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Seawater Air Conditioning

UH Sea Grant-funded researcher created world’s first seawater air conditioning unit

In the early 1980’s, Dr. Arlo Fast, a University of Hawai‘i Sea Grant College Program-funded researcher, successfully created the world’s first Sea Water Air Conditioning Unit (SWAU). The prototype SWAU consisted of two components, an old truck radiator and a household box fan. It worked by pumping cold seawater through the radiator’s coils and blowing hot room air over the same coils. The radiator transferred heat from the hot lab air into cold seawater flowing through these coils, while the box fan circulated air over the coils. Today, deep seawater cooling technology is recognized as a sustainable and economic way to cool entire buildings and, in some cases, entire cities. From its humble beginnings as Dr. Fast’s innovative SWAU using deep seawater while working on a project for UH Sea Grant, to the implementation of such technology into Downtown Honolulu buildings and cities around the world, the future of deep seawater cooling technology will provide environmental and economic benefits to a growing number of coastal communities.

Seawater Air Conditioning in Waikīkī

Visitors to Hawai'i consume more energy, place a greater burden on infrastructure, and generate more greenhouse gas emissions than residents. The high energy and infrastructure intensity of visitors as compared with residents suggests the importance of efficiency and demand-side management for any tourism related industry. Waikīkī, with the highest tourist to resident ratio in the state, could be the most important area for an energy efficiency program. For large buildings and hotels, air conditioning represents the single major source of energy demand and cost, with an estimated 42% of Hawai'i's hotel energy consumption being used for AC. 

Comparing Resident and Visitor Infrastructure and Petroleum Demands

Comparing Resident and Visitor Infrastructure and Petroleum Demands

Source: Konan (2004)

With funds received through the American Recovery and Reinvestment Act of 2009 (ARRA), Public Law 111-5, the Strategic Industries Division (SID) of the State of Hawai'i Department of Business, Economic Development, and Tourism (DBEDT) contracted with the University of Hawai'i Sea Grant College Program to provide an analysis of, and corresponding public outreach program on, implementing a district-wide seawater air conditioning (SWAC) system for Waikīkī. SWAC has been used in many parts of the world and is a proven energy efficiency technology. As one of the most energy intensive areas of the state, Waikīkī, with its high building density, is considered a prime location for a SWAC system.

- Konan, D. E. (2004). Tourism and Climate Change in Hawaii. Report delivered at 2nd International Workshop on
  Integrated Climate Models: An Interdisciplinary Assessment of Climate Impacts and Policies