Amid a countrywide heatwave, a neighbourhood in Xuzhou has been keeping nearly 100 households cool using an unlikely source: water from one of the city’s many abandoned coal mines.
After the Woniushan mine closed, it gradually filled up with groundwater, creating a large underground reservoir of cool water, noted Xinhua.
The central cooling system pumps water from this reservoir to a heat exchange station, where water is kept at around 20C. The cooled water is then transported to residents’ underfloor heating pipes. With outside temperatures exceeding 35C, the system has kept houses around 10C cooler, the outlet reported.
After circulating in the underfloor pipes, the water is pumped back to the mine in a closed loop, ensuring a continuous supply of cool water and no wastage, noted China Environment.
Compared to air conditioning, the central cooling system halves energy consumption, said Zhang Tao, head of research and development at Jiangsu Xukuang Heating, which is conducting the pilot. It also avoids the “urban heat island” issue caused by air conditioning units expelling heat back into the environment.
A key challenge for this cooling method is dehumidification. If the temperature of the underfloor heating pipes is too low, condensation will form, potentially leading to slippery floors and mouldy furniture. To mitigate this, the project team developed a water-cooled dehumidifier, and added fans and supporting pipes to stabilise humidity, Xinhua reported.
Can such central cooling be implemented on a large scale in places with abandoned mines? This will depend on factors such as the presence of a large groundwater reservoir, and whether the mine water has impurities that will corrode existing pipelines, Zhang Xiaosong, a professor at Southeast University and head of the project’s research team, told Xinhua.
Read Dialogue Earth’s previous analysis on Shanxi’s coal phase-out.