JP2018071949A - Underground heat utilization system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an underground heat utilization system that prevents deficiency in quantity of underground heat used for air-conditioning of a building, hot water supply, or the like.SOLUTION: An underground heat utilization system includes: heat supply means 30 for sending exhaust heat from buildings 12A, 12B, 12C, and 12D to the underground so as to be stored; an impervious wall 50 for surrounding the underground in which the exhaust heat is stored; and heat use means 40 for taking out and using the underground heat stored in the underground.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a geothermal heat utilization system.

  In the geothermal heat utilization system described in Patent Document 1 below, heat is exchanged between the fluid circulated in the multiple pipes embedded in the ground and the underground heat. As a result, geothermal heat is used for cooling and heating the building.

JP 2010-261633 A

  In the geothermal heat utilization system disclosed in Patent Document 1, for example, when the geothermal heat is used as a heating heat source for a building in winter, the ground is gradually cooled due to the deprivation of the geothermal heat. For this reason, when the usage-amount of heating is large, there exists a possibility that the heat amount required for heat exchange may be insufficient.

  In view of the above facts, an object of the present invention is to provide a ground heat utilization system in which the amount of ground heat used for air conditioning, hot water supply, and the like of a building is less likely to be insufficient.

  The geothermal heat utilization system according to claim 1 is a heat supply means for sending waste heat from a plurality of buildings to the ground to store heat, a water shielding wall surrounding the ground where the waste heat is stored, and the ground. Heat utilization means for extracting and using the stored underground heat.

  In the underground heat utilization system according to the first aspect, exhaust heat sent from a plurality of buildings is stored in the ground. And the stored underground heat can be taken out and utilized. For this reason, the heat discharged from any building can be stored in the ground, and the stored heat can be used as a heating heat source or a hot water supply heat source for other buildings. Moreover, the cold heat | fever discharged | emitted from one of the buildings can be stored in the ground, and the stored cold heat can be utilized as a heat source for cooling of another building.

  In this way, waste heat from any building can be stored in the ground and used as an air conditioning or heat source for other buildings. For this reason, the amount of underground heat used for air conditioning, hot water supply, etc. of a building is hardly short.

  In the underground heat utilization system according to the first aspect, the stored ground is surrounded by a water shielding wall. For this reason, it is suppressed that the stored heat flows out into the surrounding ground, and heat storage efficiency is improved compared with the case where there is no impermeable wall.

  In the underground heat utilization system according to claim 2, a plurality of underground portions surrounded by the water shielding wall are formed.

  In the underground heat utilization system according to the second aspect, the underground portion storing hot heat and the underground portion storing cold heat can be partitioned by a water shielding wall. Since the flow of groundwater is blocked between the compartments, the heat and cold stored in the ground are not easily mixed, and the heat storage efficiency is increased.

  According to a third aspect of the present invention, there is provided a ground heat utilization system comprising: a temperature detection means for detecting a temperature of the geothermal heat extracted by the heat utilization means; and the heat utilization means based on the detected temperature of the ground heat. And a control device that controls the amount of underground heat to be extracted.

  In the geothermal heat utilization system of claim 3, the temperature of the geothermal heat extracted by the heat utilization means is detected, and the amount of underground heat extracted from the ground is controlled, so that the stored underground heat is effectively used. Available to:

  According to the geothermal heat utilization system according to the present invention, the amount of underground heat used for air conditioning, hot water supply, etc. of a building is unlikely to be insufficient.

It is an elevation sectional view showing a geothermal heat utilization system in an embodiment of the present invention.

(overall structure)
The geothermal heat utilization system 20 in the embodiment of the present invention is a system for storing and using exhaust heat discharged from a plurality of buildings 12 in the ground, and each heat source in the buildings 12A, 12B, 12C, and 12D. Installed in the ground, heat supply means 30 (heat supply means 30A, 30B, 30C, 30D) for sending waste heat from the device 14 to the ground, heat utilization means 40 for extracting and using the ground heat from the ground And a water shielding wall 50.

(Impermeable wall)
The ground 10 includes an aquifer 10W through which groundwater flows and an impermeable layer 10Y through which groundwater does not flow. The ground 10 is provided with a water-impervious wall 50 made of soil cement, and the lower end of the water-impervious wall 50 is embedded in the impermeable layer 10Y. Further, the impermeable walls 50 are also arranged on the near side and the far side between the left and right impermeable walls 50 shown in FIG. Thereby, in the aquifer 10 </ b> W, the portion surrounded by the impermeable wall 50 and the groundwater in the other portion are prevented from affecting each other.

