JP2016049480A - Desalination plant using solar heat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an atmospheric distillation type of desalination plant excellent in utilization efficiency of solar heat.SOLUTION: A desalination plant 10 includes a raw water tank 20, a heat-collection and evaporation part 30 which is installed so as to tilt with respect to the horizontal and of which the lower end communicates with the raw water tank 20, and a fresh water tank 40 which communicates with the upper end of the heat-collection and evaporation part 30. The heat-collection and evaporation part 30 is equipped with a vacuum insulation evaporation tube 31 which collects the heat of sunlight for evaporation of raw water and a reflector plate 32 serving as condensing means to collect sunlight to the vacuum evaporation tube 31.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a desalination apparatus using solar heat for desalinating raw water such as seawater, and more particularly to an atmospheric distillation type desalination apparatus.

  The desalination apparatus is for desalinating raw water such as seawater to obtain drinking water and irrigation water. As a desalination method, an evaporation method or a reverse osmosis membrane method has been used.

  Some desalination apparatuses using the evaporation method use solar heat. Conventionally, in order to reduce the heat loss by lowering the operating temperature, a vacuum distillation method in which raw water is heated and evaporated under reduced pressure has been the mainstream. Therefore, a pump or the like for creating a reduced pressure state is required, and there is a problem that the apparatus becomes large and complicated. Moreover, since electric power is required to drive a pump or the like, energy supply other than solar heat is required, and there is a problem that the installation location is limited.

  Here, a desalination apparatus using solar heat is required mainly in developing countries where infrastructure is not sufficient. In particular, it is not expected to use electric power or the like in remote areas, and thus this type of desalination apparatus is required to operate independently without requiring any energy other than solar heat. Furthermore, it is also important that the device itself is inexpensive and simple and easy to assemble, handle, maintain and repair. However, a conventional desalination apparatus using a vacuum distillation system does not satisfy these requirements.

  Then, the desalination apparatus of the atmospheric pressure distillation system which heats raw water at atmospheric pressure using solar heat and evaporates is proposed (patent document 1).

JP 2001-70929 A

  However, the desalination apparatus described above has a structure in which the heat collecting part collects solar heat by means of a flat plate-like heat collecting surface. I couldn't let you. Therefore, it is necessary to take a configuration in which the raw water is evaporated in the evaporation tank (separate from the heat collection unit) after raising the temperature of the raw water in the heat collection unit, and both the heat collection unit and the evaporation tank are heated and radiated. There was also a problem that the loss was large.

  Due to these problems, in the above desalination apparatus, a sufficient amount of raw water cannot be desalinated, and the time zone in which desalination can be performed is limited due to the limitation of sunlight, and raw water using a heat source other than solar heat is used. Had to be heated.

  This invention is made | formed in view of the above, and it aims at providing the desalination apparatus of the atmospheric pressure distillation system excellent in the utilization efficiency of a solar heat.

  The desalination apparatus according to the present invention is arranged to be inclined with respect to a raw water tank, a horizontal plane, and a lower end thereof communicates with the heat collecting / evaporating unit communicating with the raw water tank, and an upper end of the heat collecting / evaporating unit. A fresh water tank, and the heat collecting and evaporating unit has a vacuum heat insulating evaporation tube for collecting sunlight and evaporating raw water, and a condensing means for collecting the sunlight on the vacuum heat insulating evaporation tube. It is characterized by.

  Here, “inclination with respect to the horizontal plane” includes a state perpendicular to the horizontal plane. Further, the “vacuum adiabatic evaporation tube” is a vacuum glass tube type heat collector that can evaporate raw water in the heat collector.

  According to such a configuration, the sunlight is condensed on the vacuum adiabatic evaporation tube by the condensing means, and the condensed sunlight is used to heat the raw water by the vacuum adiabatic evaporation tube excellent in utilization efficiency of sunlight. Since it is used, raw water can be heated efficiently using solar heat. In addition, since the raw water is directly evaporated in the heat collecting section, heat loss can be reduced, and the solar heat utilization efficiency can be improved in this respect.

  The condensing means may be a reflecting mirror.

  According to such a configuration, the focal length can be shortened, and solar heat can be efficiently collected on the heat collecting / evaporating section even if the accuracy of solar tracking is low. Details of the sun tracking will be described later.

  The heat collecting / evaporating unit may further include a transparent plate, and the vacuum heat insulating evaporator tube may be surrounded by the reflecting mirror and the transparent plate.

