JP5963790B2 - Groundwater circulation type geothermal heat collection system and geothermal use air conditioning or hot water supply system - Google Patents

Description

The present invention relates to a groundwater circulation type geothermal heat collection system and a geothermal utilization cooling / heating or hot water supply system.

  The geothermal heat collection system is roughly classified into an open type geothermal heat collection system and a closed type geothermal heat collection system according to the structure of the heat collection device. Among these, closed-type underground heat collection systems are described in Patent Documents 1 and 2, for example. Among these, the closed type geothermal heat collection system described in Patent Document 1 is a vertical type geothermal heat collection system (closed type vertical geothermal heat collection system). The described closed-type heat collecting device is a horizontal geothermal heat collection system (closed-type horizontal geothermal heat collection system).

  Among these geothermal heat collection systems, the open type geothermal heat collection system is used more than the closed type geothermal heat collection system because it directly collects groundwater and exchanges its thermal energy. Although the amount of heat exchange possible is large and practical, there is a problem that a separate facility for groundwater recharge is necessary, maintenance such as a scale that accumulates in the piping is necessary, and the maintainability is poor.

  The closed-type geothermal heat collection system does not have the above-mentioned problems, but among the closed-type geothermal heat collection systems, the closed-type vertical geothermal heat collection system has a construction cost (construction cost). ) Is high, it is expected that a closed horizontal geothermal heat collection system with a lower construction cost (construction cost) than a closed vertical geothermal heat collection system will be popularized.

JP 2011-191014 A JP 2013-217603 A

  However, closed horizontal geothermal heat collection systems are susceptible to temperature changes due to atmospheric climate change, and heat exchange is performed in shallow underground areas where there is no or very little groundwater. Therefore, there is a problem that the amount of heat exchange available is small and not practical.

  Therefore, the present invention has been made to solve such a problem, and has a larger amount of heat exchange available than a conventional closed-type horizontal geothermal heat collection system. It aims to provide a thermal system.

  As a result of intensive efforts to achieve the above-mentioned object, the present inventors are inherently susceptible to temperature changes accompanying atmospheric climate change, and there is no or very little underground water. Even in a closed horizontal geothermal heat collection system that must perform heat exchange in shallow layers, heat is exchanged by supplying a sufficient amount of groundwater to such shallow layers. In addition, it is possible to increase the amount of heat exchange that can be used by gradually infiltrating underground water with reduced thermal potential after heat exchange. The present inventors completed the present invention by thinking that it would be possible to provide a practical geothermal heat collection system that has a larger amount of heat exchange available than the geothermal heat collection system.

[1] The geothermal heat collection system of the present invention is a closed horizontal geothermal heat collection that collects geothermal heat by circulating a heat exchange medium through a heat exchange pipe embedded in a shallow underground layer. A heat system, which is installed in a shallow underground layer and has water permeability, the heat exchange pipe embedded in the heat exchange layer, and the heat exchange from above the heat exchange pipe And a groundwater supply device for supplying groundwater to the layer.

[2] In the underground heat collection system of the present invention, it is preferable that the heat exchange layer is an artificial soil layer.

[3] In the geothermal heat collection system of the present invention, the artificial earth and sand layer is preferably an artificial earth and sand layer that does not contain fine-grained soil (that is, an artificial gravel layer).

[4] In the geothermal heat collection system of the present invention, a civil engineering sheet (also referred to as a civil engineering stabilization sheet) is disposed on the bottom surface of the heat exchange layer and / or inside the heat exchange layer. Preferably it is.

[5] In the geothermal heat collection system of the present invention, the heat exchange layer is preferably composed of a porous concrete layer and an artificial soil layer provided on the porous concrete layer.

[6] In the geothermal heat collection system of the present invention, it is preferable that a civil engineering sheet is disposed on the bottom surface of the heat exchange layer.

[7] In the geothermal heat collection system of the present invention, the groundwater supply device includes a well, a pump and a conduit for transferring groundwater from the well to the heat exchange layer, and groundwater from the conduit to the heat exchange layer. It is preferable to have a supply port for supplying water.

[8] In the geothermal heat collection system of the present invention, the heat exchange layer is provided with a water level meter for monitoring the groundwater level and a thermometer for monitoring the temperature of the heat exchange layer. The groundwater supply device preferably has a function of controlling the groundwater supply operation based on the water level information monitored by the water level gauge and the temperature information monitored by the thermometer.

[9] In the geothermal heat collection system of the present invention, the heat exchange layer satisfies the relationship of vg> vf, where vg is the ground penetration rate of groundwater and vf is the natural convection velocity of groundwater. It is preferable.

[10] A geothermal cooling / heating or hot water supply system of the present invention includes the geothermal heat collection system of the present invention and a heat pump that exchanges heat using a heat exchange medium of the geothermal heat collection system. And

  According to the underground heat collection system of the present invention, as described above, since the groundwater supply device that supplies groundwater to the heat exchange layer from above the heat exchange pipe is provided, a sufficient amount of the underground shallow layer portion is provided. While supplying groundwater to perform heat exchange, it becomes possible to gradually infiltrate underground water whose thermal potential has been lowered after heat exchange. As a result, the underground heat collection system of the present invention can increase the amount of heat exchange that can be used, and the amount of heat exchange that can be used is higher than that of a conventional closed horizontal geothermal heat collection system. Many practical geothermal heat collection systems. In addition, the geothermal cooling / heating or hot water supply system of the present invention is similar to the geothermal heat collection system of the present invention in that it uses a conventional closed-type horizontal geothermal heat collection system. The amount of heat exchange that can be used is larger than that of a hot water supply system, so that it becomes a practical underground heating / cooling or hot water supply system.

