JP4668089B2 - Geothermal utilization system with rainwater storage tank - Google Patents

Description

The present invention relates to a geothermal system excellent in heat exchange efficiency with rain water reservoir soil Ru can stably hold the wet state.

  In recent years, the water retention capacity of the earth has decreased due to deforestation, etc., and disasters such as flash floods and water shortages are increasing year by year. As countermeasures, rainwater during torrential rains is temporarily stored in rainwater storage tanks and discharged when the water level of the river drops, or the stored rainwater is used for toilets, washing, car washing, watering for rooftop greening, etc. It has been broken.

  On the other hand, as a method of using geothermal heat (approximately 15 ° C. throughout the year) for cooling and heating, a method of disposing a heat medium pipe (cool tube) of a heat exchanger inside or below a rainwater storage tank buried underground (Patent Document 1) 2) has been proposed, but sufficient heat exchange efficiency has not been obtained. Further, in the method (Patent Document 3) in which the heat medium pipe is disposed in the soil containing the water-absorbent resin, once the water-absorbent resin is warmed, there is almost no movement of water and the heat exchange efficiency is lowered. In addition, there is a problem that the water absorption function of the water absorbent resin cannot be sufficiently obtained in soil having a high Na ion concentration.

Japanese Patent Laid-Open No. 9-292153 JP-A-9-137478 JP 2001-74316 A

In view of such a situation, the present inventor examined improvement and stabilization of heat exchange efficiency between the heat medium pipe line of the heat exchanger embedded in the ground and the soil. As a result, it has been found that the heat exchange efficiency between the soil and the heat medium is significantly improved by leaching the water in the rainwater storage tank into the soil in which the heat medium pipe is embedded, and further studies are made to complete the present invention. It came to.
The present invention has an object to provide a geothermal system excellent in heat exchange efficiency with rain water storage tank that can hold soil stably the wet.

The invention according to claim 1, or a liquid to at least a portion of the outer side wall lower part of the rain water storage tank at least partially that is formed by the permeable member of the wall of the rainwater storage tank which is buried in the ground The heat medium pipe of the heat exchanger that uses air as the heat medium is buried, the water of the rainwater storage tank is leached from the wall to the soil where the heat medium pipe is buried, and the buried heat medium pipe is used. a geothermal system with the rainwater reservoir and heat medium pipe to perform soil and heat exchange.

According to a second aspect of the invention, the rain at least a portion of the upper portion of the side wall of the rainwater storage tank is formed by water-permeable member, the lower portion of the sidewall upper portion that have a side wall surface formed by an impermeable member Soil in which the heat medium pipe of a heat exchanger that uses liquid or air as a heat medium is embedded in at least a part of the outside of the lower part of the side wall of the water storage tank, and the heat medium pipe is embedded from the wall to the water of the rainwater storage tank It is a geothermal utilization system having a heat medium pipe and a rainwater storage tank that exudes and heat-exchanges with soil using the buried heat medium pipe.
Even if such a side wall surface is not the entire surface of the rainwater storage tank, it is sufficient that at least one of the side wall surfaces has the above-described configuration.

According to a third aspect of the present invention, at least a part of a wall portion of the rainwater storage tank buried in the ground is formed of a water permeable member, and an outer wall is provided at a predetermined interval outside the rainwater storage tank. are to claim 1 or claim 2 which is a geothermal system having a heat medium pipe and rainwater storage tank to perform a soil heat exchanger utilizing the buried thermal medium conduit according.

The invention described in claim 4 is a part of the outer wall of the other storage tank in which the outer wall provided at a predetermined interval outside the rainwater storage tank has a container shape that covers the rainwater storage tank from the outside. provided reservoir as the reservoir is a double structure, between the inner reservoir and the outer reservoir of using heat medium conduit embedded was according to claim 3 which is disposed a sediment soil a geothermal system having a heat medium pipe and rainwater storage tank for exchanging heat with.

