Seawater temperature difference energy refers to the thermal energy that maintains the water temperature difference between surface seawater and seawater deep. It is an important form of ocean energy. The ocean surface converts most of the sun's radiant energy into warm water and stores it in the upper layers of the ocean. On the other hand, large areas of near-freezing water flow slowly from the poles toward the equator at depths less than 1,000 meters. In this way, vertical seawater temperature differences of more than 20°C occur throughout the year in many tropical or subtropical marine areas. This temperature difference can be used to carry out thermodynamic cycles and produce electricity.
The cause of the difference in ocean temperatures is solar energy. The energy difference of temOcean temperature is also called ocean thermal energy. The water temperature difference in the middle and upper layers of the ocean contains a certain amount of energy, called the seawater temperature difference energy.
About 60% of the Solar radiation reaching the water surface is transmitted to a depth of 1 meter. 18% can reach a depth of 10 meters below the sea surface, and a small amount of solar radiation can even penetrate to a depth of less than 100 meters underwater. Sea water temperature changes with water depth. Generally, the deep water zone can be roughly divided into three layers. The first layer extends from the sea surface to a depth of about 60 meters, called the surface layer. The seawater layer on the one hand absorbs the radiant energy of the sun and is also affected by the influence of wind and vagues, which causes the seawater to mix and the temperature of this seawater layer changes relatively little. The water temperature is around 26 to 27 degrees Celsius. The second layer extends from a water depth of 60 meters to 130 meters. The temperature of sea water decreases sharply with depth and the temperature changes significantly, becoming a variable temperature layer. The depth of the third layer is more than 300 meters. Due to the influence of cold water from the polar regions, the temperature of this seawater layer drops to around 4 degrees Celsius. There is a temperature difference of more than 20 degrees Celsius between surface seawater and deep seawater, which is a huge source of energy.