JP2010281176A - Water-retaining structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-retaining structure which is simply constituted and which exerts a high cooling effect brought about by the evaporative latent heat of water. <P>SOLUTION: Water-retaining ceramics 24 are arranged on a water-flowing sloped surface 20 on a roof floor; and water is supplied onto the water-flowing sloped surface from a porous water supply pipe 22 which is provided on a portion on the water. The water-retaining ceramics 24, which are made of sintered porous ceramics, are provided with a vent hole 24a with an inside diameter of 1 mm or more, penetrating in a vertical direction; and portions equivalent to 53-70% of the total volume are composed of air holes with a hole diameter of 1-100 μm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a water retention structure using a ceramic for water retention, which is applied to a rooftop of a building or the like.

  Japanese Patent Laid-Open No. 8-312018 discloses a system for cooling a building by laying a block-shaped water retaining body made of porous ceramics on the roof of a building, turning a water supply pipe for sprinkling to sprinkle the water retaining body. . The publication describes that a sprinkler may be used instead of the above-described swivel type water supply pipe.

  In paragraph 0005 of JP-A-8-73282, a method for producing a porous ceramic is described in which clay, a water-absorbing polymer and water are kneaded, molded, dried in a microwave oven, and then fired at 1100 ° C. for 2 hours. Yes. The same publication discloses that the water-absorbing water-absorbing polymer has a particle diameter of 0.1 to 2.0 mm (claim 4). Thus, when the particle size of the water-absorbing polymer is large, the pores of the porous ceramics are also coarse, and the water retention of the porous ceramics is not high.

JP-A-8-312018 JP-A-8-73282

  When the water retaining body is sprinkled using a swivel type water supply pipe as in Patent Document 1, the facilities are large and the cost is high. In addition, since there is a drive unit, maintenance management is costly and the frequency of failure is high.

  When using a sprinkler to spray water on the water retaining body, the water may scatter around the roof of the building, causing inconvenience to the neighborhood.

  An object of this invention is to provide the water retention structure which can supply water uniformly with simple equipment with respect to the ceramic for water retention distributed on the rooftop etc.

  The water-retaining structure according to claim 1 includes a flowing water gradient surface provided on a building or the ground surface, water retention ceramics distributed on the flowing water gradient surface, and water supply means for supplying water to the upper surface of the flowing water gradient surface. Is provided.

  The water-retaining structure according to claim 2 is characterized in that, in claim 1, the water-retaining ceramic is distributed in a container, and the bottom surface of the container is the flowing water gradient surface.

  A water retention structure according to claim 3 is the water supply means according to claim 1 or 2, wherein the water supply means detects the amount of water on the flowing water gradient surface, and the water supply means when the amount of water detected by the detection means falls below a predetermined amount of water. And a control means for actuating.

  According to a fourth aspect of the present invention, there is provided the water retention structure according to the second aspect, wherein the weight detection means for detecting the total weight of the container and the contents of the container, and the weight detected by the weight detection means is a predetermined weight or less. And a control means for operating the water supply means at the time.

  The water retention structure according to claim 5 is the temperature detection means for detecting the temperature of the ceramic for water retention according to claim 1 or 2, and the water supply means when the temperature detected by the temperature detection means exceeds a predetermined temperature. And a control means for actuating.

  The water-retaining structure according to claim 6 is the water-retaining structure according to any one of claims 1 to 5, wherein the water-retaining ceramic comprises 53 to 70% of pores having a pore diameter of 1 to 100 μm. It is.

  A water retention structure according to a seventh aspect is characterized in that, in any one of the first to sixth aspects, the water retention ceramic is provided with a vent hole having an inner diameter of 1 mm or more penetrating in the vertical direction. is there.

  In the water retention structure of the present invention, ceramics for water retention are distributed on the flowing water gradient surface provided on the roof of the building or on the ground surface, and water is supplied to the water (minakami) portion of the flowing water gradient surface. Since this water supply flows on the flowing water gradient surface in the direction of the water below (not considered) according to the gradient, water can be spread over the entire flowing water gradient surface. Therefore, water can be uniformly contained in each water retention ceramic on the flowing water gradient surface without using a large facility such as a swivel type water supply pipe.

  Further, since no sprinkler is used, it is possible to prevent the vicinity from being splashed.

  The running water gradient surface may be a roof surface, a concrete surface placed on the ground surface, an asphalt surface, or the like, or may be constituted by the bottom surface of the container.

  In the present invention, the amount of water on the flowing water gradient surface may be detected, and water may be supplied to the flowing water gradient surface when the amount of water falls below a predetermined amount. When the water retaining ceramic is distributed in the container, the weight of the container and its contents (water retaining ceramic and water) are detected, and when the weight falls below a predetermined weight, water is supplied into the container. Also good.