  The inner portion defined by the water-impervious wall 50 is further composed of soil cement, and is defined by a water-impervious wall 52 whose lower end is embedded in the impermeable layer 10Y. As a result, a plurality of underground portions surrounded by the impermeable walls 50 and 52 are formed. That is, the heat storage tank 10A, the heat storage tank 10B, the heat storage tank 10C, and the heat storage tank 10D that are not easily affected by the flow of groundwater and from which heat does not easily flow out are formed. As will be described in detail later, the heat storage tanks 10A and 10B store heat and the heat storage tanks 10C and 10D store heat. Further, the water shielding wall 52 is not formed between the heat storage tanks 10B and 10C.

In addition, although the water-permeable coefficient of the water-impermeable layer 10Y is approximately 1 × 10 ⁻⁸ m / s or less, in the ground where the water-impermeable layer 10Y does not exist at an appropriate depth, the water-permeable coefficient is replaced with the water-impermeable layer 10Y. ^{May be} incorporated into a low water permeability layer of approximately 1 × 10 ⁻⁶ to 10 ⁻⁷ m / s. Moreover, in the ground where neither the impermeable layer 10Y nor the low permeable layer is present at an appropriate depth, the impermeable walls 50 and 52 are formed longer and need not be embedded.

  In the present embodiment, the buildings 12A, 12B, 12C, and 12D are built adjacent to each other (in a serial arrangement), and the heat storage tanks 10A, 10B, 10C, and 10D partition the impermeable wall 50 from the interior thereof. Although formed adjacent to the water-impervious wall 52, the embodiment of the present invention is not limited to this. For example, when the buildings 12A, 12B, 12C, and 12D are built apart (not in series), the impermeable walls that are constructed along the boundary line of the site and the outline of the building are the ground 10 directly under each building. The heat storage tanks 10A, 10B, 10C, and 10D that are surrounded by and separated from each other may be configured.

(Heat source equipment)
In the underground heat utilization system 20, exhaust heat from the heat source devices 14 of the plurality of buildings 12 is utilized. Examples of the heat exhaust heat device 14H that exhausts the heat exhaust heat of the heat source device 14 include a cooling device, a hot water supply device (gas water heater), and a combustion device in an incinerator. Moreover, as an example of the cold exhaust heat apparatus 14C which discharges cold exhaust heat, a heating apparatus, a hot water supply apparatus (heat pump water heater), etc. are mentioned.

  In each building 12, since cooling equipment, heating equipment, hot water supply equipment, and the like are used in combination as the heat source equipment 14, both the hot exhaust heat and the cold exhaust heat are discharged from each building 12. In addition, in buildings with living rooms, heating is used more frequently in the winter and cooling is used more in the summer, so the ratio of warm heat and cold heat varies depending on the season. Furthermore, the ratio of hot and cold exhaust heat varies depending on applications such as distribution warehouses, data centers, office buildings, hotels, physical education facilities, hot bath facilities, and animal and botanical gardens.

  In the present embodiment, the building 12A is an incineration site and a plurality of heat source devices 14 are provided. However, in order to simplify the description, warm exhaust heat is sent from the warm exhaust heat device 14H having a large amount of exhaust heat to the ground. Shall.

  Moreover, the building 12B is a data center, and the heat exhaust heat from the heat exhaust heat device 14H having a large amount of exhaust heat among the plurality of heat source devices 14 is sent to the ground.

  Further, the building 12C is an office building, and cold exhaust heat from the cold exhaust heat device 14C having a large amount of exhaust heat among the plurality of heat source devices 14 is sent to the ground.

  Further, the building 12D is a hotel, and cold exhaust heat from the cold exhaust heat device 14C having a large amount of exhaust heat among the plurality of heat source devices 14 is sent to the ground.

(Heat supply means)
The heat supply means 30 includes a circulation pipe 32 that sends exhaust heat from the heat source device 14 (the warm exhaust heat apparatus 14H and the cold exhaust heat apparatus 14C) in the building 12 to the ground, and the circulation pipe 32 that is formed in the ground 10 is inserted. And a solid hole 34.

