HARDWARE PROJECT REPORT ON TOPIC : FABRICATION OF STERLING ENGINE

SUBMITTED BY :Nikhil Agrawal

Contents Abstract

Introduction

Literature

Materials and tools required

Calculations

Applications

AbstractWorldwide attempts are being made to increase the use of renewable energy sources as well as to use our current fossil fuel energy sources more efficiently.

The aim of this project was to build a prototype of a Stirling engine and analyse its performance. This project provided a great opportunity to gain experience with mechanical design, manufacturing, and the fundamentals of Stirling engines.

We applied our knowledge of thermodynamics to the design of the engine, and developed formulas to predict its power output at different temperature differentials

IntroductionHistoryThe Stirling Engine is one of the hot air engines. It was invented by Robert Stirling (1790-1878) and his brother James. His father was interesting in engine and he inherited it. He became a minister of the church at Scotland in 1816. At this period, he found the steam engines are dangerous for the workers. He decided to improve the design of an existing air engine. He hope it wound be safer alternative. Earlier Sterling Engine

DIFFERENT TYPES

Alpha Stirling Engine Gamma Stirling EngineBeta Stirling Engine

Literature Stirling engines are external combustion engines, which means no

combustion takes place inside the engine and there’s no need for intake or exhaust valves. As a result, Stirling engines are smooth-running and exceptionally quiet.

Because the Stirling cycle uses an external heat source, it can be run on whatever is available that makes heat — anything from hydrogen to solar energy to gasoline.

Sterling engine is a device that converts heat energy to mechanical power by alternately compressing and expanding a fixed quantity of working fluid at different temperatures.

Working PrincipleI. One side of the engine is continuously heated while the other side is

continuously cooled.

II. First, the air moves to the hot side, where it is heated and it expands pushing up on a piston.

III. Then the air moves through the regenerator to the cold side, where it cools off and contracts pulling down on the piston.

IV. Temperature change inside the engine produces the pressure change needed to push on the piston and make the engine run.

STIRLING CYCLE

1-2: constant volume process

2-3: isothermal expansion process

3-4: constant volume process

4-1: isothermal compression

process. P- V Di agr am

CYCLEEFFICIENCYNet work, Wnet= Wexp+ Wcomp

Net heat, Qtotal = Qheat+ Qexp

Recovered mechanical energy:Wnet = Wexp+ Wcomp

Wnet = ∫exp PdV + ∫comp PdV (P = nRT / V)Wnet = ∫exp (nRTmax/ V) dV+ ∫comp (nRTmin/ V) dV Wnet= nR (Tmax-Tmin) ln (Vmax/ Vmin)

Provided heat :Qexp= ∫exp PdV Qexp= nR Tmax ln(Vmax/ Vmin )Qheat= nCv (Tmax-Tmin)Qtotal = nCv (Tmax-Tmin) + nR Tmax ln (Vmax/ Vmin)

Cycle efficiency : η = [R (Tmax-Tmin) ln (Vmax/ Vmin)] [Cv (Tmax-Tmin) + R Tmax ln (Vmax/ Vmin)]

Efficiency Theoreticallyo Stirling engine efficiency = Carnot efficiency.o Unfortunately working fluid or gas is not ideal,this causes the

efficiency to be lower than Carnot efficiency.

In fact, Stirling engine efficiency depends ono Temperature ratio (proportionally).o Pressure ratio (inversely proportional).o Specific heat ratio (inversely proportional)

Materials Required 2 cylindrical tin cans 22 mm PVC pipe elbow Double sided foam tape Fishing line or thick string/line Sandpaper (80-120 grit) 18 gauge steel wire(1.5 mm) 24 gauge steel wire(0.6 mm) CD Bottle cap Balloon 8-12 bolt,nut,and 2 washers

Tools Required Exacto knife Scissors(Tin snips) Thumb Tack Plyers Wire cutters Alcohol lamp or Tea light/candle Magnet An iron

Output prototype

Applications Water pump stations. Combined heat and power plant. Solar power generation. Stirling cyrocoolers. Heat pump. Marine engines. Nuclear power. Aircraft engines. Micro CHP .

Conclusion The Stirling engine is noted for its high efficiency compared to

steam engines, quiet operation, and the ease with which it can use almost any heat source.

This engine is currently exciting interest as the core component of micro combined heat and power (CHP) units, in which it is more efficient and safer than a comparable steam engine.

REFERENCES https://en.wikipedia.org/wiki/Stirling_engine THERMAL ENGINEERING by Er.R.K.RAJPUT Engineering Thermodynamics by PK Nag

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