1 is a cross-sectional view of a geothermal heat collection system 100 and a geothermal cooling / heating or hot water supply system 10 according to Embodiment 1. FIG. It is sectional drawing which shows the principal part of the geothermal heat collection system 100 which concerns on Embodiment 1. FIG. It is sectional drawing which shows the principal part of the geothermal heat collection system 100 which concerns on Embodiment 1. FIG. It is sectional drawing of the geothermal heat collection system 200 which concerns on Embodiment 2. FIG. It is sectional drawing which shows the principal part of the geothermal heat collection system 200 which concerns on Embodiment 2. FIG. It is sectional drawing of the underground heat collection system 300 which concerns on Embodiment 3. FIG. It is sectional drawing which shows the principal part of the geothermal heat collection system 300 which concerns on Embodiment 3. FIG.

  The geothermal heat collection system 100 and the geothermal cooling / heating or hot water supply system 10 of the present invention will be described in detail based on the embodiments shown in the drawings.

[Embodiment 1]
1. Diagram 1 of the underground heat Tonetsu systems and geothermal heat air conditioning or hot water system is a sectional view of the underground heat Tonetsu system 100 and ground heat air conditioning or hot water system 10 according to the first embodiment. In FIG. 1, symbol A ₁ indicates the direction in which the heat exchange medium flows through the heat exchange pipe 120, and symbol A ₂ indicates the direction in which groundwater penetrates the heat exchange layer 110. The same applies to the following drawings.
FIG. 2 is a cross-sectional view illustrating a main part of the underground heat collection system 100 according to the first embodiment. FIG. 2A is a longitudinal sectional view showing a state in which the heat exchange pipe 120 is laid inside the heat exchange layer 110, and FIG. 2B is a diagram showing water level meters 141 and 142 and a thermometer 143 inside the heat exchange layer 110. It is a longitudinal cross-sectional view which shows the laying state. In FIG. 2, the civil engineering sheet 112 is not shown.
FIG. 3 is a cross-sectional view showing a main part of the underground heat collection system 100 according to the first embodiment. FIG. 3A is a cross-sectional view showing a state in which the heat exchange pipe 120 is laid inside the heat exchange layer 110, and FIG. 3B is a cross section showing a state in which the conduit 133 is laid inside the heat exchange layer 110. FIG.

  As shown in FIGS. 1 to 3, the geothermal cooling / heating or hot water supply system 10 according to the first embodiment includes a geothermal heat collection system 100 (a geothermal heat collection system 100 according to the first embodiment), and an underground It is a geothermal cooling / heating or hot water supply system including a heat pump 21 that performs heat exchange using a heat exchange medium of the heat heat collection system 100 and an air conditioner (cooling / heating machine) or a hot water heater 22 in a building. The heat pump 21 is an indirect heat pump heat exchanger including an evaporator and a condenser.

  And as shown in FIGS. 1-3, the geothermal heat collection system 100 which concerns on Embodiment 1 circulates a heat exchange medium to the heat exchange pipe embed | buried in the underground shallow layer part, and it carries out underground heat. A closed horizontal geothermal heat collection system for collecting heat, which is installed in the shallow underground layer G1 and has a water permeability and a heat exchange layer embedded in the heat exchange layer 110. A pipe 120 and a groundwater supply device 130 that supplies groundwater to the heat exchange layer 110 from above the heat exchange pipe 120 are provided.

  The underground subsurface layer G1 refers to a layer or the ground that is generally shallower than 10 m from the ground, and the underground deep layer G2 described later is a portion deeper than the underground subsurface layer, The ground G3 to be described later refers to the ground below the underground shallow layer portion G1.

  The heat exchange layer 110 is composed of an artificial earth and sand layer that does not contain fine-grained soil (that is, an artificial gravel layer). As the artificial earth and sand layer, for example, crushed stone or river washed gravel is used. Among them, it is preferable to use river-washed gravel that has no sharp gravel and is less likely to damage the heat exchange pipe 110 or the civil engineering sheet 112.

As shown in FIGS. 1 to 3, civil engineering sheets 111 and 112 are disposed on the bottom surface of the heat exchange layer 110 and inside the heat exchange layer 110. The civil engineering sheets 111 and 112 are used to adjust the hydraulic conductivity of the heat exchange layer 110 as a whole within a predetermined hydraulic conductivity. As the civil engineering sheets 111 and 112, general-purpose civil engineering sheets (for example, woven fabric for general civil engineering using polyester fibers) having an appropriate gap between fibers can be used. Among them, it is preferable to use a civil engineering sheet having a thickness of 0.19 to 1.14 mm and a water permeability coefficient of 5 × 10 ⁻³ cm / s to 5 × 10 ⁻² cm / s.

  As shown in FIGS. 1 and 2, a water shielding sheet 113 is disposed on the side surface of the heat exchange layer 110. The water-impervious sheet 113 is used to prevent water from flowing between the heat exchange layer 110 and the surrounding ground G1. As the water-impervious sheet 113, for example, a general-purpose water-impervious sheet (for example, a vinyl chloride civil engineering water-impervious sheet, a vulcanized rubber civil engineering water-impervious sheet, etc.) can be used.