  Circulating water as a heat medium circulates inside the circulation pipe 32, and the exhaust heat of the heat source device 14 is taken in from one end portion 32A formed by joining the end portions of the forward path pipe and the return path pipe to each other. . In this embodiment, the heat medium is water, but various heat mediums such as antifreeze, oil, and air can be used.

  The other end 32B of the circulation pipe 32 is inserted into a hard hole 34 formed by excavating the ground 10, and the circulating water releases exhaust heat into the ground in the process of passing through the forward pipe and the return pipe. . And in the ground 10, the exhaust heat from the heat source device 14 carried by the circulating water is stored. Note that silica sand is filled between the hard hole 34 and the circulation pipe 32.

  In this embodiment, the circulation pipe 32 is used as the heat supply means 30 (so-called closed loop), but the embodiment of the present invention is not limited to this. For example, the ground 10 may be stored by injecting water heated (or cooled) by exhaust heat from the heat source device 14 into the ground (so-called open loop). The closed-loop heat supply means 30 is easy to maintain, and the open-loop heat supply means is easy to collect heat. For this reason, when increasing the thermal efficiency in the underground heat utilization system 20, it is preferable to use an open loop heat supply means.

  Of the heat supply means 30, the heat supply means 30A sends heat from the warm exhaust heat device 14H of the building 12A to the ground, and the heat supply means 30B sends warm heat from the warm exhaust heat device 14H of the building 12B to the ground. The supply means 30C sends cold heat from the cold exhaust heat apparatus 14C of the building 12C to the ground, and the heat supply means 30D sends cold heat from the cold exhaust heat apparatus 14C of the building 12D to the ground.

  Thereby, warm heat is stored in the heat storage tanks 10A and 10B immediately below the buildings 12A and 12B, and cold heat is stored in the heat storage tanks 10C and 10D immediately below the buildings 12C and 12D.

(Heat utilization means)
The heat utilization means 40 is a heat sharing system for utilizing the underground heat extracted from the ground with the heat utilization devices 14E installed in the plurality of buildings 12, respectively.

  The heat utilization means 40 includes a heat utilization device 14E provided in each building 12, a heat transmission pipe 42 that transmits underground heat from the ground to each heat utilization device 14E, and an underground that transmits underground heat to each heat utilization device 14E. And a central controller 46 that controls the amount of heat.

  A heat medium flows in the heat transfer pipe 42, and heat is transferred by supporting the underground heat in the ground on the heat medium. In this embodiment, the heat medium is water (circulated water), but various heat mediums such as antifreeze, oil, and air can be used.

  The heat transfer pipe 42 is composed of a hot-heat pipe 42H and a cold-heat pipe 42C as separate systems. The heat pipe 42H has circulating water flowing through the heat storage tank 10A in which the heat exhaust heat of the building 12A is stored, the heat storage tank 10B in which the heat exhaust heat of the building 12B is stored, and the buildings 12A, 12B, 12C, and 12D. It arrange | positions in the loop shape so that the heat utilization apparatus 14E may circulate.

  Thereby, the circulating water in the heat pipe 42H collects heat from the heat storage tank 10A and the heat storage tank 10B, and the collected heat is used in each heat utilization device 14E.

  Similarly, in the cold heat pipe 42C, the circulating water flowing inside is a heat storage tank 10C in which the cold exhaust heat of the building 12C is stored, a heat storage tank 10D in which the cold exhaust heat of the building 12D is stored, and the buildings 12A, 12B, 12C, and 12D. These heat utilization devices 14E are arranged in a loop so as to circulate.

  Thereby, the circulating water in the cold-heat pipe 42C collects cold from the heat storage tank 10C and the heat storage tank 10D, and the collected cold is used in each heat utilization device 14E.

  Similarly to the circulation pipe 32 of the heat supply means 30, the heat collecting portions of the hot and cold pipes 42 </ b> H and 42 </ b> C are inserted into the hard holes 44 formed in the ground and filled with silica sand, In the process of passing through the hard hole 44, the stored ground heat is taken out.

  A temperature sensor CT that measures the temperature of the circulating water after taking in heat or cold from the ground is provided inside the heat pipe 42H and the cold pipe 42C. Further, a bypass BP for flowing the circulating water without passing through the hard hole 44 and an electromagnetic valve M1 for switching the flow path of the circulating water are provided.

