Techno-economic analysis of the Sea Water Air Conditioning technology under real operating conditions as a sustainable space cooling solution on a global scale

The deep water of seas and oceans is an important resource that remains currently poorly known and underutilized. Thermal energy production is one possible use, but there are many others. The use of deep water for space cooling is a particularly promising application because air conditioning of buildings is expected to become a significantly more energy-intensive sector in the coming years due to economic growth, population expansion, and the intensifying effects of climate change. While conventional air conditioning systems, predominantly relying on vapor compression cycles, have attained technological maturity, their energy efficiency is expected to cease significant growth. Meanwhile, passive cooling solutions such as natural ventilation and electric-powered fans may prove insufficient in maintaining indoor comfort in hot and humid climates. Addressing these challenges necessitates the pursuit of more efficient cooling solutions, especially to ensure indoor comfort during extreme heatwaves. Deep Sea Water Air Conditioning (SWAC) technology emerges as a promising alternative to both conventional and passive cooling methods, as recent measurements showcase its remarkable performance. By drawing seawater from great depths (over 900m), SWAC systems directly cool buildings without the need for supplementary backup systems, ensuring precise indoor temperature regulation. This article provides a comprehensive performance analysis of two SWAC installations deployed in French Polynesia across various building types. One installation has been serving a hotel since 2011, while the other was commissioned to supply a hospital in 2022. These installations are fully instrumented, enabling precise determination of energy performance metrics and operating parameters, which influence performance. Moreover, the great originality of this study is that one of the two buildings operated for more than 10 years with a conventional air conditioning (chillers) before transitioning to SWAC. The measurements carried out on this building before and after connection to the SWAC make it possible to clearly establish experimentally the gains offered by this technology. To complete the energy performance characterization, this article proposes an economic evaluation based on actual operating costs, highlighting the advantages and potential drawbacks of SWAC as a replacement for conventional air conditioning systems. At the end, this article presents the worldwide potential for SWAC application, identifying all regions where the technology can be utilized.