  Further, the temperature of the water retaining ceramic may be detected, and water supply may be performed when the temperature becomes equal to or higher than a predetermined temperature.

  In this way, water supply is performed in accordance with a decrease in the amount of water, a decrease in weight, or a rise in the temperature of the ceramic for water retention, so that water breakage can be prevented and the water retention ceramic can always be in a wet state.

  The water retention ceramic used in the present invention is made of porous ceramics and exhibits a cooling effect by the latent heat of evaporation of the contained water. In the present invention, the water retaining ceramic is preferably provided with a vent hole having an inner diameter of 1 mm or more. In this case, water easily penetrates to the deep part of the water retaining ceramic, and the water embedded in the deep part of the water retaining ceramic also easily evaporates. Therefore, the water absorption speed and evaporation speed are large.

  In the present invention, it is preferable that the water retaining ceramic comprises 53 to 70% of pores having a pore diameter of 1 to 100 μm. Thus, the water retention ceramic having a large amount of relatively fine pores has high water retention, a large specific surface area on the surface, and good water evaporation. Accordingly, it is possible to quickly absorb a large amount of water by rain or water spray and prevent urban flooding. In addition, the pores of this pore diameter are not very fine. When freezing, the water in the pores is rapidly pushed out of the water retaining ceramic with the volume expansion of the water at the time of freezing. However, there is almost no risk of cracking.

  As described above, a large latent heat is removed from the retained water retaining ceramic by the evaporation of water. Therefore, the water retention structure of the present invention in which this water retention ceramic is spread on the rooftop or garden of a building is excellent in the cooling effect of the building or garden.

It is sectional drawing of the water retention structure which concerns on embodiment. It is a perspective view of the upper part of the water of FIG. It is a perspective view of the ceramic for water retention used in an embodiment. It is a top view of the water retention structure concerning an embodiment. It is a water supply system figure of the water retention structure concerning an embodiment. It is sectional drawing which shows the water retention structure which concerns on another embodiment. It is sectional drawing of the water retention structure which concerns on another embodiment. It is explanatory drawing of the test method in an Example and a comparative example, (a) A figure is a top view, (b) A figure is the BB sectional drawing of (a) figure. It is a pore size distribution map of the ceramics for water retention of Experimental Examples 1-5. It is a hole diameter distribution map of the pores of the ceramics for water retention of Experimental Examples 6-10. (A) The figure is typical sectional drawing which shows the test body 1, (b) The figure is a graph which shows the time-dependent change of the slab temperature of the test bodies 1-3. It is a graph which shows a time-dependent change of the slab surface temperature of the test bodies 1 and 3. FIG. (A) The figure is typical sectional drawing which shows the test body 4, (b) A figure is a graph which shows the time-dependent change of the upper atmospheric temperature of the test bodies 4 and 5. FIG. It is a graph which compares the initial stage and the maintenance cost of cases 1-3. It is a graph which shows by contrast the amount of transpiration and water absorption in the test period of water retention ceramics and lawn. It is a graph which shows the cumulative total of the amount of transpiration and water absorption of ceramics for water retention and lawn. It is explanatory drawing of the test method in an experiment example, and is a schematic diagram which shows the accumulation state of the ceramic for water retention on a pallet.

  Hereinafter, embodiments will be described with reference to the drawings.

[First Embodiment]
1 to 5 show a first embodiment. 1 is a cross-sectional view of a water retention structure according to an embodiment, FIG. 2 is a perspective view of the upper portion of the water, FIGS. 3 (a) and 3 (b) are perspective views of a ceramic for water retention, and FIG. A plan view of the structure, FIG. 5 is a water flow system diagram.

  As shown in FIGS. 1, 2, and 4, a running water gradient surface 20 is provided on a waterproof surface such as a concrete surface or asphalt placed on the ground surface or the roof surface of a building. When the flowing water gradient surface 20 is the upper surface of a building, it is desirable that a careful waterproof finish is applied. The gradient of the flowing water gradient surface 20 is preferably about 1/200 to 1/20, particularly about 1/50 to 1/20.

  A dam portion 21 is provided around the flowing water gradient surface 20. A water supply pipe 22 is routed to the water (minakami) portion of the flowing water gradient surface 20. The water supply pipe 22 is provided with a plurality of water discharge holes 22a at intervals in the longitudinal direction. The water supply pipe 22 extends along the weir 21 on the water side. By extending the water supply pipe 22 along the side on the water upper side of the flowing water gradient surface in this way, water can be sufficiently spread over the entire area of the flowing water gradient surface.

  A drainage groove 23 is provided in the underwater (deemed) portion of the flowing water gradient surface 20.

