THE IMPACT OF DEPTH ON SWAC INSTALLATION: WHAT YOU NEED TO KNOW

The key to efficiency: deep-sea temperatures

The performance of a SWAC is based on a fundamental physical principle: the deeper you go into the ocean, the lower the water temperature. At depths of 900 to 1,000 meters, the water remains stable at 5 to 7°C year-round, even in the tropics. This thermal gradient enables capturing “natural frigories” and transferring them to buildings via heat exchangers, without the need for energy-intensive compressors.

This depth is therefore a performance lever… but also a technical challenge that only specialists such as Geocean can meet.

Challenges mastered by Geocean

The further the cold water is from the coast, the longer the suction pipe (SWAC pipeline) must be, subject to high pressure and complex marine constraints. Its design, installation and safety require advanced expertise in underwater engineering.

• Geocean, a subsidiary of VINCI Construction Grands Projets, is now a world leader in deepwater SWACs. With over 40 years of experience in marine engineering, the company has completed several landmark projects:
• French Polynesia Hospital Center (CHPF) – Tahiti: 4 km SWAC capturing water at a depth of 900 m, reducing the hospital’s electricity consumption by 35% and avoiding more than 5,000 tons of CO₂ per year.
• The Brando Resort – Tetiaroa: a SWAC at a depth of 960 m supplying 35 luxury villas, with annual energy savings of 2.3 GWh.
• Intercontinental Bora Bora: the world’s first hotel SWAC (installed in 2006), still in service, with a 95% reduction in energy requirements for air conditioning.

These achievements show that the constraints associated with depth–pressure, currents, underwater topography, and corrosion can be overcome with the right materials (HDPE, titanium) and installation techniques (controlled immersion, ballasting, anchoring).

Why choose a deep SWAC for your buildings?

• Whether you manage a hotel, hospital, airport, data center, or coastal urban complex, a deep SWAC can offer you:
• Up to 90% energy savings on air conditioning
• No use of refrigerants (less maintenance, zero leaks)
• Constant cooling 24/7, even during heat waves
• A significant reduction in your carbon footprint
• A lifespan of over 30 years for marine infrastructure

Unlike surface thalassothermy, which is often associated with heat pumps, deep SWAC provides direct cooling at very low temperatures, offering exceptional energy efficiency.

A tailor-made approach, according to your context

• Every coastal area is unique. That’s why Geocean designs tailor-made projects based on:
• The underwater topography and accessible depth
• Your thermal requirements (size, use, expected level of comfort)
• Your land or environmental constraints
• The stages of a Geocean SWAC project include:
• Feasibility study, thermal modeling, and sizing
• Complete system design (water intake, exchangers, discharges)
• Specialized marine work (HDPE, installation by flotation, trenching, or pipe jacking)
• Assistance with commissioning, maintenance, operation, and financing

Geocean thus guarantees the safety, performance, and long-term profitability of each project.