.

What is a displacer piston on a Stirling engine?

In order to control when heat is transferred to or from the working fluid most Stirling engines have what is called a “displacer” piston which simply prevents contact between the working fluid and either the hot section or the cold section depending on its position.