SOLAR STIRLING ENGINE HISTORY Inventor Robert Stirling 1790

SOLAR STIRLING ENGINE

HISTORY ØInventor = Robert Stirling (1790 - 1878) ØSought to replace the steam turbines of his days due to frequent explosion caused by unsustainable high pressure killing and injuring workers ØInvented Stirling engine in 1816 which could not explode and produce more power than the steam engine used.

WHAT IS STIRLING ENGINE ? Ø Device that converts heat energy to mechanical power by alternately compressing and expanding a fixed quantity of working fluid at different temperatures. Ø Regeneration as alternative.

WHY STIRLING ENGINE? Ø Best teaching and learning for any engineering students device especially in the field of thermodynamics. Ø Unique technology. Ø An innovation with hundreds of application. Ø An innovation with a mission to save the earth. Ø Fuel independency.

MAIN COMPONENTS v Power piston – small tightly sealed piston that moves up when the gas inside the engine expands v Displacer – larger piston and it is very loose in its cylinder so air can move easily between the heated cooled sections of the engine as the displacer moves up and down v These piston move by the action of compression and expansion. v Difference in pressure causes the piston to move and produce power.

WORKING PRINCIPLE I. 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.

EFFICIENCY Ø Theoretically q Stirling engine efficiency = Carnot efficiency q Unfortunately working fluid or gas is not ideal this causes the efficiency to be lower than Carnot efficiency. Ø In fact, Stirling engine efficiency depends on q Temperature ratio (proportionally) q Pressure ratio (inversely proportional) q Specific heat ratio (inversely proportional)

ALPHA STIRLING ENGINE

BETA STIRLING ENGINE

ADVANTAGES Ø Various heat sources (solar, geothermal, nuclear energy, waste heat, biological) Ø Environmental friendly Ø Heat is external and the burning of a fuel-air mixture can be more accurately controlled. Ø Operates at relatively low pressure and thus are much safer than typical steam turbines Ø Less manpower needed to operate any type of commercial Stirling engine.

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

APPLICATION ØWATER PUMP STATION q A Stirling engine used for pumping water can be configured so that the water cools the compression space. This is most effective when pumping cold water.

APPLICATION Ø STIRLING CYROCOOLERS q Any Stirling engine will also work in reverse as a heat pump. When a motion is applied to the shaft, a temperature difference appears between the reservoirs. Ø NUCLEAR POWER q Replacing the steam turbines of the nuclear power plant with Stirling engine might simplify the plant, yield greater efficiency, and reduce the radioactivity by products.

CONCLUSION Ø Unlimited source of heat source Ø Political awareness of green heat and power production. Ø Large market experiencing rapid growth. Ø Many different possible applications. Ø Time to change.