Thermoelectric generation apparatus

A thermoelectric generation apparatus 1 including a high-temperature pipe 10through which a high-temperature fluid passes; a low-temperature pipe 20 disposed horizontally adjacent to the high-temperature pipe 10 and through which a low-temperature fluid having a temperature lower than that of the high-temperature fluid passes; a thermoelectric module 32 interposed between the high-temperature pipe 10 and the low-temperature pipe 20 and generating power using a temperature difference between the high-temperature pipe 10 and the low-temperature pipe 20; a fluid chamber 28 connected to an upper portion and a lower portion of the low-temperature pipe 20, parallel to the low-temperature pipe 20; and a fluid replenisher 110 capable of replenishing the fluid chamber 28 with the low-temperature fluid in a liquid state.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a thermoelectric generation apparatus.

2. Description of Related Art

A known example of conventional thermoelectric generation apparatuses is disclosed as a steam generation apparatus in WO 2011/121852A. The steam generation apparatus is provided, inside its housing, with pipe members through which a high-temperature heating medium passes, and a thermoelectric element module is attached on the surface of the pipe member. The thermoelectric element module is covered with a heat transfer plate, and water is ejected onto the surface of the heat transfer plate from a spray nozzle.

With the steam generation apparatus including the above-described configuration, water supplied to the heat transfer plate is heated by the high-temperature heating medium to produce water vapor, and at the same time, electric power can be generated using the temperature difference occurring in the thermoelectric element.

When the supply of the heating medium to the pipe member and the ejection of water onto the heat transfer plate both stop due to a power failure or the like in the above-described conventional steam generation apparatus, the heating of the pipe member is maintained by the high-temperature heating medium remaining inside the pipe member, whereas the cooling of the heat transfer plate is stopped after the ejected water has evaporated. Therefore, especially the heat transfer plate side tends to be heated to a higher temperature than usual, which may result in degradation of the electric wiring of the thermoelectric element module, the insulating structure, and so forth.

For the above-described conventional steam generation apparatus, it has been also proposed to cascade thermoelectric, element modules for high temperature, and thermoelectric element modules for low temperature by stacking these thermoelectric element modules in order to increase the power generation efficiency.

However, there is the possibility that, when the thermoelectric element modules for low temperature are heated to a high temperature as a result of a power failure or the like as described above, the thermoelectric elements made of a material for low temperature (for example, Bi-Te) themselves or joint portions made of solder or the like may undergo degradation and damage due to oxidation or the like.

SUMMARY OF THE INVENTION

Therefore, it is an object of the present invention to provide a thermoelectric generation apparatus capable of reliably preventing damage during operational. shutdown and maintaining a good power generation performance.

The above-described object of the present invention can be achieved by a thermoelectric generation apparatus including; a high-temperature pipe through which a high-temperature fluid passes; a low-temperature pipe disposed horizontally adjacent to the high-temperature pipe and through which a low-temperature fluid having a temperature lower than that of the high-temperature fluid passes; a thermoelectric module interposed between the high-temperature pipe and the low-temperature pipe and generating power using a temperature difference between the high-temperature pipe and the low-temperature pipe; a fluid chamber connected to an upper portion and a lower portion of the low-temperature pipe, parallel to the low-temperature pipe; and a fluid replenisher capable of replenishing the fluid chamber with the low-temperature fluid in a liquid state.

In the thermoelectric generation apparatus, the fluid chamber preferably includes a level sensor capable of detecting a. liquid level of the low-temperature fluid inside the low-temperature pipe.

Preferably, the thermoelectric generation apparatus further includes a vessel containing the high-temperature pipe, the low-temperature pipe and the thermoelectric module and the internal pressure of which can be reduced. Preferably, the fluid chamber is provided outside the vessel.

The fluid replenisher may be configured by a tank for storing the low-temperature fluid for reserve. Preferably, this configuration further includes fail-safe valves respectively provided on a supply side and a discharge side of the low-temperature pipe and configured to block the supply side of the low-temperature pipe while opening the discharge side of the low-temperature pipe, when the supply of the low-temperature fluid to the low-temperature pipe is stopped.