  As shown in FIGS. 1 and 2, a water shielding sheet and a heat insulating material 114 are disposed on the upper surface of the heat exchange layer 110. The water shielding sheet and the heat insulating material 114 are used to prevent rainwater from entering the heat exchange layer 110 and to make the temperature of the heat exchange layer 110 less susceptible to the temperature of the ground surface. As the water-impervious sheet and the heat insulating material 114, the above-described general-purpose water-impervious sheet and a general-purpose heat insulating material (for example, a sheet made of polystyrene foam having a thickness of 10 cm) can be used.

  The size of the heat exchange layer 110 is set to a size capable of storing the groundwater and the amount of heat in the ground corresponding to the amount of heat energy required for extraction according to the output of the heat pump.

  As a place where the heat exchange layer 110 is installed, select a place where the ground is rich in groundwater to some extent and there is a ground (for example, a gravel layer, especially a gravel ground near a river) that easily penetrates the groundwater. Is preferred.

  The heat exchange pipe 120 is, for example, a pipe made of high-density polyethylene having an outer diameter of 27 mm to 50 mm and an inner diameter of 21 mm to 41 mm. As the heat exchange pipe 120, a commercially available underground heat exchange system pipe can be used. As shown in FIG. 3, the heat exchange pipe 120 is laid in a loop shape, for example. The heat exchange pipe 120 is laid so as to have a plurality of stages in the vertical direction as shown in FIGS. 1, 2, and 3 (b). Moreover, the heat exchange pipe 120 may be constructed by laying a plurality of heat exchange pipes in parallel according to the output of the heat pump (see FIG. 3A).

  As shown in FIG. 1, the groundwater supply device 130 includes a well 131, a pump 132 and a conduit 133 that transfer groundwater 137 from the well 131 to the heat exchange layer 110, and a heat exchange layer from the conduit 133 (conduit tip 134). 110 and a supply port 135 for supplying groundwater. In FIG. 1, reference numeral 136 denotes a water level meter for monitoring the level of groundwater. The water level gauge is an input water level gauge. The depth of the well 131 is, for example, 10 m to 50 m, although it depends on the form of groundwater.

  As shown in FIG. 2B, the heat exchange layer 110 is provided with water level meters 141 and 142 for monitoring the level of groundwater and a thermometer 143 for monitoring the temperature of the heat exchange layer 110. ing. The groundwater supply device 130 includes an operation control unit 140 having a function of controlling the groundwater supply operation based on the water level information monitored by the water level meters 141 and 142 and the temperature information monitored by the thermometer 143. The water level meter 141 is an input water level meter, and the water level meter 142 is an electrode water level meter.

2. Example of Use of Geothermal Heat Collection System (1) Connection with Heat Pump First, as shown in FIG. 1, the geothermal heat collection system 100 according to Embodiment 1 is connected to the heat pump 21, and the heat pump 21 is connected to the inside of the building. It is connected to an air conditioner (air conditioner) or a water heater 22. At the time of cooling in the summer, at the time of heating in the winter, and at the time of hot water supply, the geothermal heat collection system 100 and the underground heat cooling / heating or hot water supply system 10 according to the first embodiment are used as follows.

(2) Summertime Groundwater (for example, 15 ° C.) is supplied to the heat exchange layer 110 at night to lower the temperature of the heat exchange layer 110. When the temperature of the room increases during the daytime, the room is cooled by exchanging heat between the cold heat of the heat exchange layer 110 and the indoor heat through a heat exchange medium (for example, water, antifreeze liquid, etc.). The indoor heat is discharged to the heat exchange layer 110. Then, the heat exchange layer 110 gradually warms up, but in the process in which the warm water gradually permeates into the earth and sand layer (ground G3) located below the heat exchange layer 110, the heat is applied to the earth and sand layer (ground G3). ). Accordingly, the temperature of the heat exchanging layer 110 is difficult to rise, and the heat exchanging amount is higher than that of the conventional closed horizontal geothermal heat collecting system, so that a practical geothermal heat collecting system is obtained.

(3) Winter Season Groundwater (for example, 15 ° C.) is supplied to the heat exchange layer 110 at night to raise the temperature of the heat exchange layer 110. When the temperature of the room decreases during the day or at night, the room is heated by exchanging heat between the heat of the heat exchange layer 110 and the cold of the room through a heat exchange medium (for example, water, antifreeze liquid, etc.). While heating, the indoor cold heat is discharged to the heat exchange layer 110. Then, the heat exchange layer 110 gradually cools, but in the process in which the cooled water gradually permeates into the earth and sand layer located below the heat exchange layer 110, the cold heat is discharged to the earth and sand layer (ground G3). The Therefore, the temperature of the heat exchanging layer 110 is difficult to decrease, and the heat exchanging amount is higher than that of the conventional closed horizontal geothermal heat collecting system.

(4) When the water heater hot water storage tank is heated up Groundwater (for example, 15 ° C.) is supplied to the heat exchange layer 110, and the temperature of the heat exchange layer 110 is brought close to the temperature of the groundwater. When the temperature of the hot water storage tank is raised, the heat energy of the heat exchange medium (for example, water, antifreeze, etc.) exchanged in the heat exchange layer 110 is raised by a heat pump to store the hot water in the hot water tank, and the heat exchange medium Cold heat (for example, water, antifreeze, etc.) is discharged to the heat exchange layer 110. Then, the heat exchange layer 110 gradually cools, but in the process in which the cooled water gradually permeates the heat exchange layer 110 below, the cold heat is applied to the earth and sand layer (ground G3) located below the heat exchange layer 110. Discharged. Therefore, the temperature of the heat exchanging layer 110 is difficult to decrease, and the heat exchanging amount is higher than that of the conventional closed horizontal geothermal heat collecting system. In summer, the heat exhaust due to cooling and the heat absorption due to the temperature rise in the hot water storage tank are offset, which is convenient.

