CONDENSATION CONTROL SYSTEM FOR RAILWAY TUNNELS

Overview

Condensation-Inducing Device for Energy-Efficient Tunnel Drip Control

Condensation on tunnel pavement and lining cannot be fully eliminated, causing persistent public anxiety.
Conventional dehumidifier-based countermeasures require large electricity consumption.
The 2024 Road Tunnel Condensation Countermeasure Guideline allows installation of “condensation-inducing facilities” in tunnels.
A low-power device with a surface cooler than pavement and lining induces condensation away from visible tunnel surfaces.
Circulating inflow water at 15–18℃ keeps the device cold and drains induced condensate to tunnel drains.

Core Competencies

Purpose
This device is a low-power condensation-inducing system that controls tunnel dripping by drawing condensation from the pavement and lining to a dedicated surface and drainage system.

Low-Temperature Induction Surface

Device surface is maintained at 15–18℃, lower than 21℃ pavement and lining temperatures.

Use of Tunnel Inflow Water

Inflow or drainage water at 15–18℃ is recirculated to keep the device cold with pump-only power.

Dual-Stage Condensation Reduction

Air vapor content is reduced first; remaining condensation occurs only on the device and is drained to longitudinal pipes.

Chamber Testing with Fans

Constant-temperature/humidity chamber tests measure induced condensation; fans achieve about 10% humidity reduction in 3 minutes.

CFD-Based Performance Evaluation

CFD analysis under Boryeong Tunnel conditions shows up to 14.1 dehumidifiers per km can be replaced by the device.

Improved Drainage Structure

Extended trays and floor waterproof sheets collect condensation from distributors, hoses, and frame, protecting tunnel electrical cables.

Expected Benefits

User Safety & Comfort
– Induced condensation reduces dripping on pavement and lining, easing tunnel user anxiety.

Reduced Driver Risk
– Less moisture on the pavement lowers skid risk and improves driving safety.

Infrastructure Protection
– Reduces condensation-induced corrosion of tunnel facilities and equipment.

Energy Savings
– Replacing dehumidifiers with low-power pumps sharply reduces tunnel electricity use and annual costs.

Guideline Compliance
– Provides a practical implementation of “condensation-inducing facilities” defined in national road tunnel guidelines.

Targeted Water Management
– Collects induced condensate into longitudinal drains and sumps, protecting nearby electrical cables and facilities.

Certifications

Induced-condensation performance verification via indoor constant-temperature/humidity chamber tests.
Dehumidification efficiency and power-saving evaluation via CFD analysis under Boryeong Tunnel conditions.
Field test at the Boryeong Undersea Tunnel confirmed dehumidification performance of up to 4 L/hour.
Recognition as a “condensation induction facility” in MOLIT’s Road Tunnel Condensation Countermeasure Guideline (2024.4.18).

TRL 6

Contact

Korea Railroad Research Institute (KRRI)
Global Business Department
Dr. Jungjun Park
E-mail: jjpark@krri.re.kr