DK165644B - Method for melting snow on a road or a building site - Google Patents

Description

1 ·

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a method of melting snow by utilizing the heat storage capability of a soil-deep water-bearing layer without spraying water on the snow, and more particularly to a method of melting snow 5 on a road or building structure by utilizing only artificially stored heat. groundwater and return the used water to the ground for recycling the same, as described in WO82 / 01386.

Until now, a process of melting and removing snow on roads and building structures in cold snow-plowed areas by groundwater spraying has been widespread. However, this approach poses the major problem that, after being grounded for melting snow 15, for example, the groundwater is discharged into the trenches adjacent to the road and then passed through rivers into the sea, the groundwater as a water resource is gradually reduced, and in some cases For example, the reduction of groundwater can cause soil to collapse.

20 In order to avoid the aforementioned problem of the prior art, JP Publication No. 49-59429 (59429/1974) discloses a method and apparatus for heating water for melting snow on a road using the heat of the groundwater. This apparatus 25 comprises groundwater pumps arranged in two artesian wells which reach aquifer layers near the ground surface, pumps for pumping up river or lake water, a heat exchanger, snowmelt pipes and snowmelt nozzles. Using this type of apparatus, river or lake water, which in the snow season has a temperature of about 1 ° C, is heated to a temperature of about 7-8 ° C through the heat exchanger using ground water of about 14 ° C as heat source, and the thus-heated river or lake water is sprayed out through the snowmelt nozzles to thereby melt snow on a road or the like.

JP usage pattern No. 45-25945 (25945/1970) discloses a pathway in which a carbon or carbonaceous

DK 165644B

2 material is mixed in the concrete or asphalt coating which forms the surface layer of the road, for example a highway to improve the thermal conductivity of the road during the cold period of snow. In the road 5 surface layer thus formed is laid a groundwater passage with a discharge port open to the road discount, by a road of this kind snow is melted on the road by sending pumped groundwater, which near the ground surface, mainly at a temperature of 10 ° C throughout the year, and the spent groundwater is then discharged into a river or lake.

However, the prior art described above includes the following problems.

by the method disclosed in JP No. 49-59429 15, river or lake water with a temperature of about 1 ° C to just 7-8 ° C in the heat exchanger is heated by means of ground water of about 14 ° C, and thus the heat transfer efficiency is not good, and no noticeable snowmelt effect is to be expected. As it is further difficult to spray the water evenly over the road and unmelted snow can freeze, which is dangerous for motorists and pedestrians, and a large amount of groundwater and river water is required to melt the snow on the road due to heat. -25 the exchange between groundwater of approx. 14 ° C and the river water of approx. 1 ° C, which temperature is considerably lower than the previous one, a large amount of water will be spread over the road surface, and this water can be sprayed on pedestrians or residential houses or buildings along the road by a moving car.

According to the technique or method described in JP Usage Pattern No. 25945/70, groundwater is gradually reduced as a water resource, groundwater near the ground surface being used to melt snow and then diverted to a river via a drain next to the road. which may be the cause of soil degradation, a serious societal problem. Furthermore, since the groundwater near the soil surface generally has a temperature of approx. 10 ° C, which is a relatively low temperature, requires a large amount of groundwater to effectively melt and remove the snow that has fallen on the way.

The object of this invention is to eliminate these problems or disadvantages of the prior art for removing snow lying on a road or the like, and to provide a method for melting snow lying on the road or the like without spraying water and by utilizing the heat storage capability of a water-bearing layer in the subsurface.

DE Publication No. 3 009 990 describes a groundwater storage from which water is withdrawn and cyclically returned. The water taken from the warehouse is pumped through cables and is either heated or cooled in the cables before being returned to the warehouse. The returned water then causes the remaining water in the storage 20 to either heat up or cool down, depending on the temperature difference between the stored water and the returned water.

It is to be understood that in order for two groundwater storage areas or aquifer to be maintained at different temperatures, the two aquifer must be thermally insulated from each other.

According to a feature of this invention, geothermally heated water from the aquifer layer is circulated through pipes which are laid substantially beneath the entire surface of the road or the like, or groundwater heated for a warm period by solar heat is circulated through the pipes for a cold period. with snow.