Alternatively, the fluid replenisher may be configured by a condenser interposed between the discharge side of the low-temperature pipe and a supply side of the fluid chamber and configured to condense the steam generated from the low-temperature fluid discharged from the low-temperature pipe. Preferably, this configuration further includes fail-safe valves respectively provided on the supply side and the discharge side of the low-temperature pipe and configured to block both the supply side and the discharge side of the low-temperature pipe to form a closed loop between the low-temperature pipe and the fluid chamber, when the supply of the low-temperature fluid to the low-temperature pipe is stopped.

Preferably, each of the above-described thermoelectric generation apparatuses further includes fail-safe valves respectively provided on a supply side and a discharge side of the high-temperature pipe and configured to block both the supply side and the discharge side of the high-temperature pipe, when the supply of the high-temperature fluid to the high-temperature pipe is stopped.

According to the present invention, it is possible to provide a thermoelectric generation apparatus capable of reliably preventing damage during an operation stoppage and thus maintaining a good power generation performance.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an embodiment of the present invention will now be described with reference to the accompanying drawings.FIG. 1is a schematic configuration diagram of a thermoelectric generation apparatus according to one embodiment of the present invention.FIG. 2is a cross-sectional view taken along the arrows A-A inFIG. 1. As shown inFIGS. 1 and 2, a thermoelectric generation apparatus1is configured by containing, inside a vessel2, a main body40including high-temperature pipes10, low-temperature pipes20and thermoelectric units30. The vessel2, which has a cylindrical shape, includes, at one longitudinal end thereof a lid head plate2acapable of being opened and closed, and is installed horizontally on a floor or the like. A vent outlet2bof the vessel2is connected via a valve2cto a suction device2dsuch as a vacuum pump or a steam ejector, and the pressure inside the vessel2can be reduced to a vacuum state by discharging air by the suction device2d. The inner surface of the vessel2is laminated with aluminum or mirror finished so as to be able to suppress heat radiation to the outside of the vessel2.

A plurality of high-temperature pipes10, each having a flat rectangular section, are disposed extending along the longitudinal direction of the vessel2. The branched portions of branch pipes11and12, each having a plurality of branched portions, are connected to the lower portion and the upper portion, respectively, of the high-temperature pipes10at one longitudinal end thereof. The branch pipes11and12are connected, via flange portions15and16, respectively, to a high-temperature fluid feed pipe13and a high-temperature fluid outlet pipe14, respectively, which are fixed to the side wall of the vessel2, thus providing a configuration that allows a high-temperature fluid to be supplied from the lower portion and be discharged from the upper portion of the high-temperature pipes10. As indicated by a dashed line inFIG. 1, the interior of each of the high-temperature pipes10is divided into vertically arranged sections by partition walls17, forming a high-temperature fluid flow channel such that the high-temperature fluid flowing along the high-temperature pipes10rises at the ends, turns back, and moves back and forth in this manner. Preferably, the high-temperature fluid is a liquid heated to 200° C. or higher (preferably 300° C. or higher) and having a large heat capacity. Specific examples thereof include molten salt, oil, and molten metal. Although there is no particular limitation with respect to the production of the high-temperature fluid, it is preferable to use an apparatus that produces the high-temperature fluid heated by solar energy.

Control valves13aand14aare provided in the high-temperature fluid feed pipe13and the high-temperature fluid outlet pipe14, respectively. The control valves13aand14aare fail-safe valves, each of which is configured to block the flow channel when the supply of the high-temperature fluid to the high-temperature pipe10is stopped upon occurrence of an abnormality such as a electrical power failure. Any known actuators, including, for example, pneumatic actuators and electrically operated actuators, may be used for the control valves13aand14ahaving this fail-close mechanism. The blocking of the flow channels using the control valves13aand14aupon occurrence of an abnormality can also be performed manually.

