With a neat sketch, explain the working principle of a closed-cycle OTEC power station.

Closed-Cycle Ocean Thermal Energy Conversion (OTEC) System

A Closed-cycle OTEC system utilizes the temperature difference between warm surface seawater and cold deep seawater to generate electricity. The process involves a working fluid with a low boiling point, such as ammonia, which is cycled through the system to convert thermal energy into mechanical energy and then into electrical energy.

Components and Working:

1. Warm Water Intake: Surface seawater, warmed by the sun, is pumped into the heat exchanger (evaporator).
2. Heat Exchanger (Evaporator): The warm seawater heats the working fluid (e.g., ammonia) in the evaporator. The working fluid boils and turns into high-pressure vapor.
3. Turbine: The high-pressure vapor drives a turbine connected to a generator. The turbine converts the thermal energy of the vapor into mechanical energy.
4. Generator: The mechanical energy from the turbine is converted into electrical energy by the generator.
5. Condenser: Cold deep seawater is pumped into the condenser. The vaporized working fluid is condensed back into a liquid by transferring its heat to the cold seawater.
6. Pump: The liquid working fluid is pumped back to the evaporator to repeat the cycle.

Working Steps:

1. Heat Absorption: Warm surface seawater is pumped into the evaporator, where it heats and vaporizes the working fluid.
2. Energy Conversion: The vaporized working fluid expands and drives the turbine, which converts the thermal energy into mechanical energy.
3. Electricity Generation: The turbine is connected to a generator, which converts the mechanical energy into electrical energy.
4. Heat Rejection: Cold deep seawater is pumped into the condenser, where it cools and condenses the vaporized working fluid back into a liquid.
5. Cycle Continuation: The liquid working fluid is pumped back to the evaporator to continue the cycle.

or