  A water retaining ceramic 24 shown in FIG. 3A is distributed on the flowing water gradient surface 20. The water retaining ceramic 24 is a columnar shape made of porous ceramics having a height of about 30 to 150 mm, and a vent hole 24a having a hole diameter of about 1 to 50 mm penetrating in the column axis direction is provided at the axial center of the column. Yes. By providing this air hole 24a, the water occluded in the deep part of the water retaining ceramic 24 is also easily evaporated. Further, when rain is applied to the water retaining ceramic 24, the rain water is easily absorbed to the deep part of the water retaining ceramic.

  In place of the water retaining ceramic 24 having one air hole 24a, a porous ceramic water retaining ceramic 25 having a plurality of air holes 25a shown in FIG. 3 (b) may be used. The water retention ceramic is not limited to a cylindrical shape, and may be an elliptical column shape, a prismatic shape, a spherical shape, an elliptical spherical shape (for example, a rugby ball shape), a cube, a rectangular parallelepiped, a spindle shape, a disk shape, or the like. Further, the vent hole may be omitted. Suitable pore diameters, materials, manufacturing methods and the like of the porous ceramic will be described later.

  The water retaining ceramics 24 are closely arranged by bringing adjacent ones into contact with each other, but may be arranged with a slight gap (for example, 5 to 30 mm) between them. Moreover, you may spread randomly without arranging.

  The water flow system will be described with reference to FIG.

  A water supply tank 30 is installed at a position higher than the water supply pipes 22 at appropriate places such as the rooftop. The water in the water supply tank 30 can be supplied to the water supply pipe 22 by a pipe 31 having a valve 32. A water level gauge 33 is provided in the water supply tank 30, and the detected water level signal is input to the controller 34. The valve 32 is opened and closed by a signal from the controller 34. Tap water (may be well water or the like) can be introduced into the water supply tank 30 via a pipe 35 having a valve 36. This valve 36 is controlled by a controller 34.

  A water level gauge 37 for detecting the water level of water accumulated on the flowing water gradient surface 20 is provided below the flowing water gradient surface 20, and the detected water level signal is input to the controller 34.

  A drain pipe 40 is connected to the drain groove 23, and a valve 41 is provided in the middle of the drain pipe 40. A pipe 42 branches from the drain pipe 40 upstream of the valve 41, and the end of the pipe 42 faces the water supply tank 30. The pipe 42 is provided with a valve 43 and a pump 44, and these valve 43 and pump 44 are controlled by the controller 34.

  The controller 34 controls the valves 32, 41, 43 and the pump 44 so that water below the lower limit water level and lower than the upper limit water level is accumulated on the flowing water gradient surface 20. The lower limit water level is the water level at which the lower end of the water retaining ceramic 24 on the uppermost water side is in contact with the water surface, and the upper limit water level is the intermediate height in the vertical direction of the water retaining ceramic 24 on the lowermost water side. The upper limit water level is not limited to this as long as the upper end of the most water-holding ceramics 24 protrudes from the water surface rather than the water surface.

  When the detected water level of the water level gauge 37 is equal to or lower than the lower limit water level, the valve 32 is opened, the water in the water supply tank 30 flows out from the water supply pipe 22, and the water level is increased to the middle between the lower limit water level and the upper limit water level. To do. At this time, when water is insufficient in the water supply tank 30, the valve 36 is opened to supply water to the water supply tank 30.

  When the water level of the water level gauge 37 exceeds the upper limit water level due to rain or the like, the valve 43 is opened and the pump 44 is operated to send water to the water supply tank 30. When there is no remaining free capacity in the water supply tank 30 or when there is no free space, the valve 43 is closed and the pump 44 is stopped, and the valve 41 is opened to discharge water to the sewer or the like.

  In this way, the lower portions of all the water retaining ceramics 24 on the flowing water gradient surface 20 can be kept in contact with water at all times. Therefore, the water retaining ceramics 24 are always kept in a wet state, and a cooling effect is reliably obtained by water evaporation. be able to. Further, water can be supplied evenly to all the water retaining ceramics 24 without using a swivel type water supply pipe or the like. Since no sprinkler is used, water does not splash around.

  In this embodiment, since the surplus water is stored in the water supply tank 30 by the pump 44, rainwater when there is a large amount of rainfall can be used in fine weather. However, the piping 42, the valve 43, and the pump 44 may be omitted, and the equipment cost may be simplified.

  Instead of using the water level gauge 37, the temperature of the upper surface of the water retaining ceramic 24 on the uppermost water side is detected by a temperature sensor such as a radiation thermometer or a thermocouple, and this temperature is equal to or higher than a predetermined upper limit temperature (for example, 50 ° C.). The water supply pipe 22 may be allowed to flow out when the temperature reaches the predetermined lower limit temperature (for example, 45 ° C.), and the water flow may be stopped.

[Second Embodiment]
In the present invention, a container may be installed on the ground surface or the roof of the building, ceramics for water retention may be arranged in the container, and water may be supplied into the container.