  According to such a configuration, since the vacuum heat insulating evaporator tube is protected by the reflecting mirror and the transparent plate, it is possible to prevent dust and the like from adhering and to improve durability. Moreover, since a vacuum heat insulation evaporation pipe is thermally insulated by a reflective mirror and a transparent plate, the utilization efficiency of solar heat can be improved.

  The condensing means may be a Fresnel lens.

  According to such a structure, sunlight of a wide area can be condensed and the utilization efficiency of solar heat can be improved.

  The desalination apparatus further includes a discharge port disposed below the heat collecting / evaporating unit, the raw water tank, a lower end of the heat collecting / evaporating unit, and a three-way valve respectively communicating with the discharge port. And when the three-way valve is in the first state, the raw water is supplied to the heat collecting and evaporating unit, and when the three-way valve is in the second state, the raw water is discharged from the discharge port. You may comprise.

  According to such a configuration, when the specific gravity increases due to evaporation and concentration, the concentrated water accumulates in the lower part of the heat collecting and evaporating section as the raw water evaporates, so the concentrated water can be easily removed. it can. “Concentrated water” refers to raw water having an increased impurity concentration due to evaporation of the raw water in the heat collecting and evaporating section. For example, when the raw water is seawater, it refers to the raw water having a high salinity concentration. And

  It is desirable that a gas-liquid separator is provided above the heat collecting / evaporating section.

  According to such a configuration, it is possible to prevent raw water that has not been desalinated by bumping in the heat collecting / evaporating section from flowing into the fresh water tank.

  Steam utilization means for at least one of cooking, salt production, and sterilization may be provided between the heat collecting / evaporating unit and the fresh water tank.

  According to the desalination apparatus according to the present invention, high-temperature steam can be obtained from the upper part of the heat collecting / evaporating section because of the atmospheric distillation system. Moreover, since it is excellent in the utilization efficiency of solar heat, such high temperature steam can be obtained stably. Therefore, according to such a structure, the high temperature steam supplied stably can be utilized for cooking or sterilization.

  In addition, the "high temperature steam" in this specification is the term contrasted with the steam obtained by vacuum distillation, and shall mean the 100-130 degreeC steam obtained by atmospheric pressure distillation.

  As described above, according to the desalination apparatus according to the present invention, since the solar heat utilization efficiency in the heat collecting / evaporating section is excellent, a sufficient amount of raw water can be desalinated even by the atmospheric distillation system.

It is the schematic which shows the basic composition of the desalination apparatus of 1st Embodiment. It is sectional drawing of the heat collection and evaporation part of 1st Embodiment. It is sectional drawing of the vacuum heat insulation evaporation pipe of 1st Embodiment. It is a figure which shows the three-way valve | bulb of 1st Embodiment, Comprising: (a) It is a figure which shows a 1st state, (b) It is a figure which shows a 2nd state. It is a figure which shows the baffle of 1st Embodiment, Comprising: (a) It is sectional drawing of a vertical direction, (b) It is sectional drawing of a horizontal direction. It is sectional drawing of the heat collection and evaporation part of the Fresnel lens type of 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, all of these embodiments are illustrative and do not give a limited interpretation of the present invention. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

  In the following embodiments, raw water is intended to increase in specific gravity by being evaporated and concentrated. Examples of such raw water include seawater.

(First embodiment)
FIG. 1 is a schematic diagram showing the basic configuration of the entire desalination apparatus 10 of the first embodiment. A desalination apparatus 10 according to the first embodiment is mainly arranged with a raw water tank 20, a heat collecting and evaporating unit 30 whose lower end communicates with the raw water tank, and a heat collecting and collecting unit. A fresh water tank 40 communicating with the upper end of the evaporation unit 30.

  The raw water tank 20 communicates with the lower end of the heat collecting / evaporating unit 30 via the first pipe 21 and the three-way valve 23, and the lower end of the heat collecting / evaporating unit 30 passes through the three-way valve 23 and the discharge pipe 22. Via the concentrated water tank 24.