(5) Timing of groundwater supply In the geothermal heat collection system 100 according to the first embodiment, when the ground heat energy in the heat exchange layer 110 is insufficient (decreased), groundwater is supplied to the heat exchange layer in the daytime. May be. Control of the groundwater supply operation by the groundwater supply device 130 is performed based on the water level information and temperature information monitored by the water level meters 141 and 142 and the thermometer 143 installed in the heat exchange layer 110 and the operating state of the heat pump.

3. Action and Principle of Geothermal Heat Collection System The present invention is a so-called horizontal loop type in which groundwater flow is artificially realized in the ground (shallow ground layer G1) near the ground surface, and the installation cost is low there. The heat collecting pipe (heat exchange pipe 120) is laid to realize a system having excellent heat collecting efficiency and low installation cost. First, a method for realizing flowing groundwater in the underground shallow layer part G1 will be described with reference to FIG. Groundwater with high thermal energy stagnating in the deep underground layer G2 is pumped by, for example, a submersible pump 132 by a single well 130 installed in the ground. The pumped ground water is supplied (sprinkling, water supply) to the top end portion of the heat exchange layer 110 constructed near the ground surface. The inside of the heat exchange tank 110 is filled with, for example, crushed stone with high water permeability, and the bottom surface is in direct contact with the highly permeable ground G3, so that the groundwater supplied to the upper part of the heat exchange tank 110 Flows down through the heat exchange layer 110 by the action of gravity and penetrates into the ground below. Eventually, the underground infiltration progresses and is returned to the aquifer of deep underground part G2. With such a mechanism, a groundwater flow downward in the vertical direction is realized in the heat exchange layer 110. This enables highly efficient underground heat collection (Effect A).

  In the geothermal heat collection system 100 of the present invention, for example, a horizontal loop heat exchange pipe 120 is arranged in a form orthogonal to the vertical groundwater flow to collect heat energy of the groundwater. Thus, by laying the heat exchange pipe 120 near the ground surface in the horizontal loop method, the construction cost can be reduced (effect B).

  The groundwater inside the heat exchange layer 110 has a free water surface and basically allows fluctuations in the water level. This water level has a mechanism in which fluctuation is measured by a water level meter installed in the heat exchange layer 110 and temperature change information is obtained by a thermometer installed in the heat exchange layer 110. Heat pump operation information is added to the water level and temperature information, and control is performed to optimize the pump operation. As an example of control, when a cooling demand in summer is assumed, the submersible pump is operated at night when there is surplus power to fill the heat exchange layer 110 with water and to increase the heat energy in the heat exchange layer. During the daytime when power is tight due to cooling demand, the pump operation is suppressed, and the peak power during the daytime is reduced by operating the heat pump with high operating efficiency. In this way, effective utilization of energy can be realized in the daily cycle by pumping up groundwater with surplus power at night and supplying it as daytime energy that requires air conditioning (effect C).

The heat exchange layer 110 not only accumulates the heat energy of the supplied groundwater and supplies the heat energy to the heat exchange pipe 120 together with the groundwater, but also suppresses free convection of the groundwater in the heat exchange layer 110 to exchange heat. The heat load exchanged with the heat exchange medium in the pipe 120 (a rise in the temperature of groundwater when using cooling in summer) is prevented from accumulating at the upper part of the water surface. Assuming that the temperature rise of the groundwater after heat exchange is, for example, 5 ° C. to 10 ° C., by setting the hydraulic conductivity of the ground G3 below the heat exchange layer 110 to about 1 × 10 ⁻⁴ cm / s, Forced convection due to underground seepage is superior and natural convection due to temperature rise can be prevented. That is, the exhaust heat after heat exchange is permeated into the basement without remaining in the heat exchange layer 110 (effect D). The water permeability coefficient can be calculated using the formula described later.

  In the geothermal heat collection system 100 of the present invention, the groundwater does not go out to the ground surface, and the water circulation is completed in the underground sealed space. In other words, the groundwater flow in the ground is artificially realized, so it does not fall under the groundwater pumping. Therefore, the system will be highly applicable to the restriction of groundwater intake and prevention of groundwater contamination (contamination) that are expected in the future (Effect E).

  There are indirect and direct expansion types of geothermal heat pumps that are currently popular in Japan. The indirect method is a method in which a heat exchanger made of resin or metal is installed between the heat pump and the underground heat exchanger, and heat is indirectly collected from the ground via water or antifreeze circulating through the heat exchanger, This method is widely used in Japan. On the other hand, the direct expansion type is a method in which the heat collecting pipe of the heat pump is buried in the ground and directly exchanges heat with the soil, and the operation efficiency of the heat pump is said to be higher than the indirect method. However, depending on the pipe length and distribution type, the pressure loss increases, the risk of leakage of the heat exchange medium, the sealing technique, etc. are difficult, and high construction accuracy is required, and it is not popular in Japan.

  The underground heat collection system according to the present invention enables the construction of a loop-shaped heat collection pipe having a short length and a small pressure loss in a situation where the loop-shaped heat collection pipe is sufficiently managed in an open space on the ground. . For this reason, since it is suitable for enclosing a directly expanded heat exchange medium as compared with the conventional borehole type, it is suitable for realizing a heat pump system that is directly expanded and inexpensive and excellent in heat exchange efficiency (effect F). .