The invention according to claim 5 is a geothermal heat utilization system having a heat medium pipe and a rainwater storage tank for exchanging heat with soil using the buried heat medium pipe according to any one of claims 1 to 4. In
At least a portion of the outer side wall lower part of the rainwater storage tank buried heat medium pipe of a heat exchanger, and a heat medium pipe mentioned above embedded, further heat medium pipe of the heat exchanger to the storage water of the rainwater storage tank Geothermal utilization having a heat medium pipe line and a rain water storage tank for exchanging heat with the soil using both the buried heat medium pipe line and the heat medium pipe line arranged in the rain water storage tank System.

A sixth aspect of the present invention is a geothermal utilization system having a heat medium pipe that performs heat exchange with soil using the embedded heat medium pipe according to any one of claims 1 to 5 and a rainwater storage tank. The wall portion of the rainwater storage tank is made of a material having a thermal conductivity of 0.1 W / (m · K) or more.

A seventh aspect of the present invention is a geothermal heat utilization system having a heat medium pipe that performs heat exchange with soil using the embedded heat medium pipe according to any one of claims 1 to 5 and a rainwater storage tank. In the geothermal utilization system having a heat medium pipe line and a rainwater storage tank, the permeability coefficient of the wall portion of the rainwater storage tank is made smaller than that of the earth and sand outside the wall portion of the rainwater storage tank. is there.

The invention according to claim 8 is a geothermal heat utilization system having a heat medium pipe that performs heat exchange with soil using the embedded heat medium pipe according to any one of claims 5 to 7 and a rainwater storage tank. The rainwater storage tank has a heat storage function for use of geothermal heat and a combined function of use as rainwater for daily use, and is a geothermal utilization system having a heat medium pipe line and a rainwater storage tank.

Since the rainwater storage tank of the present invention is embedded in the ground and has a water permeable wall, the stored water in the storage tank oozes out to the soil near the rainwater storage tank through the water permeable wall. Accordingly, the soil in the vicinity of the rainwater storage tank is stably maintained in a wet state.
Since the geothermal utilization system of the present invention is obtained by burying a heat medium pipe of a heat exchanger in the wet soil, sufficient heat exchange efficiency can be stably obtained.

The present invention will be specifically described with reference to the drawings. Description of overlapping symbols is omitted.
As shown in FIG. 1, the rainwater storage tank 1 used in the geothermal utilization system of the present invention is embedded in the underground 2, and at least a part of the wall 3 of the rainwater storage tank 1 is formed by a water permeable member 4. ing.
When the rainwater 5 flows into the rainwater storage tank 1 from the rainwater inflow pipe 6 and the stored rainwater (reserved water) 5 exceeds the lower end of the permeable wall portion 7 formed by the permeable member 4, the stored water 5 becomes permeable. It begins to gradually exude from the sex wall 7 into the ground 2, and the vicinity of the rainwater storage tank 1 becomes wet soil 8. In FIG. 1, 9 is a lid of the rainwater storage tank 1.

  As shown in FIG. 2 (a), the exuded water 10 that exudes from the water permeable wall portion 7 gradually descends the ground 2 while exchanging heat with the soil, and the preheated heat medium conduit 11 Heat exchange with the heat medium pipe 11 is performed while the surface is wet. As the amount of the exudate 10 increases, the portion of the soil where the heat medium pipe 11 is embedded is moistened to form a wet soil region 12. The heat exchange efficiency between the soil region 12 and the heat medium pipe 11 is drastically improved because the exudate 10 wets the heat medium pipe, and the heat medium in the heat medium pipe 11 is efficiently heated or cooled. The

The heat medium pipe 11 is connected to a heat exchanger main body 14 installed in the house 13, and the heat medium in the heat medium pipe 11 is radiated or absorbed in the heat exchanger main body 14.
The heat medium may be a liquid such as water or a gas such as air. In the case of using a liquid as the heat medium, water mixed with a water-soluble organic solvent such as alcohol or water containing an antifreeze or a preservative can be used in addition to water. In the case of air, air conditioning can be performed by circulating air using a blower instead of the heat exchanger body.

