DE102006026531B3 - Ground probe for recovering heat, has pipes arranged concentrically around central pipe and connected with each other, where probe is made of stainless steel and sum of nominal sizes of all pipes is larger than nominal size of central pipe - Google Patents

Abstract

The probe has a set of pipes arranged concentrically around a central pipe (1), where the pipes are connected with each other, and the probe is made of stainless steel. The sum of nominal sizes of all the pipes arranged around the central pipe is larger than the nominal size of the central pipe. A venturi-nozzle (5) is arranged at the transition of a lower drum (4) in the central pipe for increasing the flow rate. The central pipe is guided through an upper drum (3) and the lower drum, where borehole depth is adjusted in the central pipe.

Description

The The invention relates to a geothermal probe for heat recovery from the soil.

[Was standing of the technique]

It is state of the art, using geothermal probes. Known probes are by the type "pipe formed in tube " and usually use a fluid as a heat transfer medium. These probes are bad Energy efficiencies, as the depth of heat in the Climbing through the inner tube partially to the pumped in the depth Fluid is discharged. Insulated inner tubes are usually very costly designed and thus often costly.

However, geothermal probes are also designed in such a way that side-by-side guided feeders and return leads are partially connected by spacers to form groups of several ground probes ( EP 582118 A1 ). However, energy efficiency is not optimal here through the use of plastics. Plastic has a thermal conductivity λ of only 0.4.

A much higher thermal conductivity value can be achieved if, instead of the plastic earth probes made of cast iron ( EP 1468226 B1 ) or metals (eg EP 1486741 A1 ) be used. On an alloyed stainless steel is in DE 3047397 C2 pointed. However, the known probes have the problems of the "tube-in-tube" technique.

All probes mentioned have the feature that elaborate work such as. Deep bores are performed during installation have to, the partially exclusively can be done by specialist companies. Resulting from deep drilling often harmful to the environment drilling muds, the costly transported away and treated as hazardous waste Need to become. Another environmentally harmful Aspect is that with very deep-reaching geothermal probes several layers of earth and thus also different water-bearing layers are pierced. It may, inter alia, also to mixing between fresh water and a salty water from another layer. Around Environmental protection requirements must be very high Effort to be operated.

A combination of multiple leads and a central feedback is from the scriptures CH 687043 A5 and DE 20106707 U1 respectively. DE 10216739 A1 known. Here again, plastics with the above-mentioned problems are used. In addition, deformations can occur during the laying of plastic pipes, which makes it impossible to adequately fill or press the borehole.

Known Ground probes that are not made in one piece can be have to welded together on site become. This procedure is due to the high amount of time the assembly very expensive.

The earth probes described usually give off the energy obtained at a heat exchanger, which is connected to the heat pump in a second circuit. Out EP 1194723 B1 It is known that gases are used in addition to liquid heat transfer media. In order to ensure proper condensation again high technical effort is operated.

The introduction of a ground probe made of plastic in building components is out EP 582118 A1 known. Here, the goal is the extraction of geothermal heat in the field of pile foundations. It will only be made use of the fact that in a pile foundation in the required hole in addition a probe can be inserted.

disadvantage of this invention is that through the concrete casing efficiency the heat recovery is very low and the possibly usable heat energy of the building lost the exchange with the immediately surrounding earth again goes.

In CH 687 043 A5 describes a geothermal probe consisting of a central return pipe and a plurality of return pipes arranged around the return pipe, which are closed by a single collector at the lower end. By reducing the cross section of the return pipe relative to the sum of the cross sections of the flow pipe, the flow velocity of the ascending in the return pipe medium is increased. Another means for increasing the return speed is not named. The probe is used at very great depths. This makes the method of installation very expensive. In addition, the backfilling of the borehole at great depths can lead to problems, not least due to a deterioration of energy efficiency in the formation of cavities. A deformation of the plastic used can also not be excluded. When the pipes break, depending on the medium used, this may be harmful to the environment. A repair of the geothermal probe or just the simple shutdown would be associated with high financial costs or losses. To counteract the resulting pressures, the wall thickness of the lines, especially the central line must be very large. This makes the production of the Probe very expensive.

