Ambitious ORC Steam Turbine Plant

Made In Thailand’s Only (ORC) Organic Rankine Cycle Turbine Engine

Mike, like many of us, is an expat retired here to Thailand. Unlike (most of) us though, he embarks on some really ambitious projects. (Wasn’t my own half sized Little Samson Traction Engine ambitious enough to qualify?)

Already completed a CNC milling machine, Mike has been steadily over the years been designing and building this fantastic steam plant. Here is Mike’s schematic diagram of the steam turbine plant he is building:-

Mike’s goal is to build the smallest, lightest turbine possible that develops around 200 HP (150 kW) with the best fuel efficiency that he can achieve, and the entire system must also be mobile. With those requirements in mind, Mike set out to build an ORC (Organic Rankine Cycle) turbine engine.

For several reasons Mike decided to use a 3 stage axial flow turbine. This is a closed system which constantly re-cycles the working fluid, which in this case is not water, but an organic liquid instead. Below is a rough sketch of the turbine and other parts, to be discussed later.

Turbines can be tricky to regulate, especially small ones. They can over-rev in the blink of an eye. Also, Mike chose to use a supercritical boiler with high flow and heated with a forced air burner with high flow rate. For safety and for best control, he decided to use a microcontroller along with sensors and servo motors to take full control of the entire system. These on-board computers are often referred to as a FADEC, for Full Authority Digital Electronic Control. Here is the FADEC block diagram:-

Mike has been contructing the boiler and the burner. Here is a movie of the boiler burner in action:-

And here are some of the boiler tubes coils:-

In case you were wondering how the boiler tubes and burner are integrated refer to this boiler schematic diagram:-

And finally a photo of the boiler burner in action.

I’m sure you’ll join me in wishing Mike all the best with finishing off his ambitious ORC steam plant project.

Isn’t it quite exraordinary what us model engineers get up to here in Thailand?

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