The Evaporator Is the Heart
The evaporator transfers waste-heat energy into the working fluid. Its type and material decide reliability and life, especially with harsh industrial streams.
Common Evaporator Types
- Shell-and-tube: robust, easy to clean, good for oil or fouling streams.
- Brazed or welded plate: compact, high efficiency, best for clean streams.
- Finned, air-heated: used when the source is hot gas with an intermediate loop.
Material Choices
Clean exhaust allows stainless steel. Corrosive or chloride-rich streams need Incoloy or even titanium. For high-dust flue gas, keep the ORC loop indirect: recover heat first with an isolated plate air-to-air exchanger, never a rotary wheel that would foul and cross-contaminate.
Design Notes
Size the evaporator for the real, not peak, heat profile. Pair it with the right working fluid so pressure and material ratings align. Hygiene-sensitive plants such as food and pharma must keep exhaust fully separated from any supply air.