JP2010281178A - Water-retaining structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-retaining structure which exerts a high cooling effect brought about by the evaporative latent heat of water. <P>SOLUTION: Water-retaining ceramics 23 are housed in a bag 22 which is made of a net, so as to constitute a water-retaining material package 21. The water-retaining material packages 21 are laid and arranged on an asphalt or concrete surface of a roof floor or a ground surface, etc. The numbers of the tiers of stacked water-retaining material packages 21 are set different from each other, so as to increase an evaporation area. Preferably, the water-retaining material packages 21 are stacked in a staircase pattern. The water-retaining ceramics 23 are made of sintered porous ceramics; 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. .

  Japanese Patent Laid-Open No. 2002-364130 describes that a lightweight artificial soil material such as pearlite is laid on the rooftop, and gravel is laid on the laid light to prevent the heat island phenomenon. FIG. 5 of the publication describes that a lightweight artificial soil material is packed in a non-woven bag.

  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 2002-364130 A JP-A-8-73282

  In the said patent document 1, the upper surface of a water holding body is flat, the contact area with air | atmosphere is small, and the cooling effect by transpiration of water is low.

  In Patent Document 2, gravel is laid on the lightweight artificial soil material, so that transpiration of water from the lightweight artificial soil material is suppressed, and the cooling effect is low.

  An object of the present invention is to provide a water retention structure that can easily evaporate water from ceramics for water retention distributed on a rooftop or the like and can obtain an efficient cooling effect.

  The water retention structure according to claim 1 is a water retention structure formed by arranging a water retention material package containing water retention ceramics in a housing material having air permeability and water permeability on a building or the ground surface, The arrangement height of some of the water retention material packages is different from the arrangement height of the other water retention material packages.

  The water retention structure according to claim 2 is the water retention structure according to claim 1, wherein the water retention material packages are stacked in one or more stages, and the arrangement height of the water retention material packages varies depending on the number of stacking stages of the water retention material packages. It is different from the arrangement height of the water retaining material package.

  In the water retention structure according to claim 3, the height per one of the water retention material packages is different from the height per other water retention material package, so that the arrangement height of the water retention material package is different from that of the other water retention material package. It is different from the arrangement height of the water retaining material package.

  According to a fourth aspect of the present invention, there is provided the water retention structure according to any one of the first to third aspects, wherein the accommodating material is a perforated bag or a perforated case.

  In the water retention structure according to claim 5, the water retention ceramics having different heights are arranged on the building or the ground surface, and the upper end level of at least some of the water retention ceramics is different from the upper end level of the other water retention ceramics. It is characterized by this.

  The water-retaining structure according to claim 6 is characterized in that, in claim 5, the average value of the difference between the levels of the upper ends of adjacent water-retaining ceramics is 1 to 30 cm.

  The water-retaining structure according to claim 7 is the water-retaining structure according to any one of claims 1 to 6, wherein the water-retaining ceramic comprises 53 to 70% of pores having a pore diameter of 1 to 100 μm. It is.

  In the water-retaining structure according to the first aspect of the present invention, a water-retaining material package in which water-retaining ceramics are accommodated in an air-permeable and water-permeable accommodating material such as a net is arranged on a building or the ground surface. The arrangement height of the water-retaining material package is different from other water-retaining material packages. For this reason, the contact area between the water retention material package and the atmosphere is large, and water efficiently evaporates from the water retention ceramics in the water retention material package, so that the cooling effect is high.

  In addition, by storing the water retaining ceramic in the housing material to form a water retaining material package, workability when the water retaining ceramic is laid on a rooftop or the like is improved.

  Moreover, the arrangement | positioning height of a water retention material package can be easily varied by varying the number of stacking stages of a water retention material package. Alternatively, the arrangement height of the water retention material package differs from the arrangement height of the other water retention material packages because the height per one of the water retention material packages is different from the height per one of the other water retention material packages. Can be.

