Outline of Current Theme and their Results
OTEC Power Generation System with Ammonia-Water Mix as the working fluidThe Rankine Cycle, which uses pure substances such as ammonia as the workingfluid, used to be the main stream in OTEC technology.
These days, however, anew system "Uehara Cycle", which uses ammonia-water mix as the working fluid, isbeing keenly watched by people concerned. Theoretical verification of UeharaCycle has been successfully finished to affirm of unrivaled higher efficiency ascompared to other methods.
We are currently conducting experimental andtheoretical study to enhance efficiency of each component part such ascondenser, heat exchanger, turbine, etc.
Desalination TechnologyAn OTEC power plant can generate not only electric power but also fresh watertoo by simple addition of related devices. Aiming at increased efficiency ofthis integrated OTEC plant, we are currently conducting theoretical andexperimental studies on desalination by means of spray flash method.
Refrigerator with Ammonia as RefrigerantNo more Freon is allowed to use, while the world attention is being given to useof natural refrigerant. Under these circumstances we are carrying on studies,with environment friendly ammonia as refrigerant, of performance improvement ofrefrigerator with plate type heat exchanger. Especially, how to lessen thevolume of ammonia to be filled up is an important subject.
Antifouling TechnologyAn OTEC plant as well as thermal power plants uses seawater and thereforeantifouling technology for heat exchanger is very critical subject.
We aredeveloping antifouling technology with ozonization, instead of chloride method,which used to most popular. Ozonation is more environmental friendly andeffective than chloride method.
Antifouling is particularly critical for heatexchanger and seawater intake pipings.
Research Works for Advanced Evaporator and CondenserEvaporator and condenser of shell and tube type used to be the sole idea in theconventional OTEC system. In pursuing ways and means forever improvedefficiency, we Saga University have successfully developed for the first time inthe world that equipment with plate version. Our plate type heat exchangers areaffirmed to make an OTEC system economically competitive enough forcommercialization.
We are the patent holder of this Plate type heatexchanging technology.
Needless to say, Plate type heat exchangers have beenwidely used in other fields, where heat exchanging between liquids is applied,which is referred to as single phase heat exchanging. What we have developed isfor application for evaporation and condensing, which is referred to astwo-phase heat exchanging in the gas and liquid region of several workingfluids.
We are currently engaged in further developing of plate type heatexchangers for power generation system, refrigerators, heat pumps, anddesalination, etc. by utilizing pure substances and/or mixed working fluids.Representation Journal paper
Article of Newspaper and Journal (since 1992)
on TV (since 1992)