In the present invention, the wall portion of the rainwater storage tank may be entirely formed of the water permeable member 4, but as shown in FIG. If the heat medium pipe 11 is embedded in the lower portion of the side wall, the exudate 10 descends while exchanging heat with the soil, so that the heat medium pipe 11 is efficiently cooled. At this time, the heat medium pipe to be buried may not be arranged so as to surround the rainwater storage tank, but may be arranged on some of the side walls. For example, when only one side wall of the rainwater storage tank is formed of the water permeable member 4 and the heat medium pipe is disposed in the soil of the side wall, the stored water is effectively used.

  As shown in FIG. 2B, when the stored water 5 in the rainwater storage tank 1 falls to the lower end of the water permeable wall portion 7, the exudation of the stored water 5 stops, and the heat exchange efficiency is lowered. If you want to keep the heat exchanger running but there is no rain, it is possible to replenish the rainwater storage tank with fresh water. When the lower part of the side wall is a permeable wall part, it is possible to use up the stored water in the rainwater storage tank and the rainwater in the rainwater storage tank may be depleted. It is advantageous to stably use a geothermal utilization system having a long time.

  If the water permeability of the water-permeable wall is too high, the stored water will ooze into the ground in a short time and the wet state of the soil will not be maintained. descend. Accordingly, it is necessary to appropriately determine the water permeability of the water permeable wall portion in consideration of the state of the soil, the capacity of the storage tank, and the like.

  In the present invention, a resin molded product having a fine hole or a slit, a porous ceramic, a nonwoven fabric, or the like is used as the material of the water permeable wall. In terms of material, a material having appropriate strength and workability and capable of water permeation processing (processing to provide fine holes and slits) is used.

  The size of the fine holes and slits is appropriately set in the range of usually 1 mm to 10 μm in consideration of the size of sand particles and sand particles and the water permeability coefficient. This is because if the particle diameter exceeds 1 mm, soil particles and sand particles gradually enter the storage tank and accumulate in the storage tank, and if it is less than 10 μm, the holes and slits are clogged.

The pore size must be determined in consideration of the size and shape of earth and sand particles and sand particles. The actual sediment is not constant in type, size, shape, hardness, etc., and is often a mixture of different types of particles, so it is empirical depending on the type and size of the sediment particles and sand particles. To be determined. If the size of the earth and sand particles or sand particles is relatively coarse and the hydraulic conductivity (permeability coefficient k under atmospheric pressure) is slightly large, the size of the holes and slits is set relatively large in the above range, and When formed from fine sand, silt, clay, or a mixture thereof and having a small size and a low permeability coefficient, the size of the hole and slit is set to be small within the above range. Moreover, the water permeability coefficient is often designed in the range of 10 ⁻¹ cm / s to 10 ⁻⁷ cm / s in practice. If the soil is clayey and the soil particles are ultrafine and almost impermeable, the size of the holes and slits may be set to 10 μm to 1 μm very rarely.

When the storage tank has a double structure as in the invention described in claim 4, earth and sand having a small hydraulic conductivity are inserted between the inner rainwater storage tank and the outer rainwater storage tank, and the periphery of the inner rainwater storage tank. If the residence time of the exudate water is increased, the heat exchange efficiency between the soil and the heat medium pipe can be improved. In this way, selecting the permeability coefficient of the earth and sand around the rainwater storage tank within a predetermined range includes a heat medium pipe and a rainwater storage tank having a single rainwater storage tank structure that does not have an outer wall outside the rainwater storage tank. Even if it is a geothermal system, it is effective.

  In addition to the above, by setting the permeability coefficient of the permeable wall part of the rainwater storage tank formed of the permeable member to be smaller than the permeability coefficient of the earth and sand around the wall part, the outside of the storage tank can be transferred to the storage tank. Inflow of rainwater can be prevented, and the effect of the present invention can be made sufficient. Thus, the ratio of the permeability coefficient of earth and sand and the permeability coefficient of the permeable wall of the rainwater storage tank is 1.2 to 1.3 times the permeability coefficient of earth and sand and the permeability of the permeable wall of the rainwater storage tank. It is necessary to make a difference in degree, and should preferably be doubled or more.

