Strathclyde Partnership for Transport (SPT) is working with Glasgow Caledonian University (GCU) to exploit wastewater in Subway tunnels to turn it into heat.
SPT is to trial new energy-efficient heat-pump systems using water and air in the Subway following successful research with the University.
Given the proximity of the River Clyde to Subway stations, and that tunnels vary in depth between seven and 115 feet below the Clyde’s high water level, water ingress is continually monitored. Tunnel lining repairs, water sealing and drainage improvements with upgraded pumping equipment are on-going.
In order to develop a financially and environmentally effective method of harvesting heat from the water, SPT embarked on a two-year Knowledge Transfer Partnership (KTP) project with GCU last year.
Gordon Maclennan, SPT Chief Executive, said: “SPT is delighted to be working with GCU on this important trial. The potential of exploiting wastewater in Subway tunnels to turn it in to power is very exciting. Until now, work has focused on analysis and study. The next stage is the tangible application of the analytical study at two of our subway stations.”
GCU researchers have established that the water captured in the underground tunnel has a temperature of around 10-14°C, which is sufficient for extracting heat for use as a sustainable heat source.
New heat-pump systems will be trialled in St George’s Cross and Bridge Street Subways over the next few months, with potential for roll out across the system’s network.
KTP associate Konstantinos Ninikas, supervised by GCU’s Dr Nicholas Hytiris, a geotechnical specialist, has been analysing all 21 sumps in the tunnels to monitor water flow and water temperature.
The team also established that the warm, humid air in the Subway can be captured and used to heat station offices. Since June 2014, measurements for the air temperature, air humidity and air flow have been undertaken.
Mr Ninikas and his team have proposed the air and water heat pumps as cost effective development strategies for improved water management.
The KTP is worth £130,000 to the University, partly funded by SPT and partly by the programme.