Mine water heat storage

Old mine workings offer a significant, untapped resource: heat. County Durham has extensively worked coal seams, and the main University site sits above two seams at different depths, now flooded.

The ICHS project explores the use of these mine workings for inter-seasonal heat storage and reuse.

ICHS concept

The ICHS project concept is to use the water within these mines as a large heat storage reservoir. Two boreholes, one into each coal seam, will be used to heat up the water within the mines. The Busty seam is at a depth of 150m, and the Hutton seam at 60m. There is some connection between these seams via mineshafts.

Waste heat sources, for example from a data centre, can be used to heat the mine water:

• Water will be pumped from one seam to the surface

• This water will then be heated (typically by a few degrees) by heat exchange with the waste heat sources

• This warmer water is then reinjected into the second seam.

• Water will flow between the two seams, dispersing the heat throughout the mine.

Preliminary investigations

We will drill two boreholes, one into each seam.

Warm water will be pumped into one seam, and extracted from the other, forming a closed cycle.

This will allow us to investigate:

• water flow rate within the mine

• percolation rates

• heat storage capacity

• whether the minewater is static or flowing

• suitability for inter-seasonal heat storage

Ground movement

We have analysed ground movement around the drilling site over the past decade aided by TerraMotion, and see very little movement at the mm level.