With alternative energies growing in the U.S., one process that might not be as well known is called ocean thermal energy conversion (OTEC). The process generates electricity from the heat accumulated in the Earth's oceans. The energy recovery method is most practical when the difference in temperatures from the top of the ocean and the colder and deeper ocean water is more pronounced.
When the colder water is brought to the surface, ocean thermal energy conversion processing plants are able to use intake pipes that are submerged around a mile deep to capture the energy.
Using heat exchangers in OTEC
There are several complementary pieces of equipment that are used to help generate power in the OTEC process, the Office of Energy Efficiency and Renewable Energy reported. One of them is a heat exchanger, which converts the different temperatures of water through the device into energy.
"Warm surface seawater is pumped through a heat exchanger, where the low-boiling-point fluid is vaporized," the EERE stated. "The expanding vapor turns the turbo-generator. Cold deep seawater – which is pumped through a second heat exchanger – then condenses the vapor back into a liquid that is then recycled through the system."
OTEC plant adds two heat exchangers
Recently, Maki Ocean Engineering based in Kona, Hawaii, obtained two massive heat exchangers for its OTEC process and demonstration plant, Pacific Business News reported. The processing plant was created to help educate the public and businesses on the commercial practicability of OTEC working as a renewable energy source.
Maki Ocean Engineering pumps massive volumes of deep cold seawater and the warmer surface water to run its power cycles and generate power, the source reported. The Kona-based plant is the largest OTEC research facility across the globe and the two new 100-kilowatt ammonia turbine generator heat exchangers will be used in different stages.
The new heat exchangers will perform numerous tests and the OTEC plant has already tried out four condensers and three evaporators. All of the research equipment has been made of either aluminum or titanium, the Pacific Business Journal reported.
The facility was created for engineers to easily swap heat exchangers for OTEC and have the ability to test up to six at the same time as well, OTEC News reported. While the heat exchangers will be the most expensive piece of the commercial offshore plant, the equipment will help optimize its lifetime, performance and eventual return on investment.
The research center also allows engineers to build, test and design different options for the heat exchangers to find the best solution while generating the renewable energy. The system includes thousands of high precision sensors that will be able to analyze the information gathered from the heat exchangers to determine corrosion resistance.
They will also be able to test the heat exchangers' performance, such as heat transfer and hydraulic efficiencies and the cost of the entire OTEC platform all together, the source reported.
With the new facility turning to the heavy-duty equipment, other industries can also see benefits from switching to stainless steel and other higher alloys for their shell and tube heat exchangers, which prevent corrosion and last for years.