3.4. Ocean thermal energy conversion (OTEC)
Ocean thermal energy conversion (OTEC) makes use of the
temperature difference between the warm surface of the ocean
and the colder layers underneath as illustrated in Fig. 9. The
amount of energy due to solar heating available in the temperature gradient between the hot and cold seawater can be substantially larger than the energy required to pump the cold
seawater up from the lower layers of the ocean. The warm water
from the surface is used to boil a working fluid (the seawater itself
under low pressure in open cycle systems). The working fluid
then runs through a turbine and being condensed using the cold
seawater pumped from the depths. OTEC is best suited to areas
near the equator, where the intense solar radiation warms the
surface significantly [52].