Island territories
Réunion, French West Indies, Polynesia: cold water accessible near the coast.
Expertise · 03 / 04
Sea water air conditioning: cooling at its lowest carbon cost.
Sea Water Air Conditioning uses deep sea water (naturally 5°C in tropical zones) as a direct cold source to cool coastal buildings and data centres. Our historical know-how, illustrated by the CHU Sud Réunion project.
COP ≈ 25
typical energy ratio of a well-designed SWAC loop
−80%
cooling electricity consumption vs conventional system
30 yrs
typical lifespan of a well-maintained SWAC infrastructure
- 0 m
At the surface
Tropical water sits at around 26°C. Far too warm to cool a building.
A conventional system therefore has to manufacture its cooling, at an efficiency (EER) of 2.5 to 3.5.
- ≈ 200 m
The thermocline
Light fades and the temperature drops fast: we are crossing the thermocline.
The sun only warms the upper layers. Further down, the water stays cold all year round.
- 400 m
Depending on the seabed
The intake depth depends on the site: from 400 m to more than 1,000 m depending on the zone.
Our resource study sets it: bathymetry, thermal profile, currents, pipe route.
- 700 m
Cold, all year round
From 700 m down, the water is at 5-6°C, summer and winter, day and night.
A stable cold source: it depends on neither the weather nor the season.
- 1 000 m
The intake
At 5°C, the pipe draws the cold water and brings it up to an onshore heat exchanger.
HDPE, GRP or coated-steel pipes, 400 to 1,600 mm in diameter.
- ↑
Back up, then cooling without a chiller.
Through a heat exchanger, the deep sea water cools a fresh-water loop that air-conditions the building. Then it returns to the sea.
Titanium heat exchangers, resistant to sea water · From 5 to 50+ MW of cooling on a single loop · Thermal discharge studied and monitored (ICPE study, coastal law)
How it works
A cooling loop driven by the deep ocean.
Cold seawater intake5°C · −1000 mWarmed-up return~10°C · released at the surfaceOn-site heat exchangeCools the building loop
Our approach
A SWAC project is designed as a marine work, not as a classical air conditioning system.
Oceanographic studies, deep-pipeline engineering, large-capacity heat exchangers, integration with the existing cooling network. A rare expertise we have operated since 2015.
01
Resource study
Bathymetry, thermal profile, currents. Identification of the optimal route for the intake pipe.
02
Techno-economic feasibility
Loop sizing, economic model, financing and risk scenarios.
03
Detailed design
HDPE/GRP pipes, pumping stations, titanium exchangers, secondary chilled-water loop.
04
Project management
Marine and onshore works supervision, commissioning and initial operation.
Deliverables
What we hand over at the end of the mission.
Technical documents, measurable data, an immediately usable action plan.
Oceanographic study
Thermal profiles, bathymetry, discharge-plume modelling.
SWAC loop design
Full hydraulic schematic: deep intake, exchanger, distribution.
Energy model
Annual simulation, seasonal COP, pump and exchanger sizing.
Site integration
Tie-in with existing cooling production, redundancy, conventional backup.
Control architecture
Supervision, variable flow, advanced thermal control, remote maintenance.
Regulatory dossiers
Marine permit, environmental impact, ICPE, environmental authorisation.
Use cases
Sites suited to SWAC
Hospital complexes
Continuous cooling needs, massive savings, long-term reliability.
Coastal hyperscale
Record PUE without air free-cooling. Major cooling decarbonisation.
Resorts & hospitality
Heavy cooling loads, premium energy image.
Urban cooling networks
Mutualisation at the scale of a district or a port city.
Port-side facilities
Coastal industrial processes needing continuous, stable cooling.
Technologies & scope
SWAC technical scope
Depths400 m to 1000+ m depending on the zone (tropical: 5-6°C from 700 m)
CapacitiesFrom 5 MW to 50+ MW of cooling capacity per loop
PipesHDPE PE100, GRP, coated steel; Ø 400 mm to 1600 mm
ExchangersTitanium plate, shell-and-tube, multi-pass; sea-water resistant
EnvironmentICPE study, thermal-discharge monitoring, coastal-law compliance
PartnersCluster Maritime Français, Pôle Mer Méditerranée, Capénergies
FAQ
Frequently asked questions
What is SWAC (Sea Water Air Conditioning)?
SWAC, also written seawater air conditioning, is a cooling system that uses naturally cold deep sea water (around 5°C in tropical zones, from 700-1000 m depth) as its cold source. This water cools a chilled-water loop through a heat exchanger, without a conventional refrigeration machine.
How much energy does SWAC save?
SWAC reaches an EER above 10 (versus 2.5 to 3.5 for conventional air conditioning), meaning 1 kWh of electricity produces more than 10 kWh of cooling, and a COP that can approach 25 on a well-designed loop. The result: up to −80% of cooling electricity. At CHU Sud Réunion hospital, this represents a 90% cut in cooling-related electricity.
Which sites are suitable for SWAC?
Coastal or island sites with access to deep cold water within a reasonable distance: overseas territories (Réunion, French West Indies, Polynesia), hospital complexes, coastal data centres, urban cooling networks, hospitality and port-side industrial sites.
How does a SWAC project differ from conventional air conditioning?
A SWAC is designed as a marine work, not as a conventional air conditioning system: it involves deep-water pipes, pumping stations, titanium exchangers resistant to sea water and integration with the existing cooling network. It is a specific engineering discipline that Value Park has operated since 2015.
What is the environmental impact of SWAC?
SWAC runs without fluorinated gases (high-global-warming refrigerants) and with very little electricity, resulting in very low CO₂ emissions. The warmed-water discharge is subject to studies and environmental monitoring (impact assessment, coastal-law compliance) to protect the marine environment.
Where to start?
Is this the right solution for your building? Value Smart starts by optimising the regime of your chilled-water network, then compares technologies on a common basis.
Is your site coastal or insular?
A SWAC pre-feasibility study can be launched in 4 to 6 weeks. Let's talk.
Our solutions