Dehumidification in an underground utility tunnel: field experiment and modeling

The recent rapid development of underground utility tunnels (UUT) in China reflects the government’s resolve to improve municipal service amid urbanization. Although safety is primary concern design and operation UUT, moisture issue appears be neglected. In southern eastern China, however, condensation UUT noted believed responsible for high rate equipment failure deterioration air quality inside tunnel. To understand its implications construction this study investigates balance a section Suzhou city, China. An experimental dehumidification was carried out 200 m long 4.05 × 2.5 cable compartment with objective identify major sources their strengths. Two refrigeration dehumidifiers were used control relative humidity. results show that most significant source outdoor through ventilation (values dependent on change rates), followed by open water evaporation (~ 4.195 kg/hr) tunnel leakage from neighboring unconditioned compartments. concrete walls had strong buffering effect, which at beginning 17.171 kg/hr). A mathematical model developed can predict humidity fairly well. suggested needs included design, construction, future This includes reserved spaces systems, an strategy dehumidification, covered drainage system, maintenance.