PARIS, November 25 (WNM/Reuters/Geert De Clercq) - Paris plans to expand its urban cooling system, which uses a network of underground water pipes, and make it available to small companies and residential buildings as global warming increases the number of aircon units in the city, deputy mayor Jean-Louis Missika said.

Paris, in partnership with French utility Engie, operates a cooling grid using water from the Seine river, but the 75 km (47 mile) network mainly services hospitals, hotels, museums and department stores. It has no residential customers.

"We do not want global warming to lead to a profusion of individual aircon units. These are inefficient, polluting and they add to local warming. And they are ugly," Missika told Reuters.

Missika said Paris wants its Climespace cooling network - Europe's biggest - to cover 100% of the city's area over the next 20 years, from about 43% today, and make it available to non-institutional customers.

"It must be possible to connect the cooling grid to residential buildings as well as to small businesses," he said, adding that the city is already discussing this with social housing operators RIVP and Paris Habitat.