  The upper end of the heat collecting and evaporating unit 30 is communicated with the fresh water tank 40 via the steam utilization means 42, the second pipe 41, and the cooling means 43. Examples of the steam utilization means 42 include a heat insulating container used for cooking, sterilization, salt production, and the like. Moreover, as the cooling means 43, the cooler (condenser, condenser) which has a cooling fan and a cooling fin, for example is mentioned. The water vapor evaporated by the heat collecting / evaporating unit 30 is guided from the upper end of the heat collecting / evaporating unit 30 to the cooling unit 43 through the vapor utilization unit 42 and the second pipe 41 and cooled (condensed) by the cooling unit 43. As a result, it becomes fresh water (distilled water) and is stored in the fresh water tank 40.

  The heat collecting / evaporating unit 30 includes a vacuum heat insulating evaporation pipe 31 that collects sunlight and evaporates raw water, and a condensing unit that condenses the sunlight on the vacuum heat insulating evaporation pipe.

  FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, and is a cross-sectional view of the heat collecting / evaporating unit 30 of the first embodiment. The heat collecting / evaporating unit 30 includes a vacuum adiabatic evaporation tube 31, a reflecting mirror 32 as a condensing means for concentrating sunlight on the vacuum adiabatic evaporation tube 31, and a transparent plate 33 made of acrylic or glass.

  The reflecting mirror 32 is a so-called trough type in which the longitudinal direction is along the vacuum adiabatic evaporation tube 31, the mirror surface side of the longitudinal section is a parabola, and the mirror surface is a parabola. . Such a trough-type reflecting mirror 32 can shorten the focal length and can easily track sunlight. By using such a reflecting mirror 32, sunlight can be condensed on the vacuum adiabatic evaporation tube 31 even if the accuracy of tracking the sun is low compared to a heat collecting / evaporating unit using a Fresnel lens described later. it can.

  The transparent plate 33 according to the present embodiment has a flat plate shape, and is fixed to both ends of the reflecting mirror 32 in the short direction so as to cover the mirror surface side of the reflecting mirror 32. Since the surroundings of the vacuum heat insulating evaporator 31 are surrounded by the reflecting mirror 32 and the transparent plate 33, the use efficiency of sunlight can be improved by the heat insulating effect. Moreover, the mirror surface of the reflecting mirror 32 can be prevented from being soiled, and the sales efficiency can be prevented from being lowered. Furthermore, it is possible to prevent dust and the like from adhering to the surface of the vacuum adiabatic evaporation pipe 31 and improve durability.

  In addition, the transparent plate 33 is not limited to a flat plate shape, and may be appropriately changed or omitted within a range where the above-described effects are achieved. Moreover, the both ends of the vacuum heat insulation evaporation pipe 31 in the longitudinal direction are respectively closed by a flat plate or the like, so that the heat insulation effect is enhanced and the utilization efficiency of solar heat can be further improved.

  As shown in FIG. 2, the reflecting mirror 32 and the vacuum adiabatic evaporation tube 31 are arranged so that the sunlight L incident perpendicularly to the transparent plate 33 is collected by the reflecting mirror 32 onto the vacuum adiabatic evaporation tube 31.・ Designed.

  In some conventional desalination apparatuses, a structure that absorbs a large amount of solar heat by providing heat-absorbing fins or the like and receiving sunlight in a large area has been adopted. However, since the surface area of the high temperature portion is increased, radiation loss is increased, and as a result, it has been difficult to greatly improve the utilization efficiency of solar heat.

  In that respect, the desalination apparatus 10 according to the present embodiment collects solar heat in the vacuum heat insulating evaporator 31 by the light collecting means. Therefore, the high-temperature part is only the vacuum adiabatic evaporation pipe 31, and the utilization efficiency of solar heat can be improved as compared with the conventional structure.

  The heat collecting / evaporating unit 30 is preferably provided with a sun tracking mechanism (not shown) so that the angle can be changed manually or automatically. By doing in this way, the heat collection and evaporation part 30 can be turned to the direction suitable for the position of the sun, and solar heat can be used effectively.

  As a simple solar tracking method, as shown in FIG. 2, the vacuum adiabatic evaporation pipe 31 may be fixed and the reflecting mirror 32 may be rotated as indicated by an arrow R. According to such a configuration, it is not necessary to move the vacuum adiabatic evaporation pipe 31, so that the solar tracking can be realized with a simple configuration, and the desalination apparatus 10 itself is stable and easy to handle.

  FIG. 3 is an enlarged view of the vacuum adiabatic evaporation pipe 31 of FIG. 2, and is a cross-sectional view of the vacuum adiabatic evaporation pipe 31 of the first embodiment. As shown in FIG. 3, the vacuum adiabatic evaporation pipe 31 is formed by superposing two cylinders having substantially the same center and different cross-sectional radii, and having a small radius (hereinafter referred to as “first cylinder”). The space inside the cylinder 35 having a large radius (hereinafter referred to as “second cylinder”) 35 from the outside of the 34 is in a vacuum state.

