JPS5824762A - Extracting method of heat energy from underground water - Google Patents

Abstract

PURPOSE:To separate and extract only heat energy from underground water caused to move in the form of underground water stream without being exposed directly to open air by a method wherein a tectonic portion satisfying with a certain specific condition is bored in order to artificially connecting between respective water-bearing strata. CONSTITUTION:A main tube body 2 equipped with gate holes 21-23 for underground water stream consisting of a large number of small holes respectively at the locations corresponding to the water-bearing strata S1-S3 is inserted throughout the water-bearing strata S1-S3, which are separated by impermeable strata R1-R3 and have different water heads and water temperatures with one another. In addition, shut-off structures 3 are formed between the main tube body 2 and bored hole 1 so as to prevent the respective water-bearing strata from short-circuiting one another. Furthermore, a guide tube 4 is inserted in the interior of the main pipe body 2 and a packer 5 for preventing short-circuiting. A closing cover 6 is fitted on the upper opening of the main tube body 2 and the end of a thermal good conductor extending from a heat energy extracting device M, for example of a heat pipe, is arranged to the cover 6. Accordingly, natural underground water stream is generated and only heat energy moving with the stream is extracted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an extremely novel thermal energy extraction method for extracting thermal energy from groundwater.

Of the water that exists on land, excluding what is frozen as ice (more than 75%), the majority of water, about 22%, exists as groundwater.

This groundwater exists in various forms depending on the crustal structure, but generally forms a groundwater layer in an aquifer supplied from precipitation, rivers, and lakes.

If this aquifer exists within a series of crustal structures containing several impermeable layers, the groundwater between the upper and lower impermeable layers forms an artesian aquifer, and the hydraulic head pressure of each aquifer ( Hydrostatic pressure (also called hydrostatic pressure) and water temperature each exhibit independent and distinct values.

Groundwater that exists in such a state is usually obtained by installing wells or pipes that reach an aquifer at a certain depth, and pumping up all of the water from the aquifer that the well or pipe passes through as groundwater. After extracting the retained thermal energy, the thermal energy was extracted from groundwater either by releasing it directly above ground, or by forcing it underground with a pump or the like. However, with these conventional methods, first of all, a considerable amount of power energy is required to pump up groundwater, and the impact of pumping groundwater on the crustal structure must be taken into consideration. If this method were adopted, it would not necessarily be an efficient method of extracting thermal energy, as it would require extra costs.

This invention is an extremely novel and useful method that was achieved as a result of intensive research and development in order to address the inefficiency of conventional methods of extracting thermal energy from groundwater, and will be described in detail below. It consists of the following structure.

To explain this with reference to a typical embodiment for carrying out the present invention shown in the drawings, below the ground surface E.
There are a plurality of impermeable layers R1, R2,..., and below the unsaturated zone F following the ground surface E and above the impermeable layer R1, there is a first aquifer S1. is formed, and an impermeable layer R
There is a confined aquifer S2 between 1 and R2, and a confined aquifer 83 between impermeable layers R2 and R3, and between R3 and R4. 84...... is formed. Each of these confined aquifers is separated by an impermeable layer and is in a pressurized state, and each has a different head pressure and water temperature value.・(Of course, there are differences in head pressure and water temperature values between the unpressurized aquifer S1 and the pressurized aquifer S2.S3.) Hole 1 and create the desired impermeable layer (
In the case of the embodiment, the main pipe body 2 reaching up to R3) is inserted. This main pipe body 2 has many slits or small holes in the groundwater inflow/outflow phase at locations corresponding to the aquifer Sl or confined aquifer 82.83. is provided, and the confined aquifer part with the highest hydraulic head pressure value (in the example, Sa
), it is an inflow hole phantom, and in other parts, it is an outflow hole ρ,
2'1......

In addition, between this main pipe body 2 and the drilling hole 1, the ground surface E part,
Impermeable layer S1. S2・・・・・・・・・In a considerable part, there is a cutoff to prevent a direct short circuit between the ground and the first aquifer S1 and each aquifer within the penetration 1. A structure, for example a cement-filled sealing layer 3, must be formed.

The inside of the main pipe body 2 formed in this way reaches directly above the lowermost confined aquifer (Sa in the example), and
Guide pipe 4 having a predetermined gap between it and the main pipe body 1
is inserted, and between the main pipe body 1 and the guide pipe 4, the lowermost confined aquifer (83 in the example) and the immediately above confined aquifer (83) are inserted.
In the embodiment, a short-circuit prevention packer 5 ( ) is interposed to prevent the short-circuit between the guide pipe 82) and the pipe 82 from being short-circuited below this gap. , the thermal energy harvesting efficiency can be increased.

Once the main pipe body 1 and the guide pipe 4 are arranged as described above, the closing cover 6 is attached to the upper opening of the main pipe body 1, and the block cover 6 is planned to be positioned at a predetermined position above the guide pipe 4. At the same time, the end of a heat conductor 7 extending from the thermal energy harvesting device M on the ground, such as a heat vibrator, is arranged in this part.

