Energy From the Oceans

Energy From the Oceans

More promising technology is OTEC (Ocean Thermal Energy Generation). This takes advantage of the fact that the ocean is an enormous heat engine.

Physics of Heat Engines:

Thermodynamic Constraints:

To get the highest efficiency one wants to maximize the difference between T1 and T2 but then their are material problems (containers melt, freeze, etc)

Typical Case:

How this all works:

  • Exhaust steam is condensed back into liquid thereby decreasing its total volume by a factor of 1000
  • Therefore the work done by the pump is down by a factor of 1000 compared to if it had to pump steam directly back into the system

    Heat Energy from the Ocean

    Do this:

    Basic principle is that heat difference is used to condense a steam into a liquid then return it to be reheated.

    Since heat differences in the ocean will be smaller, then one must substitute ammonia for water as the working fluid.

    Example Calculations:

    OTEC Potential Sites:

    Above sites typically have thermal gradients higher then 22 degrees C

    Energy extracted comes from the cooling of the warmer water this is transferred to the ammonia which does the actual work of turning the turbine (as ammonia steam)

    Energy extracted proportional to the volume of water and the temperature it drops.

    Principal energy loss is when the warmer water meets the cooler water in the condenser.

    Review of OTEC (Ocean Thermal Energy Conversion)