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SWAC (Sea Water Air Conditioning) for hotel districts

Sea Water Air Conditioning (SWAC) uses naturally cold, deep seawater to cool buildings instead of conventional air conditioning systems. A pipeline brings seawater from depths of around 800–900 meters to a shore-based heat exchanger, where its cool temperature is used to chill freshwater that circulates through hotels and resorts. After use, the seawater is returned to the ocean at a depth where its temperature matches the surrounding water. This approach can cut cooling energy use by up to 90%, reducing reliance on fossil fuels and greenhouse gas emissions. For Caribbean islands, where air conditioning accounts for up to 55% of hotel electricity consumption, SWAC could offer a sustainable alternative under rising heat stress.

Feasibility & Local Applicability

Curacao, Aruba, and St. Martin have favorable conditions for SWAC: deep ocean water is accessible close to shore, and tourism creates concentrated cooling demand. Projects like the Zakito District Cooling system in Curacao show strong local interest and technical viability. However, SWAC requires high upfront investment for marine pipelines and pumping stations, and specialized engineering expertise. Environmental assessments are needed to ensure marine ecosystems are not harmed. Business models often combine public and private financing to overcome initial cost barriers.

Co-benefits

SWAC reduces operating costs for hotels, which face high electricity prices. It also lowers carbon emissions, supports sustainable tourism branding, and improves resilience by reducing dependence on imported fuels. The system is quiet, improves indoor air quality, and can integrate with other technologies like desalination or aquaculture, creating opportunities for the blue economy.

Equity & Vulnerability Considerations

To ensure equitable benefits, tariff structures should allow small and medium-sized enterprises (SMEs) to join district cooling networks. Environmental safeguards are essential to protect marine biodiversity near intake and discharge points. Community engagement and transparent governance can help avoid exclusion of smaller businesses and address concerns about ocean health.

Costs

High | Capital costs are significant—often tens of millions of dollars for district-scale systems—due to marine infrastructure and specialized equipment. However, operating costs are much lower than conventional cooling, and payback periods can be attractive for large clusters of hotels. Financial viability improves when systems serve multiple facilities, spreading costs across users.

Case studies & Examples

Literature

Adaptation Options Overview