  Thereby, for example, when the temperature of the circulating water that has taken in the heat from the heat storage tank 10B is lower than a predetermined value, the central controller 46 described later determines that the amount of underground heat in the heat storage tank 10B is insufficient, and the solenoid valve M1 is operated so that the circulating water passes through the bypass BP. Thereby, the heat collection from the heat storage tank 10B is interrupted to promote heat storage. The same applies to the heat storage tanks 10A, 10C, and 10D.

  Further, a flow meter CV that measures the flow rate of circulating water to each heat utilization device 14E of the buildings 12A, 12B, 12C, and 12D and an electromagnetic valve M2 that adjusts the flow rate are provided inside the hot and cold tubes 42H and 42C. It has been. Thereby, the flow volume of the circulating water sent to each heat utilization apparatus 14E can be adjusted.

  In addition, in this embodiment, although the heat exchanger tube 42 is laid in the loop shape between the underground and each heat utilization apparatus 14E, embodiment of this invention is not restricted to this. For example, the groundwater stored from the solid hole 44 in each of the heat storage tanks 10A, 10B, 10C, and 10D may be pumped, and the groundwater may be sent to the heat utilization device 14E and used as a heat source. In this case, the groundwater after the heat is taken out by the heat utilization device 14E is re-discharged to the ground surface or underground.

  The central control device 46 is a heat transfer management device provided in the district heating and cooling plant 16, and controls the amount of underground heat extracted from the ground and the amount of distribution of the extracted underground heat to each heat source device 14, The heat transfer between the buildings 12A, 12B, 12C, 12D and the heat storage tanks 10A, 10B, 10C, 10D is managed.

  In order to control the amount of underground heat extracted from the ground, the central controller 46 receives the electrical signal from the temperature sensor CT and controls the electromagnetic valve M1.

  Further, in order to control the distribution amount of the extracted ground heat to each heat source device 14, the central control device 46 receives the electrical signal from the flow meter CV and controls the electromagnetic valve M2.

  Further, the hot pipe 42H and the cold pipe 42C are provided with bypasses and solenoid valves (not shown) at various places, and the central controller 46 controls these bypasses and solenoid valves. Thereby, heat storage tank 10A, 10B, 10C, 10D which takes out geothermal heat, and building 12A, 12B, 12C, 12D using the taken-out underground heat can be set up by arbitrary combinations. For example, all the underground heat extracted from the heat storage tanks 10A, 10B, 10C, 10D can be used in the building 12A, or all the heat used in the buildings 12A, 12B, 12C, 12D can be used from the heat storage tank 10A. It can also be taken out.

(Ground heat distribution control method)
An example of the control method of the underground heat distribution amount by the central controller 46 will be shown. The heat utilization device 14E in the building 12C normally uses the underground heat (cold heat) of the heat storage tank 10C immediately below the building 12C as a cold heat source. However, for example, if the heat utilization device 14E continues to use the underground heat (cold heat) of the heat storage tank 10C in the summer, the heat storage tank 10C may be warmed and the cold heat source may be insufficient.

  The shortage of the heat source in the heat storage tank 10C is detected by the temperature sensor CT measuring the temperature of the circulating water in the cold heat pipe 42C immediately after passing through the heat storage tank 10C, and this temperature is detected to be higher than a predetermined temperature. Is done.

  When the cooling heat source of the heat storage tank 10C is insufficient, the central control device 46 controls the electromagnetic valve M1 provided in the cooling heat pipe 42C to reduce the amount of underground heat extracted from the heat storage tank 10C and use the heat of the building 12C. The underground heat (cold heat) taken out from the heat storage tank 10D is sent to the device 14E. Thereby, the heat source of the heat source device 14 of the building 12C is ensured, and the heat storage tank 10C is limited in acquiring cold and can store cold.

  In this way, the central controller 46 controls the amount of underground heat extracted from the heat storage tanks 10A, 10B, 10C, and 10D based on the temperature of the underground heat extracted from the heat storage tanks 10A, 10B, 10C, and 10D, and the building 12A. , 12B, 12C, and 12D can be prevented from being short of heat sources.

  In the present embodiment, the heat utilization device 14E and the heat exhaust heat device 14H are described as different devices, but the embodiment of the present invention is not limited to this, and the heat utilization device 14E and the heat exhaust heat device 14H. May be the same device. For example, the cooling device is used as a heat utilization device 14E that uses cold as a heat source, but can also be used as the warm exhaust heat device 14H because it discharges warm exhaust heat. Similarly, the heat utilization device 14E and the cold exhaust heat device 14C may be the same device.

