Something new from the blog …
Here the first post regarding an old idea lying in the drawer for several years: Small sized Organic Rankine Cycle Heat Motor. Project name is Thermodyna. Step by step we will publish the latest results regarding 1. cycle configuration, 3. working fluid, 4. generator, … Today we start with the logical number 2, the expander.
2. Expander / Expansionsmaschine
The most important part in a Rankine cycle system is the expander, tbe unit converting the energy stored in the pressurized fluid into mechanical i.e. rotational energy. Off the shelf industrial parts driven by pressurized air are airmotors. Many different types are available:
2.1. Radial Piston Engine / Radialkolbenmotor
Radial engine in a cut-away view
http://en.wikipedia.org/wiki/File:Radial_engine.gif
Section Drawing
Type P1V-P, Parker Hannifin Catalog
2.1.1 Huco Dynatork
Type Dynatork 7, Huco Catalog
Specification:
- Maximal input pressure: ~7 bar
- Maximal temprature: < 70 deg.
- Oil required: yes
- Operation time: ?
- Power, air consumption, speed: see below
2.1.2 Globe Airmotors
Type RM110 – Datasheet – Globe. Globe Catalog
Specification:
- Maximal input pressure: ~8 bar
- Maximal temperature: <80 deg.
- Oil required: yes
- Operation time: 5000 – 8000h
- Power, air consumption, speed: see below
- Inside the housing there has to be a pressure of ~1 bar
2.1.3 Parker
Germany – Karrst
Type P1V-P SERIES – Datasheet – Parker, Parker Hannifin Catalog
Specification:
- Maximal input pressure: ~7 bar
- Maximal temperature: < 70
- Oil required: yes
- Operation time: ?
- Power, air consumption, speed: see below
2.1.4 Tonson
2.2 Rotor Vane Motor / Lamellenmotor
Section Drawing
Parker Hannifin Catalog
2.2.1 Gast
Type: NL – Non-Lubricated Air Motor, www.gastmfg.com
No lubrication necessary for these corrosion resistant air-motors.
Type: AM (SS) Series – Lubricated / Stainless Steel Air Motor, www.gastmfg.com
Fully sealed and sanitary design, these corrosion resistant
Type: AM – Lubricated Air Motors, Datasheet – Gast
2.2.2 Parker
Type: P1V-A SERIES – Datasheet – Parker, Parker Hannifin Catalog
Specification:
- Maximal input pressure:
- Maximal temperature:
- Oil required:
- Operation time:
- Power, air consumption, speed: see below
2.3 Gas Pressure Motor / Drehkolbenmotor
2.3.1 Armak
Specification:
- Maximal input pressure: ~15 bar
- Maximal temperature: < 150 deg.
- Oil required: no
- Operation time: ?
- Power, air consumption, speed: see below
Manfacturers characterize their engines with diagramms showing the mechanical energy versus rotational speed and air consumption versus speed for different air intake pressures. Information about the engine’s efficiency are hard to find. As a first attempt to compare different engine’s efficiencies we suggest to calculate the normalized value of specific power, the quotient of power devided by air consumption ( [ ] = W / (l/sec) ) and plot it versus intake pressure. The results are shown below. The data values have been taken from the abowe cited data sheets. The plot also includes the maximum power that could be achived from pressurized air. As comparative process we use an isentropic expansion. The red curve shows power generated by filling the engine’s volume and the green power generated by expansion. The mathematical model is published here. We are in an ongoing process to discuss those results with some manufacturers.
Normalized Power per Inlet Air Consumption
Normalized Power per Exhaust Air Consumption (Free Air)
