JP2007071439A - Triple u-shaped tube type underground heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a triple U-shaped tube type underground heat exchanger having enough strength so that it is not damaged by ground pressure even when it is buried about 300m under the ground rich in geothermal heat. <P>SOLUTION: All of a first U-shaped tube 1, a second U-shaped tube 2 and a third U-shaped tube 3 for circulating antifreeze liquid, and a straight guide tube 4 have equal outer diameters, the first U-shaped tube 1 and the third U-shaped tube 3 are placed in such manner that a going way D and a returning way U are formed without clearance therebetween, and they are opposite to each other with the guide tube 4 in between. The second U-shaped tube 2 is placed in such a manner that a clearance portion G in which the guide tube 4 can intrude without clearance, is formed between the going way D and the returning way U, the guide tube 4 intrudes into the clearance portion G, and the going way D and the returning way U are respectively formed between the first U-shaped tube 1 and the third U-shaped tube 3. Adjacent parts of the first U-shaped tube 1, the second U-shaped tube 2, the third U-shaped tube 3 and the guide tube 4 are respectively brought into contact with or close to each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a U-shaped underground heat exchanger capable of collecting geothermal heat used for melting snow, air conditioning, hot water pools, plant cultivation or animal breeding even from a depth of about 300 m underground. is there.

  In recent years, in consideration of environmental problems such as air pollution, a technique for melting snow or cooling and heating roads and roofs using geothermal heat, which is one of natural energy, has been developed by the present inventors.

  In order to collect underground heat, it is necessary to embed and collect heat exchangers in the ground, but one of these heat exchangers is a U-shaped (U-shaped tube type). is there. This U-shaped tube type heat exchanger supplies the heat medium from the upper end of one passage (outward path), sends it down as it is, reverses it at the lower end, and raises the other path (return path) to raise the ground. Medium heat is collected.

  This U-shaped heat exchanger has the advantage that the heat collection efficiency is high because the underground heat can be collected both in the forward path and in the return path.

  However, since the shape is U-order, the mechanical strength is inferior compared to, for example, a cylindrical concentric double tube type, and there is a risk of breakage due to ground pressure in the ground. . In particular, if it is buried to a depth (about 300 m underground) where there is abundant underground heat, it will have a strong earth pressure effect, so it must be shaped to withstand it. In addition, even if anti-freezing liquid circulating inside due to breakage leaks into the ground, it is necessary to make sure that it does not pollute the global environment.

  The present invention was devised in view of these problems, and even if it is buried to a depth of about 300 m underground where abundant underground heat exists, it has a strength that does not break due to ground pressure. It is an object of the present invention to provide a U-shaped underground heat exchanger that does not pollute the global environment with antifreeze circulating inside.

  This will be described with reference to FIGS. The invention described in claim 1 is a triple U-shaped underground heat exchanger that collects ground heat by circulating antifreeze liquid, and includes a first U-shaped tube 1 and a second U-shaped structure that circulate the antifreeze liquid. The outer diameters of the tube 2 and the third U-shaped tube 3 and the straight guide tube 4 are all set equal, and the first U-shaped tube 1 and the third U-shaped tube 3 are connected to the forward path D and the return path U. A gap is formed between the forward U and the return path U so that the guide pipe 4 can enter without a gap while the gap is formed without providing a gap between them and the guide pipe 4 is sandwiched between them. Forming a portion G, allowing the guide tube 4 to enter the gap G, and disposing the forward path D and the return path U between the first U-shaped tube 1 and the third U-shaped tube 3, respectively. The adjacent portions of the first U-shaped tube 1, the second U-shaped tube 2, the third U-shaped tube 3 and the guide tube 4 are brought into contact with or in close proximity to each other. And it is characterized in Rukoto.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, the antifreeze liquid is an alcohol-type antifreeze liquid.

  The invention described in claim 3 is characterized in that, in the invention described in claim 1, the antifreeze is a plant-based alcohol antifreeze.

  The triple U-shaped underground heat exchanger according to claim 1 applies the adjacent portions of the first U-shaped tube 1, the second U-shaped tube 2, the third U-shaped tube 3 and the guide tube 4 respectively. Since they are in contact with or in close proximity to each other, they form a so-called single block structure. Therefore, even if a large earth pressure acts, it can endure it, and it can be buried until it reaches a deep underground place where there is abundant underground heat of about 300 m underground.

  In the present invention, all the outer diameters of the first U-shaped tube 1, the second U-shaped tube 2, the third U-shaped tube 3 and the guide tube 4 are set equal to each other, so It can be touched or brought close together.

  Also, the first U-shaped tube 1 and the third U-shaped tube 3 are opposed to each other, and the forward path D and the return path U of the second U-shaped tube 2 are respectively between the first U-shaped tube 1 and the third U-shaped tube 3. Therefore, the lower ends of the first U-shaped tube 1, the second U-shaped tube 2 and the third U-shaped tube 3 can be aligned. It can be a thing.

  By the way, for example, if the bottom end of the first U-shaped tube 1 is positioned immediately above the bottom end of the second U-shaped tube 2 and both the bottom ends are overlapped vertically, inevitably, Since the bottom end portion of the single U-shaped tube 1 is a structure projecting downward, the single U-shaped tube 1 does not become one lump, and the strength is poor. The present invention does not have such a protruding portion and forms one lump, so that it has excellent strength and can withstand high earth pressure at about 300 m underground.

  Since the triple U-shaped underground heat exchanger according to claim 2 has high mechanical strength as in the invention according to claim 1, it can be buried deep in the ground. In addition, the antifreeze circulating through the first U-tube 1, the second U-tube 2 and the third U-tube 3 is an alcohol-based antifreeze, so that the safety is high. Even if the antifreeze leaks due to damage caused by the above, it does not pollute the global environment.