  In the second aspect of the present invention, the water retaining ceramics having different heights are arranged on the building or the ground, and the level of the upper end of at least some of the water retaining ceramics is different from the level of the upper end of the other water retaining ceramics. Therefore, the contact area between the tall water-retaining ceramic and the atmosphere is increased, and the water is efficiently evaporated, so that the cooling effect is improved.

  In addition, a cooling effect improves by enlarging the level difference of the upper end of adjacent ceramics for water retention.

  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 the II-II sectional view taken on the line of FIG. It is a top view 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 a perspective view of the ceramic for water retention used in embodiment of FIG. 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 3 show a first embodiment. 1 is a cross-sectional view of a water retention structure according to an embodiment, FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1, and FIG. 3 is a plan view of the water retention structure.

  As shown in FIGS. 1 and 2, a water retaining material package 21 is arranged on a target surface 20 made of a waterproof surface such as a concrete surface or asphalt or a roof surface of a building or the like placed on the ground surface.

  The water retaining material package 21 is a bag 22 made of a net filled with a water retaining ceramic 23 made of porous ceramics. A watering pipe (not shown) is provided above the water retention material package 21.

  In addition, the temperature of the upper surface of the ceramic for water retention is detected by a temperature sensor such as a radiation thermometer or a thermocouple, and when this temperature exceeds a predetermined upper limit temperature (for example, 50 ° C.), water is caused to flow out from the watering pipe, You may comprise so that the outflow of this water may be stopped when it becomes below a predetermined minimum temperature (for example, 45 degreeC).

  The water retaining ceramic 23 preferably has an average particle size of 5 to 100 mm, particularly 10 to 50 mm. This size is easy to manufacture and easy to pack in a net bag. The shape of the granular body is arbitrary, such as a spherical shape, an elliptical spherical shape (for example, a rugby ball shape), a cubic shape, a rectangular parallelepiped shape, a weight shape, a disk shape, a columnar shape, a donut shape, and the like. The preferred physical properties and manufacturing method of this porous ceramic will be described later.

  Examples of the material of the net include synthetic resin, glass fiber, carbon fiber, metal fiber, and metal wire. A composite fiber in which a glass fiber is coated with a synthetic resin, a coated wire in which a metal wire is coated with a synthetic resin, or the like can also be used.

  It is desirable that the opening of the net is as large as possible within a range in which the contained water retaining ceramic does not come out.

  From the viewpoint of the burden on the building frame, it is preferable that the weight of the water retaining material package 21 when it is wet is 60 kg at the maximum.

  In this embodiment, the water retention material packages 21 are arranged so that a portion where only one level of the water retention material package 21 is laid on the target surface 20 and a portion where two or more levels are stacked are present.

  As shown in FIG. 1, in one direction of the target surface, the water retaining material packages 21 are arranged in a step-like manner such as one-stage stacking → two-stage stacking → three-stage stacking → two-stage stacking → one-stage stacking. ing.

  Even in the direction orthogonal to this one direction, as shown in FIG. 2 (a), the water retaining material package 21 is as follows: 1-stage stacking → 2-stage stacking → 3-stage stacking → 2-stage stacking → 1-stage stacking. Are arranged in steps.

  FIG. 3 shows the stacking stage number distribution in the case where the water retaining material packages 21 are arranged stepwise in one direction (for example, the east-west direction) and the direction orthogonal thereto (for example, the north-south direction).

  Reference numerals 1, 2 and 3 in FIG. 3 indicate the number of stacked stages.

  In the water retaining structure having such a water retaining material package stacking structure, the contact area between the water retaining material package and the atmosphere is larger than that when the water retaining material packages are arranged in a uniform number of stages, and the water transpiration is excellent. High cooling effect.