  Since the vacuum part S1 has a very low thermal conductivity and a small convective heat loss, the vacuum part S1 exhibits an excellent heat insulating effect without having a heat insulating material, and heat once absorbed is difficult to escape.

  The vacuum part S1 of the vacuum adiabatic evaporation pipe 31 is formed in advance, and is maintained in a vacuum state regardless of the operating state of the desalination apparatus 10. Therefore, it is not necessary to create the vacuum part S1 during the operation of the desalination apparatus 10, and the desalination apparatus 10 does not need to have special equipment for evacuating the part.

  Further, the raw water circulates in the interior S2 of the first cylinder 34. Since this portion is at atmospheric pressure, the raw water is heated and evaporated under atmospheric pressure.

  In addition, the cross-sectional shape of the vacuum adiabatic evaporation pipe 31 is not limited to a circular shape, and can be changed as appropriate within a range where the effect is obtained.

  A selective absorption film may be formed on the vacuum adiabatic evaporation pipe 31. The selective absorption film uses the difference in wavelength region between absorbing and radiating solar heat to increase the efficiency of solar heat absorption and reduce radiant heat. It can be used for heating and evaporation.

  The selective absorption film preferably has a characteristic of reflecting infrared rays having a wavelength of 5 to 10 μm. Thereby, it becomes difficult to discharge | release solar heat more and the utilization efficiency of solar heat can be improved more.

  The selective absorption film can be produced by forming a conductive film on the black film. Thereby, a selective absorption membrane can be produced by a simple method, and the cost of the desalination apparatus can be reduced.

  In this embodiment, the vacuum adiabatic evaporation pipe 31 is used in order to obtain high thermal efficiency. However, if it is acceptable to reduce the thermal efficiency, an absorption pipe (such as a black metal pipe) that does not rely on vacuum insulation can be used. . Even in this case, it is desirable that a selective absorption film is attached to the surface of the tube. In particular, in a medical sterilization apparatus that uses steam at a high temperature exceeding 120 ° C., the evaporation section becomes a high pressure of 4 atmospheres at maximum, and a glass tube cannot be used. Therefore, it is necessary to use a metal tube.

  The heat collecting / evaporating unit 30 is disposed to be inclined with respect to the horizontal plane. Therefore, the concentrated water whose concentration increases with the evaporation of the raw water accumulates in the lower part thereof, so that the concentrated water can be easily removed. In addition, while steam flows out from the upper part of the heat collecting / evaporating unit 30, raw water is supplied from the lower part thereof, so that the high temperature raw water above the heat collecting / evaporating unit 30 is used as raw water from the raw water tank. The raw water can be efficiently evaporated without being cooled.

<Desalination principle>
The raw water in the raw water tank 20 is first supplied to the heat collecting / evaporating unit 30 through the first pipe 21 and the three-way valve 23. Here, the surface of the raw water in the raw water tank 20 is preferably substantially the same as the height of the upper end of the heat collecting / evaporating unit 30. In this way, the raw water in the raw water tank 20 is continuously and automatically collected by the head pressure of the raw water (so-called “the principle of the communication pipe”) without using a pump or the like. Can be supplied to.

  The raw water supplied to the heat collecting / evaporating unit 30 is heated by solar heat in the vacuum heat insulating evaporator 31 of the heat collecting / evaporating unit 30. The desalination apparatus 10 according to the first embodiment condenses solar heat by the condensing means in the heat collecting and evaporating unit 30 and heats the raw water by the vacuum adiabatic evaporation pipe 31 excellent in solar heat utilization efficiency. In addition, it is excellent in the efficiency of solar heat, and a sufficient amount of raw water can be desalted even by the atmospheric distillation system.

  Moreover, since it is excellent in the utilization efficiency of the solar heat in the heat collecting and evaporating part 30, the raw water can be directly evaporated in the heat collecting part, and the utilization efficiency of solar heat is compared with the conventional configuration in which the heat collecting part and the evaporating part are separated. Can be improved and the apparatus can be simplified.

