World’s largest seawater air-conditioning system commissioned in Tahiti

Thanks to this system, the cold waters of the deep will cool the French Polynesia Hospital Center, saving at least 2.5 million euros of electricity per year. 

The three pumps of this seawater air-conditioning system will draw one million litres per hour from more than 900 meters deep in the Pacific Ocean. The temperature there is 5°C, much colder than at the surface. 


The air-conditioning system of the hospital located in Taaone will be supplied with cold by titanium heat exchangers connected to a 3.8 km long underwater pipe network in a closed circuit. The seawater will then be discharged at around 12°C into the lagoon which, according to the preparatory studies, will not suffer "any environmental impact". This technology will replace the previously used chillers, which consume a lot of electricity, and will be kept as a backup. 


This means that the hospital will no longer use electricity to produce cold - more than two-thirds of which was produced from imported oil - in favor of fully renewable energy. (1) 


This installation, with a refrigerating capacity of 3.6 MW, represents an investment of 31 million euros with an estimated lifespan of 30 years. According to its designers, it will pay for itself in 10 to 15 years. 


It was commissioned on November 1 and should allow the island of Tahiti, the most populous overseas community, to reduce its electricity needs by 2%. (2) 





Picture: The technical room of the SWAC of the French Polynesia hospital center, in Pirae, September 21, 2021. ® MIKE LEYRAL / THE WORLD