  Factors affecting the heat exchange efficiency of the heat medium pipe include the influence of the thermal conductivity of the wall of the storage tank in addition to the water permeability. When the water temperature in the rainwater storage tank is brought close to the soil temperature in advance, heat exchange between the soil and the heat medium pipe line is performed efficiently, so the wall (including the permeable wall) of the rainwater storage tank It is desirable to use a material with excellent thermal conductivity having a conductivity of 0.1 W / (m · K) or more, more preferably 0.5 W / (m · K) or more.

  Materials with a thermal conductivity of 0.1 W / (m · K) or higher include materials based on polyethylene resin, polypropylene resin, and polyvinyl chloride resin, and foamed styrene based on polystyrene that can easily form porous materials. Examples thereof include a resin, a nonwoven fabric of polyethylene terephthalate resin, an acrylic resin, a polycarbonate resin, and an engineering plastic.

  Examples of materials having a thermal conductivity of 0.5 W / (m · K) or higher include polyethylene-based high thermal conductive resins and polyphenylene sulfide-based high thermal conductive resins, which are functional resins that have been actively studied. It is done.

A geothermal utilization system having a heat medium pipe and a rainwater storage tank used in the invention according to claim 3 and a geothermal utilization system having a heat medium pipe and a rainwater storage tank used in the invention according to claim 4 are shown in FIG. As shown in one example, the outer wall 15 is provided so as to surround the rainwater storage tank 1 buried in the ground, and the exudate 10 from the permeable wall 7 remains in the outer wall 15, so that the soil is wet. The condition persists for a long time. Therefore, in the geothermal heat utilization system of the present invention in which the heat medium pipe 11 is embedded in the wet soil region 12, good heat exchange is stably performed for a long time.
When a ceiling is provided between the rainwater storage tank 1 and the outer wall 15, the wet state lasts longer.

  In the present invention, the height of the outer wall 15 may be lower than that of the permeable wall because exudate moves downward. However, the wet state of the soil does not protrude outside the outer wall and disturbs the backfilling operation. It is necessary to make it a height that does not become necessary.

  When the outer wall is in the shape of a saucer having a bottom plate, a large amount of exudate water may remain in the outer wall and the soil temperature may approach the outside air temperature. Therefore, it is necessary to make a certain amount of water by making a hole in the bottom. It is preferable to use a material having high thermal conductivity for the outer wall to transmit the geothermal heat outside the outer wall to the inner side of the outer wall.

  Although the excavated soil may be used as it is for the backfilling of the rainwater storage tank, the heat exchange efficiency can be improved by backfilling the soil mixed with a resin excellent in water retention, thermal conductivity and the like. As the water-retaining resin, a highly water-absorbing polymer such as a crosslinked polyacrylate salt or polyvinyl alcohol / polyacrylate salt is used.

  In the present invention, if the temperature of the stored water in the rainwater storage tank is close to the geothermal heat, a heat medium pipe 11 is arranged in the stored water 5 of the rainwater storage tank 1 as shown in FIG. It can be performed. The stored water can also be used as a heat source such as a heat pump. Furthermore, regardless of the water temperature, the stored water can be pumped and sprinkled on the outer wall of the house for cooling, or used for watering trees. Furthermore, it can be used for flushing toilets. As described above, in addition to using the rainwater storage tank as a geothermal utilization system, it is also one of the features of the present invention that it can be used in combination as domestic water.

  In the present invention, because the target to be stored in the storage tank is rainwater mainly because of economic reasons, the storage tank buried underground is collectively described as a rainwater storage tank. However, in order to operate the geothermal utilization system stably, it is necessary to always secure a certain amount of water in the storage tank. Therefore, it is necessary to use clean water or snowmelt instead of rainwater. Even when the effect is realized, it is included in the right of the present invention.