  FIG. 6 shows an example of this, and a container 51 is installed on the ground surface or rooftop 50 via a container beam portion 52 and a weight sensor 53. The container 51 has a bottom surface and a surrounding wall portion provided on the entire periphery thereof. The bottom surface of the container 51 is a running water gradient surface. Water retaining ceramics 24 are arranged on the bottom surface. A water supply pipe 22 is installed on the water upper side of the flowing water gradient surface, and water can be supplied to the water supply pipe 22 by a pipe 56 having a valve 55.

  A weight detection signal detected by the weight sensor 53 is input to the controller 54. When the weight of the container 51, the water retaining ceramic 24 and the water in the container 51 detected by the weight sensor 53 becomes equal to or less than a predetermined weight, the controller 54 opens the valve 55 and supplies water from the water supply pipe 22. To do. Since this water flows according to the flowing water gradient surface, the water is evenly supplied to all the water retaining ceramics 24 in the container 51.

  In addition, the height of the surrounding wall of the container 51 is lower than the upper ends of all the water retaining ceramics 24. Therefore, even if the inside of the container 51 becomes full due to rain or the like, the water overflows from the surrounding wall, and the upper end of the water retaining ceramic 24 always protrudes from the water surface. An overflow drain hole or notch may be provided in the surrounding wall of the container 51. When the drain hole or notch is provided, the upper end of the water retaining ceramic 24 always protrudes from the water surface if the upper end of the water retaining ceramic 24 is made higher than the maximum water level determined by the drain hole or notch. By providing a drain hole or a notch in the container 51, it is not necessary to consider the relationship between the height of the surrounding wall of the container 51 and the upper end of the water retention ceramic.

[Third Embodiment]
In FIG. 6, the moisture content of the water retaining ceramic 24 is detected by the weight sensor 53. However, as shown in FIG. 7, the surface temperature of the upper end surface of the water retaining ceramic 24 on the water side is determined by the radiation thermometer 60. The detected temperature signal is input to the controller 61, and when the surface temperature exceeds a predetermined temperature, the valve 55 is opened by the signal from the controller 61 to supply water to the water supply pipe 24. You may make it do. A temperature sensor such as a thermocouple may be used instead of the radiation thermometer 60.

  Next, suitable pore diameters, materials, compositions, production methods, and the like of the porous ceramics constituting the water retention ceramic will be described.

[Pore diameter of ceramic for water retention]
The water retention ceramic used in the present invention preferably comprises fine pores having a pore diameter of 1 to 100 μm, preferably 15 to 40 μm, with 53 to 70%, preferably 55 to 68%, of the total volume of the water retention ceramic. As described above, by containing a large amount of such fine pores, the water retention and water evaporation properties of the water retention ceramic are improved.

More preferably, 60% or more, for example 70 to 95%, of the pores having a pore diameter of 1 to 100 μm are pores having a pore diameter of 10 to 50 μm, preferably 15 to 40 μm.
In particular, the water retention ceramic used in the present invention is preferably 10 to 70%, particularly 15 to 50% of the total volume of the water retention ceramic is composed of fine pores having a pore diameter of 15 to 40 μm.

  The total porosity of the water retaining ceramic is preferably 55 to 80%. If the total porosity of the water retaining ceramic is less than 55%, 53 to 70% of the total volume cannot be realized as the water retaining ceramic with fine pores of 1 to 100 μm, and if it is larger than 80%, the strength is insufficient. The practicality as a laying material is impaired.

  In the present invention, the pore diameter is measured according to JIS R 1655 using a mercury porosimeter.

  The water in the pores having the above pore diameter is easily pushed out of the water retaining ceramic during freezing, and the water retaining ceramic is hardly cracked even when subjected to repeated freezing and thawing action.

[Composition of ceramics]
The composition of the ceramics constituting this ceramic for water retention is SiO ₂ : 50-80 wt%, especially 55-70 wt%.
Al ₂ O _3: 10~30wt% especially 15~25wt%
Total Na ₂ O and _{K 2} O: _1~10wt% especially 3～7Wt%
It is preferable that

  Such aluminosilicate ceramics containing a large amount of soda and potash are hydrophilic, and the water retention and water evaporation properties of the water retention ceramic are good.

  In order to prevent algae from being generated in the water retaining ceramic in a wet state, CuO may be mixed in the water retaining ceramic in an amount of about 0.1 to 1.5 wt%.

  The water retention ceramic used in the present invention may be provided with a photocatalyst effect by applying a photocatalyst coating liquid to a part or the entire surface thereof, thereby improving the contamination resistance of the water retention ceramic by the purification action by the photocatalyst. be able to.

[Production method of ceramic for water retention]
Next, the suitable manufacturing method of the ceramic for water retention is demonstrated.

