Capillary heat exchangers offer potential for use as heat pumps in shallow coastal waters of the seabed to provide homes with a reliable supply of heat.

An international group of researchers tested the technology at a hotel in Qingdao, China, by placing a 250 m² capillary heat exchanger 5 m deep in the shallows, 50 m offshore and 300 m distant from the building. Water was heated to 40.6° C before being pumped from the seabed and transported to heat the air in the building.

According to researchers from Beijing University of Technology Beijing Municipal Institute of LaborCapillary heat exchangers offer potential for use as heat pumps in shallow coastal waters of the seabed to provide homes with a reliable supply of heat. Source: Nottingham Trent University Protection, Zhengzhou University of Light Industry and Nottingham Trent University (U.K.), heat would be delivered to homes through air-conditioning units, and the same technology could be used to cool structures in hot countries by harnessing the cooler seabed temperatures to supply cold air. Heat or cooling energy extracted from the seabed is transferred to an indoor heat exchanger by pump. An indoor heat exchanger then heats or cools the indoor air of the property through a system similar to an air-conditioning unit.

The extensive coastlines of the U.K., China and U.S. are ideal for deployment of this relatively low-cost system, which does not require auxiliary equipment such as filtration and water treatment. With a winter seawater temperature of only 3.7° C, the technology can produce up to 60 W/m² of heat energy to nearby coastal properties. The amount required to heat an average U.K. home is 100 W/m².