  As described above, the geothermal heat collection system of the present invention has higher performance than the conventional technology.

Hereinafter, the relationship between natural convection (sometimes referred to as thermal convection) and forced convection, which are important in the present invention, will be described.
Heat transfer is due to radiation that moves heat between distant objects through space, conduction that moves heat from the hot part to the cold part of the object without the movement of matter, and the substantial flow of fluid. There are three forms of convection. When the porous body such as earth and sand is saturated with water, the heat transfer is mainly conducted and convection. Of these, convection includes natural convection caused by inhomogeneous temperature distribution in saturated water and forced convection caused by other factors. Natural convection is convection due to a change in the mass of water caused by a change in water temperature (for example, buoyancy due to a decrease in density accompanying an increase in temperature), and forced convection is a convection that does not result from a change in density. It is a convection (underground seepage flow) generated by the infiltration of water. In the case of water only (water tank or the like), natural convection occurs with a change in temperature, and the upper layer part is hot and the lower layer part is cold. On the other hand, the movement of water in the saturated earth and sand hardly causes convection because there are few voids in the earth and sand. This degree is proportional to the permeability coefficient of the sediment and the temperature difference of the water, and is proportional to the reciprocal of the porosity of the sediment, and the natural convection velocity vf is expressed by the following equation.

  In this case, if there is forced convection due to underground ground infiltration that exceeds the natural convection velocity vf generated with the change in the water temperature in the saturated earth and sand, the occurrence of natural convection in the saturated earth and sand can be suppressed. In other words, in order not to cause natural convection, the forced convection speed vg by underground infiltration should be superior to the natural convection speed vf so that vg> vf. Thereby, heat storage (so-called heat withering) in the earth and sand layer can be avoided.

  As apparent from the above equation, the natural convection velocity vf can be controlled by adjusting the porosity and hydraulic conductivity in the soil. This can be realized by adjusting the particle size of the earth and sand material or civil engineering sheet (woven fabric) or a combination of both. The forced convection velocity vg is governed by the permeability coefficient, which is a characteristic of the ground below the soil part, but when the permeability coefficient is large and the water in the soil penetrates into the ground in large quantities, It is also possible to adjust the infiltration rate by laying a civil engineering sheet on the boundary surface between the ground and the earth and sand. Such an apparatus consisting of an artificial earth and sand layer and ground is called a groundwater circulation type geothermal soil tank. A geothermal heat collecting device in which a primary heat collecting pipe is laid in the earth tub is called a groundwater circulation type underground heat collecting system.

  Therefore, the present invention aims to efficiently acquire the unused thermal energy of groundwater, and continuously or continuously has new thermal energy in a soil tank artificially constructed so as not to generate natural convection. A heat collecting apparatus that receives intermittent supply is provided.

4). Effects of Geothermal Heat Collection System and Geothermal Heating / Cooling or Hot Water Supply System According to the geothermal heat collection system 100 according to the first embodiment, groundwater supply for supplying groundwater to the heat exchange layer 110 from above the heat exchange pipe 120. Since the device 130 is provided, it is possible to supply a sufficient amount of groundwater to the underground underground layer to perform heat exchange, and to gradually infiltrate underground water with reduced thermal potential after heat exchange. It becomes. As a result, the geothermal heat collection system 100 according to the first embodiment can increase the amount of heat exchange that can be used, and heat that can be used more than the conventional closed horizontal geothermal heat collection system. It becomes a practical underground heat collection system with a large amount of replacement. As a result, there is also an effect that a site area smaller than that of the conventional closed horizontal geothermal heat collecting system can be secured to secure the same heat collecting amount.

  In particular, according to the geothermal heat collection system 100 according to the first embodiment, if the operation of the groundwater supply device 130 is performed at night, it is possible to use inexpensive late-night power, thereby suppressing energy consumption. It will also be possible and will contribute to the peak cut of power during the day.

  Moreover, although the geothermal heat collection system 100 which concerns on Embodiment 1 is a system using groundwater, since it is a closed-type geothermal heat collection system from the first, it is an open type underground heat collection system. Thus, it is not necessary to maintain a scale or the like that accumulates in the piping, and the maintenance is excellent. Moreover, it is not necessary to prepare a separate facility for recharging groundwater, and the burden on nature is small.

  In addition, according to the geothermal heat collection system 100 according to the first embodiment, since it is originally a horizontal type geothermal heat collection system, an expensive vertical borehole is not required, and so on. Compared with the medium heat collection system, the construction difficulty is low and the construction cost can be reduced easily.

  Moreover, according to the underground heat collection system 100 which concerns on Embodiment 1, since the heat exchange layer 110 consists of artificial earth and sand layers, it becomes possible to adjust a hydraulic conductivity by adjusting the particle size of earth and sand. . This makes it possible to increase the speed at which groundwater penetrates into the sediment layer below the natural convection (sometimes referred to as thermal convection), and exhaust heat (hot or cold) discharged to the heat exchange layer. ) Can be smoothly discharged to the earth and sand layer (ground G3) located below the heat exchange layer.

If the ground penetration is too slow, exhaust heat is accumulated in the heat exchange layer 110, and the heat energy that can be collected decreases. On the other hand, if the ground penetration is too fast, the amount of groundwater supplied must be increased. From these viewpoints, the water exchange coefficient of the heat exchange layer 110 is preferably about 5 × 10 ⁻² cm / s to about 5 × 10 ⁻³ cm / s.