The low-temperature pipes20are disposed on both sides of each of the high-temperature pipes10in the horizontal direction thereof (that is, both sides of the rectangular section in the shorter direction), and a plurality of the low-temperature pipes20are provided in a partitioned manner along the horizontal direction in which the high-temperature pipes10extend. In order to reduce the radiation heat loss from the high-temperature pipes10to a minimum, the low-temperature pipes20are preferably disposed so as to cover the entire side wall of the high-temperature pipes10without any gap. The branched portions of branch pipes21and22, each having a plurality of branched portions, are connected to the lower portion and the upper portion, respectively, of the low-temperature pipes20. The branch pipes21and22are connected, via flange portions25and26, respectively, to a low-temperature fluid feed pipe23and a low-temperature fluid outlet pipe24, respectively, which are fixed to the side wall of the vessel2, thus providing a configuration that allows a low-temperature fluid to be supplied from the lower portion and be discharged from the upper portion of the low-temperature pipes20. The low-temperature fluid supplied to the low-temperature pipes20preferably may be, for example, a liquid having a large heat capacity, such as water, then heated due to heat exchange between fluids in the low-temperature pipes20and the high-temperature pipes10, and discharged from the low-temperature pipes20. Although a plurality of low-temperature pipes20are connected to the low-temperature fluid feed pipe23and the low-temperature fluid outlet pipe24via the blanch pipes21and22in this embodiment, the lower portion and the upper portion of a single low-temperature pipe20may be directly connected to the low-temperature fluid feed pipe23and the low-temperature fluid outlet pipe24, respectively.

As shown inFIG. 2, a fluid chamber28is connected to the low-temperature fluid feed pipe23and the low-temperature fluid outlet pipe24via a communicating pipe27, parallel to the low-temperature pipes20. The fluid chamber28is disposed outside the vessel2so as to include at least a region having the same height as the low-temperature pipe20in the vertical direction. Also, the fluid chamber28includes a level sensor28afor detecting the liquid level inside the low-temperature pipe20. Various sensors, including, for example, float-type sensors, pneumatic sensors, electrode sensors and ultrasonic sensors, can be used as the level sensor28a. A single sensor may be provided, or a plurality of sensors may be provided at different heights of the fluid chamber28. The low-temperature fluid feed pipe23and the low-temperature fluid outlet pipe24are connected to an inlet pipe50and an outlet pipe52, respectively. Control valves50aand52aare provided in the inlet pipe50and the outlet pipe52, respectively. Further, the outlet pipe52is provided with a temperature sensor (or pressure sensor)54for detecting the temperature (or pressure) of the steam passing through the outlet pipe52. A control unit (not shown) adjusts the opening of the control valves50aof the inlet pipe50such that the liquid level inside the low-temperature pipe20detected by the level sensor28aof the fluid chamber28is maintained in a predetermined height range, and also adjusts the opening of the control valve52aof the outlet pipe52based on the detection performed by the temperature sensor (or pressure sensor)54such that the temperature or pressure of the steam passing through the outlet pipe52is maintained at a desired value. Thereby, the temperature or pressure of the generated steam can be set and adjusted in accordance with the intended use of the generated steam on the downstream side. Although the fluid chamber28is connected to both the upper portion and the lower portion of the low-temperature pipe20via the low-temperature fluid feed pipe23, the low-temperature fluid outlet pipe24and the communicating pipe27in this embodiment, it may be directly connected to the upper portion and the lower portions of the low-temperature pipe20.

The control valves50aand52aare fail-safe valves, which are, in this embodiment, configured such that the control valve50alocated on the supply side of the low-temperature pipe20blocks the flow channel (fail-closes) and the control valve52alocated on the discharge side of the low-temperature pipe20opens the flow channel (fail-opens), when the supply of the low-temperature fluid to the low-temperature pipe20is stopped upon occurrence of an abnormality such as a electrical power failure. Any known actuators, including, for example, pneumatic actuators and electrically operated actuators, may be used for the control valves50aand52aas well. The above-described operation of the control valves50aand52aupon occurrence of an abnormality can also be performed manually.

