JPH05340342A - Ocean thermal energy conversion device - Google Patents

Abstract

PURPOSE:To decrease a loss factor of plant-home use by driving hot and cold water pump by turbines, and providing a separate cycle from that for driving a generator, to improve heat cycle efficiency. CONSTITUTION:When hot seawater in an oceanic surface is successively fed to evaporators 3a, 3b, 3c by a hot water pump 2, operating media 4a, 4b, 4c of low boiling point are heated by the hot seawater and evaporated. This medium steam is guided to turbines 5a, 5b, 5c, to drive the hot water pump 2 by the turbine 5a, generator 6 by the turbine 5b and a cold water pump 9 by the turbine 5c. The medium steam of decreasing pressure and temperature by giving energy is advanced into condensers 7a, 7b, 7c, cooled by cold seawater 8 fed from the cold water pump 9 and successively condensed to become media liquid, and it is returned respectively to the evaporators 3a, 3b, 3c by media pumps 10a, 10b, 10c. In this way, evaporating and condensing temperatures of the operating media can be generated to approach a heat source temperature in high and low temperature sides, and heat cycle efficiency of a generating unit can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power generator that utilizes the temperature difference between warm seawater on the surface of the ocean and cold seawater in the deep sea, and more particularly to improving the efficiency of the power generator.

[0002]

2. Description of the Related Art A power generator that utilizes the temperature difference between warm seawater on the surface of the ocean and cold seawater in the deep sea is known as one technique of a power generator that utilizes natural energy. No.360, P.560-563.

To explain the outline of this technique with reference to FIG. 3, warm seawater 1 on the ocean surface is sent to an evaporator 3 by a warm water pump 2.
In the evaporator 3, a low boiling point working medium 4 such as ammonia is heated by the warm seawater 1 and evaporated. This medium vapor is guided to the turbine 5 and drives the turbine 5, so that the generator 6 coupled thereto rotates to generate electricity. The medium vapor that has been given energy to the turbine 5 and whose pressure and temperature have dropped enters the condenser 7. On the other hand, since the cold seawater 8 in the deep sea is supplied to the condenser 7 by the cold water pump 9, the medium vapor entering the condenser 7 is cooled by the cold seawater 8 and condensed to become the medium liquid, and the medium pump 10 evaporates it. Return to 3. The hot water pump 2, the cold water pump 9, and the medium pump 10 are driven by the hot water pump motor 11, the cold water pump motor 12, and the medium pump motor 13, respectively. Therefore, a part of the electric power generated by the generator 6 is used as the power for these power plants. It is used inside the plant, and the surplus inside the plant is transmitted to the outside.

[0004]

The energy possessed by the ocean is enormous, but the temperature difference to be utilized in such a device is only about 20 ° C., which is even better than other natural energy such as solar heat and geothermal heat. Since a small temperature cannot be taken, the problem is how to increase the temperature difference between the evaporation temperature and the condensation temperature of the working medium.

Further, since the enthalpy difference between the working medium before and after the turbine is small, the flow rate of the fluid in each system is large relative to the generated power, and the power of each pump is large. That is, since the power generation device has a large ratio of power in the plant, the plant ratio may reach 1/2 to 2/3, depending on the temperature conditions and scale, and the electrical device becomes abnormal due to the power source in the plant. It will be big. An object of the present invention is to provide an ocean thermal energy conversion power generation device having a high thermal cycle efficiency and a small in-house ratio.

[0006]

In order to achieve the above object, the present invention is characterized in that the hot water pump and the cold water pump are driven by a turbine, and a cycle different from that for driving the generator is provided.

[0007]

Since three cycles for driving the hot water pump, driving the generator, and driving the cold water pump are provided, it is possible to set the medium evaporation temperature in three stages suitable for the temperature changes of the hot seawater and the cold seawater. The overall thermal cycle efficiency is improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIG. Devices that are not directly related to the basic principle of the present invention are omitted as in FIG.

In this embodiment, warm seawater 1 on the surface of the ocean is sequentially sent to the evaporators 3a, 3b and 3c by a warm water pump 2. In the evaporators 3a, 3b, 3c, the low boiling point working mediums 4a, 4b,
4c is heated with warm seawater 1 and evaporates. This medium vapor is guided to the turbines 5a, 5b, 5c, and the turbines 5a, 5b
Drive b and 5c. The turbine 5a uses the hot water pump 2,
The turbine 5b drives the generator 6, and the turbine 5c drives the chilled water pump 9. The medium vapor whose pressure and temperature have been lowered by applying energy to the turbines 5a, 5b, 5c is transferred to the condenser 7a,
Enter 7b and 7c. On the other hand, the cold seawater 8 in the deep sea is cooled by the cold water pump 9 to the condensers 7a, 7b, 7c by the cold seawater 8 and sequentially supplied, so that the medium vapor entering the condensers 7a, 7b, 7c is the cold seawater 8. When cooled, it condenses into a liquid medium,
The medium pumps 10a, 10b and 10c are used to form evaporators 3a and 3 respectively.
Return to b and 3c. The difference in thermal cycle efficiency between the conventional technique and the present invention will be described with reference to FIGS. 2 and 4.

FIG. 4 is a heat absorption diagram of the prior art,
The vertical axis represents temperature, and the horizontal axis represents the amount of heat exchanged in the evaporator 3 and the condenser 7. The warm seawater 1 enters the evaporator 3 at a temperature of A and gives heat to the working medium 4 so that it exits the evaporator 3 at a temperature of B.
The working medium 4 enters the evaporator 3 at a temperature of C, evaporates at a temperature of D, and is guided to the turbine 5. Exhaust gas from the turbine 5 enters the condenser 7 at a temperature of E and depends on the type of the working medium 4,
Since the temperature is almost the saturation temperature, the condensation occurs at almost that temperature. That is, the temperatures of E and C are almost equal. The cold seawater 8 enters the condenser 7 at a temperature of F, the temperature thereof rises by cooling the working medium 4, and exits the condenser 7 at a temperature of G.