As pipes for laying under the surface of the road or similar, special pipes with a first class welding joint structure can be used.

According to this invention, the object can be met by a method of melting snow on a road

DK 165644B

4 or a building structure above ground utilizing the heat storage capability of a soil-deep water-bearing layer, where geothermally heated groundwater from a water-bearing layer is pumped up through a well and sent 5 through pipes to a water-bearing layer where the pipes are laid under the road or in the building structure for transferring heat to the snow lying thereon and melting it, which is a feature of pumping the groundwater from a first aquifer through a first artesian well, allowing the water to flow through pipes where it is cooled, being exposed to the atmosphere flows to a second aquifer, which is thermally insulated from the first aquifer, through a second artesian well located distant from the first 15 artesian well, that the groundwater flowing to the second artesian well is stored in it. second aquifer layer, and for a period before the next cold period of snow is heated to a higher temperature due to the heat storage capacity of the second aquifer layer, that the heated groundwater in the second aquifer layer is pumped up through the second artesian well during the next cold period of snow and caused to flow through said pipe to melt snow on the road or on the building structure, and the groundwater which has thus passed through the pipes flows to the first aquifer through the first artesian well, that the groundwater is stored in the first aquifer and heated due to its heat storage ability and that the above steps are repeated cyclically.

In another aspect, this invention provides a method of melting snow on a road or building structure above ground by utilizing the heat storage capability of a soil-deep water-bearing layer where geothermally heated ground water from a water-conducting layer in a cold period of snow is pumped up through a well and sent through pipes to a water-bearing layer, which pipes are laid beneath the road or in the building structure to transfer heat to the snow lying thereon and melt it, which method is peculiar in that the groundwater in a cold period 5 is pumped up from a first water-bearing layer, which forms a hot water zone, through a first artesian well, that the water flows through the pipes, where it is cooled by melting snow on the pipes, and then, without being exposed to the atmosphere, flows to another aquifer layer 10, which forms a cold water zone and is thermally insulated from «the first aquifer layer, through a second artesia so-called well located distant from the first artesian well, that the cooled groundwater is stored in the second aquifer, where increase in water temperature is suppressed by the heat storage capability of the second aquifer, that the groundwater is pumped up through the second artesian well for a warm period. is passed through the tubes to the first aquifer and heated by solar heat as it passes through the tubes, thereby storing the thus-heated groundwater in the first aquifer, whereby lowering of the elevated temperature of the water is suppressed by the heat storage capability of the first aquifer. that the above steps are repeated cyclically.

Preferred embodiments of the invention will now be described with reference to the schematic drawing, in which 1 is a plan view showing the first and second embodiments of the invention; FIG. 2 is a sectional view showing the first and second embodiments of the invention; 3 is a modification of FIG. 1, FIG. Fig. 4 is a graph showing the groundwater temperature as a function of time according to the first embodiment; 5 is a graph showing the temperature of the heated and cooled groundwater as a function of time according to the second embodiment;

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6 FIG. 6 is a partial sectional view showing an alternative embodiment of the system; FIG. 7 is a longitudinal section through a welded area of pipe sections constituting a pipe preferably 5 used in the embodiments of the invention; and FIG. 8A - 8C photomicrographs showing crystal structures in the regions near the welded region of the tube sections shown in FIG. 7th

The method of melting snow according to this invention is mainly based on the heat storage capability of an underground aquifer. The heat storage capability of a water-bearing layer will be described below.

For example, when hot water with a temperature of approx.

28 ° C is applied to a water-bearing layer with a cavity ratio of 15 30%, rocks, gravel, sand and the like are heated in the aquifer, thereby forming a hot water zone. The hot water zone is gradually developed into a large area, thus storing heat energy in the aquifer due to the heat storage capability of the aquifer. Conversely, a cold water zone is formed when cold water is applied to the water-bearing layer.

Preferred embodiments of the method of melting snow without spraying with water of this invention will be described in detail below, taking into account the above facts.