The fluid chamber28is connected to a tank110serving as a fluid replenisher via an inlet pipe114including an control valve112. In the tank110, a low-temperature fluid (for example, water) of the same kind as the low-temperature fluid passing through the low-temperature pipe20is stored in advance in a liquid state. The tank110is disposed above the fluid chamber28so as to be able to replenish the fluid chamber28with the low-temperature fluid using its own weight upon occurrence of an abnormality such as a power failure. The control valve112is, preferably but not necessarily limited to, a fail-open valve that is opened upon occurrence of an abnormality such as a electrical power failure. Alternatively, the control valve112may be opened manually.

It is possible to adopt a configuration in which the low-temperature fluid stored in the tank110is supplied to the fluid chamber28via the communicating pipe27, rather than being directly supplied to the fluid chamber28as in this embodiment. In either case, by supplying the low-temperature fluid to the fluid chamber28disposed outside the vessel2, the low-temperature fluid can be supplied to the low-temperature pipe20disposed parallel to the fluid chamber28. Accordingly, the supply of the low-temperature fluid in a liquid state to the low-temperature pipe20disposed inside the vessel2can be facilitated.

The thermoelectric units30are disposed on both sides of each of the high-temperature pipes10in the horizontal direction (i.e., both sides of the rectangular cross section in the shorter direction), and are interposed between the high-temperature pipe10and the low-temperature pipe20. As shown inFIG. 3, the low-temperature pipe20and the thermoelectric unit30can be attached to the high-temperature pipe10, for example, by inserting a bolt41fixed to the surface of the high-temperature pipe10through a bolt hole20bformed in a flange portion20aof the low-temperature pipe20, followed by further inserting the bolt41through a coil spring42, and screwing a nut43such that the coil spring42is sufficiently compressed. Attaching a plurality of portions of the low-temperature pipe20to the high-temperature pipe10using this assembling method makes it possible to have a reliable contact pressure of the thermoelectric unit30between the high-temperature pipe10and the low-temperature pipe20by the biasing force of the coil spring42, and keep pressing the low-temperature pipe20even if the bolt41is thermally expanded due to heat dissipation from the high-temperature pipe10as long as the coil spring42is maintained in a compressed state. That is, it is possible to reliably prevent a reduction in the contact pressure of the thermoelectric unit30by deformation due to a large temperature difference ranging from low temperatures to high temperatures, thereby achieving stable electrical power generation performance.

As shown in the cross-sectional view inFIG. 4, each of the thermoelectric units30includes a plurality of thermoelectric modules32disposed inside a seal member31made of an electrically insulating material or the like in a matrix configuration. Each of the thermoelectric modules32has a known configuration in which a plurality of p-type semiconductor elements and n-type semiconductor elements (both not shown) that are alternately connected with electrodes interposed therebetween, and is disposed so as to generate electrical power using a temperature difference between the high-temperature pipe10and the low-temperature pipe20. The size of the thermoelectric modules32is, for example, 50 mm×50 mm. In this embodiment, eight thermoelectric modules32constitute a thermoelectric unit30having substantially the same size as that of a low-temperature pipe20. The durability of the elements can be increased by preventing their degradation by sealing the interior space of the seal member31into a vacuum, or enclosing a gas therein. However, it is also possible to adopt a configuration in which the seal member31is omitted, in order to promote heat conduction from the high-temperature pipes10to the low-temperature pipes20, thereby reducing radiation heat loss. By disposing the small-sized thermoelectric modules32between the high-temperature pipe10and the low-temperature pipe20as in this embodiment, the thermoelectric modules32can be individually pressed to the high-temperature pipes10and the low-temperature pipes20. Accordingly, it is possible to reduce radiation heat loss and thus achieve high power generation efficiency.

