Portuguese 
English 
Spanish 
6 min of reading 
0 comments 
In Hawaii, the cold hidden at the bottom of the sea has become a real alternative for cooling large structures, cutting energy bills, and showing how hotels and buildings can rely less on expensive traditional systems.
Hawaii has become a showcase for a technology that replaces part of the effort of traditional air conditioning with a natural source of cold hidden in the ocean. Instead of constantly producing low temperatures with compressors, the system utilizes cold water taken from great depths.
This solution is already in operation in real structures in the archipelago and has gained traction because it addresses one of the highest costs in tropical regions. On islands, hotels and commercial buildings spend energy every day to maintain climate-controlled environments amid constant heat.
The case draws attention because it shows a concrete alternative for large consumers. The cold comes from the sea, passes through heat exchange equipment, and reduces the workload of conventional machines that usually weigh on the electricity bill.
-
Earth has hidden “scars” at a depth of 2,900 km, and scientists have just discovered that ancient plates still stir the planet’s interior.
-
Ozempic may have an unexpected effect beyond weight loss: study with nearly 100,000 people links semaglutide to reduced depression and anxiety.
-
Researchers from USP found mercury still active in the soil of the Atlantic Forest 52 years after illegal mining stopped in the area, and the contamination continues to pose a risk to plants, animals, and humans living in the region.
-
Get your heavy coat ready: an extratropical cyclone will create a corridor of cold air that hits Rio Grande do Sul starting Sunday with winds of 70 km/h, widespread frost between Tuesday and Wednesday, and a risk of rough seas on the Rio Grande do Sul coast during the week.
System in Kailua Kona uses deep water to cool administrative buildings
The real operation takes place in Kailua Kona, on the island of Hawaii, within a technology park created to research and utilize ocean resources. There, underwater pipelines capture cold water at depth and bring this resource to onshore facilities.
The system is known as seawater air conditioning. The logic is simple to understand but difficult to construct: to seek cold water where the ocean remains cool year-round and use that temperature to cool buildings.
The saltwater does not circulate within the environments. It passes through heat exchangers, cools another circuit of clean water, and that circuit carries the cold to the buildings. Thus, rooms, offices, and indoor areas receive climate control without direct contact with seawater.
Natural cold from the ocean reduces the heavy workload of compressors
Common air conditioning consumes a lot of energy because it needs to produce cold through compressors. On hot days, this effort increases, especially in large buildings that keep systems running for long periods.
With deep water, part of this cold already arrives ready from the ocean. The system still uses electricity for pumps, controls, and distribution, but cuts a significant portion of consumption because it reduces the need for compressors working at their limits.
This difference explains why the estimated savings can approach 70 percent in large-scale projects. The gain is especially evident where there is continuous consumption, high energy costs, and strong demand for climate control throughout the year.
According to Natural Energy Laboratory of Hawaii Authority, the state laboratory for ocean energy in Hawaii, the structure in Kailua Kona uses cold water from the deep sea and serves administrative buildings with ocean cooling.
This detail strengthens the case because it takes the technology out of the realm of distant promises. The system is not just a futuristic model, but an operation installed in an environment where the deep ocean is relatively close to the shore.
The geography helps a lot. In volcanic islands, the seabed drops quickly near land, making it easier to reach cold water without overly long pipelines. This condition transforms Hawaii into one of the most favorable places to test this type of cooling.
Hilton Hawaiian Village shows the scale of hotels that could benefit
The Hilton Hawaiian Village Waikiki Beach Resort, in Honolulu, helps explain why deep water cooling generates so much interest in Hawaii. The complex occupies a large area in Waikiki and brings together towers, restaurants, pools, lounges, event areas, and thousands of guests throughout the year.
There is no reliable confirmation that this Hilton operates a deep water system. Still, it well represents the type of consumer who could benefit from such a technology. In giant resorts, air conditioning is not a luxury, but an essential part of daily operation.
Rooms, corridors, kitchens, commercial spaces, lounges, and leisure areas need to maintain a pleasant temperature even under constant heat. In tropical destinations, this need becomes a heavy bill, especially when energy is expensive and hotel occupancy remains high for much of the year.
Honolulu planned to cool dozens of buildings with seawater
Honolulu even developed an urban project to use cold ocean water for cooling large commercial and public buildings. The proposal envisioned a centralized network capable of delivering climate control to dozens of buildings in a dense area of the city.
The plan worked with 25 thousand tons of cooling capacity and estimates of a reduction between 70 percent and 75 percent in electricity consumption linked to air conditioning. The idea was to replace isolated systems with a collective cooling infrastructure.
The project was canceled in 2020, after years of development, approvals, and a significant increase in costs. The case showed that the technology can generate great operational savings, but it depends on an expensive, complex, and very well-coordinated initial construction.
Energy savings became a decisive point for commercial buildings
Interest in this system is growing because climate control weighs heavily on the operation of large structures. In tropical regions, heat doesn’t just appear in one season. It pressures hotels, offices, and shopping centers almost all year round.
In hotels, this expense multiplies due to the demand for constant comfort. Guests expect cooled rooms, pleasant common areas, and air-conditioned event spaces, even when humidity and external temperature rise.
When a solution promises to reduce a large part of the energy used for cooling, it changes the logic of the sector. The impact involves not only sustainability but also operating cost, financial margin, and competitiveness in expensive tourist destinations.
Submarine cost still separates promise from reality
The main barrier is in construction. Capturing cold water at great depths requires resistant pipelines, corrosion protection, current studies, environmental licensing, and control of water return to the ocean.
This initial cost separates promising projects from viable ones. Cold water exists and the potential for savings is great, but the infrastructure needs to balance the books before the technology advances on an urban scale.
Therefore, Hawaii remains a strategic case. The operation in Kailua Kona proves that the system works in real buildings, while Honolulu showed that expanding the idea to an entire city requires much more capital and coordination.
The cold from the deep sea has entered the fight against heat. The technology doesn’t eliminate all electricity, but it reduces the burden of the most expensive part of the process, using the ocean as an invisible energy infrastructure for large coastal buildings.
Be the first to react!