FIG. 1 and 2 show a case in which the invention is used for melting and removing snow lying on a road. As shown in these figures, at least two artesian wells A and B are formed, and a heat-dissipating and heat-collecting tube (or several tubes) 4 is laid, substantially beneath the entire surface of the path 5, on a curved, bent, parallel (as shown) in Fig. 3), helical, zigzag shaped or similar. The pipe 4 can, of course, be arranged elsewhere, such as in a building structure or under a railway track where snow is desired to be melted. The ends of the tube 4 are

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7 are connected in part to the wells A and B via, for example, piping. According to this construction or combination of wells and pipe arrangement, the groundwater in a water-bearing layer 7 which is below the soil surface can be approx. 40-150 m down, is pumped up by a pump 3 from the well A, which holds groundwater of approx. 15-16 ° C even during a cold period as shown in FIG. 4th

It follows that, in a cold period, allowing the thus-pumped hot groundwater to flow through the pipe 4, 10 below the road 5 or in a building structure, preferably at a rate of 0.3 to 1.5 m / s, it is melted snow, which has fallen on the road 5 or building structure gradually, and thus freezing of the road surface can also be prevented by heat transfer from the pipe 4.

The groundwater thus used to heat the pipe 4 and generally has a temperature of approx.

6 ° C, is then sent back through a conduit to the second well B and stored deep in the soil, thereby forming a cold water zone 8. In this way, the used water is returned again to the aquifer layer 7 from the soil surface 6 to be recycled without having been exposed to the atmosphere, thereby preventing groundwater from being wasted or contaminated.

25 As shown in the graph of FIG. 4, the groundwater returned to the aquifer layer 8 after use is heated through the well B gradually, and over approx. 6 months is the temperature of the once-used groundwater. again raised to the normal groundwater temperature of approx.

30 15-16 ° C and stored there under thermally insulated conditions for use in the next cold period of snow.

As described above, snow may have fallen on. the road or building structure of this embodiment is effectively melted and removed, without the spraying of water thereon and without the use of large quantities of groundwater, in an excellent manner relative to the conventional water.

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8 conventional methods for removing snow from the road or the like.

Another embodiment of the method according to the invention for melting and removing snow that has fallen on a road or the like will be described below with reference to FIG. 1, 2 and 3.

In the second embodiment, hot or hot water heated by solar energy is stored for a hot or warm period in the well A formed in the aquifer layer 7 located 10 below the ground surface about 40-150 m down and used in a cold period of snow by inflating and circulating through the pipe arrangement 4 arranged below the road 5 in a manner which will be described in detail below.

Water heated by solar energy for a warm period and stored in the aquifer 7 maintains a temperature of approx. 23-25 ° C during a cold period of snow, which is considerably higher than the temperature approx. 15-16 ° C, which is the normal temperature of the groundwater as a result of the heat storage capacity of the aquifer 7.

According to the second embodiment of the method according to the invention for melting snow, the thus heated and stored water is pumped up by means of the pump 3 from the well A and passed through the heat-emitting and heat-collecting pipes 4 laid under the path 5 to melt and removing snow that has fallen on the road 5, building structures or the like, thus preventing the snow or melted water from freezing on the road or the like. After being used for melting the snow, the water generally has a temperature of approx. 6 ° C and sent back into the cold water zone 8 of the second well B as cooled water.

According to the second embodiment, the water returned in the well B for the next heating period 35 is used as follows. The returned water, which in the summer season has a temperature of approx. 7-10 ° C, which is low

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9 · re than the normal groundwater temperature of approx. 15-16 ° C, is pumped up by means of a pump 3 ', shown in broken lines in FIG. 2, and after being used to cool houses, it is passed through the pipe 4, thereby 5 cooling the road 5, the building structure or the like, and preventing the road surface from becoming soft during the hot period. The cool water from the well B is heated by heat transfer from the heated road and building structure during circulation through the pipe 4, and the water thus heated at a temperature of approx. 28 ° C is returned to the well A down into the deep-lying aquifer 7 without being exposed to the atmosphere. The heated water thus returned to the well A forms a hot water zone in the aquifer 15 layer 7 substantially below the soil surface zone 6 and is stored there as hot water for melting the snow on the road or building structure in the next cold period with snow in the manner described above. .