As shown in the partial cutaway view of a low-temperature pipe20inFIG. 1, a plurality of the thermoelectric units30are arranged in a matrix configuration by being assembled in a partitioned manner along the high-temperature pipe10and also along the vertical direction, which is orthogonal to the high-temperature pipe10. Electric power can be supplied to the outside of the vessel2by connecting adjacent thermoelectric units30either in series or parallel using lead wire (not shown). By arranging a plurality of thermoelectric units30each constituted by a plurality of thermoelectric modules32as in this embodiment, operations such as maintenance, repair and replacement can be performed promptly and easily for the thermoelectric units30on a unit-by-unit basis. However, the unitization of the thermoelectric modules32is not essential for the present invention, and the thermoelectric modules32may be separately disposed on the surface of the high-temperature pipes10. In this case as well, it is preferable to dispose the thermoelectric modules32sequentially along the horizontal direction in which the high-temperature pipes10extend.

There is no particular limitation with respect to the materials for the p-type semiconductor elements and the n-type semiconductor elements of the thermoelectric modules32, and the materials may be appropriately selected from known materials according to the temperature of the high-temperature pipes10in which the thermoelectric modules32are disposed. For example, Bi-Te materials can be used for a low-temperature range, and silicide materials can be used for a high-temperature range. In the case where the temperature of the high-temperature pipes10is high (for example, 300° C. or higher), the thermoelectric modules32may be cascaded with two types of high temperature and low temperature semiconductor materials so as to allow for thermoelectric generation in a wide temperature range from a high-temperature range to a low-temperature range, which makes it possible to increase the thermoelectric generation efficiency. Furthermore, since the high-temperature pipes10have a temperature gradient along the flow direction of the high-temperature fluid, the selection of the semiconductor materials for the thermoelectric modules32can be made individually, according to the area of the high-temperature pipes10where the thermoelectric modules32are disposed. This configuration makes it possible to increase the power generation efficiency of the individual thermoelectric modules32, and therefore a thermoelectric unit30and an assembly thereof that can utilize the temperature difference highly efficiently can be obtained.

As shown inFIG. 4, heating elements18each composed of an electric heater, a high-temperature steam pipe, or the like are disposed inside the flow channel formed inside the high-temperature pipes10such that they extend along the high-temperature pipes10. The high-temperature pipes10are further provided with a drain (not shown) and the high-temperature fluid can be discharged to the outside in an unused state, for example, at the time of stoppage.

As shown inFIGS. 1 and 2, the main body40, which includes the high-temperature pipes10, the low-temperature pipes20and the thermoelectric units30described above, is suspended from and supported by two guide rails3fixed to the inner upper face of the vessel2, via a plurality of support members4. The support members4are configured such that their lower end is fixed to the upper portion of the main body40(for example, the high-temperature pipe10) and their upper end is movable along the guide rails3. Also, the lid head plate2aof the vessel2is supported by a suspender (not shown) so as to be removable, for example, by being rotated. The guide rails3are configured to be extendable by means of, for example, a telescopic structure, so that conveyor rails3acan be extended to the outside of the vessel2as indicated by a dashed line inFIG. 1in a state in which the lid head plate2ais removed. Rather than being extended from the guide rails3, the conveyor rails3amay be connected to the guide rails3from the outside of the vessel2and supported by a strut (not shown) or the like.

With the thermoelectric generation apparatus1having the above-described configuration, the lid head plate2aof the vessel2is closed and the pressure inside the vessel2is reduced to a vacuum. Thereafter, a high-temperature fluid and a low-temperature fluid are supplied to the high-temperature pipes10and the low-temperature pipes20, respectively. Consequently, heat is exchanged between the high-temperature fluid and the low-temperature fluid, and the resulting water vapor is discharged from the low-temperature fluid outlet pipe24. Concurrently with this, a temperature difference occurs in the thermoelectric units30, and therefore electric power can be drawn to the outside.