In DE 26 31 552 A1 describes a method of utilizing geothermal energy, in which a double wall pipe is lowered into a cavity created by an underground blast. Through the outer ring of the double wall pipe water is passed into the cavity, which evaporates due to the prevailing heat and a part of the water vapor rises through an inner tube to a heat exchanger. A provided with a thin outer wall inner tube is held by brackets centrally within the outer wall provided with a stronger outer wall for the cold water supply. It uses the "tube-in-tube" technique, which is also used in pamphlets EP 1468226 B1 and EP 1486741 A1 was disclosed. This technique has a poor energy efficiency, which is very expensive to produce only by a costly insulation of the inner tube. The mentioned geothermal probe must also be lowered into areas that allow evaporation of the introduced medium water. This suggests very large depths with the associated problems.

In the DE 31 39 868 A1 disclosed probe for heat exchangers consists of an outer and an inner tube and inlet and outlet fittings. The outer tube is made of metal, while the inner pipe can also be formed by a hose. To protect the outer tube, the probe is surrounded by a plastic sheath and closed at the bottom with a plastic stopper. However, the "pipe-in-pipe" technique already described is used, which means that the required efficiency can not be achieved, and the production of this probe by an additional plastic coating is very expensive.

[Abandonment of Invention]

task the present invention is to develop a geothermal probe which one much higher Efficiency as the state of the art possesses, with as possible low primary energy consumption preferably a lot of heat energy from the environment can be used. Installing in the soil should as possible require little effort. additionally should the ground probe also for be used for the extraction of building waste heat.

The Earth probe according to the invention consists of tubes arranged concentrically around a central tube, the above Collectors are interconnected. It consists of a dimensionally stable Material, preferably of metal and in particular stainless steel.

It are provided means for increasing the flow velocity. This is done by adding the sum of the nominal diameters of all around the Central pipe arranged flow pipes is greater than the nominal size the central tube and / or by a Venturi nozzle, which at the transition from the lower collector is arranged in the central tube. By use a geothermal probe over has several small flow pipes, whose cross sections are greater in their sum than the cross section of the central tube, creates a Venturi effect, which is the flow velocity at the return the heat transfer medium used elevated.

The Ground probe consists of a dimensionally stable material, whereby the wall thickness of all Tubes is the same.

One considerable advantage lies in the handiness and the installation without special requirements. The limited to a dimension of about 6 meters probe is easy to transport to the destination with smaller trucks. Due to a very low weight of 20 to 25 kilograms one can Person move the probe on site.

at Demand is the size of the ground probe through extension elements varied. If a geothermal probe from several individual elements are combined must, the assembly is made easier by the use Press connections as very easy. Several extension elements come with one tail connected. It is important to make sure that the distance of the individual elements a proper connection guaranteed.

The Ground probe is operated with a fluid or a gas.

The Ground probe is for designed for installation at shallower depths, i. the necessary hole will be until the first water-bearing Layer performed. A particular advantage is that only a dry hole is necessary, thus fall on no drilling mud, which makes installation very environmentally friendly power.

The Design in stainless steel leaves a very easy and careful Pressing the well with soil to, as the material of the probe does not yield after insertion into the well and so no undesirable changes of the form arise.

A particular advantage of the present geothermal probe lies in the possibility of installation in a building foundation. The heat energy previously released to the surrounding soil from the building can be recovered at least in part, if in the foundations, preferably in ring fundamente, a geothermal probe of the present kind is inserted. The heat thus radiated to the ground can be recycled to a part of the heating circuit.

By the solution according to the invention is the VDI 4640 complied.

[Examples]

following become devices according to the invention explained in detail by means of figure descriptions.

there demonstrate:

1 a longitudinal section through the probe made of stainless steel;

2 a cross section through the probe from stainless steel;

3 a longitudinal section of a probe extension;

4 a longitudinal section through a horizontal probe to be installed.

