From belt drive to BITZER: upgrading a 10-year-old ElectraTherm ORC

We’ve had a busy few days upgrading a 10-year-old ElectraTherm ORC (organic Rankine cycle) unit, replacing its original drive train with the BITZER semi-hermetic expander generator.

Before: separate expander, shaft seal and belt drive

The original design used a separate expander with a shaft seal, belt-driven to an external generator. The shaft seal is the weak point: it is where working fluid can leak out of the system, and the belt needs regular tensioning and replacement.

Before: the original belt drive with shaft seal and external generator

After: BITZER semi-hermetic expander generator

We replaced it with the BITZER semi-hermetic expander generator, which has been standard on new ElectraTherm units for the past five years. The generator now sits inside the sealed unit, surrounded by the working fluid, so there is no shaft seal at all.

After: the BITZER semi-hermetic expander generator, with no shaft seal

Why it matters

• Significantly fewer leaks and much less working fluid lost

• No belts to tension or replace

• A simpler, cleaner design that is easier to maintain

Running an older ElectraTherm unit?

If you operate an older ElectraTherm ORC and would like to talk about upgrading it, get in touch at sales@koolbricks.co.uk.