1 Introduction

 Mini ORC Pack is small-size electricity generation hub using Organic Rankine Cycle.

 Only hot water over 60 ℃ is needed as power source. Pouring the hot water over this Mini ORC Pack can generate electricity. The electricity can drive LED in this pilot project.

 With further improvement, the Mini ORC Pack can generate stable electricity and work as electricity source in remote Camping site.

 The Organic Rankine Cycle (ORC) is an organic, high molecular mass fluid with a liquid-vapor phase change, occurring at a lower temperature than the water-steam phase change. The fluid allows Rankine cycle heat recovery from lower temperature sources like hot water, or waste heat like exhaust gas from biomass combustion.

 This is clean energy harvest project, and with great challenges.

2. Challenges

The Organic Rankine Cycle is not new and widely used in Geothermal Power Plant. Challenges like complex System Configuration, poor efficiency, rocking cost, liable to corrosion, unstable,  large in size, and difficult to maintenance altogether contribute to the unpopularity of the ORC in clean power sector. Let it to be even more difficult issues like health and green-house effect caused by the Organic Fluid.

3. Function block and Parts

3.1 This Mini ORC Pack include, as least, Fluid Gas Expander, evaporator, fluid pump, condenser, heat exchangers, tubes and electrical power generator.

 This design need external power supply to drive auxiliary load for the continuously operation, at least for the fluid-pump. In stead, the fluid pump in this Mini ORC Pack is co-axis self driven.

3.2 Key Material and Parts

  • Chloroethane C2H5Cl 

      Density      0.921 g/cm3 (0-4 °C)

      Melting point    −138.7 °C (−217.7 °F; 134.5 K)

      Boiling point     12.27 °C (54.09 °F; 285.42 K)

      decomposes at 510 °C (maximum operation temperature)

Chloroethane is liquid in cooling water below 12.27 °C and it is gas when heated by hot water.

  • In Evaporator, The liquid  Chloroethane is turned into gas by hot water.
  • In Expander, the high pressure Chloroethane Fluid Gas drive turbine and generate electricity in co-axis generator.
  • In Condenser, the exhausted fluid gas is cooled by ambient air temperature and condensate into liquid. This vacuum state keep the Evaporating-Expansion-Condensing cycle continuously, with Liquid-Gas-Liquid cycle.
  • Fluid pump drives the fluid after condenser into the evaporator.

4 Further explanation

Key design is the uniform vertical axial for Turbine, Fluid-Pump and Generator. That means, the fluid pump is self-driven once the Mini ORC Pack starts to run by evaporated High pressure Chloroethane gas.

The condenser is in upper part and the evaporator is in down part. That means, the condensate liquid Chloroethane can flow to evaporator by gravity automatically.

This delicate design makes it possible to save fluid-feed-pump and condense-pump. Only one-direction valve is needed after condenser  and before the self-driven fluid pump avoiding the risk of back-feeding.

The shortcoming of the design is obvious. Mini ORC Pack is adjusted to running at one optimal point. Little can be done if the environment condition is changed and the output efficiency is even worse.

5 Future work

  • Adjustable  To make the Mini ORC Pack more adaptable to various operation mode....
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