  Further, according to the geothermal heat collection system 100 according to the first embodiment, the groundwater supply device 130 includes the well 131, the pump 132 and the conduit 133 that transfer the groundwater from the well 131 to the heat exchange layer 110, and the conduit 133. Since there is a supply port 134 for supplying groundwater to the heat exchange layer 110, groundwater does not go out to the ground surface, and groundwater penetrates into the lower ground 3 as it is. There is no need to do.

  In addition, according to the geothermal heat collection system 100 according to the first embodiment, the groundwater supply device 130 is based on the water level information monitored by the water level meters 141 and 142 and the temperature information monitored by the thermometer 143. It is possible to supply the optimum amount of groundwater to the heat exchange layer at the optimum timing at all times, and to maximize the available heat exchange amount. Become.

  As described above, the geothermal heat collection system 100 according to the first embodiment has vg> when the ground permeation speed of water in the heat exchange layer 110 is vg and the natural convection speed of water is vf. Under the condition of satisfying the relationship of vf, that is, under the condition that the velocity vg of “water ground penetration” is superior to the velocity vf of “natural convection of water” generated with the change of the water temperature in the heat exchange layer 110. Since heat is collected, heat storage (so-called heat withering) in the heat exchange layer 110 can be avoided, and heat exchange that can be used more than a conventional closed horizontal geothermal heat collection system. It becomes a large quantity and a practical underground heat collection system.

[Embodiment 2]
FIG. 4 is a diagram for explaining the underground heat collection system 200 according to the second embodiment. 4 (a) is a longitudinal sectional view of the underground heat collection system 200, and FIG. 4 (b) is a longitudinal sectional view of the underground heat collection system 200 as viewed from a direction orthogonal to FIG. 4 (a). It is. In addition, illustration of the groundwater supply apparatus 230 is abbreviate | omitted in FIG.4 (b).
FIG. 5 is a perspective view showing a main part of the underground heat collection system 200 according to the second embodiment. In FIG. 5, the illustration of the groundwater supply device 230, the connecting pipe 234, the civil engineering sheets 211 and 212, the water shielding sheet 213, the water shielding sheet and the heat insulating material 214 is omitted.

  The geothermal heat collection system 200 according to the second embodiment is similar to the geothermal heat collection system 100 according to the first embodiment by circulating a heat exchange medium through a heat exchange pipe embedded in a shallow underground layer. This is a closed horizontal geothermal heat collection system that collects geothermal heat. As shown in FIG. 4, a heat exchange layer 210 that is installed in the underground shallow layer portion G1 and has water permeability, a heat exchange pipe 220 embedded in the heat exchange layer 210, and a heat exchange pipe 220 And a groundwater supply device 230 for supplying groundwater to the heat exchange layer 210 from above.

  The geothermal heat collection system 200 according to the second embodiment is greatly different from the geothermal heat collection system 100 according to the first embodiment in the configuration of the heat exchange pipe. That is, in the geothermal heat collection system 200 according to the second embodiment, as the heat exchange pipe 220, a sheet-like heat exchange pipe 223 (for example, a width of 900 m and a length of 5600 mm) in which a thin polyethylene pipe is configured in a sheet shape. And a connecting pipe 224 is used. As such a sheet-like heat exchange pipe, a commercially available resin sheet-like heat exchange pipe (for example, G-carpet) can be used. As shown in FIGS. 4 and 5, the heat exchanging pipe 220 is laid so that the sheet is folded in the vertical direction and has three levels in the vertical direction using the reinforcing steel or resin bases 250 and 251.

  As in the case of the underground heat collection system 100 according to the first embodiment, the heat exchange layer 210 uses an artificial earth / sand layer that does not contain fine-grained soil (that is, an artificial gravel layer). As shown in FIG. 4, the artificial earth and sand layer is provided with civil engineering sheets 211 and 212 on the bottom surface of the heat exchange layer 210 and on the inside of the heat exchange layer 210, and on the side surface of the heat exchange layer 210. A water sheet 213 is disposed, and a water shielding sheet and a heat insulating material 214 are disposed on the upper surface of the heat exchange layer 210.

  The size of the heat exchange layer 210 is set to a size capable of storing the groundwater and the amount of heat in the ground corresponding to the amount of heat energy required for extraction according to the output of the heat pump. Further, a plurality of sheet-like heat exchange pipes may be connected in series or in parallel depending on the output of the heat pump.

  In the geothermal heat collection system 200 according to the second embodiment, the groundwater supply operation by the groundwater supply device 230 is controlled in the same manner as in the first embodiment, such as a water level meter and temperature installed in the heat exchange layer 210. This is based on the water level information and temperature information monitored by a meter (both not shown) and the operation status of the heat pump.

  As described above, the underground heat collection system 200 according to the second embodiment is different from the case of the underground heat collection system 100 according to the first embodiment in the configuration of the heat exchange pipe, but the shallow underground layer G1. A heat exchange layer 210 having water permeability, a heat exchange pipe 220 embedded in the heat exchange layer 210, and a groundwater supply device 230 for supplying groundwater to the heat exchange layer 210 from above the heat exchange pipe 220. Therefore, as in the case of the underground heat collection system 100 according to the first embodiment, the amount of heat exchange that can be used is more practical than the conventional closed horizontal geothermal collection system. It becomes a geothermal heat collection system.