In order to produce this water-retaining ceramic, ceramic raw materials, alumina cement and powdered water-absorbing polymer and preferably further lithium carbonate are dry-mixed, then water is added and mixed, followed by molding, drying and firing. . The blending ratio at this time is preferably
Ceramic materials: 75-95 wt%, especially 80-95 wt%
Alumina cement: 3-15 wt%, especially 5-15 wt%
Water-absorbing polymer: 0.5 to 10 wt%, especially 1 to 5 wt%
Lithium carbonate: 10 wt% or less, especially 1-10 wt%, especially 1-5 wt%
It is.

  In addition, the mixing ratio of water is about 130 to 170 wt% with respect to the total weight of all raw materials other than water, and about 80 to 150 times that of the water-absorbing polymer is easy to handle, moldability, It is preferable from the viewpoint of the water-absorbing expansibility of the water-absorbing polymer, subsequent drying, and firing efficiency.

As the ceramic material, one or more kinds of potash feldspar, clay, silica sand and the like can be used, but are not limited thereto. These ceramic materials are selected and used so that the ratio of SiO ₂ , Al ₂ O ₃ , and Na ₂ O + K ₂ O is as described above.

  As the alumina cement, those defined in JIS can be used.

  Since this alumina cement is hardened quickly, when it is mixed by adding water and molded, a molded body that can be handled in a short time is obtained.

  As the powdery water-absorbing polymer, those having a particle size of about 10 to 50 μm, particularly about 20 to 30 μm are suitable.

  As the water-absorbing polymer, one of various kinds such as polyacrylate, saponified vinyl acetate / acrylic acid ester copolymer, starch / acrylic acid graft copolymer is used alone, or two or more kinds are mixed. Can be used.

  To form this mixture, a quantitative filling machine, a cast molding machine, an extrusion molding machine, a honeycomb molding machine, or the like can be used, but the present invention is not limited to this.

  The molded body is preferably heated and dried at 80 to 250 ° C. for 5 to 40 hours, particularly 6 to 12 hours, and then preferably at 1050 to 1200 ° C., particularly 1100 to 1150 ° C. for 0.2 to 20 hours, particularly 0.3 to. Firing for 2 hours to obtain a sintered body. A roller hearth kiln, a tunnel kiln, a shuttle kiln, etc. can be used for this baking.

[Application examples and effects of ceramics for water retention]
Ceramics for water retention are porous ceramics whose pore diameter and the ratio thereof are strictly controlled, and have a performance of controlling water by absorbing rainwater and evaporating the absorbed water by solar radiation.

  Therefore, environmental measures such as A and B below can be achieved by laying the ceramic for water retention on the roof of a building, a passage of a private house or public facility, a plaza, a garden, and the like.

A. Environmental measures for individual buildings A-1. Energy-saving · CO ₂ reduction of the building:
By laying water retaining ceramics on the building roof, the roof slab temperature can be lowered and the power consumption of the air conditioner downstairs can be reduced by rainwater control and transpiration with the water retaining ceramics.

  Moreover, the ambient temperature of the air-conditioning outdoor unit installed on the roof can be lowered, the air-conditioning operation efficiency of all floors can be improved, and the amount of power used can be reduced. In particular, it is possible to greatly reduce the amount of power used for air conditioning in the summer on the rooftop floor.

As a result, CO ₂ emission can be reduced.

A-2. Alternative to rooftop greening in buildings:
Water-retaining ceramics have the same water retention and cooling performance as plants such as lawn, and are highly durable, long-life, maintenance-free materials that use natural rainfall, and are therefore promising candidates for replacing rooftop greening.

  The current rooftop greening takes time to maintain and high management costs, but the ceramics for water retention can solve this problem.

A-3. Reducing maintenance costs for building roof waterproof layers:
Since the ceramic for water retention has a low thermal conductivity of about 0.2 W / m · K and a high heat insulating property, the roof slab temperature can be kept constant by laying it on the building roof. In addition, ultraviolet rays can be prevented.

  At present, repair of the waterproof layer is required in about 10 years, but this maintenance frequency can be reduced by applying a water retaining ceramic.

B. Urban environmental measures B-1. Heat island measures:
Water-retaining ceramics can be laid under various equipment (outdoor units, heat sources, etc.) that occupy the building roof. By laying the water-retaining ceramics of the present invention in various places, the transpiration area of the city can be increased, and the entire block This temperature can be further reduced.

  Moreover, since the ceramic for water retention has a high transpiration capacity compared with lawn, the temperature reduction effect per unit area is also high compared with lawn.

B-2. Guerrilla heavy rain measures:
Water-retaining ceramics have a higher flood control capability than lawn, so if they are laid on the roof of the building as much as possible, peak cuts in guerrilla heavy rain can be expected.

B-3. Reuse of resources Ceramics for water retention can be produced using feldspar glitter, which has been conventionally regarded as waste, as a main raw material (for example, 90% of the raw material). The feldspar killer is a by-product of mining the feldspar as a raw material for tiles, and was previously considered as waste.

