By:

S.Sai ganesh

C.Santhosh

R.Shivasudhan

Guided by:

Anand Chakravarthi M.C.

LIST OF JOURNALS

Biomass Stirling engine – Dept. of mechanical engineering, Ichinoseki National College of Technology, Japan

Multi phase Stirling engine – Dept. of mechanical engineering, University of California.

BIOMASS STIRLING ENGINE

In order to improve the global environment, a new society utilising biomass is considered more environment friendly than our current lifestyle which depends too much on fossil fuels.

A possible advantage of biomass fuel is balance of CO2 in the atmosphere.

So it is decided to provide a heat source to a Stirling engine powered by biomass fuels such as wood, saw dust etc.

TECHNICAL SPECIFICATIONS OF A PRACTICAL BIOMASS POWERED STIRLING ENGINE

SCHEMATIC LAYOUT OF A COGENERATION SYSTEM USING THE BIOMASS POWERED STIRLING ENGINE

FEATURES OF THE COGENERATION SYSTEM

The burner of the Stirling engine behaves like a high quality biomass burning stove which gives enormous amount of clean heat.

Additionally heat is recovered from the cooling water by a simple heat exchanging element called Fan Coil Unit (FCU)

This process of recovering heat from the cooling water itself is called cogeneration

A heat pump (HP) is additionally used to recover even more heat from the cooling water. This improves the system efficiency.

The heat recovered is converted to electricity using a special unit called Thermo-Electric conversion module.

MULTIPHASE STIRLING ENGINE In a multiphase Stirling engine each engine is an

alpha type Stirling engine that is connected to its neighbouring two engines via its two pistons.

It operates three engines and hence requires a minimum of three pistons.

Each piston is linked to the neighbouring two pistons via pressure waveform inside corresponding engine chambers

The working fluid is not exchanged or shared

Each piston is double acting, i.e. It acts as compression piston for one engine and expansion piston for the other.

It does not require a displace piston so the system is less complex and it can also be self starting

CONSTRUCTION

The main parts of the system are heat exchangers, diaphragm pistons, flexures and actuators.

Heat exchangers: A heat exchanger is used to maintain uniform heat transfer characteristics

Diaphragm pistons: Pistons that are specially fabricated by casting silicone rubber in custom wax moulds which virtually eliminate friction.

Flexures: These are mechanical linkages which connect one engine to the other.

Actuators: The actuators assist piston movement and help coordinate all the three pistons

Diaphragm piston

Heat exchanger

Actuators

Finally fabricated multiphase Stirling engine

CONCLUSIONS

Power was rapidly increased from 3 KW to 12 KW.

It was noted that gas spring hysteresis loss was high

Gas spring hysteresis: Loss of excessive heat due to difference in temperature.

To be overcome by suitable design methods.