During this time, the heat of Q _E -Q _o is given to the working medium 4 from the warm seawater 1 in the evaporator 3. A small part of the heat is used to preheat the working medium 4 from the temperature C to the temperature D, and a large part is used to vaporize the working medium 4 at the temperature D. On the other hand, the condenser 7, Q _C -Q _o heat the cold seawater 8
Take away from the working medium 4, the working medium 4 condenses at the temperature C. Part of the heat obtained by the working medium 4 from the evaporator 3 is converted into power by the turbine 5, so that the heat exchange amount of the condenser 7 is smaller than the heat exchange amount of the evaporator 3.

Although the temperatures A to G depend on the temperature conditions of the ocean, one example is shown in Table 1. As is clear from this, while the phenomena of evaporation and condensation are performed at a constant temperature, the temperatures of the hot seawater 1 and the cold seawater 8 that are heat sources are
Since it changes in the process of heat exchange, evaporation temperature D, condensation temperature E
Cannot be sufficiently close to the heat source temperatures A and F, respectively.

FIG. 2 is a heat absorption diagram in the case of the present invention. In the present invention, the warm seawater 1 enters the first evaporator 3a at a temperature of Aa, heats the working medium 4a, and then the second at a temperature of Ab.
At the temperature of the evaporators 3b and Ac, they enter the third evaporator 3c to apply heat to the working media 4b and 4c, respectively, and at the temperature of B, they exit the evaporator 3c. The working media 4a, 4b, 4c enter the evaporators 3a, 3b, 3c at the temperatures of Ca, Cb, Cc, evaporate at the temperatures of Da, Db, Dc, and the turbine 5a,
5b, 5c. The exhaust gases of the turbines 5a, 5b, 5c are respectively at the temperatures of Ea, Eb, Ec and the condensers 7a, 7b.
It enters b and 7c and condenses at about that temperature. In contrast to the flow of the warm seawater 1, the cold seawater 8 has a temperature of Fc, and the third condenser 7c
After cooling down the working medium 4c, the second medium is cooled at the temperature of Fb.
Into the first condenser 7a at the temperature of the condensers 7b, Fa of
Heat exchange is performed in each of them, and the condenser 7a is exited at a temperature of G. Table 1 shows an example of the temperatures A to G in comparison with the conventional technique.

[0014]

[Table 1]

As is apparent from the above, in the present invention, since the evaporation temperature D and the condensation temperature E are divided into three stages, the temperature difference between the two can be expanded as compared with the prior art, and Table 1 in Table 1 In the example, the temperature difference between D and E is 13 ° C. in the conventional technique, while it is 14.3 ° C. in the present invention, which is 10% larger.

Since the output of the turbine 5 is proportional to the enthalpy difference between the inlet and the outlet, if the temperature difference D-E is widened, the enthalpy difference increases accordingly, and as a result, the output of the turbine 5 increases. In the case of Table 1, the increase is about 10% as compared with the conventional technique.

As described above, according to this embodiment, the working medium 4
Since the evaporation temperature D and the condensation temperature E can be brought close to the heat source temperatures A and F, the heat cycle efficiency of the power generator can be improved.

In FIG. 1, it seems that a plurality of evaporators 3 and a plurality of condensers 7 are provided at first glance, and the apparatus becomes complicated. However, in the case of a large-capacity apparatus, there are problems in manufacturing and transportation. Due to restrictions, it is difficult to use a single number, so it is not unnatural to have a plurality of configurations.

In the above-mentioned embodiment, for hot water pump, for power generation,
Although a total of three medium systems for cold water pumps are configured, this configuration does not necessarily have to be three systems, and hot water pumps,
One of the cold water pumps may be driven by a motor so that the whole system has two systems.

[0020]

As described above, according to the present invention,
In the ocean temperature difference power generator consisting of hot seawater system piping device, working medium system piping device, cold seawater system piping device, evaporator, condenser and turbine, for warm seawater intake pump drive, cold seawater intake pump drive, power generation Since each is equipped with an independent working medium system piping device, evaporator, condenser, and turbine, it is possible to bring the evaporation temperature and condensation temperature of the working medium close to the high temperature side and low temperature side heat source temperatures, respectively. The thermal cycle efficiency of the power generator is improved.

[Brief description of drawings]

FIG. 1 is a basic system diagram showing an example of an ocean temperature difference power generator using the present invention.

FIG. 2 is a heat absorption diagram of the apparatus shown in FIG.

FIG. 3 is a basic system diagram of a conventional technique.

4 is a heat absorption diagram of the apparatus shown in FIG.

[Explanation of symbols]

 1 ... Warm seawater 2 ... Warm water pump 3,3a, 3b, 3c ... Evaporator 4, 4a, 4b, 4c ... Working medium 5, 5a, 5b, 5c ... Turbine 6 ... Generator 7, 7a, 7b, 7c ... Condensation Container 8 ... Cold seawater 9 ... Cold water pump 10, 10a, 10b, 10c ... Medium pump 11 ... Hot water pump motor 12 ... Cold water pump motor 13, 13a, 13b, 13c ... Medium pump motor

Claims (1)

[Claims] 1. An ocean temperature difference power generator comprising a warm seawater system piping device, a working medium system piping device, a cold seawater system piping device, an evaporator, a condenser, and a turbine, for driving a warm seawater intake pump and a cold seawater intake pump. An ocean temperature difference power generation device comprising an independent working medium piping device for driving and power generation, an evaporator, a condenser, and a turbine.