  Hereinafter, experimental examples or trial calculation examples showing the effects A and B of the porous ceramics will be given.

<A-1. Energy saving and CO ₂ reduction of buildings>
As shown in FIG. 11 (a), a concrete slab 12 is laid in a box-shaped container having a bottom and four side surfaces made of a heat insulating material 11, and a porous ceramic (for example, an experimental example described later) is formed thereon. The porous ceramics manufactured in the same manner as in No. 2) was laid in a thickness of 10 cm to obtain a test body 1. The laying area of the porous ceramic is 1 m ² . A temperature sensor 14 was provided between the bottom heat insulating material 11 and the concrete slab 12.

  Separately, instead of the porous ceramics, a specimen planted with lawn was used as a test specimen 2, and a specimen without porous ceramics was used as a test specimen 3.

  These specimens 1 to 3 were placed side by side, and the time-dependent changes in the temperature and the temperature measured by the temperature sensor 14 of each specimen were examined. The results are shown in FIG. 11 (b).

  In the graph of FIG. 11 (b), the water absorption period was a period when there was rainfall, and the rest was cloudy or sunny.

  As apparent from FIG. 11 (b), the test body 1 in which the porous ceramics was laid had a temperature reduction effect of -8 ° C. at the maximum under the slab relative to the test body 3 without laying. And the transpiration | evaporation effect of the test body 1 was a bigger thing than the test body 2 which planted the lawn.

  From this result, it can be seen that rainwater control and transpiration with porous ceramics can lower the roof slab temperature and reduce the amount of power used for air conditioning downstairs.

  Next, as shown in FIG. 11 (a), the surface temperature of the roof slab is measured by the test body 1 in which the porous ceramics 13 are laid and the temperature sensor 14 is provided, and the test body 3 in which the porous ceramics are not laid. As a simulation of this change, the measured temperature of the temperature sensor 14 for 24 hours a day was examined, and the results are shown in FIG.

  The general thermal conductivity of porous ceramics, concrete slabs, and soil is as shown below.

Porous ceramics: 0.20 W / m · K
Concrete slab: 0.15 W / m · K
Sat: 0.63 W / m · K

  As is apparent from FIG. 12, the daily change in the surface temperature of the roof slab is 2 ° C. in the specimen 1 in which the porous ceramic is laid, whereas it is 15 in the specimen 3 in which the porous ceramic is not laid. It was ℃. From this result, it can be seen that the thermal load on the slab caused by solar radiation is reduced by laying the porous ceramics.

Next, as shown in FIG. 13 (a), a concrete slab 12 is laid in a box-shaped container having a bottom portion and four side surfaces made of a heat insulating material 11, and a porous ceramic (for example, described later) is laid thereon. The porous ceramics manufactured in the same manner as in Experimental Example 2) was laid in a thickness of 10 cm to obtain a test specimen 4. The laying area of the porous ceramic is 1 m ² . A temperature sensor 14 was provided at a position 1 cm above the laying surface of the porous ceramic.

  Separately, the test body 5 was not laid with porous ceramics. In this test body 5, a temperature sensor 14 was provided at a position 1 cm above the concrete slab 12.

  These specimens 4 and 5 were placed side by side, and the change in temperature measured by the temperature sensor 14 for 24 hours a day was examined. The result is shown in FIG. 13 (b).

  As is clear from FIG. 13 (b), there was a difference of 5 ° C. maximum as the atmospheric temperature above 1 cm between the test body 4 laid with porous ceramics and the test body 5 not laid.

  From this result, it can be seen that by laying the porous ceramics, the ambient temperature of the air conditioner outdoor unit installed on the roof can be lowered, the operating efficiency of air conditioning on all floors can be improved, and the amount of power used can be reduced.

<A-2. Alternative to rooftop greening of buildings and A-3. Reduction in maintenance costs for roof waterproofing layer of buildings>
Per unit area when porous ceramics are laid on the roof of the building (case 1), conventional specifications without laying this (case 2), and rooftop planting with lawn or shrub (case 3) The initial cost (laying or planting cost) and the maintenance (maintenance) cost for 20 years were estimated, and the comparison results are shown in FIG.

  As shown in FIG. 14, the porous ceramics is only an initial cost, and the subsequent maintenance is almost unnecessary. On the other hand, in the case 2 of the conventional specification in which no porous ceramic is laid, maintenance costs such as repair of the waterproof layer are required, and as a result, it is equivalent to the product of the present invention.

  In the case of rooftop greening 3, in addition to the initial cost, pruning, pruning, lawn mowing, fertilization, weeding, pest control, irrigation equipment inspection, and other comprehensive inspections are in addition to the costs shown in Fig. 14. In addition, the electricity and water costs necessary for the operation for watering by irrigation equipment will be charged.

