04/08/2026
As Europe endures another scorching summer, here's an interesting cooling idea from China.
In Xuzhou, a city about halfway between Beijing and Shanghai, a residential community is using the same network of pipes that provides winter heating to cool homes in summer.
Instead of circulating 104°F (40°C) hot water, the system sends 68°F (20°C) water beneath the floors, keeping indoor temperatures at a comfortable 77°F (25°C) without running air conditioners.
The cool water comes from a flooded former coal mine, where underground water remains at around 66°F (19°C) year-round. After exchanging heat, it's pumped back underground through a closed-loop system, with virtually no water wasted.
No outdoor AC units. No compressors. No refrigerants. No need to tear up floors or alter a building's exterior—the existing district heating network is simply reused for cooling.
The project has reduced energy use by around 50% compared with conventional air conditioning, while also cutting carbon emissions.
As heat waves become more common around the world, perhaps solutions don't always have to mean building something new. Sometimes, it's about rethinking the infrastructure we already have.