In the illustrated embodiment, an auxiliary accelerator 8 is installed inside the guide pipe 4.
However, this is because when implementing this invention with the above-mentioned configuration, the water head pressure difference may be too small depending on the construction location, resulting in insufficient flow velocity of underground water flow that should naturally occur. This is a device that supplementarily increases the flow velocity of groundwater flow when a certain amount of groundwater flow is occurring but it is necessary to further increase the thermal energy extraction efficiency, and it is sufficient to adopt it as necessary. .

As described above, the aquifer S1 and each confined aquifer S
2,83. By artificially connecting ・・・・・・・・・・・・ without being directly exposed to the atmosphere, the aquifer S
1 and each confined aquifer S2. S3・・・・・・・・・
A difference in head pressure is generated between them depending on the respective head pressures. That is,
In the illustrated example, the confined aquifer 33 exhibiting the largest head pressure (head pressure value P3), the other confined aquifers S2 (head pressure value p2), and the aquifer S1 (Hydraulic head pressure value PI), P3-P2 knee Ql>O.

P3-P1=su>0+Q:2-Ql>o shows the positive water head difference value. Therefore, based on this head pressure difference, the groundwater in the confined aquifer S3 is artificially connected from the higher to the lower head pressure as shown by the arrow in the figure.
Following the route, it first flows into the main pipe body 2 through the inflow hole n and rises inside the guide pipe 4. On the other hand, the groundwater in the confined aquifer S2 and the aquifer 81 also tries to rise through the gap between the main pipe body 2 and the guide pipe 4 from the outflow hole η, 21 depending on the head pressure. , the groundwater rising from the confined aquifer S3, whose upper part is obstructed by the obstructing cover and has nowhere to go, is pushed away, and conversely, this groundwater flows through the gap between the main pipe body 2 and the guide pipe 4. It descends and flows out from the outflow holes 4 and 22 to the aquifer 81 and 82, and the confined aquifer S
3 to the confined aquifer S2 and the aquifer S1. This groundwater flow is not necessarily uniform depending on the crustal structure of the place where it is artificially penetrated and connected, but as long as there are layers of aquifers and artesian aquifers with different head pressures, the flow will be uniform. This is a form that uses only potential energy that exists in nature, except for the artificial energy required by the auxiliary accelerator 8, which is generated almost reliably and semi-permanently, and may be adopted as necessary. This can induce natural underground water flow.

The confined aquifer exhibiting the highest hydraulic head pressure value is caused by the one-way groundwater flow from the confined aquifer exhibiting the highest hydraulic head pressure value to other aquifers and to the confined aquifer thus generated. Since the thermal energy possessed by the groundwater in the layered portion is also carried along by the underground water flow, the thermal energy retained by the groundwater is brought into contact with a good thermal conductor 7 midway through the flow, below the closing cover 6 in the illustrated embodiment. It is possible to separate and extract only the thermal energy (the thermal energy required in the above-ground part can be negative or positive) from the underground water flow and collect it in the above-ground part.

As described above, the method of extracting thermal energy from groundwater according to the present invention involves penetrating the crustal structure of locations with specific conditions and artificially connecting each aquifer. First of all, the movement of groundwater based on the energy difference between the positions of It is economical because there is no need to pump up groundwater for energy extraction, and therefore no groundwater pumping power is required at all.

Secondly, since groundwater is not pumped up, there is no possibility of ground subsidence or groundwater depletion.
Therefore, there is no need to give any consideration to various laws and regulations regarding groundwater use. Third,
Naturally generated groundwater flow is not directly exposed to the atmosphere and there is no release of gases in the groundwater, so there is little chance of changing the chemical composition of the groundwater.・The extraction and precipitation of scale components in groundwater will be reduced, and groundwater flow will be guaranteed as a semi-permanent and smooth flow in each aquifer and within each facility. Furthermore, fourthly, since tectonic parts suitable for carrying out this invention exist almost everywhere in the world, conventional high energy recovery methods in specific areas of volcanic areas are not possible. It has high utility value not only as an energy source, but also as a method of extracting low energy that can be used directly for normal daily life, and because it exists in almost inexhaustible quantities, it is especially useful in times of energy crisis such as the current one. It can be an ideal method of harvesting thermal energy. It is a clean and ideal method of harvesting thermal energy in all respects.

[Brief explanation of the drawing]

The drawings are cross-sectional views of typical embodiments for explaining the invention in detail. 1: Penetration, 2: Main pipe body, 21, 22. Z3: Groundwater inflow/outflow hole, 3: Cement filled sealing layer, 4: Guidance pipe, 5: Short circuit prevention backer, 6: Closure lid, 7: Good thermal conductor, 8: Auxiliary accelerator, R1, R2, R3: Non-conductor Permeable layer, Sl: aquifer,
32. S3: Confined aquifer.

Claims (1)

[Claims] Aquifers that are separated by impermeable layers and have different water head pressures and water temperatures are artificially connected without being directly exposed to the atmosphere, and a natural groundwater flow is generated due to the difference in water head pressure between the two, and the groundwater flow is improved. A method for extracting thermal energy from groundwater, in which only the thermal energy that moves along with the groundwater is separated and extracted from the groundwater flow using a heat pipe or other good thermal conductor.