  From these results, as mentioned above, porous ceramics are equivalent to the performance of plants such as lawns in flood control and transpiration, and are also highly durable, long-life and do not require maintenance management using natural rainfall. Compared with rooftop greening, the initial cost is ½ and the maintenance cost is much cheaper, which makes it a good candidate for rooftop greening alternative.

<B-1. Heat island measures>
By laying porous ceramics on the entire roof of the building in Tokyo's 23 wards, the transpiration area of a city that functions for flood control and transpiration can be increased by 10%.

  Currently, equipment (outdoor units, heat sources, etc.) is installed on the roof of the building, but porous ceramics can be laid under various equipment on the building roof, increasing the transpiration area of the city and increasing the entire city block The temperature can be greatly reduced.

  As can be seen from Fig. 16 which shows the results of repeated tests of water control and transpiration of porous ceramics and lawn, porous ceramics have a transpiration capacity approximately twice that of lawn. This increase in the transpiration area of the city is doubled by 20% if replaced with lawn, and further effectiveness is clear.

<B-2 guerrilla heavy rain measures>
Regarding porous ceramics and lawn, as is clear from FIG. 15 which compares the total amount of transpiration and water absorption per unit volume over a period of 15 days from October 2 to October 16, porous ceramics are lawn. More than twice the amount of water absorption and transpiration.

If porous ceramics are laid on the rooftop of a 10 cm thick and 50 km ² area, flood control of 1.8 million m ³ can be achieved, and peak cuts of 3 mm / hr guerrilla heavy rain can be achieved in Tokyo's 23 wards.

<B-3. Reuse of resources>
The porous ceramics can be produced, for example, with 90% by weight of feldspar glitter, which has been conventionally regarded as waste, and 10% by weight of other materials. If the weight of the porous ceramics per unit area is 40 kg / m ² , the amount of feldspar glitter necessary for laying 5000 m ² is
5000 (m ² ) × 40 (kg / m ² ) × 0.9 ÷ 1000 = 180 ton
It becomes.

That is, when producing 5000 m ² per day as the laying area of the porous ceramic, the necessary waste (feldspar killer) raw material is 180 tons / day, and the effective utilization effect of the waste is extremely large.

  Hereinafter, the experimental result which shows that the porous ceramics of the said mixing | blending is excellent in water retention and transpiration | evaporation property is demonstrated. The following Experimental Examples 1 to 5 are porous ceramics using the preferred composition of the present invention, and Experimental Examples 6 to 10 are porous ceramics having other compositions.

  The raw materials used in the following experimental examples are as follows.

Potassium feldspar: Nagasaki No. 8 from Seto, Aichi Pref. Silica: Katsuno Ceramics Nagasaki Kira: Nagao from Seto, Aichi Water-absorbing polymer: Sanyo Kasei Co., Ltd.
(Under 20 μm particle size by sieve (water-absorbing polymer A), particle size
20-50 μm (water-absorbing polymer B), particle size 50-100 μm
Classification into (water-absorbing polymer C). )
Alumina cement: manufactured by Lafarge Co., Ltd. Lithium carbonate: reagent grade CuO: reagent grade

[Experimental Examples 1 to 10]
Raw materials other than water were weighed in the proportions shown in Table 1, and mixed with a mixer (Nauta mixer manufactured by Hosokawa Micron Corporation) in a dry manner. Subsequently, water was added to the mixed powder in the ratio shown in Table 1 and kneaded. This was formed into a substantially disk shape having a diameter of 70 mm and a maximum thickness of 15 mm, and dried at 80 ° C. for 24 hours. This was fired in a roller hearth kiln (maximum firing temperature as shown in Table 1. Furnace passage time was 60 minutes) to produce porous ceramics.

  Each porous ceramic was subjected to component analysis and characteristic measurement. The results are shown in Tables 1 and 2.

  The porosity was measured using a mercury porosimeter (manufactured by Quantachrome). The pore diameter distribution of the pores is shown in FIGS.

  The water retention amount was measured as follows.

The porous ceramic is dried at 105 ° C., allowed to cool, and weighed to determine the weight (W ₁ ). Next, after being immersed in water at 20 ° C. for 24 hours, it is pulled up and the surface water is wiped off with a damp cloth to make it saturated. This sample is weighed to determine the weight (W ₂ ). Further, the saturated porous ceramic is put into water in a graduated cylinder, and the volume (V) is obtained. The water retention amount (g / cm ³ ) is calculated by (W ₂ −W ₁ ) / V.

  The strength was measured by making a 10 cm × 10 cm × 0.5 cm sample by a three-point bending test (JT Toshi Co., Ltd., 50 kN digital bending tester).

  Freezing and thawing performance is the degree of damage by repeating the freezing and thawing cycle in which the saturated porous ceramic is frozen by holding at −20 ° C. for 75 minutes and then holding and melting at 30 ° C. for 90 minutes for 200 cycles. It was examined by observing and evaluated as very good (◎), good (○), slightly bad (△), and bad (x).

