Eng’r. Suravut, Snidvongs

ISEC 2007, Tokyo, Japan

Insolation in Thailand is varying between in 450 to 550 W/m2

daily whole year round, and the average value is at 550 W/m2

daily over the year.

To operate the Solar Dish Stirling with medium insolation thesystem must design to operate with proper conditions, such asincreasing dish diameter, reduce power to track dish structure,reduce piston and drive mechanism friction.

The rotary drive mechanism seems to be lower friction thanother mechanism such as gear drive, and whisper tech swashplate system

Type GammaActing DoubleDriver Mechanism Negative RotaryWorking Gas AirExpansion space Temp 650 C (+/- 5 C)Compression space Temp 40 – 50 C (+/- 5 C)Ambient Temperature 40 C (+/-5 C)Thermal Efficiency 60 %Power Control Variable PressureNo. of Cylinders 4Means Pressure 0.5 MPaMaximum Pressure 1 MpaPower Piston Diameter, mm. 48Stroke, mm. 40

Power Displacement, cc. 72 x 4Displacer Diameter, mm. 42Displacer Length, mm. 150Heater surface area, cm2 11.40Cooler surface area, cm2 29.12Regenerator surface area, cm2 161.60Expansion swept, cm3 340.00Compression swept, cm3 220.80Speed, rpm 500 – 1200Regenerator Type TubeCooling type Ethyl glycolElectric heater 220 V 700 x 4 WMechanical Output Power 215 W @ 20 psiMechanical Output Power 550 W @ 80 psi

Cost USD 1,280.00Mean Time Between Fail (hrs) 18,000Maintenance Time (hrs) 3,500Torque (N-m) 10.4Thermal Eff. % 60Mechanical Eff. % 31

• As Rotary drum is well balance the vibration is lowest.• Rotary Drive has fewer parts than other systems.• Rotary Drive are very complicate and accurate to make.• The cost of the system is medium high.• The friction is about 6.1 W.• The engine torque 10.4 N-m.• Thermal efficiency is 60 %.• Mechanical Efficiency is 31 %.• The Rotary Drive Mechanism can be improved mechanicalefficiency up to 31 %.

• SSESIII required power to track only 10 x 2 W.• By increasing dish diameter, reduce power to track, enlargedisplacer piston, reduce friction for drive mechanism, andreduce power piston friction make the SSESIII operate withThailand conditions.