  In FIGS. 2 (a) and 3, the stacking pattern of the water retaining material package 21 is the same in the one direction and the direction orthogonal thereto, but as shown in FIG. 2 (b), The stacking pattern in the orthogonal direction may be different from the stacking pattern in the one direction (FIG. 1).

  In FIG. 2 (b), the stacking pattern is 2 stacks → 3 stacks → 2 stacks → 3 stacks. Of course, other stacking patterns than those shown in FIG. Although not shown, the height of the upper surface of the water retaining material package may be made different by making the height of one part of the water retaining material package different from the others. In this case, the number of stacked layers of the water retaining material package may be only one, or two or more. There may be two kinds of height of the water retaining material package, or more. You may make it the arrangement | positioning height of a water-retaining material package differ from the arrangement | positioning height of another water-retaining material package by stacking three types of water-retaining material packages having different heights in the same kind or different combinations.

[Second Embodiment]
Although the water retaining material package is used in the first embodiment, columnar water retaining ceramics 25 having different heights may be arranged on the target surface 20 as shown in FIG.

  In FIG. 4, three water retaining ceramics 25 having a low, medium, and high height in the column axis direction are arranged so that adjacent ones have different heights. A watering pipe (not shown) is provided above the water retaining ceramic 25.

  When columnar water retention ceramics with different heights are arranged in this way, the high water retention ceramics protrude upwards from the low water retention ceramics, resulting in a large contact area with the atmosphere, and water transpiration. It becomes active and the cooling effect is improved.

  In FIG. 4, three types of water retaining ceramics having different heights are used, but two types or four or more types of water retaining ceramics having different heights may be used. Further, the level of the upper end of the water retention ceramics may be varied by stacking at least a part of the water retention ceramics at least partially. In this case, the height of the water retention ceramics to be stacked may be the same or different. Good. In this invention, you may make it the arrangement | positioning height of the water retention ceramic differ from the arrangement height of other water retention ceramics by stacking three types of water retention ceramics having different heights in the same kind or different combinations.

  The height difference between adjacent water retaining ceramics 25 is preferably 2 cm or more, for example, about 5 to 20 cm.

The height of the water retaining ceramic 25 having the smallest height is preferably about 1 to 15 cm. The horizontal cross-sectional area of the water retaining ceramic 25 is preferably about 4 to 900 cm ² .

  This columnar water retaining ceramic has vent holes 26a and 27a having a hole diameter of about 1 to 50 mm penetrating in the column axis direction, like the water retaining ceramics 26 and 27 shown in FIGS. 5 (a) and 5 (b). It may be what you did.

  By providing the vent holes 26a and 27a, the water occluded in the deep part of the water retaining ceramics 26 and 27 is easily evaporated. Further, when the water retaining ceramics 26 and 27 are rained, the rain water is easily absorbed into the deep part of the water retaining ceramics.

  The water retaining ceramic 26 in FIG. 5 (a) has one vent hole 26a in the column shaft portion. The water retention ceramic 27 in FIG. 5 (b) has a plurality of air holes 27a. The water retaining ceramic is not limited to a cylindrical shape, and may be an elliptical column shape, a prismatic shape, or the like. Further, the shape is not limited to a column shape, and may be a cube shape or a spherical shape. Further, it may be a disk or dish like a tile. Further, the vent hole may be omitted. Suitable pore diameters, materials, manufacturing methods and the like of the porous ceramic will be described later.

  In FIG. 4, the water retaining ceramics 25 are closely arranged by bringing adjacent ones into contact with each other, but may be arranged with a slight gap (for example, 5 to 100 mm) between them. In the present invention, the water retaining material package and the water retaining ceramic may be used in combination.

  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.

  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.

[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%.

[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.

  For example, the green coverage ratio in Tokyo is currently 23%, which is not improved further. However, if the transpiration area is increased to 50% by applying the water-retaining ceramic of the present invention, the outdoor temperature in summer will be 27 ° C. It is also possible to do.