  Here, as for the desalination apparatus 10 in this embodiment, the heat collecting and evaporation part 30 is arrange | positioned with inclination with respect to a horizontal surface. Therefore, since the concentrated water accumulates in the lower part of the heat collecting / evaporating unit 30 as the raw water evaporates, the concentrated water can be easily taken out, and the malfunction of the apparatus due to the clogged concentrated water can be prevented. When the raw water is seawater, seawater with a high salt concentration (concentrated water) is not only accumulated in the lower part of the heat collecting / evaporating unit 30, but salt crystals may be precipitated.

  FIG. 4 is a view showing the three-way valve 23 of the first embodiment. FIG. 4A is a diagram illustrating the first state, and FIG. 4B is a diagram illustrating the second state. In the first state, the raw water is supplied from the raw water tank 20 to the heat collecting / evaporating unit 30, and in the second state, the concentrated water accumulated in the lower portion of the heat collecting / evaporating unit 30 is discharged via the discharge conduit 22. It is discharged to the concentrated water tank 24.

  When switching from the second state to the first state, as shown in FIG. 4 (a), the handle 23a of the three-way valve 23 is rotated in the R1 direction to stop the discharge of the concentrated water and collect the raw water. It supplies to the cum evaporation part 30.

  When switching from the first state to the second state, as shown in FIG. 4B, the handle 23a of the three-way valve 23 is rotated in the R2 direction, the supply of raw water is stopped, and the heat collecting and evaporating unit The concentrated water accumulated in the lower part of 30 is discharged from the discharge pipe 22.

  In the conventional general desalination apparatus, there is no means for discharging the concentrated water, and failure due to clogging of the concentrated water has occurred. Further, even if the concentrated water discharging means is provided, it is necessary to discharge the concentrated water using the entire apparatus, and it takes time and effort to discharge the concentrated water.

  In that respect, according to the desalination apparatus 10 concerning 1st Embodiment, concentrated water can be easily discharged | emitted by switching a flow path with the three-way valve 23, without using the whole apparatus. It is sufficient to discharge the concentrated water once a day, for example, at night.

  Further, conventionally, even a desalination apparatus capable of taking out concentrated water had to discard the concentrated water. However, in the desalination apparatus 10 according to the first embodiment, the concentrated water is converted into steam. It can also be solidified (salt-produced) by heat.

  Although details will be described later, when seawater is used as raw water, the salt can be obtained by drying the concentrated water using high-temperature steam at 100 ° C. obtained from the upper part of the heat collecting and evaporating unit 30.

  It is desirable that a gas-liquid separator 36 is provided above the heat collecting / evaporating unit 30. Thereby, it is possible to prevent the raw water bumped at the heat collecting / evaporating unit 30 from flowing into the fresh water tank 40. Sudden boiling refers to a phenomenon in which a liquid does not boil even when it reaches its boiling point, but suddenly and vigorously boils at a temperature higher than the boiling point when it is further heated. Problems arise. Therefore, it is important how the gas-liquid separator 36 suppresses mixing of raw water into fresh water. Any gas-liquid separator 36 may be used as long as it blocks the sudden boiling of raw water. However, it is necessary to have an opening that does not hinder the flow of water vapor. For example, the gas-liquid separator 36 has a partition plate that passes near the central axis in the vacuum heat insulating evaporator 31 and a partition plate that passes near the inner periphery in the vacuum heat insulating evaporator 31, and these partition plates are The structure may be arranged alternately.

  FIG. 5 is a diagram illustrating a structure of a baffle 39 which is one form of the gas-liquid separator 36 of the first embodiment. FIG. 5A is a longitudinal sectional view, and FIG. 5B is a lateral sectional view. The first partition plate 39 a has a circular opening 39 c at the center, and an outer peripheral portion is joined in the vacuum heat insulating evaporation pipe 31. The second partition plate 39b has a diameter smaller than the diameter of the first partition plate 39a and larger than the opening 39c. The first partition plate 39a and the second partition plate 39b are alternately arranged with a gap, and are fixed by bolts 39e and nuts 39d. The first partition plate 39a and the second partition plate 39b can be fixed using various fixing methods such as screws, welding, spacers, bolts, and nuts.

  In the conventional vacuum distillation method, since raw water is heated and evaporated in a reduced pressure environment, the temperature of the obtained steam is less than 100 ° C., and it is difficult to use such steam for cooking or the like. In that respect, since the desalination apparatus 10 concerning 1st Embodiment is equipped with the heat collection and evaporation part 30 which has the vacuum heat insulation evaporation pipe 31 and a condensing means, it is excellent in the utilization efficiency of a solar heat, Therefore A high temperature steam stably This steam can be used for cooking sterilization and the like.

