OTEC Demonstration Plant

Project: Makai’s OTEC Demonstration Plant

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Makai is designer, owner and operator of an OTEC Demonstration Plant, which is part of Makai’s Ocean Energy Research Center. The purposes are:

  • Heat exchanger testing for OTEC and other marine applications;
  • Marine corrosion research;
  • OTEC power generation, turbine and system controls.

Years: 2009-2016
Funding source: Hawaii Natural Energy Institute & Office of Naval Research, Naval Facilities Engineering Command & Hawaii Technology Development Venture

An OTEC test facility was built at the Natural Energy Laboratory of Hawaii (NELHA), on the Big Island of Hawaii starting in 2009 and has been in operation since. The primary purpose is for corrosion and performance testing of OTEC heat exchangers, which make up a major part of the capital cost of an OTEC plant. The 40′ tall OTEC tower supports up to six heat exchangers (three evaporators and three condensers), 24″ seawater piping, and an instrumented ammonia system. A prototype heat exchanger will have about one square meter in cross section and a height ranging from 2-8 meters tall. The facility allows Makai to measure the performance of the heat exchangers as a function of water velocity, temperature difference, and ammonia flow rate. The schematic shows the facility with a condenser on the left, an evaporator on the right, and the direction of the ammonia vapor/liquid flow. In addition to heat exchanger testing, the facility is becoming a working OTEC power plant. A turbine-generator is being added to the top of the tower in 2014 to supply closed-cycle-OTEC electricity to the US grid for the first time ever. Turbine and system controls will be developed to control the power plant autonomously, with the goal of applying this software and operational knowledge to a large OTEC plant. NAVFAC/ONR sponsored the facility because both the heat exchanger test results and power plant controls can be applied to large commercial OTEC plant designs. Knowing the heat exchangers’ performance is especially critical for larger OTEC plants. In alignment with APTEP goals, Makai is collaborating with other OTEC groups in the Asia-Pacific region at this facility.

Makai Ocean Energy Research Center, Big Island (Source: Makai)

The OTEC demonstration plant is part of Makai’s Ocean Energy Researh Center, at the Natural Energy Laboratory of Hawaii (NELHA), Kailua-Kona, on the Big Island of Hawaii.

OTEC Heat Exchanger Test Facility (Source: Makai)

Read More about OTEC

News Release

Makai’s Ocean Energy Research Center (OERC) in Kona, Hawaii has received several major pieces of equipment for its Ocean Thermal Energy Conversion (OTEC) demonstration plant last October. Two new heat exchangers (2-megawatt thermal duty each), and a 100 kilowatt ammonia turbine-generator have arrived and are in various stages of installation and testing. To date, Makai has tested four condensers and three evaporators at the OERC, each made of either aluminum or titanium. The facility has been designed to easily swap out OTEC heat exchangers, and test as many as six simultaneously.

APV installation (Source: Makai)
OTEC HX APV Crossflow Oct 2014 (Source: Makai)
Turbine Installation (Source: Makai)

(Photos courtesy of Makai Engineering)

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