  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. 9 (a), a concrete slab 12 is laid in a box-shaped container whose bottom and four side surfaces are 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 test bodies 1 to 3 were placed side by side, and the changes over time in the temperature and the measurement temperature of the temperature sensor 14 of each test body were examined, and the results are shown in FIG. 9 (b).

  In the graph of FIG. 9 (b), the water absorption period was a period when there was rainfall, and otherwise it was cloudy or sunny.

  As apparent from FIG. 9 (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. 9 (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 temperature measured by 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. 10, the daily change in the surface temperature of the roof slab is 2 ° C. in the test body 1 in which the porous ceramics are laid, whereas it is 15 in the test body 3 in which the roof slab 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. 11 (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 13 produced in the same manner as in Experimental Example 2) was laid to 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 test bodies 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. 11 (b).

  As is clear from FIG. 11 (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 costs (laying or planting costs) and 20-year maintenance costs were estimated, and the comparison results are shown in FIG.

  As shown in FIG. 12, porous ceramics require only an initial cost, and 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 case 3 of rooftop greening, in addition to initial costs, maintenance costs such as pruning, pruning, lawn mowing, fertilization, weeding, pest control, irrigation equipment inspection, and other comprehensive inspections, etc. are expensive. 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, the rooftop 12 of the building is equipped with equipment (outdoor units, heat sources, etc.), but porous ceramics can also be laid under various equipment on the rooftop of the building, increasing the transpiration area of the city and the entire block The temperature can be greatly reduced.

  As can be seen from Fig. 14 which shows the results of remediation tests for porous ceramics and lawn flood control and transpiration, 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 can be seen from FIG. 13 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.

When laying a porous ceramics building roof to the area of 50 km ² with a thickness of 10cm can 1.8 million ^{m 3} things flood control, it is possible to peak cut guerrilla downpour 3 mm / hr at 23 wards of Tokyo.

<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 size 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. 6, a square-shaped enclosure 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. 6 (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, five porous ceramics 31 to 35 were prepared as shown in FIG. Then, the bottom porous ceramic 35 is stacked in five stages so that it is immersed in water about 1 mm from the bottom, and left in this state for 1 hour. The water absorption rate of the ceramic 31 (the ratio of the weight of water absorbed 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 1,30 Pallet 2 Enclosure 3 Styrofoam board 4 Concrete board 5,13,31,32,33,34,35 Porous ceramics 11 Heat insulating material 12 Concrete slab 14 Temperature sensor 20 Target surface 21 Water retention material package 22 Bag 23, 25 , 26, 27 Ceramics for water retention 26a, 27a

Claims (7)

A water retention structure formed by arranging a water retention material package containing a water retention ceramic in a accommodation material having air permeability and water permeability on a building or the ground surface,
A water retention structure characterized in that an arrangement height of at least some of the water retention material packages is different from an arrangement height of other water retention material packages.   The water retention material package according to claim 1, wherein the water retention material packages are stacked in one or more stages, and the arrangement height of the water retention material packages is different from the arrangement height of the other water retention material packages by overlapping the number of the accumulation stages of the water retention material packages. A water-retaining structure characterized by   2. The height of the water retaining material package according to claim 1, wherein the height of at least a part of the water retaining material package is different from the height of the other water retaining material package. A water retention structure characterized by being different from the arrangement height.   The water retaining structure according to any one of claims 1 to 3, wherein the containing material is a perforated bag or a perforated case.   A water retention structure in which water retention ceramics having different heights are arranged on a building or the ground surface, and the level of the upper end of at least some of the water retention ceramics is different from the level of the upper end of other water retention ceramics.   6. The water retention structure according to claim 5, wherein the average value of the difference between the upper end levels of adjacent water retention ceramics is 1 to 30 cm.   7. The water retention structure according to claim 1, wherein 53 to 70% of the total volume of the ceramic for water retention is composed of pores having a pore diameter of 1 to 100 [mu] m.

Images