Field and Laboratory Tests and Analyses on Temperature and Relative Humidity in Underground Multi-tunnels

Dam tunnel ventilation has been widely used in underground hydropower station to save energy. In order to study the dam tunnel cooling (heating) effect, a 24 hours continuous field measurement is conducted in underground multi-tunnels; and heat transfer performance about the dam tunnel has been calculated and analyzed. Meanwhile, to figure out influencing factors to dam tunnel ventilation and heat transfer performance, based on similarity theory, a small-scale experimental set-up is made to simulate heat transfer process during air passing through the tunnel. The experimental results show that the velocity and temperature of the inlet air both have significant impacts on heat exchange. Taking the underground dam tunnel as a huge natural "air conditioner" to replace some mechanical heat/cold sources is an energy-saving method for Heating, Ventilation and Air Conditioning system in hydroelectric power plants. (c) 2017 The Authors. Published by Elsevier Ltd.