According to the method of this embodiment, the groundwater used for melting the snow on the road or the like during the cold period of snow can be effectively used again for cooling the road, the building structure or the like during the hot period without being exposed to the atmosphere, thus that groundwater can be retained as a water resource without being wasted or contaminated.

The two embodiments of the method of this invention may also be carried out by means of a heat exchanger system. In FIG. 6, a system is shown in which the ground water in the well A is pumped up by means of the pump 3 and flows into the second well B through a conduit passing through a heat exchanger 10. The pipe 4 laid under the coating of the road 5 is filled with an antifreeze liquid which is circulated in the tube 4 by means of a pump 9 arranged on the conduit connecting the ends of the tube 4. According to this arrangement,

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10 heat from the groundwater to the antifreeze fluid as the groundwater passes through the heat exchanger 10, and the heat transferred to the antifreeze fluid is then transferred to the path 5 as the antifreeze fluid circulates through the tube 5 thereby melting the snow lying on the path 5 Preferably, a heat pump can be used as a heat exchanger 10.

The groundwater heated by solar heat during the warm period is stored in the well A and the groundwater 10 cold after the heat transfer in the heat exchanger 10 is stored in the well B.

Because there is anti-freeze liquid in the tube 4, effective breaking of the tube is prevented as the water in the tube 4 freezes in case the pump 9 is stopped.

In said embodiments, the heat-emitting and collecting tube 4 is disposed beneath the road surface 5, mainly for heating or cooling purposes only. Preferably, a tube having the following characteristics or structures is used. These characteristics and structures will be described below with reference to Figures 7 and 8.

A pipe used in accordance with this invention as the pipe 4 has a chemical composition as described in Japanese Industrial Standard (JIS) G-3452 and is usually composed of several pipe sections. An end surface of one pipe section abuts an end surface of another pipe section. The adjoining parts are welded by sprayed high-energy jets, such as laser beams, and the parts thus welded are quenched rapidly by blowing 30 with argon gas through valves to thereby form a weld joint and thus form a heat-transmitting and collecting tube.

FIG. 8A, 8B and 8C are photomicrographs showing crystal structures from the heat affected zone at the weld junction regions by the aforementioned welding method in which the photomicrograph of FIG. 8A shows a

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11 tensitic structure 1 a portion of a tube adjacent to the welded portion. The photomicrograph of FIG. 8B shows a fine-perlite structure in a portion of a tube adjacent to the mercenitic structure, and the photomicrograph of FIG. 8C vi-5 sees a perlite structure in a base steel tube.

As described above, the sprayed high-energy jet is radiated on the adjacent portions of the pipe sections to form a weld joint and then blown with a cooling gas to quench the welded portion rapidly.

The heat-emitting and collecting tube thus formed has a martensitic structure, a martensite and fine-perlite mixing structure, and a welded-fine-perlite structure against the base material of the tube in that order. No projections or other deformed parts were observed in the welded region of the thus formed tube, and thus a smooth welded surface is obtained. In a subsequent test of ten pipes, performed by bending the respective approx. 90 °, neither fracture nor crack were observed.

According to the method of the present invention, the ability to melt snow without spraying water is utilized, as described above, to the ability of heat-bearing water-bearing layers to store heat, whereby snow lying on roads or building structures can be effectively melted, thereby preventing, that the road surface freezes, by circulating hot groundwater through a pipe laid beneath the road surface. Further, after being used to melt the snow, the cooled groundwater is returned to the aquifer to form a cold water zone, and the returned cooled water is gradually heated by geothermal heat in the deep soil to a normal groundwater temperature for use in the next cold period of snow. Accordingly, a more efficient and economical snowmelt can be achieved, in comparison with conventional snowmelting methods by spraying water, using relatively small

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12 volumes of groundwater. Further, the groundwater is not sprayed and can be recycled without being exposed to the atmosphere, thereby preventing the groundwater from being wasted or contaminated, thus avoiding a problem 5 with soil subsidence.

