Open and closed cycle ocean thermal energy conversion

Closed Cycle Otec System

The siting of an OTEC plant, either onshore or offshore, represents one of the key decision for any proposed project. The other key decision is the type of cycle to use. There are two principle options, an open cycle plant or a closed cycle plant. Hybrids of the two have also been proposed. A closed cycle OTEC plant employs a thermodynamic fluid such as ammonia or a refrigerant like freon. This is contained in a completely closed system including the plant turbine. Hot surface seawater is used...

Combined cycle power plants

Solar Power Plant Block Diagram

A single gas turbine connected to a generator can generate electricity with a fuel-to-electricity conversion efficiency of perhaps 38 using the best of today's technology. New developments, such as those falling under the auspices of the US DOE's ATS programme aim to push the simple cycle efficiency as high as 41 without cycle adaptation, 43 with adaptation such as recuperation. This is still marginally lower than a modern coal-fired power plant can hope to achieve. Part of the reason for this...

Horizontal or vertical

Egg Beater Darrieus Dimensions Shape

As outlined above, the standard wind turbine has a vertical rotor attached to a horizontal shaft. This arrangement imposes certain restrictions on the wind turbine design. With a horizontal shaft, the rotor turns in a vertical plane and must be raised on a tower so that the blades are clear of the ground and of the turbulent layer of air next to it. Gearbox and generator are attached directly to the turbine shaft so these, too, must be placed on the tower, high above ground. This raises the...