Dr. Takeshi Yasunaga Research Progress
in Institute of Ocean Energy, Saga University, Japan
(IOES)

IOES website
CV & Research publications
Saga University
Supported by JKA
Supported by JKA

Power Generation & Water Production 
Using Low Temperature Heat

1. Power Generation Systems
   OTEC (Ocean Thermal Energy Conversion)
   ORC (Organic Rankine Cycle)
2. Water Production (Desalination) Systems
   LTTD (Low Temperature Thermal Distillation)
   MD desalination (Membrane Distillation)
   SWRO (Seawater Reverse Osmosis)
3. Heat Exchangers
   PHE (Plate Type Heat Exchangers)
   Boiling/Condensation/Constructal Theory
   Superhydrophobic Surface

1. Power Generation Systems

OTEC is an ocean renewable power generation driven by temperature difference between surface and depth (600~1000m) in the ocean. The temperature difference of OTEC is only 20 Deg.C, however, it has huge potential to produce power.
ORC operates a Rankine cycle using organic materials as working fluid. The systems are mainly applied to low temperature heat such as geothermal, hot-spring water, indusctial waste heat and OTEC as well.

For OTEC and ORC, the research topics are optimized system design, performance improvement by considering innovative system configuration, and reconsider the conventional system performance evaluation method toward appropriate engineering way based mainly on finite-time thermodynamics.

2. Water Production Systems

- Seawater desalination systems-
 LTTD (Low Temperature Thermal Distillation) using ocean thermal energy is a reasonable method by combining with OTEC. The system design optimization, performance improvement by focusing on basic phenomenas on flush evaporation and condensation are the research topics. 
 Membrane Distillation (MD) desalination is another unique research topic. This MD process has a great potential for reducing unit power on water production, although the method is on the way to vefiry the performance of each membrane.
 In addtion, energy saving of SWRO (Seawater Reverse Osmosis) process is quiet important. Nowadays, vriable energy recovery devices are developed and commercialized. New concept of energy recovery device is an unique research topic.

3. Heat Exchangers: Plate Heat Exchangers (PHEs)


- Performance evaluation of boiling and condensation heat trasnfers as well as pressure drop in PHEs
- Performance evaluation of PHEs for maximization of power generation performance in OTEC and ORCs
- Geometry development of heat transfer area in PHE based on constructal theory
- Heat trasfer performance enhancement applying superhydrophobic surface

Questions?

Please contact
Takeshi Yasunaga, Associate professor
Institute of Ocean Energy, Saga University (IOES), Japan
E-mail: yasunaga(at)ioes.saga-u.ac.jp
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