Spiral heat exchangers are configured with either a single spiral channel, where both fluids share the same wound path in a counter-current arrangement, or a dual-channel layout, where hot and cold fluids each flow through their own dedicated spiral. The two configurations are suited to different process duties.
Single-Channel Configuration
In a single-channel unit, one fluid flows through the spiral passage while the other flows across it in a cross-flow pattern, which is a common arrangement for condensing duty where the vapor side needs open flow area. This configuration is compact and effective for phase-change services like condensers and vaporizers.
Dual-Channel Configuration
Dual-channel spiral exchangers run both fluids through their own spiral in true counter-current flow, which delivers higher thermal efficiency for liquid-to-liquid duties, including fouling and viscous services. This is the configuration typically chosen for slurry-to-slurry or liquid-to-liquid heat recovery.
Matching Configuration to Duty
Condensing or vaporizing services generally favor the single-channel design, while liquid-to-liquid process-to-process heat recovery on fouling fluids favors dual-channel. Choosing the wrong configuration can leave thermal performance well below the theoretical rating of the unit, even though the material and channel spacing were correct.
Getting the Configuration Right
The duty type, not just the fluid properties, should drive the channel configuration decision. GreyTec’s spiral heat exchangers are specified against the actual process duty by our engineering and consultancy team, and our broader heat exchanger range covers alternative designs where a spiral unit isn’t the best fit.