[Embodiment 3]
FIG. 6 is a diagram for explaining the underground heat collection system 300 according to the third embodiment. 6A is a longitudinal sectional view of the underground heat collection system 300, and FIG. 6B is a longitudinal sectional view of the underground heat collection system 300 viewed from a direction orthogonal to FIG. 6A. It is. In addition, illustration of the groundwater supply apparatus 330 is abbreviate | omitted in FIG.6 (b).
FIG. 7 is a perspective view showing a main part of the underground heat collection system 300 according to the third embodiment. In FIG. 7, the artificial earth and sand layer 315, the groundwater supply device 330, the connection pipe 234, the civil engineering sheet 311, the water shielding sheet 313, the water shielding sheet, and the heat insulating material 314 are omitted.

  The geothermal heat collection system 300 according to the third embodiment is similar to the geothermal heat collection system 200 according to the second embodiment by circulating a heat exchange medium through a heat exchange pipe embedded in a shallow underground layer. This is a closed horizontal geothermal heat collection system that collects geothermal heat. And as shown in FIG. 6, the heat exchange layer 310 which is installed in the underground shallow layer part G1 and has water permeability, the heat exchange pipe 320 embedded in the heat exchange layer 310, and the heat exchange pipe 320 And a groundwater supply device 330 for supplying groundwater to the heat exchange layer 310 from above.

  The geothermal heat collection system 300 according to the third embodiment is greatly different from the geothermal heat collection system 100 according to the second embodiment in the configuration of the heat exchange layer. That is, in the geothermal heat collection system 300 according to the third embodiment, the heat exchange layer 310 includes a heat exchange layer including a porous concrete layer 315 and an artificial earth and sand layer 316 provided on the porous concrete layer. .

  As in the case of the underground heat collection system 200 according to the second embodiment, the heat exchange pipe 310 is a sheet-like heat exchange pipe 323 (for example, a width of 900 m and a length) in which a thin polyethylene pipe is formed into a sheet shape. 5600 mm) and connecting pipe 324 are used.

  A sheet-like heat exchange pipe 323 is embedded inside the porous concrete layer 315 of the heat exchange layer 310, and a conduit tip 334 and a supply port 335 of the groundwater supply device 330 are provided in the artificial earth and sand layer 316 of the heat exchange layer 310. It is arranged.

  As shown in FIG. 6, a civil engineering sheet 311 is disposed on the bottom surface of the heat exchange layer 310, and a water shielding sheet 313 is disposed on the side surface of the heat exchange layer 310. On the upper surface, a water shielding sheet and a heat insulating material 314 are disposed.

  In the geothermal heat collection system 300 according to the third embodiment, the groundwater supply operation by the groundwater supply device 330 is controlled by a water level meter installed in the heat exchange layer 310 as in the first and second embodiments. This is based on the water level information and temperature information monitored by a thermometer (not shown) and the operation status of the heat pump.

  As described above, the geothermal heat collection system 300 according to the third embodiment is different in the configuration of the heat exchange layer from the case of the geothermal heat collection system 200 according to the second embodiment, but the shallow underground layer G1. A heat exchange layer 310 having water permeability, a heat exchange pipe 320 embedded in the heat exchange layer 310, and a groundwater supply device 330 for supplying groundwater to the heat exchange layer 310 from above the heat exchange pipe 320. Therefore, as in the case of the underground heat collection system 200 according to the second embodiment, the amount of heat exchange that can be used is larger and more practical than the conventional closed horizontal geothermal heat collection system. It becomes a geothermal heat collection system.

  The underground heat collection system 300 according to the third embodiment is manufactured in a factory as a semi-finished porous concrete layer 315 provided with a heat exchange pipe 320, and the porous concrete layer 315 thus manufactured is manufactured. It is also possible to use the remaining construction work on site. By doing so, it is possible to simplify the work at the site.

  In the geothermal heat collection system 300 according to the third embodiment, the heat exchange layer 310 is adjusted by adjusting the porosity of the porous concrete by adjusting the mixing ratio of cement, admixture, fine aggregate, and coarse aggregate. It is possible to adjust the water permeability coefficient. It is also possible to adjust the water permeability coefficient of the heat exchange layer 310 as a whole by using a civil engineering sheet having an appropriate water permeability coefficient. As a result, the exhaust heat (warm or cold) discharged to the heat exchange layer can be reduced by increasing the speed at which groundwater penetrates into the lower sediment layer (ground G3) rather than the speed of natural convection. It becomes possible to discharge smoothly into the sediment layer located below.

  As described above, the geothermal heat collection system and the geothermal cooling / heating or hot water supply system of the present invention have been described based on the above embodiment, but the present invention is not limited to this, and the scope of the present invention is not deviated. For example, the following modifications are possible.

(1) In Embodiment 1 or 2, an artificial earth / sand layer composed of an artificial earth / sand layer not containing fine-grained soil (that is, an artificial gravel layer) is used as the artificial earth / sand layer, but the present invention is limited to this. It is not a thing. An artificial soil layer containing fine-grained soil can also be used.

(2) In Embodiments 1 to 3, the heat exchange layer in which the civil engineering sheet is disposed on the bottom surface of the heat exchange layer and / or the heat exchange layer is used, but the present invention is not limited to this. Absent. It is also possible to use a heat exchange layer in which no civil engineering sheet is provided. If the grain size is adjusted, the civil engineering sheet is not always necessary.

(3) In Embodiments 1 to 3, the heat exchange layer in which the water shielding sheet is disposed on the side surface of the heat exchange layer is used, but the present invention is not limited to this. It is also possible to use a heat exchange layer without a water shielding sheet.

(4) In Embodiments 1 to 3, the heat exchange layer in which the water shielding sheet and the heat insulating material are disposed on the upper surface of the heat exchange layer is used, but the present invention is not limited to this. A heat exchange layer in which a water shielding sheet and a heat insulating material are not provided can also be used.