With the thermoelectric generation apparatus1according to this embodiment, it is possible to supply the low-temperature fluid in a liquid state to the fluid chamber28from the tank110by opening the control valve112upon occurrence of an abnormality such as a power failure. Accordingly, even if the low-temperature fluid inside the low-temperature pipe20evaporates by the heat of the high-temperature fluid remaining in the high-temperature pipe10in a state in which the supply of the low-temperature fluid from the inlet pipe50to the low-temperature pipe20is stopped, it is possible to replenish the fluid chamber28with an amount of the low-temperature fluid in a liquid state corresponding to the amount of the distillation, and therefore, the low-temperature fluid in a liquid state can be maintained inside the low-temperature pipe20disposed parallel to the fluid chamber28. Consequently, there is no possibility that the low-temperature pipe20is heated to an abnormally high temperature by the heat of the high-temperature pipe10, which makes it possible to prevent the low-temperature pipe20itself and the packing, couplings and the like used for the low-temperature pipe20from being degraded or damaged by heat. Furthermore, due to the same reason, it is also possible to prevent the thermoelectric module32from being heated to an abnormally high temperature. Accordingly, there is no possibility that the thermoelectric module for low temperature undergoes degradation and damage even if the thermoelectric module32has a cascaded configuration, and therefore it is possible to maintain a good power generation performance.

Furthermore, with the thermoelectric generation apparatus1, the supply side of the low-temperature pipe20is blocked and the discharge side of the low-temperature pipe20is opened by the control valves50aand52a, which are fail-safe valves, when the supply of the low-temperature fluid from the inlet pipe50to the low-temperature pipe20is stopped as a result of a power failure or the like. Accordingly, it is possible to release the steam generated in the low-temperature pipe20to the outside to promote the heat dissipation of the low-temperature pipe20, thereby preventing thermal damage of the low-temperature pipe20and the thermoelectric module32in a more reliable manner.

Furthermore, with the thermoelectric generation apparatus1, both the supply side and the discharge side of the high-temperature pipe10are blocked by the control valves13aand14a, which are fail-safe valves, when the supply of the high-temperature fluid to the high-temperature pipe10is stopped as a result of a power failure or the like. Accordingly, it is possible to suppress the entrance of heat to the high-temperature pipe10from the outside, thus making it easy to maintain the low-temperature pipe20in a low-temperature state. It is also possible to open the drain (not shown) of the high-temperature pipe10, thus discharging the high-temperature fluid remaining in the high-temperature pipe10to the outside.

Although an embodiment of the present invention has been described thus far, specific modes of the present invention are not limited to the above-described embodiment. For example, although the tank110is used as a fluid replenisher for replenishing the fluid chamber28with the low-temperature fluid in a liquid state in this embodiment, it is also possible to adopt a different configuration as long as the fluid chamber28can be replenished with an amount of the low-temperature fluid in a liquid state corresponding to the amount of steam generated inside the low-temperature pipe20upon occurrence of an abnormality such as a power failure. For example, as shown inFIG. 5, a condenser120may be provided in the communicating pipe27connecting the discharge side of the low-temperature pipe20and the supply side of the fluid chamber28, and thereby the condenser120may serve the function of the fluid replenisher. That is, the steam generated in the low-temperature pipe20is cooled and condensed by passing through the condenser120, and thereafter the condensed water is supplied to the fluid chamber28. Accordingly, it is possible to replenish the low-temperature pipe20with the low-temperature fluid in a liquid state. There is no particular limitation with respect to the configuration of the condenser120, and the condenser120may be of an air cooling-type or a water cooling-type, or may be a combination thereof. However, the condenser120is preferably operable during a power failure. Specifically, when the condenser120is of an air cooling-type, an air cooling fan can be operated by a generator and a storage battery using solar light, wind power, an engine or the like. On the other hand, when the condenser120is of a water cooling-type, cooling water can be supplied to the condenser120from a water source such as a water service pipe via a fail-open valve.

