The osmotic pressure generation was firstly presented as pressure-retarded osmosis (PRO) power generation by S. Loeb in 1976. The possibility and problems of the production of hydroelectric power by osmotic pressure generation have been discussed by S. Loeb, Takeo Honda, Fukuoka Water Service Consortium and SINTEF. They, however, have not been realized because of the problems in membranes though the power production cost is was low. In this paper those problems in the membrane are introduced and the way how to solve them is discussed.

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Energy, water, air and food are the essential requirements for the continuous evolution of mankind. However, mankind in the 21st century will face five important issues such as lack of energy, water and food, world wide environmental problems such as climate warming and rapid growth of world populations.
Ocean thermal energy conversion (OTEC) is a system to convert the thermal energy to the electricity by using temperature difference between warm surface seawater and cold depth seawater. The large amount of warm seawater and cold seawater are used to generate large electricity in OTEC plant. The fresh water can be obtained using warm and cold seawater used in OTEC and moreover, hydrogen is produced using fresh water and electricity. Depth seawater contains 0.2 ppm lithium. The lithium can be collected from depth seawater. Moreover, seawater mixed warm and cold seawater used in OTEC plant, desalination plant, etc. is flowed to ocean and is used in aquaculture to raise many types of fish and shellfish. We call it the complex OTEC used for multiple purposes as Integrated OTEC Systems (I-OTECS). In this paper, the present status and future of I-OTECS is presented.

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This paper introduces the efforts toward the practical use of wave generation system. Firstly outline of the property of wave energy itself is briefly explained. Then the quantity of wave energy around Japan and the seasonal variation are indicated with focus on the contrast between the sides faced to the Sea of Japan and Pacific Ocean. Also, various apparatuses devised in order to extract wave energy are introduced pointing out the advantages and disadvantages. Then project for developing wave energy conversion technique held in Yamaguchi University is indicated. Basic idea, dynamic model for designing the apparatus are given, then the proposal is given for utilization with little disadvantages of unstable energy gain inevitable to natural energy.

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In order to realize a sustainable society, development of renewable energy is one of the most essential issues and introduction and expansion of wind power generation is expected. Because of stable and strong wind condition, offshore areas are considered to be suitable for wind power generation. The study on development of wind power generation at port and coastal areas was implemented under the study committee that consists of industrial, administrative and academic sectors. This report introduces an outline of the result of the study.

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An array of alternating anion and cation exchange membranes can be used to generate electric power from the free energy of mixing of dilute and concentrated salt solutions, and is referred to as a dialytic battery. Its operation is a reversal of conventional electrodialysis desalination. Experimental and theoretical studies on the dialytic batteries were reviewed and necessary conditions for the dialytic batteries of practical use and of optimum performance were discussed.

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Experimental study on the performance of an Ocean Thermal Energy Conversion (OTEC) plant was carried out using the Uehara cycle, which uses an ammonia/water mixture as the working fluid. Shell and plate type heat exchangers are used as an evaporator, a condenser, a regenerator and a heater. We estimated the system performance and the stability of the Uehara cycle for OTEC by means of steady operation with 29°C warm water temperature, 193.7kg/s warm water mass flow rate, 8°C cold water temperature, 111.1kg/s cold water mass flow rate and 30 kW turbine power for 5 hours. As a result, the system was highly stable. Under those conditions, the overall heat transfer coefficient of the evaporator was 1.401kW/(m²·K) and that of the condenser was 0.725kW-/(m²·K). The No.1 turbine output was 19.2 kW and the turbine efficiency was 60.1%. No.2 turbine output was 11.5 kW and the efficiency was 76.8%. The overall heat transfer coefficients of the evaporator and condenser were determined from the test to estimate the effect of the heat source mean velocity in the plate type heat exchangers.

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The Uehara cycle for OTEC uses ammonia/water as the working fluid. The mass fraction of the ammonia/water mixture affects the cycle thermal efficiency. In this paper, we analyzed the influence of various parameters using two regenerator models for heat transfer performance in order to bring out the optimum mass fraction that provides the maximum cycle thermal efficiency. In addition, we study how the heat transfer performance of the regenerator affects the cycle thermal efficiency. The given parameters were the evaporator outlet pressure, the evaporator outlet temperature, the condenser outlet temperature, the ratio of extraction flow rate, the extraction pressure and the evaporator outlet mass fraction. As a result, an optimum mass fraction was found to exist because changing the mass fraction alters factors that influence cycle thermal efficiency, such as the ratio of vapor separation at the separator, the condensate pressure and the heat transfer rate of the evaporator. Because a high optimum mass fraction causes an increased ratio of vapor separation at the separator, the influence of the regenerator on cycle thermal efficiency is reduced. The optimum mass fraction is affected more by the evaporator outlet temperature of the working fluid than the condenser outlet temperature of the working fluid. The condenser outlet temperature affects the optimum mass fraction significantly if the heat transfer performance of the regenerator is lower.

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This paper describes the performance analysis of desalination system in the Fiji island where is one of suitable sites proposed for the desalination. On December 12-18, 2003, December 4-6, 1999, December 3-5, 1998, December 3-4, 1997 and December 5-7, 1996 investigations of marine metrology, such as temperature, salinity, dissolved oxygen rate and submarine cross section was carried out by a research ship of the National Fisheries University. A conventional design for the desalination system is conducted with these data. The consuming electric power per product water is used as an objective function. A desalination rate of 1,000 tons per day using plate-type heat exchangers has been reported. Approximate correlation for a objective function is obtained.

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The effect of salt (NaCl, KCl, CaCl₂, MgCl₂ and MgSO₄) in various ratios on the taste of simulated mayonnaise emulsions prepared with triacylglycerol and diacylglycerol was measured. A 0.8% aqueous solution of six brands of commercial salt and emulsions containing these ingredients at concentrations of 0.8% and 2.0% were subjected to a sensory evaluation. The saltiness intensity of all the commercial salt solutions was significantly weaker than that of an NaCl solution, while the emulsions prepared with each commercial salt at both 0.8% and 2.0% concentrations did not show such a difference. The bitterness intensity of the aqueous solution of commercial salt B, which contained 57.2% of KCl, was significantly stronger than that of NaCl, the emulsion of this salt at 0.8% concentration also being more bitter. However, at a concentration of 2.0%, there was no significant difference in such bitterness. There was significantly lower preference for the salt solution and emulsions containing salt B than for the samples containing NaCl, although there was no such difference with the other commercial salt brands. It is concluded that the use of salts other than NaCl would have no effect on the taste of viscous food such as mayonnaise.

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