  The raw water that has become high-temperature steam exits from the upper part of the heat collecting / evaporating section 30 and is then condensed by the known cooling means 43 and the like, and then supplied to the fresh water tank as fresh water.

  Considering that the desalination apparatus 10 is used in developing countries where infrastructure is not established, particularly in remote areas, it is possible to use high-temperature steam generated in the desalination process for cooking sterilization. It is a big advantage. Furthermore, the desalination apparatus 10 is an epoch-making apparatus that can alleviate the burden on people in developing countries that have been expended in collecting water and collecting firewood, and give them time for studying and working. There is a possibility of becoming.

<Raw water supply method>
As a method of supplying the raw water to the raw water tank, it is conceivable to supply it with a known pump or the like in addition to being supplied manually by a person. In this case, you may make it supply the electric power for driving a pump from a solar cell.

  As long as the raw water is supplied to the raw water tank 20, the desalination apparatus 10 according to the first embodiment can be operated independently without requiring external power or the like. Therefore, by supplying raw water with a pump that uses a solar cell as a power source, a self-sustaining operation including the supply of raw water to the raw water tank 20 becomes possible, and the self-sustainability of the desalination apparatus 10 is further improved.

(Second Embodiment)
In the second embodiment, a Fresnel lens is used as the light condensing means that was a reflecting mirror in the first embodiment. Unlike a general convex lens, the Fresnel lens has a plurality of grooves formed on a thin flat acrylic resin sheet in parallel straight lines, and the light passing through the Fresnel lens is collected on a predetermined straight line. . A Fresnel lens is suitable for condensing large-area sunlight compared to a reflecting mirror.

  FIG. 6 is a cross-sectional view of the Fresnel lens type heat collecting and evaporating unit 50 according to the second embodiment. The heat collecting / evaporating section 50 includes a vacuum adiabatic evaporation pipe 31, a linear Fresnel lens 51 as a condensing means for concentrating sunlight on the vacuum adiabatic evaporation pipe 31, and a reflective container 52.

  The reflective container 52 is a container in which the inner side of the longitudinal section is substantially U-shaped, and both ends in the longitudinal direction are closed by flat plates. The heat collecting and evaporating unit 50 includes a reflective container such that the vacuum heat insulating evaporator 31 is disposed along the longitudinal direction at the bottom of the reflective container 52 and the flat linear Fresnel lens 51 covers the inside of the reflective container 52. The structure is fixed to both ends in the short direction of 52. The linear Fresnel lens 51 is adjusted so as to collect light on a straight line along the vacuum adiabatic evaporation tube 31.

  At both ends in the longitudinal direction of the reflective container 52, the vacuum adiabatic evaporation pipe 31 is inserted into a flat plate and surrounded by the reflective container 52 and the linear Fresnel lens 51. In this way, it is possible to suppress contamination on the surface having the groove of the linear Fresnel lens 51 simultaneously with the windshield of the linear Fresnel lens 51. Further, since the vacuum heat insulating evaporation pipe 31 is protected by the linear Fresnel lens 51 and the reflective container 52, it is possible to prevent dust and the like from adhering and to improve durability. Moreover, since the vacuum heat insulation evaporation pipe 31 is thermally insulated by the linear Fresnel lens 51 and the reflective container 52, the utilization efficiency of solar heat can be improved. The heat collecting / evaporating unit 50 is disposed so as to be inclined with respect to the horizontal plane in the same manner as the heat collecting / evaporating unit 30 of the first embodiment.

  Since the linear Fresnel lens 51 has a longer focal length than the above-described reflecting mirror 32, the sunlight incident direction is deviated, so that the sunlight cannot be sufficiently condensed on the vacuum adiabatic evaporation tube 31, and the solar heat is effective. It becomes unavailable. Therefore, it is desirable that the heat collecting / evaporating unit 50 includes a sun tracking mechanism (not shown) so that the angle can be changed manually or automatically. By doing in this way, the heat collection and evaporation part 50 can be turned to the direction suitable for the position of the sun, and solar heat can be used effectively. As a simple sun tracking method, the sun may be tracked by fixing the vacuum adiabatic evaporation tube 31 and rotating the linear Fresnel lens 51 as shown by an arrow R as shown in FIG.