(Action / Effect)
In the underground heat utilization system 20 according to the present embodiment, the exhaust heat sent by the heat supply means 30 from the heat source device 14 installed in each of the buildings 12A, 12B, 12C, and 12D is stored in the ground. The stored underground heat can be taken out by the heat utilization means 40 and used.

  Therefore, the heat discharged from the buildings 12A and 12B can be stored in the heat storage tanks 10A and 10B, and the stored heat can be used as a heating heat source or a hot water supply heat source for the buildings 12A, 12B, 12C, and 12D. Moreover, the cool heat discharged from the buildings 12C and 12D can be stored in the heat storage tanks 10C and 10D, and the stored cool heat can be used as a cooling heat source for the buildings 12A, 12B, 12C, and 12D.

  For this reason, the amount of underground heat used for air conditioning, hot water supply, etc. of the buildings 12A, 12B, 12C, and 12D is unlikely to be insufficient.

  In the present embodiment, the heat storage tanks 10A and 10B store the heat discharged from the heat exhaust heat devices 14H of the buildings 12A and 12B, but the embodiment of the present invention is not limited thereto. For example, the heat storage tanks 10A and 10B may store cold heat discharged from the buildings 12A and 12B, or may store hot heat or cold discharged from the buildings 12C and 12D.

  Regarding the heat storage tanks 10C and 10D, the heat discharged from the buildings 12C and 12D may be stored, or the heat or cold discharged from the buildings 12A and 12B may be stored. Thus, the exhaust heat from the buildings 12A, 12B, 12C, and 12D can be stored not only in the respective heat storage tanks 10A, 10B, 10C, and 10D but also in any heat storage tank.

  Moreover, in the underground heat utilization system 20 according to the present embodiment, the heat storage tanks 10 </ b> A and 10 </ b> D are surrounded by the water shielding wall 50. For this reason, it is suppressed that the heat stored in heat storage tank 10A, 10D flows out into the surrounding ground, and heat storage efficiency is improved compared with the case where there is no impermeable wall 50. In addition, the impermeable wall 50 is not installed between the thermal storage tank 10B and the thermal storage tank 10C. As described above, in soil or the like where the flow of groundwater is small, each heat storage tank does not necessarily have to be partitioned by the impermeable wall 50.

  Further, in the underground heat utilization system 20 according to the present embodiment, the temperature of the underground heat extracted by the hot tube 42H and the cold tube 42C is detected by the temperature sensor CT, and the central controller 46 extracts the underground from the underground. Control the amount of heat. Thereby, underground heat can be used effectively without waste.

  In addition, in this embodiment, although the central control apparatus 46 is provided in the district heating and cooling plant 16, embodiment of this invention is not restricted to this, For example, you may provide in any of buildings 12A, 12B, 12C, 12D. . The number of buildings that send waste heat to the ground is not limited to four buildings 12A, 12B, 12C, and 12D, and may be two or more.

  Moreover, in this embodiment, the material of the impermeable walls 50 and 52 is a soil cement wall. For this reason, compared with the case where the water-impervious walls 50 and 52 are formed of, for example, steel sheet piles (sheet piles), the heat insulating performance is high, and the portion surrounded by the water-impervious walls 50 and 52 is easily kept warm. In addition, embodiment of this invention is not restricted to this, As a material of the impermeable wall 28, clay, concrete, steel sheet piles (sheet pile), etc. can be used.

12A, 12B, 12C, 12D Building 12 Building 30 Heat supply means 40 Heat utilization means 46 Central control device (control device)
50, 52 Impermeable wall CT Temperature sensor (temperature detection means)

Claims (3)

Heat supply means for sending exhaust heat from a plurality of buildings into the ground and storing it;
A water shielding wall surrounding the underground where the exhaust heat is stored;
Heat utilization means for taking out and using the underground heat stored in the ground;
Underground heat utilization system.   The underground heat utilization system according to claim 1, wherein a plurality of underground portions surrounded by the water shielding wall are formed. Temperature detection means for detecting the temperature of the underground heat extracted by the heat utilization means;
A control device for controlling the amount of underground heat extracted by the heat utilization means based on the detected temperature of the underground heat;
The geothermal heat utilization system according to claim 1 or 2, comprising the following.