  Since the triple U-shaped underground heat exchanger according to claim 3 has high mechanical strength, similarly to the invention according to claim 1, it can be buried deep in the ground. Further, since the antifreeze liquid is a plant-based alcohol antifreeze liquid, the safety is further improved, and even if the U-shaped tube breaks and the antifreeze liquid leaks, the global environment is not polluted.

  An embodiment of a triple U-shaped underground heat exchanger according to the present invention is shown in FIGS. This is a ground heat exchanger that circulates antifreeze and collects ground heat, and includes a first U-tube 1, a second U-tube 2 and a third U-tube 3 that circulate the antifreeze, and a straight line. It is comprised with the guide tube 4 of a shape. The outer diameters of these tubes are all set equal.

  Then, the first U-shaped tube 1 and the third U-shaped tube 3 are formed in a state where the forward path D and the backward path U are in contact with each other without providing a gap therebetween (see FIG. 4), and the guide tube 4 is formed. They are placed facing each other. Further, the second U-shaped tube 2 is formed between the forward path D and the return path U by forming a gap portion G into which the guide tube 4 can enter without a gap, and enters the gap portion G (see FIG. 5), and Each of the forward path D and the return path U is disposed between the first U-shaped tube 1 and the third U-shaped tube 3.

  Thereby, each adjacent part of the 1st U-shaped tube 1, the 2nd U-shaped tube 2, the 3rd U-shaped tube 3, and the guide tube 4 is contacted or brought close to, respectively. Further, the length of the guide tube 4 is set slightly shorter than that of the first U-shaped tube 1, the second U-shaped tube 2 and the third U-shaped tube 3, and the first U-shaped tube 1, the second U-shaped tube The lower ends of the tube 2 and the third U-shaped tube 3 are flush with each other.

  Therefore, this triple U-shaped underground heat exchanger has excellent mechanical strength and can withstand a large earth pressure because each member gathers to form one lump structure with no protruding part. Obtainable. As a result, it can be buried to a depth of about 300 m underground where abundant underground heat exists.

  The triple U-shaped underground heat exchanger is safe because the antifreeze circulating through the first U-tube 1, the second U-tube 2 and the third U-tube 3 is a plant alcohol antifreeze. The nature is extremely high. Therefore, even if the U-shaped tube is damaged by the earth pressure and the antifreeze liquid leaks out, it does not pollute the global environment.

  Note that the triple U-shaped underground heat exchanger according to the present embodiment excavates the vertical hole 5 and then inserts the vertical hole 5 into the vertical hole 5 and buryes the vertical hole 5 with a filler F such as silica sand or grout. Alternatively, grout can be injected from the guide tube 4. The inside of the guide tube 4 can also be filled with a material having high thermal conductivity such as grout.

  A usage example of the triple U-shaped underground heat exchanger according to the present embodiment will be described by taking the case of snow melting as an example with reference to FIG. First, the antifreeze liquid radiated by the snow melting pipe 6 passes through the circulation path 8 by the circulation pump 7 and is supplied to the forward paths D of the first U-shaped pipe 1, the second U-shaped pipe 2 and the third U-shaped pipe 3. While being sent downward in D, the ground heat is collected by heat exchange.

  The antifreeze reverses at the bottom end and proceeds to the return path U and rises as it is. In this return path U, ground heat is collected by heat exchange as in the forward path D. The antifreeze liquid that has passed through the return path U is supplied to the snow-melting pipe 6 by the circulation pump 7, and the collected ground heat is discharged to melt the snow, and then returned to the forward path D of each U-shaped pipe. By repeating these processes, snow melting is performed continuously with underground heat.

It is a front view showing a triple U-shaped underground heat exchanger according to an embodiment of the present invention. It is the sectional view on the AA line of FIG. It is a bottom view of the triple U-shaped underground heat exchanger shown in FIG. It is a front view which shows the 1st U-shaped tube and the 3rd U-shaped tube in the triple U-shaped underground heat exchanger of FIG. It is a front view which shows the 2nd U-shaped pipe | tube in the triple U-shaped underground heat exchanger of FIG. It is a block diagram which shows the usage example of the triple U-shaped underground heat exchanger which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st U-shaped pipe 2 2nd U-shaped pipe 3 3rd U-shaped pipe 4 Guide pipe 5 Vertical hole 6 Snow melting pipe 7 Circulating pump 8 Circulating path D Outward F Filling G Gap part U Return path

Claims (3)

  A ground heat exchanger that circulates antifreeze and collects ground heat, the first U-shaped tube (1), the second U-shaped tube (2) and the third U-shaped tube (3 ) And all the outer diameters of the linear guide tube (4) are set equal, and the first U-shaped tube and the third U-shaped tube are separated by a gap between the forward path (D) and the return path (U). And forming the gap portion (G) through which the guide tube can enter without a gap between the forward path and the return path. A guide tube is inserted into the gap, and each of the forward path and the return path is disposed between the first U-shaped tube and the third U-shaped tube, and the first U-shaped tube and the second U-shaped tube. , A triple U-shaped underground heat exchanger characterized in that adjacent portions of the third U-shaped tube and the guide tube are brought into contact with or in close proximity to each other.   The triple U-shaped underground heat exchanger according to claim 1, wherein the antifreeze is an alcohol-based antifreeze.   The triple U-shaped underground heat exchanger according to claim 1, wherein the antifreeze is a plant-based alcohol antifreeze.

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