Ocean thermal energy conversion method and system

Patent metadata

Field	Value
Publication number	US-9835143-B2
Application number	US-201214349082-A
Country	US
Kind code	B2
Filing date	Sep 11, 2012
Priority date	Oct 7, 2011
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

The invention is an ocean thermal energy conversion method and a system in which a motive fluid having predetermined characteristics is circulated in a closed loop between a cold source in cold deep ocean water and heat sources in warm surface water. The motive fluid is compressed between the cold source and a first primary warm water heat source resulting in the motive fluid being substantially totally vaporized at an outlet of the warm water heat source. The motive fluid is heated downstream from the primary heat source by a secondary heat source. The thermal energy of the heated motive fluid is recovered from a turbine and the motive fluid is condensed in the cold source.

First claim

The invention claimed is:

1. An ocean thermal energy conversion (OTEC) method comprising:
circulating a motive fluid in a closed loop between a deep cold ocean water source providing deep cold ocean water and a warm surface ocean water source providing warm surface ocean water, the deep cold ocean water source comprising a first heat exchanger disposed between the motive fluid and the deep cold ocean water and the warm water source comprising a second heat exchanger disposed between the motive fluid and the warm surface ocean water for heating the motive fluid from heat provided from the warm surface ocean water;
compressing the motive fluid circulating in the loop downstream from an outlet of the first heat exchanger;
heating the compressed motive fluid circulating in the loop with the second heat exchanger to be at least substantially vaporized at an outlet thereof;
heating the substantially vaporized motive fluid circulating in the loop downstream from the outlet of the second heat exchanger with a secondary heat source;
recovering thermal energy with a first and a second turbine stage from the heated substantially vaporized motive fluid circulating in the closed loop which has been heated by the secondary heat source and second heat exchanger; and
condensing the motive fluid flowing in the closed loop through the deep cold ocean water source, and wherein
the secondary heat source is a heat pump;
heating the motive fluid in a third heat exchanger downstream from the first turbine stage and upstream from the second turbine stage; and
splitting the motive fluid downstream from the turbine stages into a first portion and a second portion, compressing the first portion and recirculating the compressed first portion back to the third heat exchanger to transfer heat to the motive fluid flowing through the third heat exchanger, expanding the first portion downstream from the third heat exchanger, and combining the first portion with the second portion.

2. A conversion method as claimed in claim 1 , wherein:
the deep cold ocean water source includes a closed loop containing a refrigerant which thermally exchanges heat with the deep cold ocean water.

3. An ocean thermal energy conversion (OTEC) system comprising:
means for providing closed-loop circulation of a motive fluid between a deep cold ocean water source providing deep cold ocean water and a warm surface ocean water source providing warm surface ocean water, the deep cold ocean water source including a first heat exchanger disposed between the motive fluid circulating in the closed loop and the deep cold ocean water and the warm surface ocean water source including a second heat exchanger disposed between the motive fluid circulating in the closed loop and the warm surface ocean water;
means for providing compression of the motive fluid circulating in the closed loop;
the second heat exchanger heats the motive fluid so that the motive fluid is substantially vaporized at an outlet of the second heat exchanger;
a secondary heat source disposed downstream from the outlet of the second heat exchanger for heating the substantially vaporized motive fluid circulating in the closed loop;
means for recovering thermal energy from the heated substantially vaporized motive fluid; and
the first heat exchanger condenses the motive fluid circulating in the closed loop downstream from the means for recovering thermal energy; and wherein
the secondary heat source is a heat pump;
the means for recovering thermal energy from the heated substantially vaporized motive fluid circulating in the loop comprises two turbine stages;
the system further comprising a third heat exchanger disposed between the two turbine stages; and
a means for splitting the motive fluid downstream from the turbine stages into a first portion and a second portion, a compressor for compressing and circulating the first portion in the closed loop back to the third heat exchanger to transfer heat to the motive fluid flowing through the third heat exchanger, a means for expanding the first portion downstream from the third heat exchanger, and a mixer for combining the first portion with the second portion.

4. A conversion system as claimed in claim 3 , wherein:
the deep cold ocean water source comprises a closed loop containing a refrigerant fluid that exchanges thermal energy between the motive fluid and the deep cold ocean water.

Assignees

• Teixeira David
• Mabile Claude
• Ifp Energies Now

Inventors

• Teixeira David
• Mabile Claude

Classifications

• F03G7/05 Primary

  Ocean thermal energy conversion, i.e. OTEC · CPC title

• F01K7/22

  the turbines having inter-stage steam heating · CPC title

• F01K19/02

  Regenerating by compression · CPC title

• Y02E10/30

  Energy from the sea, e.g. using wave energy or salinity gradient · CPC title

• Y02E10/34

  Cross-Sectional Technologies · mapped topic