The use of shallow geothermal energy for bridge deck deicing

English Abstract:

Bridges are examples of critical infrastructures in Canada. Exposure to the extreme winter conditions of the Prairies produces rapid freezing conditions from heat loss through both the top and bottom bridge deck surface and these results in hazardous ice and snow conditions. A practical and cost-effective geothermal system to de-ice bridges in a timely manner will significantly reduce both accident and salt corrosion concerns. The subsurface soil and rock contain very large volumes of stored energy, mainly from solar radiation; in spite of this natural-stored energy, temperature declines have and will occur in geothermal systems without seasonal thermal balancing. Manitoba (MB) faces a very cold and long winter. Consequently, this high energy requirement requires a heat pump system for the rapid temperature rise required for bridge deck heating.

A 30-year climate record was obtained from Environment Canada. The data allowed defining standard air temperature curves. We calculated the expected energy consumption for heating bridges based on these curves. The simulation software FEFLOW is capable of simulating heat conduction, groundwater advection, surface radiation, spatial ground property variation, and mass transport around a set of ground heat exchangers. We used soil temperature data from the Highway 210 Test Site, near Ile des Chenes, MB to calibrate the model. The model predicted the groundwater temperature for the life cycle of 50 years. We show in this presentation that winter heating loads require at least the same energy load to be added to the aquifer in the summer.