With the thermoelectric generation apparatus1shown inFIG. 5, both of the control valves50aand52a, which are fail-safe valves, for the low-temperature fluid are preferably fail-close valves that block the flow channels upon occurrence of an abnormality such as a power failure. In this case, a closed loop is formed by the communicating pipe27between the low-temperature pipe20and the fluid chamber28, and the entire steam generated in the low-temperature pipe20can be introduced into the condenser120, which makes it possible to maintain the liquid level inside the low-temperature pipe20in a more reliable manner. As with the configuration shown inFIG. 2, both of the control valves13aand14afor the high-temperature fluid are also preferably fail-close valves.

By providing each of the thermoelectric generation apparatuses1according to the above-described embodiments with a heat source supply apparatus for generating a high-temperature fluid heated by solar energy, it is possible to easily provide a large amount of high-temperature fluid that has been heated to a required temperature. The specific configuration of the heat source supply apparatus is known, and is disclosed, for example, in WO 2011/121852A.

In addition to being used as a power generation apparatus for generating power using a temperature difference between the high-temperature pipe10and the low-temperature pipe20, each of the thermoelectric generation apparatuses1of the above-described embodiments can also be used as a steam generation apparatus by heating and evaporating the low-temperature fluid introduced to the low-temperature pipe20using a heat exchange with the high-temperature pipe10. When the thermoelectric generation apparatus1of the present invention is also used as a steam generation apparatus, the thermoelectric generation apparatus1may be combined with an thermal seawater desalination apparatus70to form a seawater desalination system, as shown inFIG. 6. Examples of the methods used for the thermal seawater desalination apparatus70include multi-stage flash distillation and multi-effect distillation. The thermal seawater desalination apparatus70desalinates seawater by distillation using, as its heat source, the steam from the low-temperature fluid introduced from the low-temperature fluid outlet pipe24(seeFIG. 2) of the thermoelectric generation apparatus1. The steam from the low-temperature fluid that has undergone heat exchange with seawater is condensed, and thereafter supplied to the low-temperature pipes20again from the low-temperature fluid feed pipe23(seeFIG. 2) of the thermoelectric generation apparatus1. The steam temperature of the low-temperature fluid introduced to the thermal seawater desalination apparatus70is preferably set in a temperature range of 50 to 185° C. In particular, setting the steam temperature of the low-temperature fluid to 140 to 185° C. (e.g., 175° C.) makes it possible to reuse part of the steam from the low-temperature fluid that has been used for the seawater desalination process for the desalination process by means of a steam ejector, thus increasing the processing capability. As described above, the steam temperature of the low-temperature fluid introduced to the thermal seawater desalination apparatus70can be maintained at a desired temperature by adjusting the openings of the control valves50aand52a(seeFIG. 2) of the inlet pipe50and the outlet pipe52.

The seawater desalination system shown inFIG. 6includes a heat source supply apparatus60for producing the high-temperature fluid heated by solar energy, such as the one described above. The high-temperature fluid heated in the heat source supply apparatus60is supplied to the high-temperature fluid feed pipe13(seeFIG. 2) of the thermoelectric generation apparatus1, then used for power generation and steam generation, and thereafter supplied from the high-temperature fluid outlet pipe14(seeFIG. 2) to the heat source supply apparatus60for reheating.

The seawater desalination system shown inFIG. 6further includes a reverse osmosis membrane-based seawater desalination apparatus80. The reverse osmosis membrane-based seawater desalination apparatus80includes various pumps (not shown) for intake of seawater, permeation of seawater through the reverse osmosis membrane, delivery of the produced fresh water, and so forth. By driving these pumps and the like using electric power generated by the thermoelectric generation apparatus1, it is possible to realize effective utilization of energy while avoiding constraints imposed by the location conditions. In the seawater desalination system shown inFIG. 6, the electric power generated by the thermoelectric generation apparatus1can also be used for operating the heat source supply apparatus60and the thermal seawater desalination apparatus70.