1 shows a geothermal probe according to the invention, which consists of concentrically arranged around a central tube stainless steel tubes, which are connected to each other via collectors. The shape of the collector is irrelevant, in the embodiment, a cylindrical shape is preferred. But there are also other shapes, such as balls or cuboids, etc. conceivable. Through a feed 7 at the top collector 3 the heat transfer medium is fed to the ground probe. The nominal diameter of the inlet 7 is equal to the sum of the nominal widths of all supply pipes 2 , As a heat carrier, an environmentally friendly sugar solution (eg Thermera) or a gas can be used. The heat transfer medium is through the supply pipes 2 in the lower collector 4 pumped. Here and in the lower collector 4 becomes the heat energy 6 added. A slight heat transfer is achieved by the design of the probe in stainless steel. The reflux of the heated medium takes place through the central tube 1 that by a smaller nominal size than the entirety of the supply pipes 2 has an increased flow rate. By installing a Venturi nozzle 5 If the nominal width of the central tube is narrowed a little further, so that the Venturi effect can be used to further increase the speed of the ascending medium.

at The use of gases may be due to the use of a heat exchanger be waived, heat pump and ground probe are in the same circuit.

In 2 is a central tube 1 with six circular around the central tube 1 arranged flow pipes 2 shown. With a reduction in the number of flow pipes 2 must be on a sufficient increase in the diameters of the flow pipes 2 respected and accordingly reversed.

In 3 an example of an extension element is shown. The central tube 1 is here by both collectors 3 and 4 carried out. At the bottom of the lower collector 4 there is a drain pipe 8th , which has a press connection with the inlet 7 another extension or the feed 7 of in 1 represented tail can be connected. Ideally, the nominal diameter of this connection (outlet connection 8th with inlet 7 ) the sum of all nominal diameters of the supply pipes 2 to ensure unimpeded movement of the heat transfer medium.

In 4 a geothermal probe is shown, which is suitable for installation in a building foundation. The feed 7 is here so attached that the heat transfer medium as in a vertically installed probe after 1 enters the probe from above. The further structure corresponds to the properties already in 1 have been described, except for the fact that the central tube must ultimately be directed back over an arbitrarily designed curvature in the direction of the heat exchanger. Important here is the exclusive use in brine operation. An extension is also conceivable for installation in a building foundation. For this purpose, the inlets and outlets are to be adapted in accordance with the circumstances and the vertically configured probes.

For building foundations can the geothermal probes made of stainless steel are used as probation elements, which adds extra Costs can be kept low.

As well Is it possible, the geothermal probe made of stainless steel as an energy pile for the recovery of geothermal energy in the area the pile foundation use.

1

central tube

2

flow pipes

3

Oberer collector

4

lower collector

5

Venturi nozzle

6

recordable Thermal energy

7

Intake

8th

drain connection

Claims (7)

Ground probe for heat production consisting of concentrically arranged around a central tube tubes which are connected to each other via collectors, wherein the sum of the nominal widths of all arranged around the central tube flow pipes is greater than the nominal diameter of the central tube characterized in that at the transition from the lower collector ( 4 ) in the central tube ( 1 ) a Venturi nozzle ( 5 ) is arranged to increase the flow rate, that the ground probe from a dimensionally stable material, preferably made of metal, wherein the wall thickness of all tubes is the same, and that if necessary, the size of the ground probe by extension elements which by a top collector ( 3 ) and a lower collector ( 4 ) guided central tube ( 1 ), is adapted to the borehole depth. Ground probe according to claim 1, characterized that the ground probe is made of stainless steel. Ground probe according to claim 1 or 2, characterized that one or more extension elements be joined together by press connections. Ground probe according to one of claims 1 to 3, characterized that the geothermal probe is operated with a fluid or a gas. Ground probe according to one of Claims 1 to 4, characterized that the ground probe is inserted into the foundations of buildings. Ground probe according to claim 5, characterized that the ground probe made of stainless steel is used as a probation element. Ground probe according to one of claims 1 to 6, characterized that the ground probe is used as an energy pile.