STIRLING ENGINE & ITS CYCLE

HINDUSTAN COLLEGE OF SCIENCE & TECHNOLOGY

Prepared byNaman Jain

INTRODUCTION*Stirling engine was invented, developed and patented

in 1816 by Reverend Dr. Robert Stirling .

* It is a external heat engine operating by cyclic compression and expansion of air or other gas, the working fluid, at different temperature levels such that there is a net conversion of heat energy to mechanical work.

STEPS OF OPERATIONCOOLING

COMPRESSION

HEATING

EXPANSION

PRINCIPLE OF STIRLING ENGINE

STIRLING CYCLE

It is a thermodynamic cycle.The cycle is a closed regenerative cycle with a gaseous working fluid.

"Closed cycle" means the working fluid is permanently contained within the thermodynamic system.

Internal heat exchanger called a regenerator is uses, that increases thermal efficiency.

Otto cycle

Isothermal expansionThe expansion space is heated externally, and the gas undergoes near-isothermal expansion.

Constant-volume  heat removal The gas is passed through the regenerator, thus cooling the gas, and transferring heat to the regenerator for use in the next cycle.

Isothermal compressionThe compression space is intercooled, so the gas undergoes near-isothermal compression.

Constant-volume heat addition

The compressed air flows back through the regenerator and picks up heat on the way to the heated expansion space.

ALPHA TYPE It is typically in a V-formation with the pistons joined at the same point on a crankshaft.

BETA TYPEIt has a single cylinder with a hot end and a cold end, containing a power piston and a 'displacer' which drives the gas between the hot and cold ends. 

GAMMA TYPEIt has two cylinders: one containing a displacer, with a hot and a cold end, and one for the power piston. The pistons are typically in parallel and joined 90 degrees out of phase on a crankshaft. 

CONFIGURATION

ADVANTAGES*It can run directly on any available heat source

not just one.

*No valves are needed as there is no mass transfer.

*Risk of explosion is low as it uses single phase working fluid.

*Starts easily & run efficiently in cold weather, in contrast to IC engine.

*They are extremely flexible, can be used as combine heat power in winter & cooler in summer.

DISADVANTAGES

*Size and cost issue.

*Power and torque issue.

*Gas choice issue.

APPLICATIONS

*Solar power generation.

*Marine engines.

*Nuclear power.

This engine delivered 25kW output at 1000W/m2 insolation.

*CHP

combine heat power.

* Chip cooling

THANK YOU

Queries Invited