A alpine highway tunnel exhausts 120,000 m3/h of warm air in winter while drawing in cold fresh air. EN159 added a heat-pipe recovery unit at the portal to preheat intake air.
The Challenge
Portal buildings and fan rooms needed heating as minus 18 C intake air entered. The operator wanted recovery with no moving parts exposed to the tunnel environment.
Why Heat Pipe Air-to-Air Recovery
Heat pipes suit tunnel duty: passive, sealed, no rotating seal to foul. Streams stay separate, so tunnel exhaust pollutants do not enter the intake.
The EN159 Solution
Split heat-pipe modules, 120,000 m3/h, 60 percent effectiveness, installed in the portal ventilation plenum with a 4 degree tilt.
Measured Results
- Recovered heat: about 0.9 MW
- Intake preheated by 11 C
- Portal heating cost cut by 48 percent
- Estimated payback: 18 months
Compliance and Selection Notes
Separated streams, no mixing, passive operation. Rotary wheels excluded for foul-air duty.
Frequently Asked Questions
Is maintenance needed?
Heat pipes are sealed and passive. Inspection is visual; no lubricant or drive service.
Can it handle tunnel exhaust?
Yes, with separated streams. Exhaust never mixes with intake air.
Related Guides and Tools
Heat Pipe Heat Exchangers · Mine Ventilation Heat Recovery · Heat Pipe Applications · Contact EN159
Get a Site-Specific Recovery Estimate
Talk to an EN159 application engineer about your tunnel ventilation exhaust stream. Call 15753355505 or visit our contact page for a site-specific recovery estimate.