(5) Although the underground heat collection system 100 according to Embodiment 1 uses a loop-shaped heat exchange pipe as the heat exchange pipe, the present invention is not limited to this. Spiral, serpentine, spiral, ring or basket heat exchange pipes can also be used.

(6) Although the underground heat collection system 100 according to Embodiment 1 uses a heat exchange pipe made of high-density polyethylene as the heat exchange pipe, the present invention is not limited to this. A heat exchange pipe made of polybutene or a heat exchange pipe made of stainless steel can also be used.

(7) In Embodiments 1 to 3, the groundwater supply device in which the supply port is formed at the end of the conduit is used as the groundwater supply device, but the present invention is not limited to this. It is also possible to use a groundwater supply device in which the conduit tip is made of a material having water permeability.

(8) The geothermal cooling / heating or hot water supply system 10 according to the first embodiment includes the indirect heat pump 21 as a heat pump, but the present invention is not limited to this. A direct expansion heat pump may be provided.

(9) The geothermal cooling / heating or hot water supply system 10 according to Embodiment 1 includes a heat pump, but the present invention is not limited to this. It may be a passive type underground heat cooling system that does not include a heat pump.

(10) Use this heat sampling device without using a well water pumping device if a device for directing river water etc. can be added where there is a flow of water in the vicinity of a water source such as a river or pond. be able to.

DESCRIPTION OF SYMBOLS 10 ... Geothermal use cooling / heating or hot-water supply system, 21 ... Heat pump, 22 ... Air conditioner (cooling / heating machine) or water heater in a building, 100, 200, 300 ... Geothermal heat collection system, 110, 210, 310 ... Heat Exchange layer, 111, 112, 211, 212, 311 ... civil engineering sheet, 113, 213, 313 ... water shielding sheet, 114, 214, 314 ... water shielding sheet and heat insulating material, 115, 215, 315 ... manhole cover, 120, 220, 320 ... heat exchange pipe, 121 ... introduction part, 122 ... lead-out part, 130, 230, 330 ... groundwater supply device, 131, 231, 331 ... well, 132, 232, 332 ... pump, 133, 233, 333 ... Conduit, 134, 234, 334 ... Conduit tip, 135, 235, 335 ... Supply port, 136, 236, 336 ... Water level gauge, 137, 37,337 ... ground water, 140 ... operation control unit, 223,323 ... sheet heat exchange pipe, 224,324 ... connection pipe, 315 ... porous concrete layer, 316 ... artificial earth and sand layer, B ... building, G ... ground, G1 ... Shallow underground part, G2 ... Deep underground part

Claims (8)

A closed horizontal geothermal heat collection system for collecting geothermal heat by circulating a heat exchange medium through a heat exchange pipe embedded in a shallow underground layer,
A heat exchanging layer that is installed in a shallow underground layer and consists of an `` artificial earth and sand layer '' or `` a porous concrete layer and an artificial earth and sand layer provided on top of the porous concrete layer '' and having water permeability;
The heat exchange pipe embedded in the heat exchange layer;
A groundwater supply device that realizes a downward groundwater flow in the vertical direction by underground infiltration into the heat exchange layer by supplying groundwater to the heat exchange layer from above the heat exchange pipe ;
A groundwater circulation type geothermal heat collection system, wherein the geothermal heat collection system is a groundwater circulation type geothermal heat collection system. In the groundwater circulation type geothermal heat collection system according to claim 1 ,
The heat exchange layer is composed of an artificial soil layer,
A groundwater circulation type underground heat collection system, wherein the artificial earth and sand layer is an artificial earth and sand layer that does not contain fine-grained soil. In the groundwater circulation type geothermal heat collection system according to claim 2 ,
A groundwater circulation type geothermal heat collection system, wherein a civil engineering sheet is disposed on a bottom surface of the heat exchange layer and / or inside the heat exchange layer. In the groundwater circulation type geothermal heat collection system according to claim 1 ,
The heat exchange layer is composed of a porous concrete layer and an artificial soil layer provided on the porous concrete layer,
A groundwater circulation type geothermal heat collection system, wherein a civil engineering sheet is disposed on a bottom surface of the heat exchange layer. In the groundwater circulation type geothermal heat collection system according to any one of claims 1 to 4 ,
The groundwater supply device, wells and ground water recycling, characterized in that it comprises a pump and conduit for transferring the groundwater to the heat exchanger layer from the well, the supply port for supplying the ground water to the heat exchanger layer from said conduit Geothermal heat collection system. In the groundwater circulation type geothermal heat collection system according to any one of claims 1 to 5 ,
The heat exchange layer is provided with a water level meter for monitoring the level of groundwater and a thermometer for monitoring the temperature of the heat exchange layer,
The groundwater supply device based on the monitored temperature information by the water level information and the thermometer is monitored by the water level gauge, groundwater recycling ground characterized by having a function of controlling supply operation of the groundwater Thermal heat collection system. In the groundwater circulation type geothermal heat collection system according to any one of claims 1 to 6 ,
In the heat exchange layer, a groundwater circulation type geothermal heat collecting system satisfying a relationship of vg> vf, where vg is the ground penetration speed of groundwater and vf is the speed of natural convection of groundwater. . A groundwater circulation type geothermal heat collection system according to any one of claims 1 to 7 ,
A geothermal heat-use cooling / heating system or a hot water supply system comprising a heat pump for exchanging heat using a heat exchange medium of the groundwater circulation type geothermal heat collection system.