It is longitudinal cross-sectional explanatory drawing which shows embodiment of the rainwater storage tank used for the geothermal utilization system of this invention. (A) and (B) are longitudinal sectional explanatory views showing a first embodiment of the geothermal utilization system of the present invention. It is a longitudinal cross-sectional explanatory drawing which shows 2nd Embodiment of the geothermal utilization system of this invention. It is longitudinal cross-sectional explanatory drawing which shows 3rd Embodiment of the geothermal utilization system of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rainwater storage tank 2 Underground 3 Rainwater storage tank wall 4 Permeability member 5 Reservation water 6 Rainwater inflow pipe 7 Permeability wall part formed of the water permeability member 8 Wet soil 9 Rainwater storage tank lid 10 Permeation Exudate water from sexual wall 11 Heat medium conduit 12 Wet soil region 13 House 14 Heat exchanger body 15 Outer wall

Claims (8)

Heat exchanger that utilizes a liquid or air as a heating medium to at least a portion of the outer side wall lower part of the rain water storage tank at least partially that is formed by the permeable member of the wall of the rainwater storage tank which is buried in the ground The heat transfer medium pipe is used to exude heat from the rainwater storage tank from the wall to the soil where the heat transfer medium pipe is embedded, and to exchange heat with the soil using the embedded heat transfer medium pipe. A geothermal utilization system having a road and the rainwater storage tank. At least a portion of the upper portion of the side wall of the rainwater storage tank is formed by water-permeable member, the outer side wall lower portion of the rain water storage tank that having a side wall surface of the lower portion of the side wall upper portion is formed by an impermeable member The heat medium pipe of a heat exchanger that uses liquid or air as a heat medium is embedded in at least a part of the heat, and the water in the rainwater storage tank is leached from the wall to the soil in which the heat medium pipe is embedded, A geothermal heat utilization system including a heat medium pipe that performs heat exchange with soil using a medium pipe and a rainwater storage tank. The wall portion of the rainwater storage tank buried in the ground is formed of a water permeable member, and the outer wall is provided outside the rainwater storage tank at a predetermined interval. A geothermal utilization system having a heat medium conduit and a rainwater storage tank for exchanging heat with soil using the embedded heat medium conduit according to Item 2. A storage tank is provided such that the outer wall provided at a predetermined interval outside the rainwater storage tank is a part of the outer wall of another storage tank having a container shape that covers the rainwater storage tank from the outside, 4. A heat medium pipe for exchanging heat with soil using the buried heat medium pipe according to claim 3, wherein the storage tank has a double structure, and earth and sand are arranged between the inner storage tank and the outer storage tank. Geothermal utilization system with road and rainwater storage tank. In the geothermal utilization system which has a heat-medium line which performs heat exchange with the soil using the buried heat-medium line in any one of Claims 1 thru / or, and a rainwater storage tank,
At least a portion of the outer side wall lower part of the rainwater storage tank buried heat medium pipe of a heat exchanger, and a heat medium pipe mentioned above embedded, further heat medium pipe of the heat exchanger to the storage water of the rainwater storage tank Is placed,
A geothermal heat utilization system having a heat medium pipe and a rainwater storage tank that exchange heat with soil using both the buried heat medium pipe and the heat medium pipe arranged in the rainwater storage tank. A geothermal heat utilization system having a heat medium pipe for exchanging heat with soil using the embedded heat medium pipe according to any one of claims 1 to 5 , and a rainwater storage tank, wherein the rainwater storage tank The wall portion is made of a material having a thermal conductivity of 0.1 W / (m · K) or more. A geothermal heat utilization system having a heat medium pipe for exchanging heat with soil using the embedded heat medium pipe according to any one of claims 1 to 5, and a rainwater storage tank, wherein the rainwater storage tank A geothermal heat utilization system having a heat medium pipe line and a rainwater storage tank, characterized in that a water permeability coefficient of the wall portion of the rainwater is made smaller than a water permeability coefficient of earth and sand outside the wall part of the rainwater storage tank. The geothermal heat utilization system which has a heat-medium line which performs heat exchange with soil using the embedded heat-medium line in any one of Claims 5 thru | or 7 , and a rainwater storage tank, The said rainwater storage tank is geothermal A geothermal utilization system having a heat medium pipe line and a rainwater storage tank, which has a combined function of heat storage function for utilization and utilization as domestic water for rainwater.

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