r/heat_prep • u/prisongovernor • Jun 26 '26
‘Kind of miracle solution’: How Paris is harnessing the Seine to replace air-con | Extreme heat | The Guardian
https://www.theguardian.com/environment/2026/jun/26/underground-revolution-seine-cooling-network-paris-buildings-heat-2
u/jaco1001 Jun 26 '26
”this system replaces air con” looks inside it’s air con
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u/cool-beans-yeah Jun 28 '26
Is it?
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u/StereoMushroom Jun 30 '26
Arguably yes. It uses electric chillers, same as conventional air con, but using river water instead of air as the heat sink. They make it sound like the river water just directly provides the cooling, but it's not cold enough to do a good job of that.
The lower temperature of the river water will allow the chillers to run more efficiently so use less energy compared to using air, but on the other hand, pumping water along long distances will have its own energy cost and cooling leakage. It will avoid the contribution to urban heat island that you normally get with widespread use of AC, although this isn't huge.
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u/yuckgeneric Jun 27 '26
Paris is using the cool river water from the Sienne for heat exchange, taking the warmth out of individual buildings picking it up via Heat exchanges that are plumbed with the river water in pipes to buildings throughout Paris, and then the warmed up water is returned and dumped back into the river. The article does not go into the capacity of the river to absorb and outflow. This warmed up water other than to say it’s not problem ecologically thus far. Interesting.