Stirling Engine

Note: This Article is not written by me.


The Stirling engine is basically a heat engine that is vastly different from the internal-combustion engine. It was Invented by Robert Stirling in 1816, the Stirling engine has the potential to be much more efficient than a gasoline or diesel engine. A Stirling engine uses the Stirling cycle,­ which is unlike the cycles used in internal-combustion engines.

Working:

The engine is designed so that the working gas is generally compressed in the colder portion of the engine and expanded in the hotter portion resulting in a net conversion of heat into work. An internal Regenerative heat exchanger increases the Stirling engine's thermal efficiency compared to simpler hot air engines lacking this feature.

Here is a look at the three main types of Stirling Engine and their working.

Alpha Type Stirling Engine:

An alpha Stirling contains two power pistons in separate cylinders, one hot and one cold. The hot cylinder is situated inside the high temperature heat exchanger and the cold cylinder is situated inside the low temperature heat exchanger. This type of engine has a high power-to-volume ratio but has technical problems due to the usually high temperature of the hot piston and the durability of its seals. In practice, this piston usually carries a large insulating head to move the seals away from the hot zone at the expense of some additional dead space.

Beta Type Stirling Engine:

A beta Stirling has a single power piston arranged within the same cylinder on the same shaft as a displacer piston. The displacer piston is a loose fit and does not extract any power from the expanding gas but only serves to shuttle the working gas from the hot heat exchanger to the cold heat exchanger. When the working gas is pushed to the hot end of the cylinder it expands and pushes the power piston. When it is pushed to the cold end of the cylinder it contracts and the momentum of the machine, usually enhanced by a flywheel, pushes the power piston the other way to compress the gas. Unlike the alpha type, the beta type avoids the technical problems of hot moving seals.

Gamma Type Stirling Engine:

The third type of Stirling engine is a gamma type sterling engine.Gamma type sterling engine can be called simply as a beta type sterling enginein which the power piston is placed in a separate cylinder alongside thedisplacer piston cylinder instead of the same, but is still connected to thesame flywheel. The gas in the two cylinders can flow freely between both ofthem and remain as a single body. This configuration produces a lowercompression ratio but it is mechanically simpler to the others and often usedas a multi-cylinder Sterling engine.

Project Demonstration

Computer Lab 3, A-block, Air University Islamabad. (17-06-2011)

Finally I can relax :)) YAYYYY!

There was no hope of any success until today in the morning. We had already decided what will be our plan of action to complete the project in working condition. But I'm 100% sure that it were the prayers of our parents and loved ones that produced  this miracle.

The part that was compulsory for us to present was the tracking of the parabolic dish, and our LDR sensors were not at all reacting to the intensity of light.

See this for a change... Our project only worked when a demonstrator came towards our project!!! And that happened 4 times, not once!!! (Usually its the opposite xD)

We actually boiled rice for an experiment and they were tasty according to the faculty xD The response of everyone was very good and most of the people liked our project.
Btw, there were some amazing projects out there this time whose photos I will upload asap ..

I saw two people sitting in the cafeteria who ordered Milk Shake. While the order was served one of them was away. The second person sitting quickly sipped one of the glass and exchanged it for the other to drink!! :DD

Final Presentation

Currently I'm sitting at the top roof of B-block at Air university Islamabad, sorting out our FYP and its mighty hot, around 50 degree celcius according to our Digital Multimeter.

The Final Presentation was a disaster.. Yes, Well almost!

Our project was Dual axis tracking of a Parabolic Dish, Solar Power Plant using a stirling Engine to Produce electricity.

We had prepared the presentation well enough and our Advisor also approved the presentation that we had prepared, in fact he himself edited the power point for the measurements taken. But as is the case, when we presented it on the rostrum we were lost for words.

It wasn't that we did not know anything, we did. But the internal politics of the administration resulted in our punishment. There were as usual two groups of staff, both trying to let the others and their groups down.

Although we were presenting it correctly but they let our presentation all get mixed up. We did not get in any kind of rhythm at all. It was all left to the demo that we have to present tomorrow, and show the solar dish tracking the sun automatically, but the bad news is that the dish is not working at all.

The consequences.... Delay in the awarding of grade, time extension for the project deadline.