The transpiration performance is as follows. Place the dried porous ceramics in a flat container with 5 mm depth of water, absorb water for 30 minutes, pull it up, and increase the water absorption for 30 minutes in the same way as the method for measuring water retention. Ask. About the volume, the volume at the time of measuring the water retention amount is used. The water absorption amount (g / cm ³ ) for 30 minutes is defined as the transpiration performance.

  The transpiration effect duration was the duration of the cooling effect due to the latent heat of evaporation, and was measured as follows.

  As shown in FIG. 8, a square-shaped frame 2 made of a foamed polystyrene plate having a thickness of 100 mm is placed on a pallet 1 made of recycled polypropylene resin having a thickness of 150 mm to form a container. One side of this container is 1000 mm and the depth is 830 mm. Aluminum foil is stretched on the outer peripheral surface of the container.

In this container, the polystyrene foam plate 3 is spread over to a thickness of 500 mm, and the temperature sensors T _{1 to} T ₅ are arranged at five locations on the upper surface thereof.

  A concrete plate 4 having a thickness of 180 mm and a specific gravity of 2.2 is placed on the polystyrene foam plate 3. 50 kg of saturated porous ceramics 5 (shown only in FIG. 8 (b)) is deposited on the concrete plate 4. The deposition thickness is about 10 cm. The above work is performed indoors at an air temperature of 20 ° C. and a humidity of 60% RH. This container is left in a constant temperature and humidity chamber at 35 ° C. and 60% RH, and the number of days until the temperature detected by the temperature sensor rises to 35 ° C. is measured. This is the number of days for which the transpiration effect lasts.

  Further, in order to investigate the water absorption of the porous ceramics obtained in each experimental example, as shown in FIG. 17, five porous ceramics 71 to 75 were prepared, and on the pallet 70 with water. In addition, the bottom porous ceramic 75 is stacked in five stages so that it is immersed in water by about 1 mm from its bottom, and left in this state for 1 hour. The water absorption rate of the ceramic 71 (the ratio of the weight of water absorbed relative to the weight of the porous ceramic before water absorption) was calculated.

[Discussion]
As shown in Table 1, the porous ceramics of Experimental Examples 1 to 5 having the above preferred compositions are excellent in evaporation performance and evaporation effect duration days, and also have good freeze-thaw resistance and water absorption.

  On the other hand, Experimental Example 6 out of Experimental Examples 6 to 10, which do not belong to the above preferred composition, is inferior in evaporation performance, evaporation effect duration and water absorption because the pore diameter is excessive.

  Experimental Example 7 is inferior in freeze-thaw performance and water absorption because the pore diameter is excessively small.

  Since Experimental Example 8 has an excessively high porosity of 80%, it is inferior in strength, freeze-thaw performance, and water absorption.

  Since Experimental Examples 9 and 10 have a low water retention amount, the evaporation effect duration days are short and the water absorption is also poor.

DESCRIPTION OF SYMBOLS 1,70 Pallet 2 Enclosure 3 Styrofoam board 4 Concrete board 5,13,71,72,73,74,75 Porous ceramic 11 Heat insulating material 12 Concrete slab 14 Temperature sensor 20 Flowing water gradient surface 21 Weir part 22 Water supply pipe 23 Drainage Grooves 24, 25 Ceramics for water retention 24a, 25a Ventilation hole 30 Water supply tank 33, 37 Water level gauge 51 Container 53 Weight sensor

Claims (7)

  A water retention structure comprising a flowing water gradient surface provided on a building or a ground surface, water retaining ceramics distributed on the flowing water gradient surface, and water supply means for supplying water to an upper portion of the flowing water gradient surface.   2. The water retention structure according to claim 1, wherein the water retention ceramic is distributed in a container, and a bottom surface of the container is the flowing water gradient surface.   3. The water amount detecting means for detecting the amount of water on the flowing water gradient surface according to claim 1 or 2, and a control means for operating the water supply means when the amount of water detected by the detecting means falls below a predetermined water amount. A water retention structure characterized by that.   3. The weight detection means for detecting the total weight of the container and the contents of the container according to claim 2, and the water supply means is operated when the weight detected by the weight detection means becomes a predetermined weight or less. A water retention structure comprising a control means.   The temperature detection means for detecting the temperature of the ceramic for water retention according to claim 1 or 2, and the control means for operating the water supply means when the temperature detected by the temperature detection means exceeds a predetermined temperature. A water retention structure characterized by that.   6. The water retention structure according to any one of claims 1 to 5, wherein the water retention ceramic comprises 53 to 70% of pores having a pore diameter of 1 to 100 [mu] m.   The water retention structure according to any one of claims 1 to 6, wherein the water retention ceramic is provided with a vent hole having an inner diameter of 1 mm or more penetrating in the vertical direction.

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