  The linear Fresnel lens 51 is desirably formed with an ultraviolet absorbing film. By absorbing and removing ultraviolet rays thereby, deterioration of the resin of the Fresnel lens itself can be suppressed.

The effects of the desalination apparatus according to the first and second embodiments are summarized as follows.
(1) By providing the heat collecting means, the utilization efficiency of solar heat can be increased as compared with the endothermic method. The solar heat collected by the heat collecting means is used for heating / evaporation of raw water by a vacuum adiabatic evaporation tube having high solar heat utilization efficiency. Therefore, the efficiency of the heat collecting / evaporating unit in this embodiment is very high, and even an atmospheric distillation method can desalinate a sufficient amount of raw water, and also in the time zone where sunlight is not enough, such as early morning or evening. Desalination is possible.
(2) Since it is an atmospheric pressure distillation system, the apparatus can be configured with simple components, and the apparatus can be reduced in size, weight, and cost. In addition, since there is no complicated mechanism in the apparatus, assembly, handling, maintenance and repair are easy.
(3) Since it is an atmospheric pressure distillation system, high-temperature steam at 100 to 130 ° C. can be obtained from the upper part of the heat collecting and evaporating part. Therefore, this steam can be used for cooking and can also be used for sterilization of medical instruments. Furthermore, when seawater is used as raw water, salt can be produced by heating and drying the concentrated water taken out from the lower part of the heat collecting / evaporating section. Such salts can also be sold and can be a significant source of income for people in developing countries.
(4) As long as the raw water is supplied to the raw water tank, since the raw water is supplied to the heat collecting and evaporating unit by the water head pressure, a self-sustained operation that does not require energy other than sunlight is possible. Therefore, the device can be operated even in a developing country where infrastructure is not in place, and even in remote areas.
(5) Since the raw water is evaporated in the heat collecting part, and the heat collecting / evaporating part is arranged to be inclined with respect to the horizontal plane, the concentrated water is stored in the lower part of the heat collecting / evaporating part and taken out. Easy. Therefore, it is possible to prevent a failure of the device due to such clogged water clogging.

DESCRIPTION OF SYMBOLS 10 Desalination apparatus 20 Raw water tank 21 1st pipe line 22 Discharge pipe line 23 Three-way valve 24 Concentrated water tank 30 Heat collection and evaporation part 31 Vacuum heat insulation evaporation pipe 32 Reflective mirror 33 Transparent plate 34 1st cylinder 35 2nd Cylinder 36 Gas-liquid separator 37 Fresnel lens 38 Trough container 39 Baffle 40 Fresh water tank 41 Second pipe 42 Steam utilization means (for cooking, salt production, sterilization)
43 Cooling means 50 Heat collecting / evaporating section 51 Fresnel lens 52 Reflective container

Claims (7)

Raw water tank,
A heat collecting and evaporating part which is arranged to be inclined with respect to a horizontal plane and whose lower end communicates with the raw water tank;
A fresh water tank communicating with the upper end of the heat collecting and evaporating section;
With
The heat collecting and evaporating part is
A vacuum insulation evaporator tube that collects sunlight and evaporates raw water;
Condensing means for concentrating sunlight on the vacuum adiabatic evaporation tube;
An atmospheric pressure distillation desalination apparatus having The desalination apparatus according to claim 1, wherein the condensing unit is a reflecting mirror. The heat collecting and evaporating part further includes a transparent plate,
The desalination apparatus according to claim 2, wherein the vacuum heat insulating evaporation pipe is surrounded by the reflecting mirror and the transparent plate. The desalination apparatus according to claim 1, wherein the condensing unit is a Fresnel lens. A discharge port disposed below the heat collecting and evaporating section;
A three-way valve communicating with the raw water tank, a lower end of the heat collecting and evaporating unit, and the discharge port,
Further comprising
When the three-way valve is in the first state, raw water is supplied to the heat collecting and evaporating unit,
The desalination apparatus according to any one of claims 1 to 4, wherein when the three-way valve is in the second state, raw water is discharged from the discharge port. The desalination apparatus according to any one of claims 1 to 5, further comprising a gas-liquid separator at an upper portion of the heat collecting / evaporating section. The steam utilization means for at least one of cooking, salt production, and sterilization is provided between the said heat collection and evaporation part and the said fresh water tank, The any one of Claims 1-6 characterized by the above-mentioned. The desalination apparatus described.

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