In another aspect, the groundwater used and cooled by melting the snow during a cold period of snow can be used in the hot period for cooling the road or building construction by circulating it through the pipe arrangement lying beneath the road surface or the like. The groundwater used for cooling the road is heated by solar heat during circulation through the pipe arrangement, and the thus heated groundwater is returned to the well for recycling in the next cold 15 period of snow.

In yet another aspect, the pumped groundwater is circulated from one well to another well through a heat exchanger, and an antifreeze liquid filled to the pipe lying beneath the surface is circulated through the heat exchanger in which heat is transferred from the groundwater. Accordingly, the interior of the tube will never freeze even in cases where the circulation of the antifreeze stops after the snow on the road has melted, thus ensuring safe operation and reducing maintenance costs.

Further, as the tubes laid under the road have the improved structure, improved strength and flexibility are obtained, and furthermore, the welded sections of the pipe sections have no projections or other deformed parts, allowing for the free pipe arrangement, and the tubes last for long periods of use. without forming cracks or fractures. Such pipes are very suitable as pipes to be laid beneath the road surface through which groundwater is circulated in accordance with the method of melting snow in accordance with the present invention.

Claims (7)

A method of melting snow on a road or building structure above ground by utilizing the heat storage capability of a ground-deep aquifer, wherein geothermally heated groundwater from an aquifer (7) is pumped through a well (A) and sent through pipes (4) to a water-bearing layer in which the pipes are laid under the road or in the building structure to transfer heat to the snow lying thereon and melt it, characterized in that the groundwater is pumped up from a first water-bearing layer (7) through a first artesian well (A) for the water to flow through pipes (4) where it cools, after which, without being exposed to the atmosphere, it flows to a second aquifer (8) thermally insulated from the first aquifer layer (7), through a second artesian well (B) located distant from the first artesian well (A), that the groundwater flowing to the second artesian well (B) is stored in the second aquifer (8), and through a period before the next cold period of 20 snows is heated to a higher temperature due to the heat storage capacity of the second aquifer (8), the heated groundwater in the second aquifer (8) is pumped up through the second artesian well (B) below the the next cold period of snow and 25 is caused to flow through said pipe (4) to melt snow on the road or on the building structure (5), and the groundwater which has thus passed through the pipes (4) flows to the first aquifer ( 7) through the first artesian well (8), 30 that the groundwater is stored in the first aquifer (7) and heated due to its heat storage ability and that the above steps are repeated cyclically. A method according to claim 1, characterized in that the first water-bearing layer (7) is located below the soil surface at a depth of approx. 40 to 150 m. 3. A method of melting snow on a road or building structure above ground by utilizing the heat storage capability of a ground-deep aquifer, where geothermally heated groundwater from an aquifer during a cold period of snow is pumped up through a well (A) and sent through pipes (4) to a water-bearing layer, which pipes are laid beneath the road or in the building structure (5) to transfer heat to the snow lying thereon and melt it, characterized in that the groundwater in a cold period being pumped up from a first water-bearing layer (7) constituting a hot water zone, through a first artesian well (A), that the water flows through the pipes (4), where it is cooled by melting snow on the pipes (4), and then without being exposed to the atmosphere, a second aquifer (8), which is a cold water zone and thermally insulated from the first aquifer (7), flows through a second artesian well (B) disposed distant from the first scar. thesian well (A) that the cooled groundwater is stored in the second aquifer (8), where increase in water temperature is suppressed due to the heat storage capacity of the second aquifer 25 (8), that the groundwater is pumped up through the second for a warm period. artesian well (B), is passed through the tubes (4) to the first aquifer (7) and heated by solar heat as it passes through the tubes (4), thereby storing the thus heated groundwater in the first aquifer (7), wherein the lowering of the elevated temperature of the water is suppressed by the heat storage ability of the first aquifer (7) and the above steps are repeated cyclically. Method according to claim 3, characterized in that the first water-bearing layer (7) is located below the earth's surface at a depth of approx. 40 to 150 m. Process according to claim 3 or 4, characterized in that the water heated by solar heat in the first water-bearing layer (7) is kept at a temperature of approx. 23 to 25 ° C. Process according to claim 3 or 4, characterized in that the cooled water which is pumped to the second aquifer (8) has a temperature of 10 'approx. 7 to 10 ° C.